LGD-3303 is an orally active nonsteroidal SARM that shows potential to increase muscle mass and BMD in rat models. When dosed in castrated rats with androgen deficiencies this compound did not stimulate the ventral prostate despite significantly increasing the dosage.  These findings suggest that this compound does not negatively impact androgenic organs, which is a component of the ideal anabolic SARM.
The same researchers also dosed this compound two different ways, orally and continuous infusion, and found in both instances that the compound significantly increased muscle activity but was found in higher concentrations in the prostate.  It’s surprising that despite higher concentrations of the compound in the prostate, the muscles actually responded and grew in size, rather than the androgenic organs.
LGD-3303 [structural formula on the right], like LG121071, was developed by Ligand Pharmaceuticals. The chemical structure of LGD-3303 resembles that of LGD-4033, another SARM developed by Ligand Pharmaceuticals. Some of the people who have used LGD-4033 say it’s the most powerful SARM that athletes can buy at the moment. LGD-3303 is not yet available on the market, and as far as we know no doping test has been developed for it yet either. And that’s kind of strange. For the other SARMS we are pestering you about in this post, tests have already been developed whereas, on paper, this particular SARM is head and shoulders above the other substances.
We borrowed the figures below from a 2009 publication [J Pharmacol Exp Ther. 2009 Feb;328(2):663-70.], which shows the effect of orally administered LGD-3303 in rats. The solid black line represents the size of the prostate, the size of the levator ani and the concentration of LH in intact animals. The vertical bars represent the same values in castrated animals. In terms of muscle mass, a dose of 1 mg per kg per day of LGD-3303 was sufficient to completely replace the natural testosterone production. The human equivalent of this dose, for a man weighing 80 kg, would be about 11 mg per day. Animal studies have shown that a combination of LGD-3303 and bisphosphonate protects bone mass. [J Bone Miner Res. 2009 Feb;24(2):231-40.]