Protein moisture balance in hair: proteins, emollients and humectants (PEH)
Updated
Protein moisture balance means rotating products so your hair is neither stiff from too much protein nor limp or dry from too much "moisture". Three groups of ingredients sit behind it: proteins temporarily strengthen and stiffen the hair, humectants bind water, and emollients smooth the strand and slow water loss. Some hair communities call this PEH, for proteins, emollients and humectants. It is a handy way to describe what a product does, but it is a heuristic, not a prescription: there is no single right ratio or schedule that fits everyone.
What is protein moisture balance?
The split into proteins, emollients and humectants did not come from cosmetic chemistry. It comes from people who look after their hair closely and wanted a simple language for effects they can see: strength, smoothness and hydration.
When people say "moisture", they usually mean two groups at once. Humectants bring water in and emollients help hold it there, so together they are the "moisture" side of the balance, with protein on the other.
Keep in mind what the model leaves out. Shampoos contain cleansing agents, conditioners contain conditioning agents, and every product has preservatives, pH adjusters and thickeners. One product almost always mixes several PEH groups, so a "protein mask" is just a product where proteins are clearly present.
Proteins for hair
Hair is mostly keratin, a protein. In products you mostly find hydrolysed proteins, which are cut into smaller pieces, and amino acids. They sit on the surface of the hair, and the smallest ones may partly get into damaged spots.
What they do: hair feels stronger, springier and fuller, and curl can look better defined. The effect is temporary and fades with washing.
What to watch for: too much protein, or too often, can leave hair stiff, rough and brittle. The protein overload guide explains how to recognise that.
How often? There is no fixed rule. Many people start with one protein product a week or every two weeks and adjust to their hair. Bleached and damaged hair often wants more than natural hair.
Emollients for hair
Emollients are oils, butters, silicones, esters and fatty alcohols. Fatty alcohols such as Cetearyl Alcohol have nothing to do with drying alcohol. Emollients form a thin film that reduces friction, smooths the cuticle and slows water loss.
What they do: easier detangling, less frizz, shine and protection for the lengths.
Do emollients moisturise hair? They do not supply water, they help keep it in. That is why they often work best after humectants or on damp hair.
Do emollients weigh hair down? They can, especially on fine or low porosity hair when there is a lot of product or it is very rich. That is about amount and formula, not a ban on emollients for such hair. For oils in particular, see the guide to hair oiling.
Humectants for hair
Humectants are ingredients that bind water: glycerine, panthenol, aloe, propanediol, urea, honey, betaine and hyaluronic acid (as Sodium Hyaluronate).
What they do: hydration, softness and flexibility.
Are humectants bad for hair? Not by default, but they exchange water with the air, so results depend on humidity. In very dry air (winter, heated rooms) some people find hair feels drier or frizzier after glycerine; in very humid air, that it swells and loses smoothness. Concentration matters, as does whether emollients in the product soften the effect. You need not avoid humectants, just watch how your hair behaves across seasons.
What are anti-humectants?
"Anti-humectant" is a community term from curly and coily hair circles, not a formal category. It usually means film-forming polymers, silicones and heavier oils and butters that slow water exchange with the air, used against humidity frizz. Treat it as a description of an effect, not a list of ingredients.
PEH table: example ingredients on the label
Common ingredients as written on a pack in INCI, classified the same way as in the Flomsy scanner.
