To some extend it mimicks the action of hcg. By it self hcg could be the best hormone out there since it is the precusor of all the hormones in the body. The perfect results are those achieved in a hormonal state similar to that existing naturally in the body, this is why the stronger androgenic steroids are those who also aromatize into estrogens, plain and simple with estrogens the androgenics work better. Bottom line with hcg you up the total hormonal environment of the body which is best. Unfortunatelly the body will try to adapt and find its balance by limiting the natural production of testosterone while estrogens will remain in circulation.
Since tribestan works in similar ways, milder ofcourse, it is a good idea to cycle its use and give the body the chance to return to its natural balance. Not only that, but then, when you use it you will be able to notice a difference, a "push" if I may say so.