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What is the role of biotin in the body? A complete guide to the "hair and skin" vitamin

Biotin, or vitamin B7, is a water-soluble vitamin and one of the eight B vitamins that make up the B-complex. These are a group of key nutrients needed for your metabolism, nervous system, digestive function, blood sugar regulation, hair and nail health, and cardiovascular health. 

Biotin is found in certain foods, like organ meats, eggs, avocado, cauliflower, berries, fish, legumes and mushrooms. Researchers believe our intestinal digestive bacteria also have the ability to create some biotin on their own.

The role of biotin in the body and its benefits

Biotin plays an important role in acting as a coenzyme in your body. These enzymes are needed to break down fats, proteins and carbohydrates from the foods you eat. These are then turned into fatty acids, amino acids and glucose that your body can use to convert into energy. 

Biotin supports healthy hair, skin and nails 

Biotin deficiency has been linked to symptoms like thinning, splitting and brittle hair and nails, and dermatitis that results in dry, irritated skin, therefore indicating that another important role of biotin is keeping the hair, skin and nails healthy. 

Research shows that deficiency in other nutrients, such as zinc, and selenium, may also contribute to thinning hair, as well as health conditions like hormonal imbalances or endocrine disorders.

It is known that biotin helps build proteins needed to maintain healthy hair, skin and nails, including keratin. Several promising studies have found evidence that taking supplements that include biotin can promote hair growth and reduce hair loss/shedding.

A number of other studies have found that in cases of biotin deficiency, participants that had brittle nail syndrome or uncombable hair, biotin supplementation may be of benefit.

Biotin supports a healthy metabolism

Biotin is involved in gene expression which is vital for supporting a healthy metabolism. Vitamin B7, along with other B vitamins, is also needed to support a number of enzymes that convert the food you eat into energy. 

It does this in several ways:

  • Biotin converts glucose from carbohydrates and sugar into usable “fuel”, which is your body’s preferred source of energy

  • It helps your body use amino acids from proteins to carry out a number of functions

  • It activates fatty acids from fat-containing foods like oils or animal fats

Without enough vitamin B7, symptoms of a sluggish metabolism like low energy levels, fatigue, digestive problems, changes in appetite, and poor mood can occur.

Biotin’s role in helping to balance blood sugar levels

Vitamin B7, especially when combined with chromium, has been shown to help lower blood sugar and reduce insulin resistance.

Biotin supports blood glucose levels by facilitating the activity of insulin, which is the vital hormone needed to bring blood sugar back to a balanced level. Having a better insulin response helps to reduce the risk of fluctuating blood sugar levels.

Biotin's role in supporting heart health

Another role of biotin in the body is supporting heart health. According to some studies, biotin and chromium combined can help improve cholesterol levels.

Biotin has also been shown to have positive results with increasing “good” HDL cholesterol, while also helping lower “bad” LDL cholesterol and triglyceride levels. 

Biotin's role in supporting pregnancy and breastfeeding

Biotin is very important for women who are pregnant or lactating, and deficiency is common during these times. This is because the metabolic requirements during pregnancy are higher, and the body breaks down this vitamin faster during these stages.

As a result, a pregnant and breastfeeding woman’s biotin requirements are increased compared to women who are not. 

Biotin deficiency & depletion

According to some research, some underlying causes of biotin deficiency include:

  • Pregnancy: Pregnant women appear to break down biotin more quickly, and this may lead to a deficiency

  • Long-term use of certain anti-seizure medications

  • Excessive alcohol use

  • Consuming lots of raw egg whites

  • Smoking 

  • Prolonged antibiotic use

  • Intestinal malabsorption issues or serious digestive disorders like Crohn’s disease, Coeliac disease or leaky gut syndrome

Sources of Biotin

Biotin can be obtained through diet, supplements, and it’s thought that our intestinal digestive bacteria have the ability to create some biotin on their own. 

Biotin-rich foods

Biotin is found in a wide variety of foods, which is why a deficiency is fairly rare. These include:

  • Egg yolk

  • Organ meats (liver, kidney)

  • Nuts, like almonds, peanuts, pecans, and walnuts

  • Nut butters

  • Soybeans and other legumes

  • Whole grains and cereals

  • Cauliflower

  • Bananas

  • Mushrooms

Cooking and processing foods containing biotin can affect biotin levels, therefore it's best to consume these products raw, or less-processed versions as they contain more active biotin.

Biotin supplements

Biotin can be found as part of B-complex supplements or as part of other supplement blends such as a hair, skin and nails blend

Taking 0.9mg or less a day of biotin in supplements is unlikely to cause any harm.

Side effects of taking biotin supplements are rare because it is a water-soluble vitamin, which means any excess amounts in the body are eliminated through urine. 


Biotin is one of the eight B vitamins that plays a crucial role in many areas of health, especially the metabolism of carbohydrates, fats, and proteins and maintaining healthy hair, skin and nails.

Always focus on eating a healthy, well-balanced diet filled with biotin-rich foods and biotin supplements if your levels are low.


  1. Biotin

  2. Pharmacological effects of Biotin

  3. Biotin - Oregon State University

  4. Vitamins and Type 2 Diabetes Mellitus

  5. Biotin supplementation reduces plasma triacylglycerol and VLDL in type 2 diabetic patients and in nondiabetic subjects with hypertriglyceridemia

  6. Pregnancy and Lactation Alter Biomarkers of Biotin Metabolism in Women Consuming a Controlled Diet

  7. A 3-Month, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Ability of an Extra-Strength Marine Protein Supplement to Promote Hair Growth and Decrease Shedding in Women with Self-Perceived Thinning Hair

  8. A Double-blind, Placebo-controlled Study Evaluating the Efficacy of an Oral Supplement in Women with Self-perceived Thinning Hair

  9. A Review of The Use of Biotin for Hair Loss

  10. Treatment of Brittle Fingernails with Biotin

  11. Biotin: The Forgotten Vitamin

  12. Biotin Responsive Limb Weakness

  13. Smoking accelerates biotin catabolism in women

  14. Biotin and biotinidase deficiency




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