I am new to this myself but I can give the following testimony. I got my hair cut (1 inch to 1 1/2 inches in some places) 3 weeks ago. When I went to get my touch up yesterday, my hairdresser asked me how did my hair grow back to its original length that fast. The vitamins/supplements I have been taking for the last 3 weeks are:
GNC Ultra Nourish Hair
Ultra Thick Hair Shake (Nature's Plus)
Biotin (Puritan Pride)
Pant. Acid
MSM
Hope this helps. The most important thing is to listen to your body, be wise, and drink lots and lots of water!!!!