Alphabetical Cosmetic Ingredient Dictionary from Paula Begoun, the Cosmetics Cop

lactic acid

Alpha hydroxy acid extracted from milk, although most forms used in cosmetics are synthetic. It...

Lactobacillus/rye flour ferment

Lactobacillus/rye flour ferment is a non-living probiotic made by fermenting rye flour with the microorganism Lactobacillus that’s used to create sourdough bread.

Lactobacillus ferment

Lactobacillus ferment is a lab-created, non-living probiotic ingredient made by fermentation of the microorganism Lactobacillus.

lactobionate

Polysaccharide that has water-binding properties for skin.

lactobionic acid

lactoperoxidase

Enzyme derived from milk; it has purifying benefits for skin and may be helpful for...

lady's mantle extract

lady's thistle (milk thistle) extract

Extract for which there is a great deal of research showing it has many applications...

Lagerstroemia indica extract

No research shows this plant as having any benefit for skin...

Laminaria digitata

Laminaria longicruris

Laminaria ochroleuca extract

The Latin name for a species of kelp, also known as brown seaweed. Applied topically, it helps...

Laminaria sacharrina

Lamium album flower extract

A species of the nettle plant that is used topically as as a soothing ingredient...

lanolin

Emollient, very thick substance derived from sheep. Lanolin has long been...

lanolin alcohol

Emollient derived from lanolin.

lappa extract

Larrea divaricata extract

Larrea tridentata

L-ascorbic acid

Form of vitamin C that is a potent antioxidant and skin-soothing agent...

lauramphocarboxyglycinate

Mild detergent cleansing agent.

laurdimonium hydroxypropyl hydrolyzed soy protein

laurdimonium hydroxypropyl hydrolyzed wheat protein

laureth-23

Derived from lauryl alcohol and used either as a surfactant or emulsifier (or, in many cases, as...

laureth-4

Derived from lauryl alcohol and used either as a surfactant or emulsifier (or, in many cases, as...

laureth-7

A form of lauryl alcohol (a non-irritating fatty alcohol derived from coconut oil) that can...

laureths

Substances that in various combinations create a wide range of mild detergent cleansing agents...

lauric acid

One of several fatty acids found in coconut oil and other natural fats.

lauroyl lysine

Amino acid derivative that functions as a skin- and hair-conditioning agent. It also contributes to...

Laurus nobilis

lauryl alcohol

lauryl glucoside

lauryl lactate

Mixture of lauryl alcohol and lactic acid that functions as a skin-conditioning agent and...

lauryl laurate

An ester of lauryl alcohol and lauric acid...

lauryl PEG-9 polydimethylsiloxyethyl dimethicone

A silicone polymer that has multiple functions in cosmetic products, including skin/hair...

lavandin oil

Essential oil of the hybrid lavender plant Lavandula hybrida and used in cosmetics as a fragrance...

Lavandula angustifolia

Lavandula officinalis

lavender extract and oil

In-vitro research indicates that components of lavender oil, specifically linalool and linalyl acetate, can have...

L-cysteine

lecithin

Phospholipid found in egg yolks and may be plant or animal derived. It is widely used in...

lemon

Potent skin sensitizer. Though it can have beneficial properties...

lemon balm

lemongrass extract

Extract that can have beneficial properties...

lemongrass oil

Also known as Oil of Verbena; can be effective as a mosquito repellent...

lemon juice

The juice from the citrus fruit lemon, often touted in the world of skin care as being a natural option for brightening skin.

lemon oil

Commonly used citrus oil that can be a skin sensitizer, especially on abraded skin.

lentil fruit extract

Extract that functions as a skin-conditioning agent and likely has antioxidant benefit, too.

Lentinus edodes extract

Extract from the shiitake mushroom that may have antioxidant properties...

Leontopodium alpinum (edelweiss) extract

Edelweiss is a plant extract whose constituents are capable of providing antioxidant and skin-soothing benefit for skin.

Leptospermum scoparium oil

leucine

Amino acid.

leuconostoc/radish root ferment filtrate

Leuconostoc/radish root ferment filtrate is a preservative created by fermenting Raphanus sativus (radish) roots.

Levisticum officinale root extract

licorice extract

Plant extract that has skin-soothing properties. In addition, licorice root may be effective in...

licorice root

Lilium candidum bulb extract

Extract derived from the white lily bulb. There is no research showing this has any benefit for...

lime oil and extract

Citrus fruit whose volatile compounds are sensitizing...

Limnanthes alba

Plant commonly known as meadowfoam; its seed oil is a non-volatile plant oil used as a...

Limnanthes alba (meadowfoam) seed oil

Limnanthes alba (meadowfoam) seed oil is a non-fragrant, edible plant oil originally developed as an agricultural crop in the 1950s.

Limnanthes alba seed oil

limonene

Chemical constituent of many natural fragrant ingredients, notably citrus oils such as lemon (d-limonene) and...

linalool

Fragrant component of lavender and coriander that can be a skin sensitizer, or...

linden flower extract

Major constituents in linden are flavonoids and glycosides. Flavonoids are potent...

linoleic acid

Unsaturated fatty acid used as an emollient and thickening agent in cosmetics. There is some...

linolenic acid

Linolenic acid is a naturally-occurring, colorless polyunsaturated fatty acid liquid...

Linum usitatissimum (linseed) seed oil

Linum usitastissimum (linseed) seed oil is more commonly known as flaxseed oil.

Linum usitatissimum extract

lipid

Wide range of ingredients found in plants, animals, and human skin. Lipids include fatty acids,...

liposomes

Delivery system (not an ingredient) capable of holding other ingredients and releasing them after...

lithium magnesium sodium silicate

Synthetic silica-based clay composed of lithium, sodium, and magnesium. Used as a thickening agent...

Lithospermum erythrorhizon

Also known as gromwell, the root of this plant is believed to have antioxidant and...

Litsea cubeba

locust bean

Lonicera caprifolium flower extract

Lonicera japonica

Honeysuckle extract. A plant with soothing properties for skin.

Lonicera japonica flower extract

loquat extract

Extract derived from a subtropical flower that has antioxidant properties similar to...

lotus seed extract

Extract that can have soothing and antioxidant properties...

lovage root extract

In cosmetics, it is used as a fragrance....

lupine

Legume that is a source of isoflavones with antioxidant properties.

lupine oil

Extract of Lupinus albus, a legume; it has emollient and antioxidant properties.

Lupinus albus (white lupine) seed oil

Lupinus albus (white lupine) seed oil is a non-fragrant plant oil whose unsaturated fatty acid content consists primarily of oleic and erucic acids.

Lupinus albus extract

Species of legume.

lutein

Carotenoid that has antioxidant properties…

Lycium barbarum fruit extract

The extract of the fruit commonly known as goji, goji berry, or wolfberry. This fruit extract is an antioxidant...

lycopene

Carotenoid pigment that has potent antioxidant properties…

lye

lysine

Amino acid.

lysine HCI

Lysine HCI plays a role in keeping skin hydrated and helping it look smooth and youthful.