well, i haven't used it (yet), but still think there is some value in in, as long as one keeps the cycles short.
"D-Aspartate can influence the testicles via the NMDA receptors, present in both Leydig and Sertoli cells of the testes. After being taking up into a cell, D-Aspartate appears to have the ability to induce testosterone release, although it tends to work synergistically with hCG by increasing the efficacy of hCG on a testicular cell. This increase in testosterone synthesis is not seen after 1 hour of incubation (yet is after 16 hours), and can both increase cholesterol transport into the inner mitochondrial membrane by increasing expression of the StAR protein, which is a transporter that brings cholesterol into the mitochondria. hCG treatment is able to increase expression of StAR itself via a cAMP dependent pathway, and incubation of a cell with D-Aspartate can increase hCG-induced StAR mRNA upregulation 3.5-fold and protein content by 1.9-fold and can increase in cAMP levels by 3.1-fold at 0.1mM and 5.25-fold at 5.25mM."