Beauty & Skincare Glossary

The ultimate A-Z Beauty Glossary to Make You An Expert. This is our insider beauty dictionary, an ABC of products, ingredients and terminologies that will make you the go-to for beauty and skincare knowledge.

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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.

ALANIN

Alanine is an α-amino acid that is used in the biosynthesis of proteins. It contains an amine group and a carboxylic acid group, both attached to the central carbon atom which also carries a methyl group side chain.

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.

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 — as a result of eating the wrong foods or using the wrong products — it gets dry, irritated, inflamed, and more prone to wrinkling.

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.

ANTIOXIDANT

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

ARGININE

A critical building block of proteins, skin collagen and hair keratin. It helps blood vessels relax, so more oxygen-rich blood can circulate through your arteries.

ARGIRELINE

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

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.

Aspartic acid

Aspartic acid is an α-amino acid that is used in the biosynthesis of proteins. Aspartic acid is commonly used to reduce feelings of tiredness, improve athletic performance, and increase the size and strength of muscles.

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 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.

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.

Broad spectrum

A label applied to sunscreens that offer protection against both UVA and UVB rays, both of which contribute to your risk for skin cancer. 

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.

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.

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.

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.

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.

DIHYDROXYACETONE (DHA)

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

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.

Gelatin

Gelatin is collagen that has undergone only partial-hydrolyzation, leaving a powder or gel that will only dissolve in hot liquids. Since it has not undergone complete hydrolysis, the proteins are not entirely broken down making gelatin more difficult for the body to absorb. 

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.

Glutamic acid

In addition to protein synthesis, glutamic acid has several key functions within the body. It acts as an important neurotransmitter and the body uses it to create other neurotransmitters, such as GABA. Thus, this amino acid is critical for healthy brain development and function.

Glycine

Glycine is an amino acid that functions as a building block for certain proteins, most especially the collagen found in skin, ligaments, muscles, bones, and cartilage. It significantly improves skin elasticity in women, improves skin hydration and prevents water loss. In addition, Glycine stimulates the production of the serotonin, the "feel good" hormone that helps elevate mood, improve sleep quality, and enhance cognition and memory.

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

A hydrating ingredient used commonly in moisturising products. 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.

Collagen peptides (also known as collagen hydrolysate)

this is the form you’ll see most often. The hydrolyzation process breaks down the amino acids into smaller chains making them more bioavailable to the body. As a result, they’re absorbed into the bloodstream faster and easier.

Dibutyl phthalate (DBP). 

This phthalate is a common ingredient in nail polish and a known hormone disruptor. Exposure to high concentrations may cause hormone production problems in a developing baby.

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.

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. 

Histidine

Histidine is an amino acid needed in humans for growth and tissue repair, Histidine is important for protecting nerve cells and is required for blood cell manufacture and protects tissues against damage caused by radiation and heavy metals.

HYALURONIC ACID

Hyaluronic acid is found naturally in the skin. It has the properties of combining collagen fibers and binding molecules of water, provides us with firm, moisturized and nourished skin. Interestingly, only one gram of hyaluronic acid can bind about six liters of water. An additional advantage of HA is that it can also alleviate inflammation. With age, however, its amount in the skin decreases, which leads to the formation of wrinkles.

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.

Hydroxyproline

Hydroxyproline is a major component of the protein collagen. Hydroxyproline is produced by hydroxylation of the amino acid proline. Hydroxyproline and proline play key roles in collagen stability.

Hydroxylysine

Hydroxylysine, glycogenic amino acid uniquely found in collagen, the chief structural protein of mammalian skin and connective tissue. 

HYDROXYPINACOLONE RETINOATE

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

Isoleucine

is considered to be glucogenic amino acids, meaning those that the body can easily and quickly transform into the energy necessary for its functioning. This means that we will be able to not only train longer and more intensively, but also to regenerate faster.

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, glowy, no-makeup skin.

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.

Leucin

Leucine increases the degree and speed of protein utilization for muscle building.

Lysin

Participates in the production of proteins that build muscles and bones mainly. It helps to keep youth and beautiful figure. Because our body cannot produce it itself, it must be provided in the form of supplements.

MELANIN

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

Methionin

Isoleucine has diverse physiological functions, such as assisting wound healing, detoxification of nitrogenous wastes, stimulating immune function, and promoting secretion of several hormones. 

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.

NIACINAMIDE

A form of Vitamin B3, Niacinamide helps to strengthen skin and improve elasticity whilst reducing redness. 

Norvaline

L-norvaline is a compound that can boost your body's performance and aid recovery.

