I could buy that it doesn't increase growth, though I don't know for sure. But it could be that what people are taking as increased growth is actually increased retention. I went to see the dermatologist recently about hair loss, but he said it was mostly breakage. He prescribed some shampoo and told me to take a vitamin with biotin in it. Biotin is supposed to strengthen the hair so it will break less. If hair that was breaking before is now hair that you're keeping, your hair will be getting longer faster even though it's not coming out of your head any faster. Like I said, I don't know this to be the case but it's a possibility.