I have a friend who used SD extensively while being a drug-tested athlete in college, he’s also very bright and has shared PM’s with some chemists around BB.com like Patrick Arnold and some other “respected members”. As such, I consider him sort of a SD expert, if you will. He probably has 10+ cycles of 2-6 weeks with that compound under his belt.
SD should not be referred to as a prohormone. Or a prosteroid. It is chemically identical to the steroid Masteron, except it is methylated. Methylation may change the “feel” of a steroid slightly, but its general categorization and effects remain the same. Notably, an example of this would be the differences between the feel of oral Winstrol and injectable Winstrol.
Patrick Arnold has also said that on a mg-to-mg basis, SD is the most powerful oral steroid, and also the most liver toxic. Patrick Arnold is probably one of the brightest chemistry minds in the supplement industry, period, for the doubters.
Consider how many users of injectable Masteron have complained about unbearable pumps and tightness at anything above 300mg/week. My friend seems to think this rings true as well, as he has observed the same thing at anything above 40mg/day, which is 280mg/week for the mathematically challenged. He believes the “sweet spot” to be 20-30mg/day, depending on lean body mass.
In short, you are adding Masteron to your cycle should you decide to do this. Just because the Masteron (SD) was sold at GNC at one time does not mean it is not, in fact, Masteron. So consider these facts – many anecdotal, but some rooted in science – and make an informed decision.