Oxybenzone. 

This popular sunscreen ingredient may absorb UV rays and is mostly found in chemical sunscreens, but a study (on animals) has shown that exposure to oxybenzone resulted in reduced fertility so you may want to skip it. Invest in a serum containing Vitamin C that naturally protects you from sun rays or stick to mineral ingredients like zinc oxide and titanium dioxide.

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. 

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.

PEPTIDES

These are chains of amino acids, which are the building blocks of protein. Your skin is made up of proteins, like collagen, and peptides stimulate this collagen production. For that reason, peptides are prominent in anti-aging products 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.

Phenylalanine

Phenylalanine is an essential α-amino acid. Too little phenylalanine curbs physical and intellectual growth. 

Phthalates 

This is an ingredient mainly found in beauty products to help stabilize the formula and have been linked to liver, kidney, lung, and reproductive issues. Look for these terms ending in -phthalate to avoid this ingredient.

Prolin

Proline is a basic amino acid involved in the synthesis of collagen. L-proline allows to maintain healthy joints, stimulates the regeneration processes of joint cartilage and muscles, and supports the maintenance of good condition of the skin, hair and nails.

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.

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. Found in Retin-A and Accutane, retinoids are prescription acne and anti-aging medications. It may be listed on ingredient labels as retinoic acid, retinyl palmitate, retinaldehyde, adapalene, tretinoin, tazarotene, and isotretinoin. 

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. 

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.

SERUM

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

Serine

L-serine is an amino acid essential for the synthesis of phosphatidylserine, which is a component of the membrane of brain cells (i.e., neurons). It can be produced in the body, including the brain, but an external supply from the diet is essential in maintaining necessary levels.

Tryptophan

L-tryptophan is an essential amino acid that helps the body make proteins and certain brain-signaling chemicals. Your body changes L-tryptophan into a brain chemical called serotonin. Serotonin helps control your mood and sleep.

Threonine

Threonine is an amino acid. Amino acids are the building blocks the body uses to make proteins.

Tyrosine

The body makes tyrosine from another amino acid called phenylalanine. Tyrosine can also be found in dairy products, meats, fish, eggs, nuts, beans, oats, and wheat.

Unhydrolyzed collagen

This is the non-processed form of collagen where the amino acids are still fully bound to one another in full strands. Unhydrolyzed collagen is very strong and durable, but also very difficult for the body to digest. You won’t see it very often because it’s relatively ineffective to be taken as an oral supplement. 

Valin

Valin owes not only to the aforementioned need to administer all three BCAA amino acids together but also to reduce the central nervous system fatigue. In addition, as with the other two amino acids, it is easily converted into the energy consumed by working muscles and thus allows to save glycogen stores accumulated in the liver

Vitamin A

is a key vitamin when it comes to the health of our skin, hair and nails. That is why it is often an invaluable component of skin and hair supplements. The use of vitamin is particularly important for dry and acne-prone skin. It helps the skin to maintain an adequate level of hydration, thanks to which the skin is more elastic and softer. It also helps in the fight against signs of aging such as wrinkles. It proves helpful in reducing stretch marks or symptoms of flaky skin.

Vitamin B12

Vitamin B12 helps to regulate the production of pigment in the skin, helping to prevent dark spots and pigmentation. Cobalamin also assists the body with the metabolism of protein which, in turn, promotes the growth of healthy skin cells and helps to repair damaged skin.

VITAMIN B3

Vitamin B3, or niacinamide, as it is also called, is known in skin care as a soothing moisturizer. The vitamin increases ceramide production in the skin and strengthens the skin's barrier function, which is the key to locking in moisture and keeping irritants and pollutants away. Vitamin B3 has also historically been popular in the fight against acne. It has also long been used for hyperpigmentation in the skin (hyperpigmentation is darkened areas of the skin due to sun damage or inflammation.

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.

VITAMIN H  (BIOTIN)

Biotin is a vitamin that’s a part of the vitamin B family, it’s also known as vitamin H. The word “biotin” comes from the ancient Greek word “biotos,” which means “life” or “sustenance.” B vitamins, and specifically biotin, help keep your skin, hair, eyes, liver, and nervous system healthy. Biotin is also a crucial nutrient Trusted Source during pregnancy, as it’s important for embryonic growth.

Tau

Tau protein promotes assembly and stabilizes microtubules, which contributes to the proper function of neuron. 

Zinc

Zinc is needed for the proper growth and maintenance of the human body. It is found in several systems and biological reactions, and it is needed for immune function, wound healing, blood clotting, thyroid function, and much more.