Safety and Side Effects of Biotin Supplements and Topical Products
Biotin is generally considered safe for both oral and topical usage. However, one study based on food frequency questionnaires suggests that doses of biotin higher than 600 µg/day may increase risk of DNA damage. (63)
Biotin is not known to cause negative interactions with drugs, but some drugs may lead to biotin deficiency. There was one report of a potentially adverse combination of biotin and vitamin B5. (1)
Potential Side Effects
Biotin helps keep your immune system healthy. However, there are some studies that suggest it may affect the immune system in ways that aren't beneficial to some people. (64)
For example:
- In an animal model for multiple sclerosis, biotin deficiency appeared to help the condition. (64)
- Studies suggest that high doses of biotin may affect immune system status. In a small clinical study, healthy adults who were given pharmacological doses of biotin daily for 14 days. Tests revealed the study volunteers showed lower levels of PBMCs (immune system cells) at the end of the 14 days. The cells also produced less of 2 types of cytokine proteins that the body uses to activate other types of immune system cells. The researchers suggest this could affect people who take similar high doses, such as those hereditary disorders or through radioimmunotherapy. (65)
However, experts caution that there's simply not enough evidence (yet) to predict harmful immune system effects from biotin. (65)
Can Biotin Cause Cystic Acne?
If you search for "does biotin cause pimples" on the internet you'll come across hundreds of sites with people complaining they took biotin (typically for hair loss) and suddenly had large, painful cystic acne-type of pimples appear on their face. However, an extensive search through medical journals and other scholarly material shows no such association.
Interestingly, people with cystic acne who use prescription retinoic acid (isotretinoin) to treat it have been known to develop biotin deficiency. Why? Because retinoic acid reduces levels of biotinidase, an enzyme needed to maintain biotin levels in the body. Biotin deficiency is associated with conditions such as hair loss, skin problems, and depression. (66)
Topical Usage
Biotin is used in many cosmetic and personal care products for hair and skin, in concentrations ranging from 0.0001% to 0.6%. Tests show that while it does absorb some ultraviolet (UV) radiation, there does not appear to be any peaks in UVA or UVB, the types associated with skin damage. When used topically and orally, biotin is quickly metabolized and passed out of the body in urine. There has only been one report of hives as an adverse skin reaction. Based on available data of the large number of people exposed to biotin regularly with no adverse reactions, biotin is considered safe to use in cosmetic applications. (28)