Biotin: benefits for hair, skin and nails

Biotin for hair, skin and nails: what it is

Biotin is a water-soluble B vitamin, known as vitamin B7 and, in older texts, as vitamin H or B8. It is essential for the body and we get it mainly from food.

It has become very popular because of its link with hair, skin and nails, but it is worth separating what is proven from what is simply repeated. In this guide we explain what biotin does, which foods contain it, how much you need and what you can, and cannot, expect from a supplement.

What biotin does in the body

Biotin acts as a coenzyme: it helps the enzymes that turn the carbohydrates, fats and proteins in food into energy and into the building blocks the body needs.

That is why, according to the health claims authorised in the European Union, biotin contributes to normal energy-yielding metabolism, normal macronutrient metabolism, the normal functioning of the nervous system, normal psychological function and the maintenance of normal mucous membranes.

What biotin does for hair and skin

Biotin contributes to the maintenance of normal hair and the maintenance of normal skin. That is the correct, evidence-backed way to describe its role.

What cannot be claimed is that biotin cures, treats or stops hair loss, or that it makes new hair grow. If your diet already provides enough biotin, taking more will not necessarily show in your hair. It makes sense to keep an eye on it when your diet is very restrictive or there is a deficiency, which is uncommon and should be assessed by a professional.

If hair loss is intense or sudden, appears in specific areas or comes with itching, pain or flaking, see a dermatologist or doctor to find out the cause.

What about nails?

Although it is often linked to nails, biotin does not have a specific authorised claim for them in the European Union. The nutrients that do have that claim are zinc and selenium, which contribute to the maintenance of normal nails.

That is why many hair formulas combine biotin with zinc or selenium. If you want to understand what each one does, read our article on biotin, zinc and saw palmetto.

Which foods contain biotin

Biotin is found in both animal and plant foods, so a varied diet usually covers your needs without difficulty. Some of the best sources are:

• Eggs, especially cooked yolk
• Liver and other offal
• Nuts and seeds, such as walnuts, almonds or sunflower seeds
• Legumes, such as peanuts, soya or peas
• Wholegrain cereals and brewer's yeast
• Mushrooms, bananas, avocado and some vegetables such as chard

A useful detail: raw egg white contains avidin, a protein that binds to biotin and prevents it from being absorbed. Cooking the egg inactivates avidin.

How much biotin you need per day

According to the European Food Safety Authority (EFSA), the adequate intake for adults is 40 micrograms (µg) of biotin per day, and 45 µg during breastfeeding. Children need less, and the amount increases with age.

Food and supplement labels use the nutrient reference value (NRV), set at 50 µg per day. That is why hair supplements often show percentages far above 100% of the NRV: it does not mean you need that amount, only that the formula provides more than the reference.

Biotin supplements: when they make sense and precautions

A food supplement can be an option if you want to make sure you get biotin together with other nutrients related to hair, always as part of a varied and balanced diet and a healthy lifestyle.

For example, Xpecia Mujer combines biotin, zinc, iron, folic acid and vitamin B5 with plant extracts, and the Evocapil Plus nutritional complex combines zinc, selenium and biotin with other B vitamins. To learn about the rest of this group, see our guide to B vitamins for hair.

Keep these precautions in mind: do not exceed the product's recommended daily dose, talk to your doctor if you are pregnant, breastfeeding or taking medication, and always mention that you take biotin before a blood test, because high doses can affect the results of some laboratory tests, such as thyroid tests.

Frequently asked questions about biotin

Does biotin help with hair loss?

Biotin contributes to the maintenance of normal hair, but it does not cure or treat hair loss. If your diet already provides enough biotin, taking more usually makes no visible difference. If hair loss is intense, sudden or comes with itching or flaking, the best step is to see a dermatologist or doctor to find the cause.

Which foods are highest in biotin?

Foods rich in biotin include cooked eggs, liver, nuts and seeds such as walnuts, almonds or sunflower seeds, legumes such as peanuts or soya, wholegrain cereals, brewer's yeast and mushrooms. A varied diet usually covers your daily needs without the need for supplements, unless a professional advises otherwise.

How much biotin should I take per day?

EFSA sets an adequate intake of 40 micrograms of biotin per day for adults and 45 micrograms during breastfeeding. Labels use a nutrient reference value of 50 micrograms. If you take a supplement, always follow the daily dose stated by the manufacturer and never exceed it, unless your doctor tells you otherwise.

Does biotin strengthen nails?

In the European Union, biotin does not have a specific authorised claim for nails. Zinc and selenium do, as they contribute to the maintenance of normal nails. That is why many hair formulas combine biotin with one of these minerals to support hair, skin and nails at the same time as part of a balanced diet.

Does biotin have side effects or contraindications?

Biotin is water-soluble and any excess is eliminated in urine, so it is considered well tolerated. Even so, high doses can affect some laboratory tests, such as thyroid tests. Tell your doctor before a blood test and ask for advice if you are pregnant, breastfeeding or taking medication.