I understand that fraternal twins have completely different genetics (unlike identical twins). However, from your experiences with patients, if one fraternal twin is suffering from MPB at a young age (20), will the other twin be more at risk to suffer from hair loss in the future?

That is not true. The genes for balding might have been inherited in only one of the twins.  The risks, depending upon the family genetics, can be very different for the second fraternal twin.  If they were identical twins, then they would both bald of not bald in the same way. I had a pair of twins, where one lost more hair faster than the other. Stress and hair systems was the cause for the twin that lost much more hair than the other twin.

It’s been reported that Dutasteride raises scalp Testosterone by nearly 100%. I don’t know if thats bro science or what. When I took fin for 10 years, my hair line didn’t move a cm. Since taking dut for 7 months, my hair line has went from a thick NW1 to an approaching NW2.5-NW3. I can see the pattern taking shape, although I’m about a NW1.5 now. Can Scalp Testosterone cause damage to hair follicles, particular the front where they may be more sensitive to T in general? Thinking of going back to fin and cutting my losses. Enough is enough

The model for hair loss is for DHT, which is a metabolite in the breakdown of testosterone by the body. Norwood Class 1 and 2 have juvenile hairlines and the leading edge of these hairlines do not respond to DHT blockers like finasteride, so using drugs to hold onto your juvenile hairline makes no sense and just will not work.

Cedar Herle lost her hair, while her mother suffered small stroke from disease

https://www.cbc.ca/news/canada/saskatchewan/regina-girl-covid-vaccine-hair-1.6283166

Finasteride always helps by slowing, stopping and occasionally reversing hair loss. Just give it time to do its job. If you add minoxidil to it and possibly microneedling, it increases the chance of hair growth even further

I ‘m 25 and have only taken Fin for a few weeks but this entire year I have had bad hair loss.  Started at one temple now my entire hairline is getting diffused thinning.  Will the finasteride reverse it it I stick to it?

Reversal of balding is not uncommon in men under 25. The younger you are, the more likely it will occur but that does hinge on your genetics. You won’t know until you try it.

Concerning thinning hair, would it be accurate to say that something like decrease in hair density (without miniaturization) might be temporary and stress-induced, but evidence of miniaturization would almost certainly be MPB? Is miniaturization obvious from hair diameter or does it require magnification?

Hair grows in groups called Follicular units which contain between 1-5 hairs each along with one or two vellus hairs. With age or genetic balding, the hair count within these groups can be reduced making a person’s hair look thinner (less full).

This mas is 24 days after his crown hair transplant.  The healing crown itched and he responded by scratching it. Scratching it breaks the fragile skin of the recipient area and makes it vulnerable to the invasion of bacteria that normally reside on the scalp and in the pores of the scalp,  These bacteria are opportunists and take hold as shown in this photo. It is easily addressed with antibiotics