Biotin for Hair, Skin and Nails: What the Evidence Says

Biotin has become the go-to supplement for anyone hoping for thicker hair, stronger nails or clearer skin, and searches for it tend to rise in autumn and winter, when many people notice more hairs in the brush. But what can biotin realistically do, who is likely to benefit, and what should you know before you start? This guide separates the marketing from the evidence.

What biotin is

Biotin (vitamin B7, sometimes called vitamin H) is a water-soluble B vitamin. It acts as a helper for enzymes involved in turning the fats, carbohydrates and proteins you eat into usable energy. Your body cannot store much of it, so you need a regular supply from food.

In the UK, several health claims are authorised for biotin. The ones most relevant here are that biotin contributes to the maintenance of normal hair and biotin contributes to the maintenance of normal skin. It also contributes to normal energy-yielding metabolism and to the normal functioning of the nervous system.

Note the wording: "maintenance of normal". That is an accurate reflection of the science. An adequate biotin intake is part of maintaining normal hair and skin, but that is not the same as saying extra biotin will make normal hair grow faster or thicker.

Where to get biotin from food

Biotin is found in a wide range of everyday foods. Good sources include:

• eggs (the yolk in particular, and cooked rather than raw);
• liver and other offal;
• salmon and other oily fish;
• nuts and seeds, especially almonds, peanuts and sunflower seeds;
• sweet potatoes, mushrooms and avocado;
• wholegrains and oats.

Because it is so widely available, true biotin deficiency is uncommon in people who eat a varied diet. It is more likely in specific situations, such as some rare genetic conditions, long-term use of certain medicines, very restrictive diets or regularly eating large amounts of raw egg white, which contains a protein that binds biotin.

What the evidence says about biotin and hair

Reviews of the published research reach a fairly consistent conclusion: in people who are low in biotin, correcting that shortfall matters. In people with normal biotin levels, there is little good-quality evidence that adding more leads to noticeably faster growth or thicker hair.

That does not make a biotin supplement pointless. It can be a practical way to make sure your intake is covered, especially if your diet is limited, and many formulas pair biotin with other nutrients that have their own authorised claims. It does mean that expectations should be realistic.

Why hair shedding often rises in autumn and winter

If you are noticing more hair in the shower right now, you are not alone. Studies tracking healthy volunteers have found that hair shedding often follows a seasonal pattern, with more hairs in the resting phase in summer and increased shedding following in late summer and autumn. For most people this is temporary and settles on its own.

Other common, non-seasonal triggers include a recent illness or high fever, a period of significant stress, rapid weight loss, giving birth, and changes to hormonal contraception or HRT. Shedding from these causes often appears two to three months after the trigger.

See your GP if hair loss is sudden, comes out in patches, is accompanied by an itchy or sore scalp, or if you are worried. Some causes, such as low iron or thyroid problems, need proper testing.

Other nutrients that matter for hair, skin and nails

Biotin is only one piece of the puzzle. Several other vitamins and minerals have authorised claims in this area:

• Zinc contributes to the maintenance of normal hair, nails and skin.
• Selenium contributes to the maintenance of normal hair and nails.
• Copper contributes to normal hair pigmentation.
• Vitamin C contributes to normal collagen formation for the normal function of skin.
• Protein is the building material of hair itself, so an adequate total intake matters.

This is why a combined formula often makes more sense than biotin alone. Vitastrong Biotin Gummies combine biotin with zinc, selenium, and vitamins C, E, D and B6, in a vegan, berry-flavoured gummy with no added sugar.

If you prefer a tablet, Biotin Complex pairs biotin, zinc, selenium and copper with hydrolysed keratin and bamboo extract.

Important: biotin and blood tests

This is the one safety point every biotin user should know. High intakes of biotin can interfere with some laboratory blood tests that use a biotin-based method, including certain thyroid function tests and tests used to check heart health. The result can be falsely high or falsely low.

• Always tell your GP, nurse or the lab that you take biotin before any blood test.
• Follow any advice to pause it beforehand; often a couple of days is suggested, but ask.

Also check the label to see whether other products you take (multivitamins, "hair, skin and nails" formulas) contain biotin too, so you are not doubling up without realising.

How to get the most from a biotin supplement

• Be patient: hair grows roughly 1 cm a month, so any change in condition will take at least three months to judge.
• Cover the basics first: sufficient protein, iron-rich foods and a varied diet matter more than any single supplement.
• Stick to the label dose: more is not better.
• Be gentle with your hair: heat styling, tight hairstyles and harsh treatments cause breakage that no supplement can fix.

For a wider look at beauty-focused supplements, see our evidence review on whether collagen supplements work.

Products mentioned in this article

FAQs

Does biotin make hair grow faster?

Biotin contributes to the maintenance of normal hair. There is little good evidence that extra biotin speeds up growth in people whose levels are already adequate.

How long does biotin take to work?

Because hair grows slowly, allow at least three months of consistent use before judging any change in condition.

Can I take biotin with a multivitamin?

Usually yes, but check both labels so you know your total biotin intake, and tell your doctor before blood tests.

Is biotin suitable for vegans?

Biotin itself is not animal-derived. Check the full formula: our Biotin Gummies are pectin-based and vegan-friendly.

Why am I losing more hair in autumn?

Seasonal shedding is common and usually temporary. If hair loss is sudden, patchy or worrying, speak to your GP.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.