Most of the guides here deal with ingredients that could be plant or animal depending on the supplier. Keratin is different, and knowing that saves you the wrong question.
Quick answer: it is always animal, so ask which animal
Keratin is a fibrous structural protein. It is what hair, feathers, wool, hooves, horns, claws, and nails are largely made of. No plant produces it, and there is no synthetic route in commercial use.
So the usual framing on this site, that an ingredient is source-dependent and needs evidence either way, does not apply. Keratin is animal derived every time. The useful questions are which animal, and whether that animal was slaughtered according to Islamic requirements where the source is a slaughtered animal at all.
- Poultry feathers: the dominant industrial source, abundant as a meat-industry by-product.
- Sheep wool: obtained by shearing, which does not require slaughter. Several certifiers treat wool-derived material differently for that reason, as discussed in the vitamin D3 guide on lanolin.
- Bovine hooves and horns: a traditional source, and a slaughter question.
- Hog bristle and hair: prohibited outright under any halal standard, and the specific source to rule out.
- Human hair: used industrially for amino acid production, which raises a distinct question that scholars and certifiers have addressed directly.
A product advertising vegan keratin or plant keratin is using soy, wheat, or corn protein that conditions hair similarly. That is a claim about the effect, not the molecule. Read the ingredient list to see which plant protein it actually contains.
Where keratin appears
The visible uses are cosmetic. Shampoos, conditioners, hair masks, and salon smoothing treatments use hydrolyzed keratin because it binds to damaged hair. Hair, skin and nails supplements include it in capsule and gummy form, usually alongside collagen and biotin, since all three are marketed for the same outcome.
The less visible use is as a raw material. Keratin is unusually rich in the amino acid cysteine, which makes it an economical feedstock for producing amino acids by hydrolysis. That is why keratin turns up behind ingredients whose names give no hint of it.
The ingredients keratin sits behind
This is the part worth knowing, because these ingredients do not contain the word keratin anywhere.
L-cysteine, labelled E920 and used as a dough conditioner in bread, buns, and pizza bases, is frequently produced by hydrolyzing keratin. The BCAA guide covers the same route for branched-chain amino acids, where fermentation is the alternative and the finished molecule is identical either way.
In both cases the practical answer is the same: ask whether the amino acid was produced by fermentation or by hydrolysis, and if hydrolysis, from what raw material.
Topical versus ingested
Whether a shampoo raises the same question as a capsule depends on the standard you follow. Many certifiers run separate cosmetic and food schemes, and scholarly positions on topical use of animal-derived material vary.
This guide does not resolve that. What it can do is tell you that keratin in a conditioner is genuinely animal derived, so if your standard covers cosmetics, the question is live and worth asking rather than assuming a hair product is outside scope.
A quick check
- Treat keratin as animal derived without needing to verify that part.
- Ask which animal, and rule out hog bristle explicitly.
- Treat vegan or plant keratin claims as plant proteins, and read which one.
- On hair supplements, check for collagen and biotin alongside it.
- For amino acids and E920, ask fermentation or hydrolysis, and from what.
- Decide whether your standard covers topical products before applying it to shampoo.
Please confirm the animal source of the keratin or hydrolyzed keratin in this product, specifically whether it is derived from poultry feathers, sheep wool, bovine hooves or horns, or any porcine material. I would also like to know whether the source animal was slaughtered according to Islamic requirements where applicable, and whether the finished product holds a current halal certificate.
Add the product name and format with the manufacturer question generator.
Related checks
Read the L-cysteine and E920 guide, the BCAA guide, the collagen guide, the biotin guide, or the gelatin guide for the other structural animal protein. If you want the general method rather than one ingredient, read how to read a halal food label.
Frequently asked questions
Is keratin halal?
Keratin is one of the few ingredients on this site that is animal derived by definition rather than by circumstance. It is a structural protein found in hair, feathers, wool, hooves, horns, and nails, and it cannot be produced from plants. The halal question is therefore the specific animal it came from and how that animal was handled. Poultry feathers and sheep wool are the usual industrial sources, and hog bristle is the one to rule out explicitly.
What is keratin made from?
Industrially, mostly poultry feathers, which are an abundant by-product of the meat industry. Sheep wool is also used, and bovine hooves and horns are a traditional source. Hog bristle has been used historically for keratin and for keratin-derived amino acids, which is why the source needs naming rather than assuming.
Is there such a thing as vegan or plant keratin?
No. Keratin is an animal protein and plants do not make it. Products advertising plant keratin, vegan keratin, or keratin alternative are using plant proteins such as soy, wheat, or corn protein that behave similarly in hair products. The claim is a marketing description of the effect, not of the molecule, and reading the ingredient list will show which plant protein was actually used.
Is keratin in shampoo the same question as keratin in a supplement?
The ingredient is the same, but standards differ. Many certifiers treat topical cosmetics differently from things you swallow, and some scholars distinguish between the two. The ingredient logic is identical either way, so identifying that keratin is present and asking about its source is the useful step regardless of which standard you follow.
How is keratin related to L-cysteine and amino acid supplements?
Keratin is rich in cysteine, so it has long been used as a raw material for producing that amino acid. L-cysteine, labelled E920 and used as a dough conditioner in bread, is frequently made by hydrolyzing keratin. The same route has been used for other amino acids, which is why the question follows BCAA and EAA supplements too.
What should I look for on a label?
The words keratin, hydrolyzed keratin, keratin amino acids, and keratin protein. On a hair supplement, check whether collagen and biotin are also present, since they usually travel together. Look for a stated source, a halal certificate, or a vegan claim, which would rule out real keratin entirely.