Biotin (vitamin H or B7) is a water-soluble vitamin that helps the body metabolize fats, carbohydrates, and protein. It also helps maintain a healthy nervous system, nails, hair and skin, among other functions.
Water-soluble vitamins are not stored in the body, so a daily intake is necessary.
This article looks at why people need biotin, the recommended intake, sources, and any possible health risks.
Fast facts on biotin
- Biotin, or vitamin B7, is needed to metabolize fats, carbohydrates, and protein.
- Deficiency can lead to hair loss and skin problems, but it is rare.
- Dietary sources include red meat, eggs, seeds, and nuts.
- Supplements are unlikely to cause harm, but they are not proven to help with hair, skin, and nail health.
The body needs biotin to metabolize fats, carbohydrates, and protein.
It is a coenzyme. This means it functions as a supporting compound for carboxylase enzymes.
These enzymes are involved in:
- synthesizing, or creating, fatty acids
- synthesizing the amino acids isoleucine and valine
- gluconeogenesis, or generating glucose
Biotin is important for a number of functions.
Maintaining a healthy pregnancy
Folic acid supplementation is recommended both the year before and during pregnancy. It is a good idea to obtain a multivitamin that provides at least
Nails, hair, and skin
Biotin supplements are available alone, combined in a supplement with other B vitamins, or included in a multivitamin.
Many manufacturers of cosmetics claim that biotin supplements may improve the strength and durability of fingernails and enhance hair and skin health. However, there is
A study published in 2015 found that women with thinning hair experienced some reduction in shedding after taking an oral marine protein supplement for 90 days. However, biotin was only one ingredient in this supplement, and the research was sponsored by a company that sells health and beauty products.
Further research is needed to support the use of biotin supplements for this purpose in healthy individuals.
Lowering blood glucose
Research from 2016 indicated that biotin may assist with glycemic control in people with type 1 diabetes.
Medical professionals need more studies before they can confirm biotin’s effects on blood sugar.
Biotin is necessary for the activity of pyruvate carboxylase. Without this, high levels of pyruvate and aspartate may arise, and this can adversely affect the nerves.
For this reason, biotin may be able to help reduce nerve damage in people who have diabetes or who are undergoing dialysis for kidney disease. However, more evidence is needed to confirm this.
In 1990, scientists found that three people who took a high dose of biotin for
Biotin-responsive basal ganglia disease
This is a rare, inherited disorder. It affects a part of the nervous system that controls movement. It can lead to involuntary tensing of muscles, muscle rigidity, muscle weakness, and other problems.
Treating multiple sclerosis
Studies have suggested that high dose biotin therapy might help improve symptoms in people with multiple sclerosis (MS). This is an autoimmune disease that affects the nervous system, leading to muscle weakness and a range of other problems.
However, biotin does have adequate intake (AI) levels, which are amounts that ensure nutritional adequacy. The AI levels for biotin are:
|birth to 6 months
|infants 7–12 months
|children 1–3 years
|children 4–8 years
|children 9–13 years
|teens 14–18 years
|adults 19+ years
According to the National Institutes of Health, the average person in a western population consumes
The Institute of Medicine suggests an AI of
Biotin deficiency is rare in humans because biotin is widely available in foods, and the “good” gut bacteria can usually synthesize more biotin than the body needs.
Signs of deficiency
- hair loss, or alopecia
- a scaly, red rash around the eyes, nose, mouth, and genitals
- numbness and tingling in the hands and feet
- a loss of control of bodily movements, known as ataxia
- weakened immune function
- increased risk of bacterial and fungal infections
Biotin deficiency is most likely to arise in:
- people during pregnancy
- people receiving prolonged intravenous nutrition
- infants who consume breastmilk with low amounts of biotin
- people with weak biotin absorption due to an inflammatory bowel disease or other gastrointestinal tract disorder
- people who smoke
It may also affect:
- those who use medications for epilepsy, such as phenobarbital, phenytoin, or carbamazepine
- those with liver disease
Biotinidase deficiency is another cause of biotin deficiency. This is an autosomal recessive metabolic disorder.
In people with this condition, the body does not produce enough of the enzyme needed to release biotin from proteins in the diet during digestion or from typical protein turnover in the cells.
Food should be the first choice when looking for sources of biotin. Biotin in foods usually binds to protein.
Foods that are rich in biotin include:
- baker’s yeast
- wheat bran
- organ meats
- cooked, whole eggs
Raw eggs contain a glycoprotein called avidin that inhibits the absorption of biotin. Eating two or more raw egg whites a day for several months
Here are some specific foods and amounts of biotin:
- 3 ounces (oz) of cooked liver: 30.8 mcg
- 1 large, whole cooked egg: 10 mcg
- 3 oz of canned pink salmon in water: 5 mcg
- 1 oz of cheddar cheese: 0.4 to 2 mcg
- 1 cup of sweet potato: 4.8 mcg
- 3 oz of cooked hamburger patty: 3.8 mcg
- 1 cup roasted sunflower seeds: 9.6 mcg
- 1 cup of roasted almonds: 6 mcg
Many foods, such as fruits and vegetables, contain a small amount of biotin.
There is no evidence that most people need to take biotin supplements, and there have been no reports of a severe biotin deficiency in any healthy person consuming a balanced diet.
A well-balanced diet is likely to supply most people’s needs unless a doctor advises them otherwise.
Anyone who is considering taking biotin supplements should first check with a doctor.
Can biotin be harmful?
Some biotin supplements contain 2,500 mcg or more, which is significantly higher than the suggested dose for most adults. However, while a person
One potential risk of taking biotin supplements is that it may interfere with getting accurate results from blood tests.
In 2019, the Food and Drug Administration (FDA)
How much biotin does a person with a biotin deficiency need?
Those with biotinidase deficiency usually start with a dose of
However, those who do not have biotinidase deficiency should first try to get enough biotin from their diet, as dietary biotin also enhances the intake of other beneficial nutrients that work alongside it.
A person should always speak to a doctor before taking supplements and choose brands carefully, as supplements are not monitored by the FDA.
Is biotin safe for the kidneys?
There is no evidence that biotin can harm the kidneys themselves. However, there is minimal