Skin Care Glossary

Your Skincare Glossary

A

AÇAI

A palm tree, native to Central and South America, known for its deep purple berries. The fruit extract is used as a potent antioxidant in skin-care products and supplements.

ACETONE

A colorless, strong-smelling solvent found in many nail-polish removers, it works by softening and dissolving the polymer molecules in polishes, gels, and acrylics. Because it’s drying to the nails and skin, many removers containing it are also spiked with moisturizers, like glycerin.

ACIDIC

Having a pH (“potential hydrogen”) less than 7. The skin’s barrier, or acid mantle, is naturally slightly acidic, with a pH hovering around 4.5 to 5.5. When it drops out of range, skin becomes prone to breakouts and irritation.

ACTIVATED CHARCOAL

Long used in emergency rooms to treat alcohol poisoning and drug overdoses, this form of carbon — found in cleansers, masks, toothpastes, health drinks — has been specially treated to increase its absorbency, allowing it to sponge up dirt and oil from pores (or toxins from the stomach when taken internally).

ADENOSINE

Present in all living organisms, this molecule plays a critical role in regulating blood flow and providing cells with usable energy. When applied topically, the ingredient can smooth and firm the skin, repair sun damage, and relax wrinkles.

AGAR

Used as a thickener in makeup, skin-care products, and shampoo, this gelatinous, algae-derived sugar molecule also has mild antioxidant benefits.

ALCOHOL (SD ALCOHOL)

Undrinkable ethyl alcohol has many uses in skin care. It delivers other ingredients into the skin and drives them deeper down. In toners and acne products, it can help dissolve oil and temporarily tighten pores. When added to certain moisturizers, like gel-based lotions, it makes them less tacky and helps them dry down faster on the face.

ALGIN

This soothing, water-absorbing algae extract is commonly added to thicken hair- and skin-care products and to help makeup glide on smoothly. It’s also found in the filmy coating created by some face masks and peels.

ALGURONIC ACID

A blend of naturally sourced, sustainably produced algae extracts developed and trademarked for the Algenist line, it claims to minimize wrinkles while firming and brightening the skin.

ALKALINE

Having a pH (“potential hydrogen”) greater than 7. Alkaline substances are also known as “basic” — the opposite of acidic. When skin is too alkaline — because of eating the wrong foods or using the wrong products — it gets dry, irritated, inflamed, and more prone to wrinkling.

ALLANTOIN

Known for its soothing properties, this chemical moisturizes and encourages cell turnover.

ALOE BARBADENSIS

With the same pH as skin, this extract is extremely soothing. It’s also an effective healing agent.

ALPHA HYDROXY ACIDS (AHAS)

These chemicals loosen the fluid that binds surface skin cells together, allowing dead ones to be whisked away. This “glue” becomes denser as we age, slowing down the natural cell-turnover process that reveals younger skin — making AHAs a particularly useful ingredient in fine line-fighting creams and cleansers.

ALPHA LIPOIC ACID

This fatty acid found in all cells in the body contributes to skin’s smoothness. It dissolves in both fat and water, enabling it to penetrate well into all parts of skin cells.

AMINO ACIDS

The building blocks of the proteins that make up collagen and elastin — substances that give the skin its structural support. Aging and a combination of external factors (including UV light and environmental toxins) reduce the level of amino acids in the body; creams containing amino acids may help restore them.

ANTHOCYANINS

A class of flavonoids, these red, blue, and violet plant pigments are thought to protect against inflammatory diseases and free-radical damage. The most recent data suggests they may help slow skin aging by curbing UV-induced skin damage.

ANTIOXIDANT

Any ingredient that reduces free-radical damage to the skin.

ARBUTIN

Extracted from the bearberry plant, this complexion-brightening antioxidant is known as a natural (and milder) alternative to skin-bleaching hydroquinone. Arbutin works by directly inhibiting the activity of tyrosinase enzymes central to the production of melanin.

ARGAN OIL

This fast-absorbing, vitamin E-rich extract has become a darling of the beauty aisle for its ability to moisturize without clogging pores, reduce the appearance of fine lines, smooth hair, and strengthen nails.

ARGININE

A critical building block of skin collagen and hair keratin, synthetic versions of this wound-healing amino acid are found in fine line-fighting topicals (as well as sports drinks and oral supplements).

ARGIRELINE

This peptide is marketed as “Botox in a cream” because of its apparent ability to temporarily prevent tensing of facial muscles.

ARNICA (ARNICA MONTANA)

A medicinal herb with antimicrobial and anti-inflammatory properties, its inherent flavonoids can help strengthen blood vessels to reduce leakage. Applied topically (as a gel or ointment) or taken orally (in low-dose homeopathic tablet form), it’s been shown to help reduce the bruising and swelling associated with certain surgeries and cosmetic injections.

ASCORBIC ACID

Also known as l-ascorbic acid, this topical form of antioxidant vitamin C brightens the skin, increases collagen production, and stems free-radical damage, making it a popular ingredient.

ASTAXANTHIN

A naturally occurring carotenoid (yellow, orange, or red pigment), originally isolated from lobsters, but also found in other crustaceans and certain fish, like salmon. Studies have shown that long-term supplementation with astaxanthin may help slow skin aging via its anti-inflammatory and antioxidant effects.

AVENA SATIVA

Also known as colloidal oatmeal, the anti-inflammatory antioxidant is commonly used in skin care to quell dryness, itch, and irritation.

AVOBENZONE

A chemical found in sunscreens; it absorbs UVA rays to reduce their penetration into the skin but does not protect against UVB rays.

AZELAIC ACID

It’s a natural component of wheat, barley, rye, and the yeast normally living on human skin. Used in topical rosacea and acne treatments, synthetic versions help kill bacteria living in pores while reducing inflammation. It’s also used to lighten melasma patches and other hyperpigmented areas.

