Wish it had a tad more biotin, which is why the 4 stars. I'm a guitarist and have long nails for fingerpicking - biotin helps me keep them from chipping. I'll have to take some biotin on the side to help with that problem, despite the Rooster Booster's huge biotin content.
That said, I don't know if it's the placebo effect, but I honestly believe it rounds out my hair-loss regimen of Rogaine and Finasteride - felt as though something was missing while I was on just those two. I feel as though the addition of the Rooster Booster makes me look like a guy with some hair loss (but still attractive with a short cut or the right style) vs. a guy who's just given up.
And my beard comes in very quickly between shaves. I've been told you can't grow new pores, so my guess is the Booster strengthens what you already have, because even though I just have a goatee, I can tell from how the rest of my beard comes in, in between shaves, that if I wanted I could grow a very full beard with all-around coverage. There's a very healthy, uniform look to the beard as it grows in fast.