Απ: minoxidil
Warnings:
Initial Shedding: Topical minoxidil can cause an initial mild increase in shedding of follicles that were going to shed within 100 days anyway. However, it's important to realize that the sustained use of topical minoxidil will result in an improvement in the number and quality of the hairs on your scalp.
Minoxidil allows hair that is already in the telogen phase to shed. Normally, the hair shaft sheds at the end of the telogen phase. 10% of normal hair is in the telogen phase, but in areas affected by MPB up to 20% of thinning, miniaturized follicles are in the telogen phase. This is why minoxidil induced shedding may appear so dramatic when it affects thinning hair. The hair shafts, which are shed, will be replaced at the end of the telogen phase with healthier hair. On the other hand, untreated MPB will result in progressive miniaturization of the hair follicles.
Tolerance: There are misconceptions about minoxidil and 'tolerance'. Minoxidil will help to recruit atrophic follicles to grow thicker hair again for about two years (sometimes as long as three years). Beyond that time, it continues to help keep the hair in the anagen phase, so the new hair has a longer anagen phase.
But, because most patients do not see any significant continued improvement after a few years, they might assume that the minoxidil has caused a tolerance and is no longer working. If they are unfortunately convinced to stop minoxidil treatment, the hair that they have regrown will shed again in 3-4 months.
