It’s actually a function of the HPA axis called a neuro endocrine response. It’s not so much HEAVY weights as you put it as much as it is as difficult workout as you can stand to do. Most people lift “moderate or regular” as you’ve put it. Mostly for the mental fell good that they’ve “worked out”. But workouts are supposed to push you to what would feel like death. Simulating a hunt or being hunted that is life threatening. This with consistency yields the most natural testosterone production.
I bit the bullet and just shaved my head. It takes some getting used to but I decided to do this rather than continuing to take finasteride. I took finasteride for many years (off and on). I’ve been off of it for about 3 years now. I would exercise some caution using any kind of medication. This medication never affected my ability to have an erection but about 3 yrs ago when we tried to get pregnant, it didn’t happen. I’m not certain if it was a possible side affect of using finasteride for so long or whether my partner had issues. I suspect the latter because she had never had kids before and was up in age. Nevertheless, I’d be careful using it. I’m glad I’ve been off of it for some time now.