AZULENE

A staple in at-home waxing kits, this blue oil is derived from chamomile and revered for its soothing properties.

B

BARLEY EGF

A human-like epidermal growth factor (EGF) produced in bioengineered barley seeds and used in skin-repairing products from Bioeffect and DNAEGF Renewal. The barley-made protein is a messenger molecule said to have the same amino acid sequence and 3-D structure as human EGF, so it can detect and bind to EGF receptors on human skin cells, ordering them to grow, divide, and rejuvenate.

BENTONITE

Sometimes referred to as Montmorillonite, this absorbent clay is derived, most often, from weathered volcanic ash. Rich in antibacterial minerals, it’s commonly used in “purifying” or “detoxifying” cleansers and masks, as it pulls pollutants, sebum, and grime from pores.

BENZOYL PEROXIDE

An acne medicine that kills pimple-causing bacteria and exfoliates pores. It can be found in concentrations up to 10 percent in over-the-counter products.

BETA CAROTENE

A red-orange pigment found in certain fruits and vegetables, it’s a precursor to vitamin A (retinol); upon ingestion, the body converts beta carotene into antioxidant vitamin A, which helps maintain skin and eye health. It’s essential for normal cell growth and turnover and may help improve the skin’s tone and texture.

BETA GLUCANS

Long-chain sugar molecules found in the cell walls of bacteria, fungi, yeasts, algae, lichens, and grains, such as oats and barley. Powerful humectants and soothers, they can strengthen the skin’s moisture barrier and stave off bad germs.

BETA HYDROXY ACID (BHA)

These chemical exfoliants can smooth fine lines, even pigmentation, and penetrate deeply into pores, dissolving sticky plugs of sebum and dead skin. One of the most common BHAs, salicylic acid, is found in many acne washes, creams, and peels.

BIOCELLULOSE

A popular sheet-mask material, this biodegradable, bacteria-derived fiber is known for its unparalleled moisture retention and snug fit, both of which help drive active ingredients into the skin.

BIOSTIMULATORY FILLER

Products like, poly-L-lactic acid (brand name: Sculptra) and calcium hydroxylapatite (Radiesse), which volumize skin by gradually stimulating collagen production.

BIOTIN

Small amounts of this B vitamin are found in carrots, almonds, milk, and other foods. Aside from helping the body process fats and sugars, oral biotin is important for regulating hair and nail growth. Shampoos and conditioners containing it claim the ingredient reduces hair breakage and increases elasticity.

BISABOLOL

This floral-scented chamomile extract has been used topically as a moisturizer, anti-inflammatory, and anti-microbial for centuries.

BLACKHEAD

A skin blemish that forms when the sebum (oil) draining from a pore becomes blocked by a clump of dead skin cells. Its color results from the sebum’s pigment, which darkens when exposed to air.

BOTOX

The trademark name for one of the forms of botulinum toxin used in injections targeting facial wrinkles. Botox paralyzes facial muscles, such as those that cause frown lines, to soften wrinkles.

BROAD SPECTRUM

A term for sunscreens proven to defend against both UVA (aging) and UVB (burning) radiation. Passing the FDA’s broad-spectrum test shows that a product provides UVA protection that is proportional to its UVB protection. “Scientific data demonstrated that products that are ‘Broad Spectrum SPF 15 [or higher]’ have been shown to reduce the risk of skin cancer and early skin aging when used with other sun protection measures, in addition to helping prevent sunburn,” states the FDA website.

BROMELAIN

An anti-inflammatory enzyme culled from the stem or fruit of the pineapple plant. Some aesthetic doctors recommend eating fresh pineapple or taking homeopathic bromelain supplements in the days before and after cosmetic injections to minimize bruising and swelling.

BTL VANQUISH ME

A non-invasive body shaping device that uses radiofrequency energy to heat and destroy fat cells, thereby reducing the circumference of the abdominal area, or inner and outer thighs.

BUTYLENE GLYCOL

A form of alcohol that draws water from the air, making it a lightweight moisturizing agent. The ingredient is commonly found in makeup removers as a solvent — as well as in makeup, where it thins formulas, helping them glide on more easily.

C

CAFFEINE

Produced in the leaves and seeds of various plants, it can also be made in a lab. Commonly used in cellulite creams and eye creams, it constricts blood vessels, reducing redness and puffiness.

CALAMINE

Used to treat itching and minor skin irritations, this pink liquid is a mixture of zinc oxide and ferric oxide.

CANNABIDIOL (CBD)

One of over 80 compounds called cannabinoids extracted from the cannabis sativa plant. The oil is used in beauty products mainly for its anti-inflammatory, analgesic, and moisturizing properties. It cannot produce a high.

CARNITINE

Also called L-carnitine, this amino acid helps convert fat into energy when naturally present in the human body. In the skin-care aisle, the ingredient is often found in cellulite and eye creams. Though there’s little clinical data supporting its long-term effectiveness, its anti-inflammatory activity can temporarily smooth puckering and puffiness.

CARNOSINE

This naturally occurring amino-acid pairing quells damaging inflammation, glycation, and free-radical activity, and levels of it in our bodies decline with age. Some research indicates that oral supplements and topical creams containing it can stave off premature wrinkling, collagen breakdown, and thinning of the skin.

CASEIN

A protein found in mammalian milk that may contribute to acne in certain people.

CELL COMMUNICATION

A broad term referring to the way cells send information using proteins and other signaling molecules — and receive information from inside or outside the body via receptor sites located on cell membranes. Increasing numbers of skin creams contain ingredients, like retinol, carnosine, and peptides, claiming to bind to receptor sites and encourage cells to behave like younger, healthier versions of themselves.

