Me again
MK-677 is a oral avaiable GHRP which acts as a (endogene) GH-Booster. 25mg/ed was tested in serveral studies. The intake was mosty before sleeping because of the high peaks and GH activity during the night. But also during the day the normal GH peaks were higher than normal. The younger you are the more sensefree MK-677 ist. While young persons (24 years old) have "only" a boost of 2-3x of their normal GH bandwidth eldery persons (elder than 39 years) had a benefit of 4-9x of their normal GH range. A problem is, that our body also has its security system - in case of the higher GH (somatropin) it's the somatostatine. It's only a question of time when the somatostatin increases that much that our "supplementation" with MK-677 is worthless. Therefore use Huperzine-A (100-200mcg every 5.5hours due to the half life) to inhibit the somatostatin. But be careful with the dosage: despite Huperzine-A is from nature it also has its toxicity effects in a higher dose range (dosages up to 500mcg are used exerimentally in therapy). Also it's sensless to run MK-677 over a long period of time. The reason is, that MK-677 is only a GH booster and looses its effect rapidly (already after a week the effect of MK-677 is not the same anymore like on the first intake). Pretty interesting stuff I will also use it soon.
LGD-4033 (now named VK-5211 due to selling from Ligand to Viking) is also interesting. More powerful than ostarine and has also an androgenic effect - which Ostarine doesn't has. LGD ist times more suppresive, so a proper PCT should be made (but also have a look on your bloodwork. If you stay low dose and the axis is not that suppressed you probable won't need SERM or only low dose).
SR-9009 is a very new component. It is a PPAR-alpha, whereas GW-501516 is a PPAR-delta. The effect is more or less the same but there is only one slight difference: PPAR-alpha have a better positive effect on tryglicerides and cholesterol values in blood than PPAR-delta (use google for more information, otherwise it will be too long). Me personally won't use it until it doesn't hit a Phase I status. A intake of a pre-clinical drug is not that clever. Even the dosage intake is unclear and the whole (side) effect profile. Furthermore, SR-9009 acts on the Rev-Erb alpha. The main problem is that rodents don't have this protein and with SR-9009 it will be activated over other pathways. What will happen to humans who have this protein? We don't know that and it's only a further risk.
Same with RAD140 with is a SERM. Also in pre-clinical studies and a huge risk to take it. The main difference of RAD140 and the other SARM is that it's the only SARM with is tested in combination with a AAS (testosterone propionate). The effects were that the anabolic effect of these two components togheter raised and the androgenic effect decreased - which are pretty interesting news. But it's only tested in mice and rats.
So personally, I wouldn't use SR-9009 and RAD140 until they don't hit the Phase I studies at least (in this case the components are in the first step more or less "safe" to test it on humans. But without guarantee that it will work, as always). The probably strongest stack without AAS and PH could be LGD-4033, S4, GW and MK-677 and in the PCT Tamox with low dose Ostarine as an anti-catabolic/anabolic compound.