Alphabetical Cosmetic Ingredient Dictionary from Paula Begoun, the Cosmetics Cop

macadamia nut oil

Used in cosmetics as an emollient for dry skin.

madecassoside

One of four principal bioactive compounds in the plant extract Centella asiatica.

magnesium

Earth mineral that has strong absorbent properties and some disinfecting properties…

magnesium aluminum silicate

Dervied from clay, this absorbent, dry-feeling, white solid is used as a thickening agent and powder in cosmetics.

magnesium ascorbyl palmitate

Fatty acid-based derivative of vitamin C that can be an effective antioxidant. There is some...

magnesium ascorbyl phosphate

Form of vitamin C that is considered stable and an effective antioxidant for skin (Sources:...

magnesium aspartate

Magnesium aspartate is the magnesium salt of aspartic acid that plays a role in maintaining proteins in skin.

magnesium carbonate

Inorganic mineral salt used as an absorbent, opacifying agent, coloring agent, or to adjust the pH...

magnesium hydroxide

Active ingredient in milk of magnesia. It is an absorbent and has disinfectant properties for skin.

magnesium laureth sulfate

Mild detergent cleansing agent.

magnesium oleth sulfate

Mild detergent cleansing agent.

magnesium palmitoyl glutamate

Magnesium palmitoyl glutamate is an amino acid (glutamic acid) and mineral (magnesium) blend that conditions and softens skin.

magnesium PCA

Magnesium PCA is the magnesium salt of PCA (pyrrolidone carboxylic acid), which is part of skin’s intercellular matrix.

magnesium stearate

Used as a thickening agent in cosmetics.

magnesium sulfate

Commonly known as Epsom salt, a magnesium salt used as a texture enhancer.

malic acid

malic acid

mallow

Can be used as a texture enhancer in cosmetics and may have soothing...

Malpighia emarginata (acerola) fruit extract

Acerola fruit extract is a potent source of antioxidants and hydrating polysaccharides.

maltodextrin

A plant-based sugar created by hydrolyzing a saccharide with starch from corn, potato, or rice.

maltooligosyl glucoside

A polysaccharide that’s naturally-derived and then combined with a starch. It has multiple functions in cosmetics, including binding agent, emulsifier, hydrator, texture enhancer, and film-forming agent.

malvaceae extract

Extract from plants of the Malvaceae family, which includes over 1,000 species, found in tropical...

Malva sylvestris extract

Extract from the blue mallow flower, it may have some soothing properties for...

mandarin orange oil or extract

Primarily used as a fragrance; it can be a skin sensitizer. There is no research showing it has any...

mandelic acid

A type of alpha hydroxy acid (AHA) that works as an exfoliant. Due to its large molecule size, it’s generally better tolerated by those with sensitive skin than glycolic acid.

manganese gluconate

Mineral found in trace amounts in tissues of the body. While manganese plays a vital role in the...

manganese violet

Coloring agent/additive permanently listed (as of 1976) by the FDA for use in cosmetic products,...

Mangifera indica (mango) seed butter

More commonly known as mango butter, this ingredient is a very good plant-based...

Mangifera indica root

Extract derived from the mango tree; it can have antioxidant properties (Source: Journal of...

mannitol

Mannitol is a plant-derived or lab-made sugar that works in skin care to bind moisture and condition.

manuka honey

Manuka honey is a type of honey found in many skin care products.

manuka oil

Extract derived from the New Zealand tea tree; the oil is similar to that of the Australian tea...

marigold

marionberry

Fruit that has potent antioxidant properties.

marjoram

Herb with a fragrant component used in cosmetics; can be a skin sensitizer…

marshmallow

A flowering plant native to Africa that has soothing effects...

Mastocarpus stellatus

mate extract

matricaria oil

MEA

Abbreviation for monoethanolamine.

Medicago sativa

Melaleuca alternifolia

Melaleuca cajeputi oil

There is no research showing that this oil, which is derived from a plant in the same family as the...

Melia azadirachta (chinaberry) leaf extract

Latin term for the extract from the leaf of the neem plant.

Melia azadirachta extract

The chinaberry is a popular plant throughout India, where use of every part of the plant can be seen in the practice of Ayurvedic medicine.

Melia azadirachta oil

melibiose

Saccharide that can have good water-binding properties.

