[lII1lIlI11ll]

The comments here are unfortunately reddit-level of (in)correctness, but if you really want to know: testosterone doesn't affect your hair in any way, what does affect it is DHT which is synthesized from testosterone by your body with 5α-Reductase and the way to significantly dial down that process is to take 5α-Reductase inhibitors (widely available and affordable medications).

[noisy_boy]

That means maybe the people with great muscles and good hair have a genetic mutation that reduces the efficiency of DHT synthesis? I am assuming DHT doesn't affect muscle growth.

[lII1lIlI11ll]

Firstly, "working out increases your T bro" is reddit-tier simplified. For example, if you are shredded, your testosterone (especially free testosterone due to higher SHBG) can be lower than normal. Just because someone is muscular doesn't mean they have a naturally high T.

Secondly, yes, someone might have just won a genetic lottery but 5α-Reductase inhibitors are quite popular these days.