This is the version of the explanation I wish somebody had given me, written down before I forget what confused me. It is about the hormone panel, and it is deliberately narrow — everything I am not confident about is marked as such.
What is actually established
Most of the hormonal change here is a consequence of adiposity falling rather than a drug effect. Less adipose tissue means less aromatase activity, so in men testosterone commonly rises and estradiol falls, and SHBG rises as insulin resistance improves — which means total testosterone can rise while free testosterone moves less than expected. In PCOS, improved insulin sensitivity frequently restores ovulation, which is a fertility change people are not always expecting.
The condition it depends on
This is a case where measuring the free fraction rather than the total matters, because SHBG is moving at the same time.
What I am not sure about
So the question, as narrowly as I can put it: why total and free can move differently here, and which of the two is worth tracking. Practical detail welcome, however dull — the duller the better.
— DadBodDave · corrections welcome and will be edited into this post with credit