From the Guidelines
Taking too much biotin is generally considered safe, with no established upper limit, and the only effect of excess doses is increased urinary excretion. According to the most recent guideline, the espen micronutrient guideline published in Clinical Nutrition in 2022 1, high doses of biotin may rarely lead to anaphylaxis, particularly with high IV doses, and doses exceeding 400 mg may cause nausea, anorexia, and mild ataxia. Some key points to consider when taking biotin supplements include:
- Increased urinary excretion is the primary effect of excess biotin intake 1
- High IV doses of biotin have rarely led to anaphylaxis 1
- Doses of more than 400 mg may induce nausea, anorexia, and mild ataxia 1 It is essential to note that biotin is a water-soluble vitamin, and the body can eliminate excess amounts through urine, making it relatively safe even at high doses. However, it is crucial to be aware of the potential for misleading results in blood tests, particularly those measuring thyroid hormones, troponin levels, and hormone tests, when taking high doses of biotin. If you are taking biotin supplements, it is recommended to inform your healthcare provider before any blood tests, as they may advise stopping supplementation 72 hours before testing.
From the Research
Biotin Overdose
- There is limited research on the effects of taking too much biotin, but available studies suggest that biotin is generally well-tolerated and has a low risk of adverse effects 2.
- High doses of biotin are not typically associated with hypervitaminosis, and the risk of interference with laboratory tests is low if administration is controlled by physicians and follows a medical diagnosis and prescription 2.
- However, the use of biotin as a hair and nail growth supplement is prevalent, despite limited research demonstrating its efficacy in healthy individuals 3, 4.
- Some studies suggest that biotin supplementation may be beneficial in cases of acquired and inherited causes of biotin deficiency, as well as pathologies such as brittle nail syndrome or uncombable hair 3, 2.
Potential Risks
- There is no clear evidence on the specific risks associated with taking too much biotin, but it is essential to follow the recommended dosage and consult with a physician before taking any supplements 2.
- The custom of treating women complaining of hair loss with oral biotin supplementation without demonstrating biotin deficiency and its significance for the complaint of hair loss is to be rejected 5.
- More research is needed to fully understand the effects of biotin overdose and to determine the optimal dosage for various conditions 4.
Available Research
- Most studies on biotin focus on its use in treating hair loss, nail changes, and other skin disorders, rather than its potential risks or side effects 5, 3, 2, 4.
- One study found that biotin deficiency was present in 38% of women complaining of hair loss, and that biotin supplementation may be beneficial in these cases 5.
- Another study reviewed the literature on biotin's efficacy in hair and nail growth and found limited evidence to support its use as a supplement in healthy individuals 3.