[at-w]

>It seems that he is spending a lot of his time & effort on maintaining his hair (huge kudos for admitting that!). If his body was functioning like an 18-year old he should not need to do that. If Bryan really set back his true aging clock he probably would not be battling with ongoing hair loss (as he most likely did not battle hair loss 20 years prior), or at least it would stop (which does not seem to be the case).

Androgenetic hair loss (what Johnson has and what the medications he takes are designed to treat) is caused by genetic sensitivity to DHT and DHT levels in the body, not aging. People who don't have the genetic predisposition to AGA or who have very low DHT levels can often make it to 60+ with no visible hair loss. It's not like they're "not aging," they just don't have the combination of genes and DHT levels needed for significant hair loss to occur.

[drooby]

Biological aging is a fuzzy concept that we define relative to various social constructs and other objective markers compared to the general population.

I don't see much issue with its usage in this context.

[xorbax]

You could define it as "the degradation of cellular maintenance". Androgenic hair loss is more like a non universal signal of hormonal maturity, like pubic hair growth.

[xnx]

> is caused by genetic sensitivity to DHT and DHT levels in the body, not aging

Is the formula something like: DHT sensitivity * time = hair loss ?

[at-w]

I'm not super well versed but my understanding is that that's right, with your actual DHT levels being the third variable. There are other non-hormonal causes of hair loss, like alopecia areata, but they're much less common.

DHT damages the hair follicles that are sensitive to it, causing them to grow back thinner after each growth and shedding cycle (which is typically a few years). As a result most men don't have visible hair loss until years after puberty kicks in.

[deadbabe]

So does a man without hair loss imply they are slower aging?