Mesterolone is similar to dihydrotestosterone in that it does not aromatise or offer any anabolic properties. It is used in medicine for androgen therapy in order to treat issues such as loss of libido, impotence etc.

It is sometimes used in combination with compounds such as deca, in order to add an androgenic component to the cycle and thereby prevent libido and impotence issues. However, it makes much more sense to use testosterone here, as even small doses such as 250mg every 10 - 14 days will prevent such issues more effectively than mesterolone.

Another misconception is the belief that mesterolone will make a steroid cycle more effective by freeing up more testosterone. Around 98% of the testosterone within the body is bound to "sex hormone binding globuline" (SHBG) and albumin. Only roughly 2% are free and hence active.

Since mesterolone has a higher SHBG affinity than testosterone, it is believed to increase free testosterone levels and thereby letting the user benefit from increased active testosterone.

However, there are enough studies that document an actual decrease in total testosterone levels when taking mesterolone. This testosterone reducing effect occurs because mesterolone acutally does repel testosterone from its binding. The body immediately reacts to the increase in free testosterone within the blood by metabolising excess testosterone molecules in the liver, leaving the user with a lower level of total testosterone contrary to the desired effect.

Finally, the last misconception is the belief that mesterolone binds to the aromatase enzym, thereby making it useless and causing a decreased conversion from testosterone to estrogen. This is also not correct, because as we now know the mesterolone repels the testosterone from its bond, thereby causing increased breakdown of testosterone molecules.

Obviously, less testosterone will equal less aromatisation, which is why people who take mesterolone will report less bloat and fat increase on-cycle.

Why mesterolone is not good for PCT should be clear by now: decreased testosterone and LH levels are hardly what anyone wants when trying to keep gains.

In the end, it will only be competing athletes who use mesterolone in the last 2 - 3 weeks before a competition. This is because the high androgenity will give the muscles a greater fulness, hardness and density. As a DHT derivative the mesterolone acts as an aldosterone-antagonist, which means that it will cause an increased excretion of sodium and water, giving the athlete better definition shortly before a competition.

Proviron is pure DHT, which means it has only masculinising properties and none of the anabolic effects you'd expect from a steroid. However it does help in releasing more free testosterone from the steroids you're taking for your cycle and it helps keeping estrogens at bay (which means it can be used to compliment your AI, not that it can be used for PCT at all, you got that wrong).

Being pure DHT means it contributes to well being (it's been used to treat depression in men in the past) and to dry you up if you're competing, but there's Masteron for that and it might be a better option.

To sum it all up: you can supplement your cycle with Proviron (never during PCT, mind you) to get better results from your steroids, but that's it.

Can help in terms of bonking (a bit) but there are better things than that if sex is an issue.

It will help gains on a cycle cause it free up more test I read, don't think it's a pct tho just helps get the wind back in the old boy

It is pretty useless. If you want I can explain exactly why later, don't have enough time right now. Only competing athletes may benefit from the effect it has on muscle fulness, density and hardness.