I had dramatic hairloss due to an illness and the dermatologict suggested raising my biotin to 10,000 mcg. That is probably more than any of us would get ordinarily. But I did and I have stayed on it and have had no hair loss due to pred. Also it has helped my nails. (BTW: It is what we give to our horses when then have hoof problems, So it is the real deal, but it does take a while.)