CELLFINA

The only FDA-cleared nonsurgical procedure clinically proven to improve the appearance of cellulite on the thighs and buttocks for at least three years. The derma-office device uses an automated needle-like blade to sever and release the individual connective bands (septa) woven throughout fat, smoothing puckered skin in a matter of days. Divots are treated one at a time, following an injection numbing lidocaine.

CELLULITE

Affecting up to 90 percent of women (due to estrogen and genetics), cellulite occurs when fat cells swell and push through the tight, fibrous tissue bands (or septa) walling them in, creating a dimpled or lumpy appearance. Only about 10 percent of men suffer cellulite, as their septa is constructed differently, and better able to contain fat cells to prevent bulging.

CERAMIDES

Naturally occurring in sebum (skin’s oil), these fats hold together the cells of the epidermis to reinforce the skin’s protective barrier.

CETYL/STEARYL ALCOHOL

Fatty alcohols that stabilize creams and cleansers and create a silky feeling.

CHAMOMILE-FLOWER EXTRACT

A popular ingredient in cleansers and creams for sensitive skin, this moisturizing botanical is known for calming inflammation while combating free-radical damage.

CHOLESTEROL

One of the three main lipids (or fat molecules) comprising the skin barrier, it helps prevent water loss to keep skin moisturized and functioning properly.

CITRIC ACID

Found in many fruits, the antioxidant alpha hydroxy acid acts as a natural preservative. When used in peels, masks, and washes, it brightens and exfoliates the upper layers of the skin, encouraging new collagen formation.

CLEAR + BRILLIANT

This gentle fractional laser creates microscopic holes in the skin, leaving surrounding areas untouched, to spark the body’s natural healing process, thereby triggering new collagen growth and promoting cell turnover for a more even tone and texture with little to no downtime. A series of treatments (four to six) is generally needed for best results.

COENZYME Q10 (UBIQUINONE)

Levels of this antioxidant in the skin decline with age and UV exposure. CoQ10 is added to fine line-fighting products to preserve skin-cell function and improve skin texture.

COFFEEBERRY

A strong antioxidant, this plant extract is an expensive, patented ingredient that is not widely available (you’ll find it in Priori Skincare and RevaléSkin).

COLLAGEN

This protein makes up 80 percent of the skin, and its fibers give skin its firmness and strength. Collagen naturally breaks down over time, but certain ingredients, such as retinol and peptides (including Matrixyl), can stimulate new collagen production. The most abundant protein in the human body, it makes skin thick, strong, and smooth. Laser treatments and retinoids build it up; UV rays and free radicals tear it down.

COMEDONE

A broad term for a pore, or hair follicle, that’s blocked by sticky dead skin cells and the sebum that can’t drain properly. When the follicle remains open, the sebum’s pigment darkens from air exposure, forming a blackhead. When P. Acnes bacteria invade the clogged pore, the resulting inflammation creates a whitehead.

COOLSCULPTING

Invented by Harvard dermatologists, Dieter Manstein and R. Rox Anderson, CoolSculpting is a nonsurgical fat-reduction treatment that uses extreme cold to permanently kill fat cells (i.e., the science of cryolipolysis). Crystalized fat cells are naturally metabolized and eliminated by the body over the course of several weeks.

COPPER PEPTIDES

Found in many fine line-fighting formulas, these amino acids help to heal wounds, protect collagen from free-radical injury, soothe inflammation, and promote new collagen formation.

CYSTIC ACNE

This severe, potentially scarring form of acne develops when a plug of dead skin cells, sebum, and P. Acnes bacteria lodges deep inside a pore, creating a tender, pus-filled bump that sometimes ruptures the pore wall, spreading to surrounding tissue.

D

DECYL GLUCOSIDE

Ideal for sensitive skin, this mild, coconut-derived surfactant is typically found in cleansers and shampoos from green beauty brands.

DIFFERIN GEL

An over the counter, full-face acne treatment containing the retinoid adapalene 0.1 percent, it normalizes cell turnover to minimize pore-clogging and fights inflammation.

DIHYDROXYACETONE (DHA)

A natural carbohydrate, DHA is the active ingredient in most sunless tanners.

DIMETHICONE

A slippery form of silicone that hydrates and protects the skin; often found in oil-free moisturizers.

DMAE

Shorthand for dimethylaminoethanol, it’s produced by the human brain and found in sardines and other small fish. While the research is mixed, oral, and topical forms claim to protect skin-cell membranes from free-radical damage, while firming, smoothing, and brightening the complexion.

DNA REPAIR ENZYMES

Proven to correct the UV-induced DNA damage underlying wrinkles, brown spots, and skin cancer, these liposomally encapsulated marine extracts break the abnormal bonds forged by UV light, causing atoms in our DNA to resume their normal positions. In a study published in The Lancet in 2001, 30 subjects with a rare genetic disorder predisposing them to skin cancer applied a lotion with DNA repair enzymes daily for one year. At the trial’s end, they saw a 68 percent reduction in the development of precancerous lesions, and 30 percent fewer basal cell carcinomas.

DOUBLE CLEANSE

The Korean ritual of using a cleansing oil in tandem with a water-based face wash to thoroughly dissolve and remove oil-based makeup, sunscreen, and pollutants.

DYSPORT

Like Botox, another injectable form of botulinum toxin that combats wrinkles by paralyzing underlying muscles.

E

ECZEMA

The most common form of this chronic, noncontagious skin disorder is atopic dermatitis, which is characterized by itchy, red, scaly patches that often show up on the inner elbows, behind the knees, and around the neck and eyes. Prevalent in young children, it’s increasingly diagnosed in adults — especially those with a family history of the condition — and may flare with exposure to harsh soaps, fragrances, and foods that provoke an allergic response.

