A colourless, 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.
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 the surface of the skin.
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.
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.
A blend of algae extracts developed and trademarked by the biotech company Solazyme for the Algenist anti-aging line, it claims to minimize wrinkles while firming and brightening the skin.
Known for its soothing properties, this chemical moisturizes and encourages cell turnover.
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 anti-aging 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.
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
A supercharged serum in higher concentrates.of active ingredients that you are meant to use for a finite amount of time when you are having a skin crisis of some kind. We recommend using them before the serum. Ampoules usually come in smaller bottles.
Any ingredient that reduces free-radical damage to the skin.
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.
A critical building block of skin collagen and hair keratin, synthetic versions of this wound-healing amino acid are found in anti-aging topicals (as well as sports drinks and oral supplements).
This peptide is marketed as "Botox in a cream" because of its apparent ability to temporarily prevent tensing of facial muscles.
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 anti-aging ingredient.
A chemical found in sunscreens, it absorbs UVA rays to reduce their penetration into the skin, but does not protect against UVB rays.
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.
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 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.
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.
This floral-scented chamomile extract has been used topically as a moisturizer, anti-inflammatory, and anti-microbial for centuries.
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.
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, in order to soften wrinkles.
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.
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.
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.
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.
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.
Naturally occurring in sebum (skin's oil), these fats hold together the cells of the epidermis to reinforce the skin's protective barrier.
Fatty alcohols that stabilize creams and cleansers and create a silky feeling.
A popular ingredient in cleansers and creams for sensitive skin, this moisturizing botanical is known for calming inflammation while combating free-radical damage.
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.
COENZYME Q10 (UBIQUINONE)
Levels of this antioxidant in the skin decline with age and UV exposure. CoQ10 is added to anti-aging products to preserve skin-cell function and improve skin texture
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).
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.
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.
Found in many anti-aging formulas, these amino acids help to heal wounds, protect collagen from free-radical injury, soothe inflammation, and promote new collagen formation.
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.
A slippery form of silicone that hydrates and protects the skin; often found in oil-free moisturizers.
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.
Like Botox, another injectable form of botulinum toxin that combats wrinkles by paralyzing underlying muscles.
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.
Stretchy structural proteins that allow skin to snap back into place, elastin is particularly vulnerable to sun damage.
Any ingredient that increases water levels in the epidermis. Synonym: moisturizer.
Chemicals such as cetyl alcohol that bind together ingredients in skin-care products.
This plant-derived antioxidant reduces sun damage and helps stabilize vitamins C and E in skin-care products.
A plant extract, it reduces redness, fights free radicals, and calms inflammation.
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.
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.
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 have to be revealed on the label. Fragrance is the number-one cause of allergic reactions to skin-care products.
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.
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.
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.
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.
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 anti-aging products, such as cleansers, creams, and peels.
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.
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.
This hydrating ingredient's high fatty acid and antioxidant content makes it a popular addition to moisturizers, wrinkle creams, and hair-care products.
Extracted directly from green-tea leaves, this potent antioxidant fights free radicals and quells inflammation. It's typically used in face creams and lotions.
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.
This class of moisturizing ingredients pulls water from the atmosphere into the top layer of the skin.
Available without a prescription in strengths up to 2 percent (4 percent in prescription formulas), it inhibits pigment production to lighten dark spots.
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.
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, especially on certain skin types.
Similar in structure to skin's natural oil, it penetrates skin to hydrate without clogging pores.
A claylike mineral that absorbs oil and tamps down shine.
A hydrating compound found in plants that encourages cell division, the popular anti-aging ingredient is thought to reduce wrinkling and even skin tone and texture.
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.
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.
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.
A type of sea algae that diminishes oil and soothes skin.
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.
A molecule found in licorice-root extract, licochalcone has the ability to both soothe inflammation and help control the production of oil in the skin, making it an effective treatment for acne and redness.
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.
The pigment that gives hair, skin, and eyes their color; patches of excess melanin can cause dark spots.
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.
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.
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.
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.
Microblading uses a small blade with many micro needles to create fine hair strokes. It is a manual tool and each stroke is individually pressed in by a professional. The blade is dipped into ink and then carefully pressed into the first two layers of a client’s skin. Because of the precision involved in this procedure, the lines stay sharp and the ink does not bleed—unlike traditional permanent make-up.
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.
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.
A form of vitamin B3, it strengthens the skin's outer layers, improves elasticity, and curbs redness and irritation.
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.
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.
A B vitamin that moisturizes and strengthens both skin and hair.
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 deemed safe when used at very low levels (.01 to .3 percent) in cosmetics.
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.
Permanent make-up uses a traditional tattoo gun with a rotary and coil to draw on eyebrows. Because of this approach, it’s hard to get precise and small lines, which causes eyebrows to look thicker and less natural.
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.
Tiny protein fragments that promote collagen growth and help repair skin.
Found in apples, this chemical enhances the activity of other skin-care ingredients that reduce sun damage.
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.
PLANT STEM CELLS
When part of a living apple tree, melon vine, or other plant, these unspecialized cells have the ability to 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.
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.
Psoriasis occurs when skin cells are replaced more quickly than usual. It's not known exactly why this happens, but research suggests it's caused by a problem with the immune system.
Filler made from hyaluronic acid that doctors use to replace lost volume in the skin; it is especially effective for plumping the lips.
An antioxidant found in grapes, it neutralizes free radicals to protect skin cells from damage.
The brand name for the prescription vitamin A derivative tretinoin. First approved 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.
This is the catchall phrase used to describe all vitamin A derivatives used in skin care.
A derivative of vitamin A used in anti-aging 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.
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.
A skin-care product that contains high concentrations of active ingredients and claims superior penetration of the skin's surface when applied.
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.
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.
A fat that binds together the ingredients in creams and cleansers and gives them a silky texture.
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.
A radio-wave machine used by doctors to penetrate into the deepest layers of the skin and generate heat that stimulates the formation of new collagen to firm skin.
A mineral in sunscreens that shields the skin from UVA and UVB 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.
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.
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.
Deionized, distilled, or purified, it's often used as a vehicle to deliver other ingredients into the skin.
A mineral in sunscreen that prevents UVA and UVB light from entering skin and doing damage.