Proteins in hair cosmetics — types, the PEH balance and protein overload
Discover the proteins in hair cosmetics: keratin, silk, wheat. Learn what the PEH balance is and how to spot protein overload in your hair.
Why are proteins important for hair?
Human hair is made up of around 90% keratin — a structural protein. Everyday activities (washing, drying, brushing), chemical treatments (colouring, perming) and environmental factors (UV, chlorine) damage this structure, creating micro-damage in the hair cortex. Proteins in cosmetics can partially fill these gaps, strengthening the hair from within.
However — and this is crucial — not every hair type needs proteins to the same degree. An excess of protein can lead to protein overload, which shows up as stiffness, brittleness and dryness. That is exactly why the PEH balance matters so much.
What is the PEH balance?
PEH stands for the three pillars of hair care:
- P — Proteins (strengthening the structure)
- E — Emollients (softening and smoothing — oils, butters, silicones)
- H — Humectants (moisturising — glycerin, hyaluronic acid, panthenol)
Healthy hair needs all three elements in the right proportions. Damaged, high-porosity hair usually needs more proteins. Healthy, low-porosity hair needs more emollients and humectants. Look for the right ingredients in our INCI database.
Types of proteins in cosmetics — INCI names
Keratin
INCI name: Hydrolyzed Keratin or Keratin. This is a protein identical to the structural protein in hair. The hydrolysed form (broken down into smaller fragments) penetrates the hair shaft more easily. It is effective at rebuilding damaged hair, especially after chemical treatments.
Silk proteins
INCI name: Hydrolyzed Silk or Silk Amino Acids. Lighter than keratin, they give hair softness and shine without weighing it down. A good choice for fine, delicate hair that needs gentle strengthening.
Wheat proteins
INCI name: Hydrolyzed Wheat Protein. They form a moisturising film on the hair, adding volume and elasticity. Popular in shampoos and conditioners for fine hair. Note: people with coeliac disease may react to topical application — although the evidence is limited, it is worth being cautious.
Rice proteins
INCI name: Hydrolyzed Rice Protein. They strengthen hair and add volume. Well tolerated by most hair types.
Collagen proteins
INCI name: Hydrolyzed Collagen. Large molecules that act mainly on the hair surface. They moisturise and smooth, but rebuild less effectively than keratin.
Milk proteins
INCI name: Hydrolyzed Milk Protein or Lactis Proteinum. They moisturise and strengthen, adding softness. Medium molecule size.
Molecule size matters
Not all proteins work the same way, and a key factor is molecule size (molar mass):
- Small molecules (e.g. amino acids, low-molecular-weight keratin) — penetrate the hair cortex and rebuild it from within
- Medium molecules — partly penetrate, partly act on the surface
- Large molecules (e.g. collagen, non-hydrolysed proteins) — form a film on the surface and smooth the hair, but do not rebuild its structure
The keyword to look for is Hydrolyzed — it means the protein has been broken down into smaller fragments capable of penetrating the hair.
Protein overload — how to recognise it?
Protein overload occurs when an excess of protein builds up on the surface and inside the hair. The hair loses its elasticity and becomes brittle. The symptoms:
- Hair is stiff like straw, rough to the touch
- Increased breakage — hair snaps when brushed
- Lack of elasticity — wet hair does not stretch and breaks immediately
- A dull appearance despite moisturising
- Hair refuses to style and feels unnaturally stiff
What to do about protein overload?
- Immediately stop using cosmetics containing proteins
- Focus on moisturising (humectants) and softening (emollients)
- Use deeply moisturising masks with glycerin, aloe vera and honey
- Reintroduce proteins gradually, once your hair regains its elasticity
How to check whether a product contains proteins?
Look for these keywords in the INCI list:
- Hydrolyzed + the name of a protein (Keratin, Silk, Wheat Protein, Rice Protein)
- Amino Acids (the building blocks of proteins)
- Protein in the ingredient name
- Keratin, Collagen, Elastin — on their own or in hydrolysed form
The quickest way to check is with our cosmetics search engine — we automatically flag protein ingredients in every product.
Who needs proteins most?
- Coloured and bleached hair — a weakened keratin structure
- Hair after perming or keratin straightening
- High-porosity hair — open cuticles make it easier for proteins to penetrate
- Hair exposed to high temperatures (straighteners, blow dryers)
Healthy, low-porosity hair may not need extra proteins — emollients and humectants are enough. Browse our conditioner catalogue to find a product with the right formulation.
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FAQ
Dried-out hair is soft, frizzy and porous — it lacks moisture. Protein-overloaded hair is stiff, rough and brittle — it has too much protein. The test: wet hair that does not stretch and breaks immediately points to protein overload.
No. Keratin straightening is a chemical treatment that uses formaldehyde or its derivatives to change the hair structure. Proteins in care cosmetics act on the surface and rebuild the hair without altering its structure.
It depends on the condition of your hair. Damaged hair may need proteins every 1–2 weeks. Healthy hair — once a month or less often. Watch how your hair responds and adjust the frequency accordingly.
Amino acids are the building blocks of proteins — their smallest units. They have even smaller molecules than hydrolysed proteins, so they penetrate the hair more easily, but their structural effect is weaker.
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