ELASTIN

Stretchy structural proteins that allow skin to snap back into place, elastin is particularly vulnerable to sun damage.

ELLAGIC ACID

Commonly added to skin-care products and supplements, this polyphenol exists naturally in pecans, pomegranates, raspberries, strawberries, cranberries, walnuts, dark-colored grapes, and red wines, and possesses antioxidant and anti-cancer properties.

EMOLLIENT

Any ingredient that increases water levels in the epidermis. Synonym: moisturizer.

EMULSIFIER

Chemicals such as cetyl alcohol that bind together ingredients in skin-care products.

EPIGALLOCATECHIN GALLATE (EGCG)

The main active component of green tea, this anti-inflammatory polyphenol has been shown to reduce sun damage and slow signs of aging by neutralizing free radicals.

ERYTHRULOSE

A berry-derived sugar that slowly and subtly darkens the skin. It’s typically used in conjunction with DHA to deliver a longer-lasting, more natural-looking glow.

ESSENCE

A Korean skin-care staple, these concentrated formulas with a water- or serum-like consistency are splashed on post-cleansing to boost hydration and prepare the skin to absorb subsequent products.

ETWO LASER

This nonablative device offers two settings that can be used together or separately: One remodels and stimulates collagen growth deep in the dermis, using infrared light and radio frequency (RF). The other selectively heats portions of the upper dermis with fractionated RF, fading wrinkles, fine lines, and acne scars while evening skin tone.

EXILIS

By directing radio-frequency heat one to three centimeters under the skin, this device claims to tighten and contour the arms, legs, abdomen, jaw line, and regions around the eyes. Reviews from dermatologists are mixed.

F

FERULIC ACID

This plant-derived antioxidant reduces sun damage and helps stabilize vitamins C and E in skin-care products.

FEVERFEW

A plant extract, it reduces redness, fights free radicals, and calms inflammation.

FIBROBLASTS

Plentiful in connective tissue throughout the body, including the dermis, these cells produce the collagen and elastin responsible for keeping skin pliant and springy. Topical retinoids ramp up collagen production in fibroblasts.

FILLER

Injectable dermal fillers, made from FDA-approved hyaluronic acid or a biostimulatory (collagen-growing) materials, restore fullness to the face. They can be used to plump lips, minimize wrinkles and scars, smooth under-eye hollows, and contour cheeks, temples, noses, and jaw lines.

FLAVONOIDS

While they’re present in all plants, this class of antioxidant phytochemicals is especially abundant in deeply pigmented fruits and vegetables, along with coffee, nuts, and seeds.

FRACTIONAL LASER

Developed in 2001 to deliver significant resurfacing results with less downtime than traditional CO2 lasers, fractional devices produce small columns of thermal injury to the skin, which, upon healing, promote improvements in skin tone and texture to address everything from sun damage to scarring.

FRAGRANCE

The generic term for natural and/or synthetic compounds used to scent products. Blends are typically considered trade secrets and can contain numerous ingredients (mainly oils and alcohols), none of which must be revealed on the label. Fragrance is the number-one cause of allergic reactions to skin-care products.

FREE RADICALS

Highly unstable molecules created in the body by sunlight, cigarette smoke, and pollution that latch onto and damage cells in ways that can lead to roughness, sagging, and wrinkling.

FRUIT ENZYMES

Typically sourced from papaya, pineapple, and pumpkin, they break down the keratin proteins comprising dead skin cells, offering a mild form of exfoliation.

G

GENISTEIN

A phytoestrogen, or plant hormone, found in soybeans. In skin care, it’s known for its skin-brightening and antioxidant effects. Studies show it can stimulate collagen production in postmenopausal women.

GLABRIDIN

A chemical found in the root extract of licorice; this skin-brightening antioxidant inhibits pigment production in the skin.

GLUCOSAMINE

Found throughout the human body, the antioxidant, anti-inflammatory ingredient has long been used as an oral supplement to relieve arthritis. Research shows that topical application may reduce hyperpigmentation and boost hyaluronic acid production, smoothing fine lines and wrinkles.

GLYCATION

This age-accelerating process occurs when sugar molecules in the bloodstream bind to protein tissue throughout the body, creating advanced glycation end products (AGEs), free-radical damage, and inflammation. Among the tissues affected are the collagen and elastin fibers responsible for keeping skin smooth, plump, and flexible, which is why scientists now link a chronically high-glycemic diet to premature wrinkling and sagging.

GLYCERIN

It’s a humectant, meaning it pulls moisture from the atmosphere to hydrate skin. Commonly used in moisturizers and hydrating cleansers, this is an inexpensive ingredient.

GLYCOLIC ACID

An alpha hydroxy acid derived from sugarcane, it dissolves the gluelike substance between skin cells, aiding in exfoliation and improving skin texture. It’s commonly used in high-end products, such as cleansers, creams, and peels.

GOJI EXTRACT

Derived from a small fruit native to Asia, it’s rich in zinc, fatty acid, and antioxidants. Taken orally or applied topically, the ingredient claims to slow the signs of aging and fend off environmental damage to skin, though there have been no large clinical studies on humans.

GRAPE-SEED EXTRACT

Boasting antioxidant levels that are far more powerful than vitamins E and C, topical and oral formulations of the ingredient are used to protect the skin against UV damage and other environmental assaults.

GRAPE-SEED OIL

This hydrating ingredient’s high fatty acid and antioxidant content makes it a popular addition to moisturizers, wrinkle creams, and hair-care products.

GREEN TEA

Extracted directly from green-tea leaves, this potent antioxidant fights free radicals and quells inflammation. It’s typically used in face creams and lotions.

