Generally, no. Vitamin B7, also known as biotin, is a water-soluble vitamin and therefore healthy humans will excrete what they don’t use unless dosages chronically exceed an established Upper Limit (UL), which at this time has not been set for biotin. Animal studies using high doses of biotin, well above the average human needs (~30-100mcgs/day), have shown no adverse effects. There are no reported cases of adverse effects from high doses of the vitamin used in treatments of metabolic disorders. There are virtually no known contraindications but concerns about biotin overdose have been raised in individuals with “health risk” issues such as pregnant women, people with kidney or liver problems or a history of seizures -- all of whom should consult a qualified physician before supplementing. Most daily multivitamin and mineral formulas (MVM) contain all the biotin necessary (and probably a little more) for normal healthy people. Although biotin deficiencies are rare, marginal deficiencies have been shown in certain populations such as during pregnancy, athletes, dieters, elderly, alcoholics, and burn patients, which can lead to decreased energy production and other biotin related functions. For this reason we always recommend a daily MVM to all populations containing between 100-300mgs of biotin (B7). Active people maintaining low body fat may do better at the higher part of this range.