Melissa officinalis

Mentha arvensis

Mentha piperita

Mentha spicata

Mentha viridis

menthol

Derived from peppermint; menthol can have the same sensitizing effect as peppermint on skin…

menthone

Major constituent of peppermint.

menthoxypropanediol

Synthetic derivative of menthol. It is known to produce effects that are twice as strong as...

menthyl anthranilate

Also known as meradimate, this is a synthetic sunscreen active is a partially effective UVA...

menthyl lactate

Used as a cooling agent and fragrance in cosmetics. It is a derivative of menthol and is supposed...

meradimate

methanol

methicone

One of the simpler silicones due to its less complex molecular structure. It helps give skin products a silky feel and helps skin retain moisture.

methionine

methylchloroisothiazolinone

In combination with methylisothiazolinone, it goes by the trade name Kathon CG (among others)....

methyldibromo glutaronitrile

Formaldehyde-releasing preservative...

methyldihydrojasmonate

Synthetic fragrant component.

methyl gluceth-20

Made by combining polyethylene glycol with glucose to create a new synthetic compound that draws and holds moisture to skin.

methyl gluceth-20 benzoate

The ester of methyl gluceth-20 and preservative and pH adjuster benzoic acid. Esters are ingredients formed from alcohols and acids by eliminating water. Functions as an emollient and solvent.

methyl glucose sesquistearate

A mixure of the diesters of methyl glucoside and stearic acid. Functions as a skin-conditioning...

methylglucoside phosphate

A type of monosaccharide (simple sugar) derived from glucose, it serves as a skin-conditioning agent...

methylisothiazolinone

Preservative that’s generally recommended for use only in rinse-off products such as cleansers or...

methylparaben

Parabens are a group of controversial preservatives that include butylparaben...

methylpropanediol

Solvent that can be used to enhance the absorption of other ingredients into skin for improved efficacy. Also provides hydrating properties.

methylsilanol mannuronate

methylsilanol PEG-7 glyceryl cocoate

A glyceryl ester used as an emollient and texture enhancer in cosmetics.

methylsufonylsulfate

methyl trimethicone

Mexoryl SX

mica

Earth mineral included in products to give them sparkle and shine.

microcrystalline wax

Used as a thickener and to give products a semi-solid to solid smooth texture. Utilized most abundantly in lip care products.

Microcystis aeruginosa

Latin name for spirulina.

milk protein

milk vetch root

Root with potential antioxidant properties, although there isn't conclusive research that it functions that way when applied topically.

millet seed extract

Extract from a cereal grain that has no established benefit for skin, but is added to cosmetic...

mimosa oil or extract

Extract used as a fragrance in cosmetics.

mineral oil

Clear, odorless oil derived from petroleum that is widely used in cosmetics because it rarely...

mint

Can be a skin sensitizer…

mixed fruit extracts

montan wax

A type of natural wax derived from lignite, which is a type of coal that’s made from wood. Most...

montmorillonite

A type of clay that is a mix of bentonite and fuller's earth, with the latter being a white to brown substance found in sediment...

Morinda citrifolia

Moringa oleifera seed oil

Moringa oil is a non-fragrant plant oil that contains several antioxidants and vitamins.

Morus alba (white mulberry) root extract

Morus alba (white mulberry) root extract has antioxidant properties, but its main benefit for skin has to do with calming signs of irritation.

Morus bombycis root extract

Morus nigra root extract

mucopolysaccharide

Also known as glycosaminoglycans. This is a large class of ingredients that includes hyaluronic...

Mucor miehei extract

Extract of a type of mold whose enzymes are used as a food additive and flavor enhancer in cheeses....

mugwort extract

There is no research showing this extract has any benefit for skin (Sources:...

mulberry extract

Non-fragrant plant extract (Latin name is Morus alba) whose various parts such as the leaf and root, have shown potential to brighten and improve the look...

murumuru seed butter

Myrciaria dubia (camu camu) fruit extract

Camu camu is a small berry that, especially when fully ripe, possesses strong antioxidant capacity due to its levels of vitamin C.

myristamidopropyl PG-dimonium chloride phosphate

myristamidopropyl PG-dimonium chloride phosphate

myristic acid

Cleansing agent that also creates foam and can be drying.

myristoyl hexapeptide-16

Myristoyl hexapeptide-16 is a synthetic, fatty acid-linked peptide known to improve skin’s resilience, visibly calm, and help skin look and feel smoother.

myristoyl pentapeptide-17

Myristoyl pentapeptide-17 is a synthetic peptide known to increase skin's hydration and resilience.

myristoyl tripeptide-31

A synthetic peptide made from combining the fatty acid myristic acid with tripeptide-31. This peptide is believed to have a retinol-like effect on skin’s appearance.

myristyl alcohol

A lighter-weight fatty alcohol that functions as a thickener, emulsion stabilizer, and emollient.

myristyl myristate

Used as a texture enhancer and emollient. It has a wetter feel and is best for dry skin.

myristyl nicotinate

A derivative of nicotinic acid, a component of vitamin B3 (niacin) that isn’t the same ingredient...

myrrh

Fragrant gum resin that can be a skin sensitizer. There is little research showing it has any benefit...

myrtle extract

Contains volatile oil and tannins...

Myrtus communis extract