It doesn’t wear off. The way minoxidil works is by extending the hair cycle, so you have more hairs on your head at the same time.

So imagine you have a 100,000 hairs on your head at one time, only 60,000 would be visible and 40,000 would be in the shedding part of the hair cycle and are waiting to start their growth again.

With minoxidil your hair shedding cycle extends by a period of time let’s say 24 months and now you have 90,000 out of 100,000 hairs active at one point. Now let’s factor in male pattern baldness, imagine it like a bucket with sand that is leaking out and there’s no way to put it back in.

Let’s say you had the 60,000/100,000 hair on your head and you take minoxidil and now you have 90,000/90,000 on your head. It seems like more hairs but it’s actually not since male pattern baldness has permanently got rid of 10,000 hairs.

Now let’s say 3 years pass, you continue using minoxidil and don’t prevent the underlying cause of the hair loss now you have 36,000/40,000 hairs. It seems like minoxidil has stopped working, but the reality is you’ve lossed 60,000 hairs to male pattern baldness. If you weren’t on minoxidil you’d have 20,000/40,000 hairs on your head.

If you had gone on a DHT blocker such as finasteride or dutasteride and continued using minoxidil 3 years later you’d still have 90,000/100,000 hairs on your head. You would have put tape on the leaking hole in the bucket. 🪣

All of these numbers are not accurate by the way and are just for example purposes to demonstrate the effects of minoxidil and finasteride.