GROWTH FACTORS

Produced by stem cells throughout the body, these large proteins relay messages crucial to cellular growth and division. The human-derived growth factors used by cosmetic companies like SkinMedica and Regenica have been shown to help rejuvenate skin by stimulating collagen and elastin synthesis while improving radiance, moisturization, and pigmentation.

GUARANA

A go-to ingredient in cellulite creams, this caffeine-packed seed extract is said to smooth the skin slightly by ramping up blood flow.

H

HELIOCARE

A dietary supplement containing Polypodium leucotomos, an antioxidant-rich extract derived from a tropical fern, shown in clinical studies to reduce UV-induced inflammation and free-radical formation to help protect skin against sun damage (when used in conjunction with broad-spectrum sunscreen).

HELIOPLEX

Helioplex is the trademarked name of a sunscreen technology that combines avobenzone with a stabilizing ingredient called oxybenzone to offer protection from both UVA and UVB sunlight.

HEMP SEED OIL

Pressed from the seeds of industrial hemp plants, this supercharged moisturizer packs vitamins, minerals, and inflammation-quelling essential fatty acids.

HYALURONIC ACID

A sugar molecule found naturally in the skin, it increases skin’s moisture content and prevents water loss. It can hold 1,000 times its weight in water and is typically found in expensive creams and serums.

HYDRAFACIAL

The trademarked name for a four-step exfoliating treatment offered at spas and dermatologist offices. The facial includes a gentle acid peel, vacuum pore extraction, a moisturizing cocktail of hyaluronic acid and antioxidants, and a tailored take-home kit of topical.

HYDROGEL

A thick, transparent polymer material comprising certain sheet masks, known for its close fit and water-binding capabilities.

HYDROLYZED COLLAGEN

Found in beauty supplements and drinks aiming to plump and hydrate the skin, these collagen proteins have been broken down into smaller peptides to make for easier absorption into the bloodstream.

HYDROXYPINACOLONE RETINOATE

A wrinkle-fighting form of vitamin A shown to be less irritating and more stable than traditional retinol.

HUMECTANTS

This class of moisturizing ingredients pulls water from the atmosphere into the top layer of the skin.

HYDROQUINONE

Available without a prescription in strengths up to 2 percent (4 percent in prescription formulas), it inhibits pigment production to lighten dark spots.

HYPERPIGMENTATION

Often triggered by UV light exposure, a wound, illness, hormonal changes, or certain drugs, this darkening of the skin might appear as a uniform tan, melasma (patches of discoloration), or an isolated acne scar.

I

IDEBENONE

This synthetic antioxidant compound reduces inflammation and UV damage to skin cells that can cause wrinkles and hyperpigmentation. (It’s only found in Prevage products by Elizabeth Arden at a 0.5 percent concentration and in Prevage MD, available in dermatologists’ offices, at a 1 percent concentration.)

INGESTIBLE

The common term for any oral beauty aid — pills, drinks, powders, and the like.

INJECTABLE

Any substance capable of being injected into the body. In the cosmetic realm, it refers mainly to neuromodulators, fillers, and fat dissolvers.

INTENSE PULSED LIGHT (IPL)

A machine that emits many wavelengths of light — as opposed to lasers, which use just one concentrated beam — to remove hair or erase acne, dark spots, wrinkles, spider veins, and more. While gentler and less expensive than lasers, it isn’t always as effective.

ISOLAZ

FDA-cleared for mild to moderate acne, this in-office device combines vacuum suction with broadband light to extract gunk from pores and destroy zit-causing bacteria before infusing skin with treatment serums.

J

JELLY (ALSO: GELÉE)

The name(s) given to cleansers and masks with a bouncy, non-drippy, gel-like consistency. Like pack-leader Glossier Milky Jelly, they tend to be mild and conditioning.

JESSNER’S PEEL

A medium-depth chemical peel administered by dermatologists and plastic surgeons, the solution combines three peeling agents — resorcinol, lactic acid, and salicylic acid — to remove the outermost layer of dead skin cells, thereby minimizing signs of sun damage, and helping to improve acne and melasma.

JOJOBA OIL

Similar in structure to skin’s natural oil, it penetrates skin to hydrate without clogging pores.

JUVÉDERM

The trademarked name of a gel made from hyaluronic acid that’s injected into wrinkles and lips to restore lost volume.

JUVÉDERM VOLBELLA XC

A fine hyaluronic acid-based filler that plumps lips and smooths lines for up to one year.

JUVÉDERM VOLLURE XC

FDA-approved for the correction of moderate to severe facial wrinkles and folds (think: smile lines), this injectable filler, made from sugar-based hyaluronic acid, may last up to 18 months. Finer and more fluid than the original Juvéderm, it moves naturally (and imperceptibly) with facial expressions.

JUVÉDERM VOLUMA XC

Made of hyaluronic acid, a water-absorbing sugar molecule found throughout the human body, and spiked with the anesthetic lidocaine, this injectable gel filler is FDA-approved for restoring lost volume in the cheeks.

K

K-BEAUTY

A category of skin-care products (essences, sheet masks, cushion compacts), rituals (à la double-cleansing and multi-step routines), and trends (hi, glass skin) hailing from South Korea that emphasizes healthy, hydrated, glowing, no-makeup skin.

KAOLIN

A claylike mineral that absorbs oil and tamps down shine.

KINETIN

A hydrating compound found in plants that encourages cell division, the popular ingredient is thought to reduce wrinkling and even skin tone and texture.

KERATOSIS PILARIS

These red bumps on the legs and the backs of arms occur when sticky cells within the hair follicle clump together to form a plug, preventing them from being whisked away through routine exfoliation. This common condition, believed to be genetic, can be minimized but not cured with lactic acid creams or scrubs.

