What Type of Supplement is Biotin?

November 30, 2025 •

4 min read

According to the National Institutes of Health, the average person in Western populations gets sufficient biotin from their diet, making deficiency rare. Biotin, also known as vitamin B7, is a dietary supplement and a water-soluble B-complex vitamin essential for metabolizing fats, carbohydrates, and protein.

Quick Summary

Biotin, or vitamin B7, is a water-soluble nutrient functioning as a coenzyme in metabolic processes, essential for converting food into energy. Supplements containing biotin are commonly used to support hair, skin, and nail health, though evidence for healthy individuals is limited.

Key Points

Water-Soluble Vitamin: Biotin is a water-soluble B-complex vitamin (B7), so the body excretes excess rather than storing it.
Metabolic Coenzyme: Its primary function is to serve as a coenzyme for metabolic reactions that process fats, carbohydrates, and proteins.
Potential for Lab Interference: High doses of biotin supplements can cause false results in important laboratory blood tests, including those for thyroid and cardiac function.
Benefits for Deficiency: While often promoted for healthy hair and nails, significant benefits are most evident in people with a diagnosed biotin deficiency.
Food Sources are Key: Most healthy individuals obtain adequate biotin through a balanced diet of foods like eggs, nuts, and meats.
Safety Profile: Excess biotin is not known to be toxic, but the interference with diagnostic testing is a serious health risk.

Biotin: A Water-Soluble B-Complex Vitamin

Biotin, or vitamin B7, is an essential water-soluble B-complex vitamin. This means the body cannot store it for long periods, and any excess is typically excreted in the urine. Therefore, a daily intake is necessary to ensure the body has an adequate supply. As a supplement, biotin is available in several forms, including stand-alone products, B-complex formulas, and multivitamins. The term 'vitamin H' was also used historically for biotin, stemming from the German words for hair and skin, reflecting its long-standing association with beauty supplements.

The Role of Biotin as a Coenzyme

Biotin's primary function in the body is to act as a coenzyme, meaning it helps enzymes perform their jobs effectively. Specifically, it assists carboxylase enzymes, which play a crucial role in the metabolism of several key nutrients. These metabolic processes are vital for energy production and include:

Fatty Acid Synthesis: Biotin is involved in creating new fatty acids from other substances.
Amino Acid Metabolism: It aids in breaking down certain amino acids, such as isoleucine and valine.
Gluconeogenesis: This is the process of generating glucose from non-carbohydrate sources, which is particularly important for maintaining stable blood sugar levels.

This role in metabolism is why biotin is critical for overall health and cellular function. Without sufficient biotin, these metabolic pathways can be disrupted.

Common Uses of Biotin Supplements

While biotin is an essential nutrient, many people take supplements for specific cosmetic or health-related benefits. The most common use is to support the health of hair, skin, and nails. Many manufacturers and cosmetic brands market biotin for these purposes, claiming it can help with hair growth, strengthen brittle nails, and improve skin texture. This is because biotin is involved in the production of keratin, a key protein that forms the structure of hair and nails.

However, it is important to note that the scientific evidence supporting the use of biotin supplements for healthy individuals is limited. For those with a true biotin deficiency—a condition that is extremely rare—supplementation can effectively reverse symptoms like hair loss and skin rashes. For the general population, the benefits for hair and nails are not well-established by rigorous scientific studies.

Potential Risks and Interactions

Biotin supplements are generally considered safe, even in high doses, because of their water-soluble nature. The body simply excretes any excess. However, there is a notable health risk associated with high biotin intake that consumers need to be aware of: interference with laboratory test results.

Biotin vs. Dietary Biotin


Feature	Biotin as a Supplement	Dietary Biotin (from Food)
Source	Concentrated doses in pills, capsules, or gummies.	Naturally found in various foods.
Dosage	Often contains high doses, sometimes thousands of micrograms.	Amounts align with the daily recommended Adequate Intake (AI).
Storage	Not stored by the body; excess is excreted daily.	Also not stored; requires daily intake from food sources.
Benefit for Healthy Individuals	Evidence is limited and inconclusive for hair, skin, and nails.	Provides sufficient biotin for normal metabolic function.
Risk of Lab Interference	High doses can cause inaccurate blood test results.	Unlikely to cause interference due to lower dosage.

Drug and Test Interference

High doses of biotin can cause clinically significant falsely high or falsely low results in various diagnostic blood tests that use biotin-streptavidin technology. These tests are used to measure levels of crucial substances, including thyroid hormones, reproductive hormones, and markers for heart attacks like troponin. This can lead to a misdiagnosis or inappropriate treatment. Healthcare providers and laboratories have issued warnings about this issue, advising patients to stop taking biotin supplements for a specified period before certain tests. It's crucial to inform your doctor about any supplements you are taking, including biotin.

Conclusion

Biotin is an essential, water-soluble B-complex vitamin (B7) that plays a critical metabolic role in breaking down fats, carbohydrates, and proteins into energy. As a supplement, it is widely marketed for improving hair, skin, and nail health, though robust evidence for this benefit in healthy individuals is lacking. While generally safe, high-dose biotin supplements can interfere with laboratory blood tests, potentially leading to inaccurate results and misdiagnosis. For most people, a balanced diet provides sufficient biotin, and supplementation is not necessary unless a deficiency is present. Always consult a healthcare provider before starting a new supplement, especially if you have an upcoming lab test.

Key Takeaways

Vitamin B7: Biotin is a water-soluble B-complex vitamin, meaning the body does not store it.
Metabolic Function: It acts as a coenzyme for carboxylase enzymes that are critical for metabolizing fats, carbohydrates, and amino acids.
Cosmetic Claims: While popular for hair, skin, and nails, scientific evidence for these benefits in healthy people is limited.
Deficiency is Rare: Most people get enough biotin from a balanced diet, and deficiency is uncommon.
Lab Test Interference: High doses can interfere with common blood tests, causing inaccurate results.
Safety Profile: Biotin is generally safe, as excess amounts are excreted, though high doses carry a risk of test interference.

Frequently Asked Questions

Biotin is a water-soluble vitamin, which means the body doesn't store excess amounts. Instead, any unused biotin is excreted through the urine, requiring regular intake through diet or supplementation.

Biotin is also widely known as vitamin B7. Historically, it was sometimes referred to as vitamin H, based on the German words for 'Haar und Haut' (hair and skin).

Yes, high-dose biotin supplements can significantly interfere with the results of certain laboratory blood tests, potentially leading to a misdiagnosis. It is crucial to inform your doctor if you are taking biotin before any lab work.

While biotin is often marketed for hair growth, there is limited scientific evidence to support this claim in healthy individuals. The most significant benefits are seen in people who have a confirmed biotin deficiency.

Biotin can be found in various foods, including eggs, meat (especially liver), nuts, seeds, and certain vegetables like sweet potatoes and spinach.

Because it is water-soluble, excess biotin is typically passed through the urine and is not considered toxic, even at high doses. The main risk is interference with blood test results rather than direct harm to the body.

Biotin deficiency is rare but can occur in certain groups, such as pregnant or breastfeeding women, individuals with chronic alcohol use, or those with specific genetic disorders like biotinidase deficiency.