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Biotin: Benefits, Sources, and Safety



Biotin (Vitamin B7) is an essential micronutrient vital for energy production, nervous system health, and other bodily functions. It acts as a cofactor for enzymes involved in metabolizing fats, carbohydrates, and amino acids[1]. Found in various foods and available as a supplement, it’s best known for strengthening hair and nails and combating hair loss[2].

While more research is needed, some evidence suggests biotin may improve peripheral neuropathy symptoms and help manage blood sugar in people with diabetes[1]. Biotin is generally safe but may interfere with certain lab tests and medications: inform your healthcare provider if you plan to use it[2].

This article explores biotin’s benefits for health and hair, its safety, and how to choose the right biotin product.


What is Biotin?

Biotin is an essential nutrient your body cannot produce in sufficient amounts, so it must be obtained from diet or supplements, ideally from daily food intake. It supports[2]:

  • Converting food into energy

  • Regulating cellular signaling

  • Managing gene activity

It’s found in many foods, such as liver and eggs, and primarily stored in the liver. Intestinal microflora may also synthesize biotin, though its contribution is unclear[2].


Symptoms of Biotin Deficiency

Biotin deficiency is rare. Symptoms may include[2]:

  • Thinning hair or hair loss

  • Brittle nails

  • Red, scaly rash around eyes, nose, or mouth

  • Neurological issues (e.g., depression, fatigue, hallucinations in adults)

  • Seizures


If you suspect a deficiency, consult a healthcare provider for diagnosis via symptom analysis and lab tests. Increasing dietary biotin or supplements may correct it.

You’re at higher risk of deficiency if you have[3]:

  • Biotinidase deficiency (a rare genetic disorder)

  • Chronic alcohol use disorder

  • Inflammatory bowel disease (e.g., ulcerative colitis, Crohn’s disease)

  • Regular consumption of raw egg whites (contains avidin, which binds biotin)


Certain medications, like anticonvulsants or antibiotics, may also contribute to deficiency[2]. Smoking may lower biotin levels[4].


Benefits of Biotin Supplements

Biotin is often promoted for strengthening hair and nails, though most evidence is anecdotal, with some promising scientific support.

1. Hair Growth

Biotin is marketed for hair loss, but it’s only effective if a deficiency causes the issue[5].

2. Nail Strength

Biotin may improve brittle or damaged nails and conditions like trachyonychia. Small clinical trials suggest it can enhance nail hardness and thickness, but more research is needed[6].

3. Other Conditions

  • Blood Sugar Control: Limited studies suggest biotin may improve blood sugar control in some type 2 diabetes patients by aiding glucose conversion[7].

  • Neuropathy: Some evidence indicates biotin may alleviate peripheral neuropathy symptoms in type 2 diabetes patients, but clinical trials are lacking[8].


Biotin Side Effects

Biotin is generally well-tolerated, even at high doses, with no upper intake level set due to insufficient evidence of adverse effects[1]. However, it can interfere with lab tests, potentially causing inaccurate results for[9]:

  • Thyroid levels

  • Vitamin D levels

  • Cardiac tests

Consult your healthcare provider before starting supplements, and consider pausing biotin before lab tests.


Dosage

The Nutrient Reference Values for Australia and New Zealand recommend the following Adequate Intakes (AI) for women[1]:

  • Women (19–70+ years): 25 mcg/day

  • Pregnancy (14–50 years): 30 mcg/day

  • Lactation (14–50 years): 35 mcg/day

  • Men (19–70+ years): 30 mcg/day

Most people meet or exceed these levels through diet[1].



References

  1. National Health and Medical Research Council (Australia) and Ministry of Health (New Zealand). Nutrient Reference Values for Australia and New Zealand: Biotin.

  2. National Institutes of Health, Office of Dietary Supplements. Biotin.

  3. Ramamoorthy K, Sabui S, Srinivasan P, et al. Effect of chronic alcohol exposure on gut vitamin B7 uptake: involvement of epigenetic mechanisms and effect on alcohol metabolites. Am J Gastrointest Liver Physiol. 2021 Aug;321(2):123-133. doi:10.1152/ajpgi.00144.2021

  4. Oregon State University. Biotin.

  5. Patel DP, Swink SM, Castelo-Soccio L. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981

  6. Lipner S, Scher R. Biotin for the treatment of nail disease: What is the evidence?. J Dermatol Treat. 2017 Oct;29(4):1-17. doi:10.1080/09546634.2017.1395799

  7. Zhang Y, Ding Y, Fan Y. Influence of biotin intervention of glycemic control and lipid profile in patients with type II diabetes mellitus: A systematic review and meta-analysis. Front Nutr. 2022 Oct;9(1):1-12. doi:10.3389/fnut.2022.1046800

  8. Créange A, Hutin E, Sedel F, et al. High-dose pharmaceutical-grade biotin in patients with demyelinating neuropathies: a phase 2b open label, uncontrolled, pilot study. BMC Neurol. 2023;23(1):389. Published 2023 Oct 30. doi:10.1186/s12883-023-03440-y

  9. Bowen R, Benavides R, Colón-Franco JM, et al. Best practices in mitigating the risk of biotin interference with laboratory testing. Clin Biochem. 2019;74:1-11. doi:10.1016/j.clinbiochem.2019.08.012

 
 
 

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