Growth hormone-releasing peptide-6 (GHRP-6) is a small, six-mer peptide that stimulates the release of growth hormone by activating the ghrelin receptor found in the brain [1-3]. Activating this receptor and increasing the levels of growth hormone within the body can modulate food intake and energy metabolism and also influences glucose and fat metabolism [4, 5]. GHRP-6-induced metabolic changes result in less fat absorption, increased fat breakdown and stimulate the production of lean muscle mass. GHRP-6 can also be combined with additional growth hormone enhancers, such as GHRP2, sermorelin and CJC-1295. GHRP-2 is another peptide activator of the ghrelin receptor and has been shown to potently stimulate growth hormone secretion and increase appetite, leading to increased lean muscle growth . Combined dosing of sermorelin and GHRP-6 results in the enhanced production of human growth hormone and increased muscle mass, as does the combined dosing of CJC-1295 and GHRP-6.
Although GHRP-6 and GHRP-2 are both small peptides that stimulate growth hormone release, they each have different chemical and metabolic properties. GHRP-2 causes higher growth hormone release and a lower hunger response in comparison to GHRP-6. Additionally, GHRP-2 stimulates higher prolactin and adrenocorticotropic hormone secretion when compared to GHRP-6. However, the half-life of GHRP-2 is much shorter than that of GHRP-6 (15 minutes compared to 2 hours), which means that it is eliminated from the body much more rapidly and will require more frequent dosing [7, 8].
GHRP-6 is stable and effective when administered both orally and intravenously and was demonstrated to be safe in clinical trials using healthy human volunteers [9, 10]. GHRP-6 is packaged into vials as a powder and needs to be completely dissolved in sterile water. The water should be injected directly into the vial. The vial should not be shaken, but can be gently rotated in order to dissolve any remaining powder. GHRP-6 10 mg can be dissolved by adding 5 ml of water to provide a 2 mg of GHRP-6 in every 1 ml of solution. A 5 mg vial of GHRP-2 can be dissolved in 2.5 ml of water to provide a solution of the same concentration. These solutions should be stored in the fridge for up to one month. For fat loss and muscle gain, three doses of 100 µg of either GHRP can be administered daily. A 100 µg dose is then equivalent to 0.05 ml of solution, or 5 IUs on a standard insulin syringe. Both subcutaneous and intramuscular injections are suitable when administering these peptides and should be carried out with clean, sterile needles after cleansing the injection site with antibacterial agents.
Side effects of using GHRP-6 can include an increase in appetite, an initial drop in blood glucose and headaches. However, these side effects can be minimised by dietary adjustments that counter the drop in glucose. Side effects can be minimised by not exceeding the recommended dose of three 100 µg injections per day. Finally, the body will eventually adapt to GHRP-6 and side effects should subside.
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