Encyclopedia
Every molecule that touches your hair
From proven medicines to kitchen-cupboard oils, with the studies behind each one.
43 entries
1
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other
18-MEA (18-methyleicosanoic acid)
The fatty acid on the outer surface of virgin hair that makes it water-repellent and smooth, lost with weathering and chemical treatment.
A
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styling polymer
Acrylates copolymer
A family of acrylic polymers that thicken styling gels and dry to a hard, clear film for strong hold.
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other
Alcohol denat.
Ordinary ethanol made undrinkable, a fast-drying solvent in hair sprays and gels that is not the same as the fatty alcohols in conditioners.
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silicone
Amodimethicone
A dimethicone with positively charged amine groups, so it clings to damaged hair and resists rinsing better than plain dimethicone.
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oil or butter
Argan oil
A popular finishing oil for shine and anti-frizz, with only small lab studies behind it and no significant evidence for hair quality or growth.
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oil or butter
Avocado oil
A rich oleic-acid oil common in deep conditioners, with no hair-fibre or clinical hair studies found.
B
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oil or butter
Beeswax
The classic hold-and-grip wax in pomades and braiding waxes; harmless for most people but a documented contact allergen for a minority.
-
conditioning agent
Behentrimonium chloride
A long-chain, positively charged conditioning ingredient that clings to hair and detangles it, with good lab evidence for smoothing and none for repair.
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conditioning agent
Behentrimonium methosulfate
The methosulfate salt of the same C22 conditioning ingredient as behentrimonium chloride, slightly weaker in head-to-head lab testing.
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silicone
Bis-aminopropyl dimethicone
An amino-terminated silicone related to amodimethicone, used in conditioners and colour-care products to stick to damaged hair.
C
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oil or butter
Candelilla wax
A plant wax from a Mexican desert shrub, used as the vegan alternative to beeswax in pomades and balms.
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conditioning agent
Cetearyl alcohol
A waxy blend of cetyl and stearyl alcohols that thickens conditioners and builds the gel that carries the conditioning agent; despite the name, it is not a drying alcohol.
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conditioning agent
Cetrimonium chloride
A shorter-chain conditioning ingredient, a bit less effective than the behentrimonium salts but lighter, found in many shampoos, light conditioners and sprays.
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conditioning agent
Cetyl alcohol
A 16-carbon fatty alcohol that thickens conditioners and pairs with conditioning surfactants to form the gel; it is not a drying alcohol.
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chelator
Citric acid
The most common pH adjuster in shampoos and conditioners and, in a 2025 lab study, a calcium-removing treatment that strengthened chemically treated hair.
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oil or butter
Coconut oil
The best-studied hair oil; in lab work it cut protein loss and fatigue damage when used before washing, but almost all studies come from coconut-oil sellers.
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silicone
Cyclopentasiloxane
A volatile silicone that spreads easily and evaporates, used to carry heavier silicones in serums; now restricted in the EU for environmental reasons.
D
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silicone
Dimethicone
The standard hair silicone, a water-insoluble oil that coats the fibre for slip, shine and friction control without repairing anything.
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silicone
Dimethiconol
A dimethicone with hydroxyl end groups, usually supplied as a thick gum emulsion for longer-lasting slip in rinse-off conditioners.
F
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botanical
Flaxseed gel
A homemade or commercial gel of boiled flax seeds, popular as a natural curl definer, with no published study on it as a hair styler.
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chemical treatment
Formaldehyde and formaldehyde releasers (methylene glycol)
The cross-linker behind classic keratin smoothing; it works but releases a human carcinogen when heated, and even "formaldehyde-free" versions can exceed workplace limits.
G
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humectant
Glycerin
A cheap water-binding ingredient in nearly every conditioner; no peer-reviewed hair study tests it, and the popular humidity rules are untested.
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chemical treatment
Glyoxylic acid
Marketed as a safe "formaldehyde-free" straightening agent, but it has been linked to acute kidney failure and the EU has begun a safety review.
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conditioning agent
Guar hydroxypropyltrimonium chloride
A plant-derived cationic polymer used in conditioning shampoos and "natural" conditioners to ease wet combing; it can build up on hair.
H
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protein or peptide
Hydrolyzed rice protein
A plant, gluten-free protein used in conditioners and volumizers; we found no hair study for it.
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protein or peptide
Hydrolyzed silk
Silk-derived peptides added for gloss and softness; the cosmetic safety panel judged most silk proteins safe, but there is no hair efficacy study.
L
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oil or butter
Lanolin
A sheep-wool wax used as an emollient in pomades and conditioners; a weak but real contact allergen whose true allergy rate is probably under-detected.
M
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oil or butter
Mineral oil
A cheap, non-penetrating hydrocarbon oil that coats hair for shine and slip but, unlike coconut oil, did not protect against protein loss in lab tests.
O
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oil or butter
Olive oil
A traditional hair oil whose only supporting hair data is that its film thinned on hair like coconut oil did, suggesting some absorption.
P
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humectant
Panthenol
A small vitamin B5 alcohol that enters the hair cortex and raised break stress in a lab study; the only humectant here with real hair-fibre data.
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silicone
PEG-12 dimethicone
A dimethicone with polyethylene glycol side chains that makes it water-dispersible, so it rinses out more easily than classic silicones.
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oil or butter
Petrolatum
A refined mineral-oil-and-wax jelly that is the base of many greasy pomades; it seals and adds shine but does not enter the hair.
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conditioning agent
Polyquaternium-10
A positively charged cellulose polymer that coats hair during shampooing, easing wet combing and helping deliver silicones, with some build-up risk.
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styling polymer
Polyquaternium-11
A positively charged vinylpyrrolidone copolymer used in mousses, gels and sprays for clear, flexible hold with some conditioning.
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conditioning agent
Polyquaternium-7
A synthetic positively charged copolymer used in shampoos and rinse-offs to improve wet combing and feel.
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styling polymer
PVP (polyvinylpyrrolidone)
A water-soluble film-forming polymer that gives temporary, washable hold in gels, mousses and sprays.
R
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other
Rice water
Rice water is the starchy water left after soaking or boiling rice, a free and harmless rinse with no clinical hair study behind its growth claims.
S
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oil or butter
Shea butter
A heavy plant butter widely used on coily hair, with no fibre-science data behind it.
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chemical treatment
Sodium hydroxide and guanidine relaxers (lye and no-lye)
Chemical relaxers permanently straighten tightly curled hair; they work, but are linked to scalp burns, breakage and cancer associations still being investigated.
-
conditioning agent
Stearamidopropyl dimethylamine
A conditioning agent that only becomes positively charged in acidic formulas, used in "quat-free" conditioners; no independent hair data were found.
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conditioning agent
Stearyl alcohol
An 18-carbon fatty alcohol, a slightly heavier cousin of cetyl alcohol, used to thicken and soften conditioners; safe at cosmetic levels and rarely allergenic.
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oil or butter
Sunflower seed oil
In the classic Marico study sunflower oil did nothing for protein loss, though later work suggests oils of its type can penetrate hair.
V
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styling polymer
VP/VA copolymer
A vinylpyrrolidone and vinyl acetate polymer used in sprays, mousses and gels for firmer, less humidity-sensitive hold than plain PVP.