I contacted the author of the above text and requested more information regarding the "direct androgen receptor stimulation" and role of testosterone VS DHT
Losing your hair involves the shrinkage of hair follicles. There?s less of a growth cycle as the follicles shrink. New hairs become finer and finer until there?s no hair left at all and the follicles become dormant. This hair loss is caused by hormones and the certain genes.
DHT is primarily used by the body in the prostate, the skin, and in hair follicles. Your hormone levels may affect your exact MPB symptoms. Men with high levels of testosterone are more likely to have vertex baldness. The same study suggested that men with higher levels of the binding protein SHBG may have thinner hair on their chests.
The actions of DHT and the sensitivity of hair follicles to DHT is what causes hair loss.
Testosterone as all other androgens act through the same receptor but only affect the hair follicles, not shrink them permanently, thus they affect hair just like all other hormones but the quality of the hair and the hair cycle. Testosterone is metabolized by the liver into dihydrotestosterone (DHT). It is the DHT that is most effective at causing balding and by competitive inhibition of finasteride at the target organ, the impact of DHT is reduced when a person is on finasteride.
If you haven't lost your hair at 1 gram of test with finasteride you will more likely not loose them at 2 grams with sufficient finasteride of 5 mg.