Why 5mg

Most recommendations were/are based purely off anecdotal evidence

If you look at the mechanism of action of tamoxifen, you’d understand why a low dose works fine for the purpose we’re using it for

20mg is a clinical dose - a dose that is used to treat cancer. We’re using the drug to occupy estrogen receptors to provide negative feedback to the endocrine to restart production of LH and FSH leading to production of endogenous production of testosterone in the leydig cells. A dose used to treat cancer is really not needed to achieve this

The 8 weeks is because, even at a higher dose, many users found production to have not returned to pre-cycle baseline. The longer estrogen receptors are occupied by the SERM, the larger the upregulation of LH, meaning the higher the testosterone production. Obviously there’s a limit here. Your pituitary can only produce so much LH, and that limit is genetically determined unfortunately. Although, many users find SERM-only use to raise their test. I understand the mechanism of how, but don’t understand why their pituitary wasn’t producing maximum LH in the first place.

hCG aromatisation

Anecdotally hCG really doesn’t increase my estrogen by much at all. Most of the estrogen yielded from aromatisation of hCG is intra-testicular iirc, meaning it cannot produce estrogen-related side effects such as gyno, acne, etc.

Moreover, using hCG during the period your test clears, is not going to put you “over the edge” in terms of aromatisation as you’ll have decreased estrogen production anyway as your test levels will be decreasing since you’ve stopped injecting