Alphabetical Cosmetic Ingredient Dictionary from Paula Begoun, the Cosmetics Cop

Rating Ingredient
Good

macadamia nut oil

Used in cosmetics as an emollient for dry skin.

Categories: Plant Extracts, Emollients
Best

madecassoside

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

Good

magnesium

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

Categories: Absorbent
Good

magnesium aluminum silicate

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

Good

magnesium ascorbyl palmitate

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

Categories: Antioxidants, Vitamins
Best

magnesium ascorbyl phosphate

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

Categories: Antioxidants, Vitamins
Good

magnesium aspartate

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

Categories: Skin-Softening, Hydration
Good

magnesium carbonate

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

Categories: Absorbent
Good

magnesium hydroxide

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

Categories: Absorbent, Miscellaneous
Good

magnesium laureth sulfate

Mild detergent cleansing agent.

Categories: Cleansing Agents
Good

magnesium oleth sulfate

Mild detergent cleansing agent.

Categories: Cleansing Agents
Good

magnesium palmitoyl glutamate

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

Categories: Skin-Softening
Best

magnesium PCA

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

Good

magnesium stearate

Used as a thickening agent in cosmetics.

Good

magnesium sulfate

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

Categories: Texture Enhancer
Best

malic acid

malic acid

Categories: Exfoliant
Best

mallow

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

Best

Malpighia emarginata (acerola) fruit extract

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

Good

maltodextrin

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

Good

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.

Average

malvaceae extract

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

Categories: Plant Extracts
Good

Malva sylvestris extract

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

Poor

mandarin orange oil or extract

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

Good

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.

Categories: Exfoliant
Average

manganese gluconate

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

Categories: Antioxidants
Good

manganese violet

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

Best

Mangifera indica (mango) seed butter

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

Good

Mangifera indica root

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

Good

mannitol

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

Best

manuka honey

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

Good

manuka oil

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

Good

marigold

Good

marionberry

Fruit that has potent antioxidant properties.

Poor

marjoram

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

Best

marshmallow

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

Good

Mastocarpus stellatus

Best

mate extract

Best

matricaria oil

Average

MEA

Abbreviation for monoethanolamine.

Best

Medicago sativa

Good

Melaleuca alternifolia

Poor

Melaleuca cajeputi oil

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

Best

Melia azadirachta (chinaberry) leaf extract

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

Best

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.

Poor

Melia azadirachta oil

Categories: Sensitizing
Good

melibiose

Saccharide that can have good water-binding properties.

Categories: Skin-Replenishing
Poor

Melissa officinalis

Poor

Mentha arvensis

Poor

Mentha piperita

Poor

Mentha spicata

Poor

Mentha viridis

Poor

menthol

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

Poor

menthone

Major constituent of peppermint.

Poor

menthoxypropanediol

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

Best

menthyl anthranilate

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

Categories: Sunscreen Actives
Poor

menthyl lactate

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

Best

meradimate

Categories: Sunscreen Actives
Poor

methanol

Categories: Sensitizing
Good

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.

Good

methionine

Poor

methylchloroisothiazolinone

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

Categories: Preservatives, Sensitizing
Poor

methyldibromo glutaronitrile

Formaldehyde-releasing preservative...

Categories: Preservatives
Poor

methyldihydrojasmonate

Synthetic fragrant component.

Good

methyl gluceth-20

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

Categories: Skin-Softening
Good

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.

Good

methyl glucose sesquistearate

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

Categories: Emollients, Skin-Softening
Good

methylglucoside phosphate

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

Categories: Skin-Softening
Poor

methylisothiazolinone

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

Categories: Preservatives, Sensitizing
Good

methylparaben

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

Categories: Preservatives
Good

methylpropanediol

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

Categories: Miscellaneous, Hydration
Good

methylsilanol mannuronate

Good

methylsilanol PEG-7 glyceryl cocoate

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

Good

methylsufonylsulfate

Categories: Antioxidants
Good

methyl trimethicone

Best

Mexoryl SX

Categories: Uncategorized
Good

mica

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

Good

microcrystalline wax

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

Good

Microcystis aeruginosa

Latin name for spirulina.

Good

milk protein

Good

milk vetch root

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

Average

millet seed extract

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

Poor

mimosa oil or extract

Extract used as a fragrance in cosmetics.

good

mineral oil

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

Categories: Emollients
Poor

mint

Can be a skin sensitizer…

Good

mixed fruit extracts

Categories: Plant Extracts
Good

montan wax

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

Categories: Texture Enhancer
Good

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...

Categories: Absorbent
Good

Morinda citrifolia

Best

Moringa oleifera seed oil

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

Best

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.

Good

Morus bombycis root extract

Categories: Plant Extracts
Good

Morus nigra root extract

Categories: Plant Extracts
Best

mucopolysaccharide

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

Categories: Skin-Replenishing
Average

Mucor miehei extract

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

Categories: Miscellaneous
Average

mugwort extract

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

Categories: Plant Extracts
Best

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...

Good

murumuru seed butter

Categories: Emollients, Plant Extracts
Best

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.

Good

myristamidopropyl PG-dimonium chloride phosphate

myristamidopropyl PG-dimonium chloride phosphate

Good

myristic acid

Cleansing agent that also creates foam and can be drying.

Categories: Cleansing Agents
Best

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.

Categories: Skin-Restoring
Best

myristoyl pentapeptide-17

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

Categories: Skin-Restoring
Best

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.

Categories: Skin-Restoring
Good

myristyl alcohol

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

Good

myristyl myristate

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

Best

myristyl nicotinate

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

Categories: Miscellaneous
Poor

myrrh

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

Poor

myrtle extract

Contains volatile oil and tannins...

Poor

Myrtus communis extract

About the Experts

Paula Begoun is the best-selling author of 20 books about skincare and makeup. She is known worldwide as The Cosmetics Cop and creator of Paula’s Choice Skincare. Paula’s expertise has led to hundreds of appearances on national and international radio, print, and television including:

The Paula's Choice Research Team is dedicated to busting beauty myths and providing expert advice that solves your skincare frustrations so you can have the best skin of your life!