KOJIC ACID

This skin lightener, especially popular in Japan, has been proven to be effective at blocking the production of new melanin in the skin, but it can also cause skin irritation when used in higher concentrations.

KYBELLA (DEOXYCHOLIC ACID)

An FDA-approved injectable treatment for fat under the chin, the drug dissolves the membranes lining fat cells, causing them to release their contents, which are then expunged by the body’s own immune cells over several weeks.

L

LACTIC ACID

Derived from fermented milk, this alpha hydroxy acid exfoliates dead skin cells and is gentle enough for people with sensitive skin or rosacea. Since it’s part of our natural moisturizing factor, it’s especially compatible with human skin.

LAMINARIA SACCHARINA

A type of sea algae that diminishes oil and soothes skin.

LASER

Intense, concentrated beams of a various colors of light used to treat a variety of skin problems, including dark spots, spider veins, wrinkles, and unwanted hair or tattoos.

LASER GENESIS

This no-downtime treatment delivers pulses of heat just below the epidermis, stimulating collagen production, reducing wrinkles, and minimizing redness.

LED

Light-emitting diode devices give off a narrow range of a specific wavelength of light. (Different wavelengths target different skin issues; for example, blue light kills the bacteria known to cause acne.) Much less intense than lasers or IPL, many LED devices are safe enough for hand-held use at home.

LICOCHALCONE

A molecule found in licorice-root extract, licochalcone can both soothe inflammation and help control the production of oil in the skin, making it an effective treatment for acne and redness.

LIPOSOME

A tiny vesicle (bubble-like sac), similar in construction to a cell membrane, used to encapsulate ingredients and enhance penetration into the skin, an effective delivery system.

LYCOPENE

A red pigment abundant in tomatoes, watermelon, carrots, and even chicken, the antioxidant helps protect skin from sun damage when consumed orally or applied topically.

M

MANDELIC ACID

Derived from bitter almonds, this oil-soluble alpha hydroxy acid dives deep to clear pores; its large molecular size keeps it from penetrating too quickly and causing irritation.

MARULA OIL

Made from the fruit of the African marula tree, this fast-absorbing oil boasts natural essential fatty acids, antioxidants, and flavonoids.

MATRIXYL 3000

A patented peptide complex shown to stimulate collagen production and reduce the look of fine lines when used consistently over time.

MELANIN

The pigment that gives hair, skin, and eyes their color; patches of excess melanin can cause dark spots.

MELANOCYTES

Though present in the brain, inner ear, eyes, and heart, these melanin producing cells are best known for the protective pigment they bring to the skin and hair — as well as to the moles and cancerous melanomas they can comprise. UV light exposure, hormonal changes, certain medications, illness, and lasers are all factors that can affect melanocyte activity.

MELANOMA

The deadliest of all skin cancers, it develops in pigment-producing cells, most commonly on the upper back, trunk, head, neck, and lower legs. While the cure rate is high when caught early, unchecked cases can spread to internal organs. Malignant moles tend to have asymmetrical or irregular borders, uneven color, a diameter greater than six millimeters, and/or a rapidly changing appearance. While genetics and immune disorders increase risk, a history of sun-or tanning-bed exposure is the most preventable cause.

MELASMA

A chronic skin disorder characterized by brown patches of pigment usually on the forehead, cheeks, and chin. It tends to occur more in women — those with ethnic skin types, in particular — and can be triggered by hormonal changes, UV rays, and heat.

MENTHOL

Originally derived from mint plants, this cooling agent is found in some lip balms, toners, and shave gels, mainly in synthetic form. It’s also used topically to relieve minor aches, stings, and itch.

MEXORYL SX

This stabilizing sunscreen ingredient is a very effective chemical filter for protecting the skin from aging UVA light when used in combination with other ingredients. Originally sold only in Europe, Mexoryl SX was approved by the FDA in 2006.

MICELLAR WATER

A mix of purified water, hydrators (like glycerin), and low doses of mild surfactants, these no-rinse liquid cleansers attract makeup, oil, and dirt when swiped over skin with a cotton pad. They’re mild enough for sensitive and acne-prone complexions.

MICROBIOME

The vast collection of essential microorganisms living in and on our bodies.

MICRODERMABRASION

Performed by dermatologists and facialists, this treatment exfoliates the top layer of dead skin cells with a wand that sprays on and then vacuums off extremely fine aluminum-oxide crystals. A newer form of the technology uses a vibrating diamond tip in place of the crystals.

MICRONEEDLING

A cosmetic procedure during which a device studded with tiny needles pierces the skin to incite the body’s natural healing response, resulting in increased cell turnover and collagen production to improve skin’s tone and texture. At-home tools have shorter pins, which work superficially; professional devices with longer needles drive deeper for more significant improvements in wrinkles and scars (along with greater downtime).

MMPI.20

An ingredient used in only a few high-end skin-care lines, this claims to inhibit the production of something called matrix metalloproteinase (or “MMPs”), enzymes that increase the breakdown of collagen and lead to skin damage.

N

NEUROMODULATORS

Injectable purified toxins that relax the muscles responsible for the development of expression lines, like those on the forehead, between the brows, and around the eyes.

NIACINAMIDE

A form of vitamin B3, it strengthens the skin’s outer layers, improves elasticity, and curbs redness and irritation.

O

OCTOCRYLENE

An active ingredient in sunscreens, this clear, colorless chemical offers only limited protection against UVA and UVB rays on its own but can stabilize and strengthen the sun-protective powers of any UV filters it’s combined with.

OCCLUSIVES

Thick moisturizing ingredients, such as petrolatum, that slow the evaporation of water from the skin’s surface.

OMEGA-3 FATTY ACIDS

Abundant in herring, mackerel, wild salmon, walnuts, flaxseed, and olive oil, these essential fatty acids maintain the function of cell membranes throughout the body, preserving cells’ ability to take in nutrients, dispose of waste, and hold onto water. In the epidermis, this can translate to smoother, more supple, hydrated skin.

