This is not accurate. It takes about four to six months just to know if Minoxidil is working for you. It takes much longer, like 12 to 18 months, before you will know how well Minoxidil is working for you. Over time and continued use, the hair that grows back continues to thicken as it transforms from vellus hair to terminal hair over the cycles of the follicle. The peak is not 12 to 16 weeks as Devineskin claims in this PDF. It is much farther out than that. It is actually 12 to 18 months.
Treating hair loss is a painfully slow process. It takes a long time. Time that is measured in months and years, not weeks.