Primobolan (Methenolone Acetate) is an anabolic steroid a bit like the original version of Masteron. User reviews are often very positive.
Considering its chemical structure and its ratio of anabolic and androgenic effects, we can guess that it is at least as effective as Masteron on an equal mg per mg basis.
Still, due to its ester (in the injectable version) it must be taken for at least 12 weeks to obtain all of its benefits.
On the other hand, many competitive bodybuilders consider Primobolan to be indispensable to their pre-competition routine and couldn’t imagine a cycle without it.
Primobolan does not tend to aromatize (convert to estrogen). Since it doesn’t aromatize, you don’t have to worry about many side effects commonly associated with estrogen, including water retention, acne and gynecomastia.
The lack of water retention combined with slow and steady gains of quality dry muscle explains why Primo has such a good reputation for building muscle. This also explains why it is so expensive.