OXYBENZONE

Also known as benzophenone-3, this chemical sunscreen absorbs mainly UVB rays, which is why it is combined with UVA-absorbing filters (like avobenzone) to create broad-spectrum sunscreens.

P

PANTHENOL

A B vitamin that moisturizes and strengthens both skin and hair.

PAPAIN

A skin-dissolving enzyme extracted from the leaves and fruit of the papaya plant, it’s used as a gentle exfoliant in certain cleansers, masks, scrubs, and peels.

PARABENS

A class of preservatives used to protect cosmetics against the growth of bacteria and fungi. These controversial ingredients — including methylparaben, propylparaben, and butylparaben — have been shown to possess weak estrogen-like properties, but the FDA deems them safe when used at very low levels (.01 to .3 percent) in cosmetics.

PARSOL

A trademarked class of sunscreen ingredients that absorb specific wavelengths of UVB and UVA light, minimizing photo damage to the skin. The most widely used, Parsol 1789 (known generically as avobenzone), absorbs UVA rays. Many broad-spectrum sunscreens pair the ingredient with others that filter out UVB light.

PETROLATUM

A purified by-product of petroleum, this thick, odorless, and colorless substance coats the skin to hydrate and prevent water loss and is used in standard (i.e., not oil-free) moisturizers. It can clog pores and cause acne in those who are prone.

PEPTIDES

Tiny protein fragments that promote collagen growth and help repair skin.

PH

A measure of the acidity or alkalinity of a substance. Water has a neutral pH of 7. A healthy skin barrier has an acidic pH of 4.5 to 5.5. And pH-balanced skin-care products generally fall on the slightly acidic side of neutral.

PHLORETIN

Found in apples, this chemical enhances the activity of other skin-care ingredients that reduce sun damage.

PHTHALATES

These common plasticizers, used some nail polishes to increase flexibility and in some shampoos and cleansers to carry fragrance, are controversial because of a possible link to disruption of the human endocrine system. Their role in a possible increase in breast cancers in women is currently being studied.

PHYTONUTRIENTS

Also called phytochemicals. Consuming or topically applying these beneficial compounds in fruits, vegetables, nuts, whole grains, and other edible plants helps prevent the damaging inflammation and free-radical activity that comes from UV exposure and other environmental insults.

PICOSECOND LASER

Originally engineered for tattoo removal, the no-downtime device delivers energy to the skin in trillionths of a second — one thousand times faster than a traditional nanosecond laser, like the Q-switched — to break apart pigment clusters and spur collagen growth.

PLANT STEM CELLS

When part of a living apple tree, melon vine, or other plant, these unspecialized cells can divide and stimulate growth in any tissue within that plant. There’s little evidence to support claims that the regenerating effects translate to human skin when plant stem cells are extracted and applied topically — though they may offer some antioxidant benefits.

PLATELET-RICH PLASMA (PRP)

A portion of one’s own blood that’s rich in growth factors. After drawing blood from a patient’s arm and spinning it down in a centrifuge to isolate the PRP, doctors customarily inject it into the scalp to encourage new hair growth or inject or apply it topically to skin to jumpstart healing for enhanced cell turnover and collagen renewal. (See also: vampire facial.)

POLYMODIUM LEUCOTOMOS

See Heliocare.

POMEGRANATE

Extracts of this fruit maintain moisture in the skin and act as an antioxidant, protecting against UV damage that can lead to wrinkles and skin cancer.

PROBIOTICS

Beneficial strains of live bacteria that can be ingested through fermented foods and supplements, or applied topically (via certain mists, creams, and serums) to improve gut and skin health.

PROPOLIS

Used for centuries to heal wounds, this honeybee-made resin has antibacterial and anti-inflammatory powers. In skin care, it’s often used as a soothing antioxidant.

PYCNOGENOL

An antioxidant derived from the bark of the French Maritime pine tree.

Q

Q-SWITCHED LASERS

Delivering quick, powerful pulses of energy, these lasers (like the Nd: YAG, the Ruby, the Alexandrite) heat and destroy pigment in the skin, making them most effective at clearing brown spots and tattoo ink.

R

RADIOFREQUENCY (RF)

Used by dermatologists to non-surgically tighten the skin, RF energy heats the deeper layers of tissue (leaving the surface intact) to spur new collagen and elastin growth for firmer, thicker skin.

RESTYLANE

Filler made from hyaluronic acid that doctors use to replace lost volume in the skin; it is especially effective for plumping the lips.

RESVERATROL

An antioxidant found in grapes; it neutralizes free radicals to protect skin cells from damage.

RETIN-A

The brand name for the prescription vitamin A derivative tretinoin. First approved by the FDA for the treatment of acne, Retin-A was eventually found to fight signs of aging by speeding up exfoliation, repairing skin on a molecular level, and boosting new collagen production.

RETINOIDS

This is the catchall phrase used to describe all vitamin A derivatives used in skin care.

RETINOL

A derivative of vitamin A used in fine line-fighting products to stimulate the turnover of skin cells and increase collagen production. The maximum amount allowed in over-the-counter products is 1 percent. Retinyl palmitate and retinaldehyde are weaker, less-irritating forms of retinol.

ROSACEA

A chronic skin disease marked by persistent redness, easy flushing, broken blood vessels, and pimples on the nose and cheeks primarily. Rosacea tends to run in families, especially those of Northern or Eastern European descent. The cause is unknown; there is no cure; and controlling triggers (heat, UV, spicy foods, alcohol) is crucial to treatment.