| Group | Examples in INCI | Typical effect |
|---|---|---|
| Proteins | Hydrolyzed Keratin, Hydrolyzed Wheat Protein, Hydrolyzed Silk, Silk Amino Acids, Hydrolyzed Collagen, Hydrolyzed Rice Protein, Hydrolyzed Oat Protein, Amino Acids | Springiness, volume, strength |
| Emollients: oils and butters | Argania Spinosa Kernel Oil, Cocos Nucifera Oil, Butyrospermum Parkii Butter | Smoothing, protection, shine |
| Emollients: silicones | Dimethicone, Amodimethicone | Smoothing, less friction, heat protection |
| Emollients: esters and fatty alcohols | Caprylic/Capric Triglyceride, Squalane, Isopropyl Myristate, Cetearyl Alcohol, Cetyl Alcohol | Slip, softness, texture |
| Emollients: occlusive | Paraffinum Liquidum, Lanolin | Strong water retention |
| Humectants | Glycerin, Panthenol, Aloe Barbadensis Leaf Juice, Propanediol, Sodium PCA, Urea, Honey, Betaine, Sorbitol, Sodium Hyaluronate | Hydration, softness |
Some popular ingredients are not in any of the three groups, such as Behentrimonium Chloride (a conditioning agent), Polyquaternium-10 or Guar Hydroxypropyltrimonium Chloride (film formers). They act on hair, but they are not proteins, emollients or humectants. For how to read the whole list and what ingredient order tells you, see the guide to reading INCI ingredient lists.
How to balance protein and moisture in practice
Balance does not mean equal amounts of every group each week. It means not letting one group dominate until your hair complains.
- Start with what you own. Check which groups your current products belong to. You may find that every conditioner is emollient-heavy or that protein is in everything.
- Rotate instead of changing everything. A common approach is alternating conditioners that lean towards different groups between washes.
- Watch the signs, not the calendar. Stiff, rough hair may point to too much protein. Limp, heavy hair may point to too many emollients. Frizzy, dull hair despite "hydration" may mean too many humectants or too few emollients to hold them.
- Change one thing at a time and judge it over several washes.
These signs have other causes too: hard water, product build-up, heat, weather. A PEH balance tells you where to look, it is not a diagnosis.
Does my hair need protein or moisture?
No test settles it. The popular wet-strand stretch test gives a clue: a strand that stretches and springs back is fine, one that barely stretches and snaps hints at too much protein, one that stretches like gum and stays stretched hints at too little. Results also depend on the hair's condition and how hard you pull, so treat it as a prompt for one small experiment, not a verdict.
Protein, humectants, emollients: which order?
No studies point to one right order. A simple logic that works in practice: water-based products first (a conditioner with humectants or proteins), then heavier emollients such as an oil or serum last, to hold in water and smooth the surface.
Balance for high porosity, low porosity and curly hair
High porosity hair loses water quickly, so emollients often matter more and proteins can temporarily fill in damage. Low porosity hair is easier to weigh down and can turn stiff with a large dose of protein. Curly and coily hair often likes humectants that support curl but shows too much protein quickly. These are directions, not rules; see hair porosity for how to read yours.
Protein moisture balance FAQ
Is PEH a scientific method?
No. It is a simplification invented by hair-care communities. The ingredients behave roughly as described, but the three groups and the idea of "balance" are a tool for observation, not a principle confirmed by research.
How can I tell how much protein a product contains?
You cannot tell exactly. An INCI list gives the order of ingredients but not their concentrations, and anything under 1% can appear in any order. Position on the list is only an approximation.
Do DIY treatments such as egg, gelatin or flaxseed count?
Often they are classed that way: egg and gelatin as protein sources, flaxseed as a humectant. They behave similarly, but their strength is harder to predict and they are harder to rinse out.
Does eating or applying protein help hair grow?
Protein in a product works on the strand, not the follicle, so it does not affect growth. What you eat is a nutrition question. If you are losing more hair than usual, see a dermatologist.
How Flomsy reads it
The ingredient scanner in Flomsy matches ingredients to a catalogue of 1,000+ names and shows which are proteins, emollients and humectants. You can paste the list in without limits or photograph the label (free-plan photo reads are limited). It estimates the split by weighting ingredients nearer the start of the list, only among the ingredients it recognised. This is not a percentage composition of the product, because manufacturers do not publish concentrations, and if fewer than half the list is recognised it shows no chart.
The weekly balance shows which PEH groups appeared in the products you used that week. Treat it as a log to compare with how your hair behaves, not as a target ratio.
