I got 1 inch in 5 weeks using Spirulina (3 tablets a day), biotin (1000mcg) and MSM 750mcg a day. The Spirulina was new to that time period and I've kept going!
My energy is still high cause I found it hard to sleep early on my long hours job (12 hour shifts 5-7days a week). I've been on-call over the weekend (did a 14+ hour shift yesterday. Still made it through today without feeling sleepy!
I believe hair growth is good, but retention of length is most important.