So somebody who continues to take finasteride and does not stop like in the example you gave, it will often continue to provide it’s benefits in retaining hair and won’t necessarily lose its effectiveness?

Correct; however, hair has its own agenda with genetic codes for Apoptosis (cell hair suicide) which is delayed by finasteride but not always a guarantee that each hair may take its own course.  Generally, finasteride slows this process down for the time you take the drug. I have had patients on finasteride for 25 years.  When they stopped it along the 25-year history, they always lost hair.  This tells me that finasteride works if you take it for anyone losing hair. 

To answer your question, I need to see photos, know your age, understand what you have been doing to grow your hair and learn about your family history.

My hairline has both started thinning and receding; I’m probably a Norwood 2/2.5. He shows no signs of receding / thinning. I wonder what sort of things could cause this?

I’d say we live pretty identical lives in terms of activity/diet / don’t smoke / medications, nothing crazily out of proportion. So I wonder what the difference in us could be. I will say as well I’ve had a full chest of hair for 3+ years, whereas his is still pretty bare – I was under the assumption that had something to do with DHT. I wonder if there is something I’m missing, like a specific lifestyle choice or an overlooked common day to day activity, which could perhaps provide me with different hormone levels? I know we all age differently blah blah, but I wonder if something like this could be narrowed down to something specific, like a as we are genetically identical twins.

 

Stress has a lot to do with precipitating hair loss. You both probably handle it differently. He will probably see the same changes, possibly just later than you. I have worked with twins in hair transplant. Way back, I had identical twins who were remarkably different; one was a landscaper, and the other a computer geek. The computer geek wore a hair system and pulled out a lot of his hair, only to find his brother making fun of him.

I did hair transplants on another set of twins about two years ago, and I was challenged to make them EXACTLY the same. I succeeded. I couldn’t tell one from the other before or after the transplant grew. To ensure that I got the identical results, I did both surgeries on the same day and at roughly the same time. At the beginning of the surgery, we drew the hairlines together in the same room.  Their mom and dad were there for support.  I performed the exact same number of grafts,  I will tell you that it produced some anxiety on my side, artistically giving them both an identical look. It was successful!

Drugs like finasteride and dutasteride, usually reverse miniaturized hairs, and not grow hair in a completely bald man; however, some men have very fine miniaturized hairs that they didn’t know existed on their bald head, so I have seen some cases where these men, who thought they were bald, grew hair on finasteride. The photo below shows a 43 y/o male who may reflect what I discussed above.  I wish I could have examined him before he went on dutasteride. 

Only the son can catch up

This is the amount of pink color change one would expect in certain skin types with microneedling.  I can’t tell how far down you are from where a mature hairline belongs.  Going further down than that, will not usually bring back the juvenile hairs below the mature hairline.