Biotin is a B vitamin found in food. It helps the body convert food into energy and plays many other important roles in health.
Biotin boosts the health of the hair and nails, supports a healthy pregnancy, and helps manage blood sugar levels, among other benefits.
This article describes seven roles that biotin plays in the body. It also explores food sources of the vitamin and safety considerations.
Biotin is one of eight B vitamins. It is also known as vitamin B-7 or vitamin H, in which case the H stands for “Haar und Haut,” the German words for “hair and skin.”
Biotin is water-soluble. The body does not store water-soluble vitamins, so people need to absorb them from their diets.
Biotin is necessary for the function of several enzymes known as carboxylases. These are part of important metabolic processes, such as the production of glucose and fatty acids.
The Office of Dietary Supplements recommend the following biotin intake per day:
- 30 micrograms (mcg) for adults, including during pregnancy
- 35 mcg when lactating
Biotin deficiency is fairly rare. However, some people — such as pregnant women and people who drink high amounts of alcohol — may develop mild deficiencies.
Also, eating raw eggs on a regular basis can cause biotin deficiency, because raw egg whites contain a protein called avidin that binds to biotin, preventing the body from absorbing it. Cooking the eggs deactivates their avidin.
Biotin plays a number of important roles in the body, including:
Breaking down macronutrients
Biotin helps the body convert food into energy — it supports a number of enzymes involved in the breakdown of carbs, fats, and proteins.
Specifically, biotin is involved in:
- Gluconeogenesis: This is the synthesis of glucose from sources other than carbs, such as amino acids, and biotin-containing enzymes help initiate this process.
- Fatty acid synthesis: Biotin assists enzymes that activate reactions that are important for the production of fatty acids.
- Amino acid breakdown: Biotin-containing enzymes are involved in the metabolism of several important amino acids, including leucine.
Supporting nail health
Brittle nails are fragile and easily become split or cracked. A biotin deficiency can lead to brittle nails.
For people with this deficiency, taking supplements that contain biotin could improve the strength of their nails.
Changing the diet and other lifestyle factors can help improve nail health, as can some commercial products.
Boosting hair health
The diet can play an important role in the health of the skin and hair. For instance, some foods for healthy hair include eggs, Brazil nuts, and fatty fish.
Many hair products that claim to encourage healthier, stronger hair contain biotin. Biotin deficiency can lead to hair loss, which indicates that the vitamin is involved in keeping the hair healthy.
However, little research has linked the vitamin with hair health in people who do not have biotin deficiencies.
Supporting pregnancy and breastfeeding
Biotin is very important for women who are pregnant or lactating.
While symptomatic biotin deficiency is rare, low biotin levels are common during pregnancy.
In fact, about 50% of pregnant women in the United States may have at least a mild deficiency. This level of deficiency may affect a person’s health, but not enough to cause noticeable symptoms.
Healthcare professionals believe that this deficiency is common among pregnant women because the body breaks down the vitamin faster during pregnancy.
As a result, a pregnant woman may need more biotin — from the diet or from supplements — than a woman who is not pregnant.
That said, it is important to consult a healthcare professional before taking supplements during pregnancy or breastfeeding.
Reducing blood sugar in people with diabetes
A biotin deficiency may disrupt blood sugar, or glucose, regulation. Some evidence shows blood biotin levels may be lower in people with diabetes.
Studies in animals have suggested that supplements containing biotin and chromium picolinate could prevent insulin resistance.
Researchers have also studied how biotin supplements affect blood sugar levels in people with type 2 diabetes. The results have been mixed, but some studies have shown that taking both biotin and chromium picolinate could help treat type 2 diabetes.
Overall, fully understanding the effects of biotin on diabetes and blood sugar control will require more high quality research.
Boosting skin health
Scientists do not fully understand biotin’s role in maintaining healthy skin. However, people with biotin deficiencies may experience skin problems, including red, scaly rashes.
Some people also believe that biotin may help improve psoriasis.
The vitamin’s influence on the skin may stem from its effect on fat metabolism. This process is important for maintaining healthy skin, and it may be impaired in people with low levels of biotin.
It is important to note that no evidence shows that biotin improves skin health in people who do not have a deficiency of the vitamin.
Supporting MS treatment
Multiple sclerosis (MS) is an autoimmune disease. It damages the protective covering of nerve fibers in the brain, spinal cord, and eyes.
This protective covering is called myelin, and biotin may play an important role in producing it.
Studies have shown that people with MS respond positively to daily biotin doses of up to 300 milligrams (mg). This supplementation may reverse the progression of the disease and reduce chronic disability.
Biotin exists in a wide variety of foods, which helps explain why a deficiency in the vitamin is fairly rare.
Foods that are particularly high in biotin include:
- organ meats, such as liver and kidney
- egg yolks
- legumes, such as soybeans and peanuts
- leafy greens
- nuts and nut butters
In addition, gut bacteria produce some biotin.
Some people take supplements that either contain biotin on its own or in a combination of vitamins.
Healthcare professionals consider biotin to be very safe. Even very high doses of up to 300 mg daily, to treat MS, have not led to adverse side effects. The recommended daily dosage for adults is much lower: 30 mcg.
Biotin is a water-soluble vitamin, and any amount that the body does not absorb is excreted in urine.
However, there have been some reports of high doses of biotin causing strange results on thyroid tests. Anyone who has a thyroid condition may benefit from checking with a doctor before trying a biotin supplement.
Biotin is a B vitamin that plays a crucial role in the metabolism of carbs, fats, and proteins. It supports health in many ways.
Biotin deficiencies are relatively rare, but they can cause skin, hair, and nail problems. Pregnant or breastfeeding women may require more of this vitamin.
Anyone who has a deficiency can increase their biotin intake by consuming foods rich in the vitamin or taking biotin supplements.