Biotin

Vitamin0.01–0.1%

A B vitamin with strong shopper appeal for hair, but little evidence it helps when applied topically.

What it is

Biotin is a B vitamin widely known from hair and nail supplements. There is no good evidence that biotin in a shampoo or serum changes how hair looks or feels. It is used mostly because shoppers recognise the name.

Good for

Fine hairFlat hairThickening shampoos

How it works

Inside the body, biotin helps enzymes that make fats and proteins, including keratin. A 2017 review found that biotin taken by mouth improved hair or nails only in people with low biotin levels or specific hair and nail conditions.

Ratings

Evidence

1/5

Weak, with no good evidence for topical hair benefits.

Gentleness

5/5

Very low irritation at cosmetic levels, reaffirmed safe in 2023.

Formulation difficulty

2/5

Poor water solubility, so pre-dissolve it or keep levels low.

Cost

2/5

Inexpensive at the low levels used.

Popularity

4/5

High shopper recognition, common on 'thickening' shampoo labels.

Pairs and cautions

Pairs well with

In a routine. Pairing in one formula depends on matching pH windows.

Take care with

None noted.

Formulations it suits

Shampoo Conditioner and hair mask

Packaging

Regional considerations

Australia	Unscheduled cosmetic ingredient. Claims to promote hair growth or reduce hair loss make the product a therapeutic good; cosmetic claims are limited to hair condition and appearance.
United States	Biotin is named in FDA's hair-grower rule, under which OTC products claiming to grow hair or prevent hair loss are unapproved new drugs, so US claims must stay cosmetic.
China	Anti-hair-loss claims make a biotin product a special cosmetic that needs NMPA registration before import, and hair-growth claims are not permitted on cosmetics.
Korea	Biotin is one of four MFDS-listed actives for functional cosmetics that help relieve hair-loss symptoms, so it can carry that claim in Korea after MFDS functional-cosmetic approval at the listed dose.

In the lab

Specifications

Typical use level

0.01–0.1%0525%

pH window

pH 4–82 acid7 neutral10 alkaline

Solubility

Water-soluble

Shampoos, conditioners and scalp serums use 0.01–0.1%, the maximum reported for hair products. The 0.6% on record was in a face product in 1999.

INCI	Biotin
Also known as	Vitamin B7, Vitamin H
Origin	synthetic

Lab notes

Solubility and phase

Water phase, but only about 0.02% dissolves at 25 °C, so pre-dissolve it in dilute alkali or glycols. Over-dosing leads to crystals.

Stability

Add at any stage, as it is heat- and light-stable at cosmetic levels.

Regulatory, Australia

Cosmetic ingredient in Australia (AICIS) and not listed in the Poisons Standard. CIR first assessed it in 2001 and reaffirmed it as safe in 2023.

Claims to take care with

Hair-growth, 'reduces hair loss' or 'treats thinning' claims are therapeutic and need ARTG entry (TGA). Cosmetic claims such as 'fuller-looking hair' must reflect the whole formula, as implying biotin alone does it could mislead (ACCC).