S

SALICYLIC ACID

A beta hydroxy acid that removes excess oil and dead cells from the skin’s surface. It’s used in nonprescription cleansers, moisturizers, and treatments for acne-prone skin in concentrations of 0.5 to 2 percent.

SCULPSURE

A non-invasive body-contouring laser the FDA cleared to reduce fat in the belly, flanks (love handles), back, thighs, and under the chin, SculpSure permanently destroys fat cells with heat. Up to a 24 percent fat reduction can be seen six to 12 weeks after treatment.

SCULPTRA

A biostimulatory injectable made from poly-L lactic acid, this filler activates the body’s own collagen production to gradually restore lost volume and minimize the look of wrinkles. Patients generally need three to four treatments, with results lasting two years or more. While Sculptra is FDA-approved for the correction of shallow to deep nasolabial folds (smile lines), contour deficiencies, and other facial wrinkles, doctors reportedly use it (off-label) on the body.

SERUM

A skin-care product that contains high concentrations of active ingredients and claims superior penetration of the skin’s surface when applied.

SHEET MASKS

Made from paper, cotton, bio cellulose (plant fiber), or hydrogel, and imbued with skin-care ingredients, these K-beauty essentials are shaped to fit the face (and other parts, like the neck, under eyes, lips, hands), delivering moisture and luminosity in a 20-minute session.

SODIUM LAURETH SULFATE (SLES)

A safe and effective foaming detergent used in facial cleansers, body washes, shampoos, and toothpastes; not to be confused with the more irritating sodium lauryl sulfate (SLS).

SODIUM LAURYL SULFATE

A detergent agent that cuts through oil and generates lather. Sulfate-free shampoos have become popular because of a misconception that the foaming agent may cause cancer, but no link has ever been established.

SOY

Rich in proteins and vitamins, this natural, non-irritating extract is a mild skin brightener that blocks the transfer of pigment from pigment-making cells to surrounding skin cells.

STEARYL ALCOHOL

A fat that binds together the ingredients in creams and cleansers and gives them a silky texture.

SQUALENE

Rich in fatty acids and antioxidants, this natural moisturizer is made by the skin, but diminishes with age. For skin-care purposes, it can also be derived from olives, rice bran, wheat germ, sugarcane, or palm trees.

SULFATES

These cleansing agents remove dirt and oil and are responsible for creating lather. There are more than 100 different varieties — some synthetic, others from natural sources, like coconut or palm oil. They’re found in facial cleansers, body washes, shampoos, and shaving creams. All types have the potential to dry and irritate the skin. They’ve come under scrutiny in recent years for their potential damage to the environment.

SULFUR

A natural element used in acne products, it kills bacteria, quells inflammation, and breaks down dead skin cells to clear pores.

SURFACTANTS

Used as oil-dissolving detergents, emollients, and foaming agents in cleansing products. Traditional high-pH soap and sodium lauryl sulfate (SLS) are stripping surfactants; milder ones include sodium laureth sulfate (SLES), decyl glucoside, coco-glucoside, and others.

T

THERMAGE

A radio-wave machine used by doctors to penetrate the deepest layers of the skin and generate heat that stimulates the formation of new collagen to firm skin.

TITANIUM DIOXIDE

A mineral in sunscreens that shields the skin from UVA and UVB rays.

TRANEXAMIC ACID

A synthetic derivative of the amino acid lysine, it interferes with UV light-induced pigment production to even the complexion. Both topical and oral forms are now being used to treat melasma and other pigmentary disorders.

TRICHLOROACETIC ACID (TCA)

A key ingredient in chemical peels used to treat sun damage and hyperpigmentation, TCA promotes shedding of the outermost layer of dead skin cells, allowing new cells to rise to the surface in the days following treatment. TCA peels are generally light to medium strength, with the former requiring a series of two to three for best results; the latter requiring only a single session (but carrying about a week of downtime).

U

ULTHERAPY

A non-invasive FDA-cleared treatment that relies on ultrasound energy to lift and tighten the skin by boosting collagen synthesis.

UVA RAYS

The wavelength of ultraviolet light that leads to signs of aging by destroying existing collagen and elastin within the skin and undermining the body’s ability to create more of each. The rays cause skin cancer, and they are also generated in tanning beds. They are constant throughout the year, which is why sun protection should be worn daily regardless of season.

UVB RAYS

The high-energy wavelength of ultraviolet light that leads to darkened pigment in the form of tanning, freckles, and age spots — plus, of course, sunburns. They are strongest in summer months.

V

VAMPIRE FACIAL

 An in-office treatment that combines microdermabrasion with an application of platelet-rich plasma (PRP) to hasten cell turnover and collagen growth.

VBEAM

A pulsed-dye laser used primarily to treat vascular issues, like broken capillaries, rosacea, port wine stains, bruises, and the like. It works by targeting and collapsing offending blood vessels and is safe for all skin tones.

VITAMIN C (ASCORBIC ACID)

An antioxidant that boosts collagen production and inhibits pigment formation. Like many antioxidants, it’s an unstable molecule that can break down quickly when exposed to light and air. Common derivatives, like ascorbyl palmitate and tetrahexyldecyl ascorbate, tend to be more stable than pure ascorbic acid but slower acting.

VITAMIN E (TOCOPHEROL)

 This moisturizing antioxidant protects against free-radical damage.

W

WATER

Deionized, distilled, or purified, it’s often used as a vehicle to deliver other ingredients into the skin.

X

XEOMIN

An FDA-approved neurotoxin, like Botox and Dysport, it blocks the release of chemicals that cause muscle contractions to soften frown lines. Said to be a purer form of the botulinum toxin, it may be less likely to cause irritation and allergic reactions.

Z

ZINC OXIDE

A mineral in sunscreen that prevents UVA and UVB light from entering skin and doing damage.