After Stopping Propecia, How Long Until My Hair Loss Plays Catch Up?

Dear Dr. Rassman–

I understand that after one stops taking Propecia for some amount of time, X, one will lose all the hair they have gained and kept as a result of using Propecia in what you term “catch up hairloss.” I also understand that this may result in what appears to be a large amount of hairloss. However, what is that amount of time, X, referenced above? That is, how long must one be off Propecia to lose all benefits of having taken the drug? For instance, I have been using the drug for 14 months–if I stop today, when will I lose all the hair I have gained and when will catch up hairloss begin–next week, next month, within 9 months? Sometimes, I forget to take the medication and skip a day or two–is this lethal to my regimen of measures taken to maintain my hair count?

The time it takes to play catch-up is about 3-6 months. Forgetting to take the pill a day or two might have a marginal effect on you.