Biotin
Biotin
INCIBiotin (Vitamin B7, also Vitamin H)
The vitamin in nearly every hair shampoo, serum and conditioner on the shelf. Real cosmetic ingredient. Real conditioning feel. The growth claims rely on a story the topical evidence does not actually tell.
What you need to know
What it is
A small water soluble B vitamin (molecular weight 244 Da). In cosmetic formulas it shows up in shampoos, conditioners, scalp serums, leave on tonics, and brow and lash conditioners. Listed on labels as Biotin or Vitamin B7.
What it does on the scalp
Acts as a humectant and conditioning agent. The hair shaft feels smoother and reflects more light. Whether topical biotin reaches living follicle cells in concentrations high enough to change keratin synthesis has never been demonstrated in a controlled study.
Best for
Inclusion in a complete topical routine where the heavy lifting is done by ingredients with stronger evidence. Reassurance ingredient. Not a standalone hair grower applied to the scalp.
Time to results
Cosmetic conditioning (slip, smoother feel, light reflection): immediate to a few washes. Hair density or growth changes from topical biotin: no controlled human trial has measured this, so any timeline given is marketing, not data.
How it actually works
The underlying biotin biology is real. The leap from biotin biology to topical hair growth is where the marketing story drifts away from the evidence.
Cofactor for keratin
Inside cells, biotin is a coenzyme for five carboxylase enzymes involved in fatty acid, glucose and amino acid metabolism. Some of those amino acid pathways feed keratin synthesis. The body needs about 30 micrograms a day total. Most diets provide many times over.
Skin penetration
Biotin is small enough to penetrate the stratum corneum to a limited degree. Penetration is not the same as functional delivery. No published study has shown topical biotin reaches the dermal papilla in active form at concentrations that change follicle behaviour.
The ceiling effect
Even if topical biotin reached the follicle, the carboxylase enzymes are not the rate limiting step in healthy hair growth. Adding more biotin to a system that is not biotin limited is like adding more spark plugs to a car when the engine is already running. The receptor is full.
The hair shaft is dead
Hair above the scalp is dead protein. You cannot feed it from outside with a vitamin. Topical biotin can sit on the cuticle, smooth the feel, and improve combability. It cannot reverse damage or grow new hair from the strand itself.
What the topical evidence shows
The most rigorous published synthesis is Patel DP, Swink SM, Castelo Soccio L in Skin Appendage Disorders (2017). They reviewed every published case of biotin use for hair growth from 1948 to 2016, oral and topical combined. The findings on topical specifically are unambiguous.
Randomised controlled trials of topical biotin alone for human hair growth
Real and documented in cosmetic literature. Smooth, soft, less static. Cosmetic effect, not biological.
Partial stratum corneum penetration shown. Functional delivery to follicle in active form not measured.
Used as a cosmetic, biotin works. Used as a treatment, it has not been shown to.
Topical biotin vs the alternatives
AnaGain has a peer reviewed topical mechanism study (FGF7 up 56%, noggin up 85%) and a clinical hair shedding endpoint. Topical biotin has none of that. They are not in the same evidence category, and they do not need to be confused with each other.
Redensyl has a controlled 84 day clinical study measuring hair density in healthy adults. Biotin has no equivalent topical trial. Categorically different evidence base.
Rosemary has a six month head to head RCT against minoxidil. Topical biotin has none. As a topical scalp active, rosemary wins on evidence by a wide margin.
Topical caffeine has follicle level evidence (some hair shaft elongation in ex vivo work, some anti DHT activity at the follicle). Biotin has neither. Caffeine is the better choice if you want a small molecule supporting active for a scalp routine.
A biotin shampoo will not damage your hair and will probably make it feel a little smoother because of the formula it is in. It is unlikely to grow new hair beyond what good cleansing and conditioning already do. The marketing is what overpromises, not the molecule itself.
Side effects and how to use
Products with biotin
Biotin appears in our Rosemary & Mint Revival Hair Oil as a supporting cosmetic ingredient. The Hair Thrivee+ system carries the actives with stronger evidence.
Pair with
Hair Thrivee+ Serum
Stronger evidenceCarries AnaGain, Redensyl and Baicapil at clinical concentrations. The actives that have published topical data, not borrowed claims from the supplement world.
Shop the serum → EFRESHMEHair Thrivee+ Shampoo
Sulfate free daily washDaily wash carrying the same hair growth complex. Cleanses without stripping.
Shop the shampoo → EFRESHMEHair Thrivee+ Conditioner
Moisturising follow upDetangles and softens with the same hair growth complex carried through.
Shop the conditioner →Common questions
Does biotin in shampoo make my hair grow?
There is no controlled study showing it does. Topical biotin can penetrate the skin to some extent, but no published trial has measured whether enough reaches the follicle in active form to change hair growth. The conditioning feel of a biotin shampoo is real. The growth claim is borrowed from oral supplement marketing, where the evidence is also weak in non deficient people.
So why is biotin in almost every hair product?
Consumer expectation. The biotin association with hair is decades old and customers look for it on labels. It is also cheap, stable, and easy to include. The cosmetic chemistry case for biotin is fine. The growth claim case is much thinner than the marketing suggests.
Does topical biotin work better than oral biotin?
Neither has strong evidence for hair growth in non deficient people. They are different questions with different evidence. Oral biotin has been studied more (and shows benefit only in documented deficiency). Topical biotin has barely been studied for hair growth at all. The honest answer is that both rely on extrapolations that the data does not fully support.
Will biotin help my brows or lashes when applied directly?
It can sit on the hairs and condition them, making each strand feel and look thicker. That is a cosmetic effect, not new growth. No published controlled trial has shown topical biotin stimulates brow or lash growth. If a brow serum is working, it is usually because of other ingredients in the formula (peptides, prostaglandin analogues, oils) doing the work.
Are biotin scalp serums worth it?
Worth it as a comfortable conditioning step that smells and feels like care. Not worth it as a sole hair growth strategy. If you are paying for a scalp serum that leans the growth claim on biotin, the price is mostly the marketing. If biotin sits alongside genuine actives (rosemary, AnaGain, Redensyl, caffeine, peptides), the formula has more to stand on.
If topical biotin does not really do much, why is it in your hair oil?
Honest answer: it earns its place as a familiar conditioning vitamin in a carrier oil formula. We do not lean any growth claim on biotin. The rosemary, peppermint and jojoba carrier are where the documented topical work happens. We would rather be transparent about that than overclaim.
The evidence
- Patel DP, Swink SM, Castelo Soccio L (2017). A review of the use of biotin for hair loss. Skin Appendage Disorders 3(3):166 to 169.
- PMC (2017). Biotin and hair loss case review (open access).
- Lipner SR (2018). Rethinking biotin therapy for hair, nail and skin disorders. Journal of the American Academy of Dermatology.
- NIH Office of Dietary Supplements. Biotin fact sheet for health professionals (includes daily requirement and dietary sources).
- Soleymani T, et al (2017). The role of vitamins and minerals in hair loss: a review. Includes assessment of cosmetic and topical formulations.