I've been taking biotin for about a month and noticed the same thing. Also, I have heard others echo the same thing before. I think it's normal. However, I'm taking quite a bit (20,000 mcg a day).
If you are taking a supplement for biotin, it's likely you are getting a lot more than the daily requirements. That's okay because most people don't have results below the 5,000mcg level which is still much higher than the daily requirements. Also, b vitamins are water soluble, so it might not be a bad thing to go over the rda (but I'm no authority so don't quote me on that). So you are likely taking more biotin than whats needed for your body, but most people don't get hair growth results at the rda level.
One weird thing I've noticed about larger doses of biotin is that my nails don't grow as fast. They also seem more weak which sucks for a classical guitar player. It seems contrary to the advertised effects in this regard. Though, my hair is growing faster and I'm grateful for that.
