I have been taking HF37 coming up on the end of two months now, and have seen good results, although I haven't been measuring my hair. I've taken HF37 on and off for a couple of years now, but never consistently. Always skipping days etc etc, but this time I have taken them religiously for two months in conjuction with conditioning washes which has helped quite a bit.
Before when I was taking them, I would skip days, and since I live in an extremely dry climate, any growth I had would break off. I started noticing results maybe four weeks after I started. I've just ordered another two months and I am thinking about trying a multi vitamin with it as well as increasing my protein in my diet..fish, chicken. Also exercising.