Is [D-Lys (3)] GHRP-6 A Potential Diet Aid?


by Anthony Roberts

I’m not entirely sure why [D-Lys (3)]GHRP-6 hasn’t made an appearance on the underground market yet, or at least been experimented with more widely. I’m guessing it’s because, in simplest terms, it can be thought of as the opposite of GHRP-6. Hence, instead of looking at a drug that will release growth hormone, we are looking at one that does the opposite.

Illustration 1: [D-Lys (3)]GHRP-6

Before you stop reading, you might want to know that rodent data indicates that [D-Lys (3)]GHRP-6 decreases appetite without a stimulant effect, and burns fat without a loss of muscle. Interested yet?

Remember, we don’t use growth hormone secretagogues or growth hormone releasing peptides because we simply want more growth hormone, we do so because we want the effects that we get from growth hormone. The drugs themselves are a means to an end, not an end in themselves. We want to burn fat, build muscle, maybe sleep a little better, etc…

Using growth hormone is a means to an end, and the use of peptides or secretagogues is just another tool in the box. But elevating growth hormone through their use is often very different than simply injecting it. In order to understand [D-Lys-3]GHRP-6, a brief review of regular GHRP-6 is necessary.

GHRP-6 is a growth hormone releasing peptide (GHRP) – meaning it signals your body to release more growth hormone. However, it is a ghrelin agonist. So if you’re naturally lean, or have difficulty eating enough to put weight on, GHRP-6 would be a good choice for you. If you’re naturally inclined to carry or put on fat, then it’s a horrible choice.

Originally, it was thought that this type of drug would operate primarily through the growth hormone secretagogue receptor (GHSR), but now it is known that these drugs act on the the ghrelin/growth hormone secretagogue receptor. Ghrelin, unfortunately, is a hormone that causes a lowering of your metabolism, along with hunger and fat storage. Sound familiar? Because the primary side effect most users report with GHRP-6 is hunger. It’s action as a ghrelin agonist is the reason.

Sorry, but this is what happens with GHRP-6, even though there have been some encouraging outcomes in rodent studies in terms of body composition, muscular gains, and other (standard, expected) GH-type results. And of course, there are plenty of users who have had great success in adding muscle and strength with GHRP-6…but facts are facts, and the mechanism that causes the increase in GH will also cause hunger, a slowed metabolism, and some degree of related fat gain.

Illustration 2: Secretion of Growth Hormone via Hypothalamus

Remember, we aren’t talking about the action of GH itself, but rather the way it is being stimulated through ghrelin. Growth hormone might burn fat, but causing your body to produce it naturally through this specific pathway, can do the opposite.

Injectable growth hormone remains a potent fat-loss drug, but secretagogues and GHRPs should be considered bulking drugs.

So if GHRP-6 boosts your natural output of growth hormone, but lowers the metabolism, we can reasonably expect [D-Lys-3]GHRP-6 to do the opposite…it will lower some of your natural growth hormone output while boosting metabolism. This is a trade-off.

It’s well-established that reducing estrogen on a cycle (usually with the use of aromatase inhibitors) will result in less muscle and weight gained – but it’s a compromise most are willing to take. We have the same bargain with [D-Lys-3]GHRP-6: increased metabolism and fat loss, but less natural growth hormone.

However, Injections of [D-Lys-3]GHRP-6 significantly lowered body weight gain and blood glucose concentrations without decreasing muscle weight – in fact, if you look at the chart below, what you’ll see is that a dose of 200 nmol per day of [D-Lys-3]GHRP-6 resulted in rodents with significantly less fat and significantly more muscle:

Table 1 from: Asakawa A, Inui A, Kaga T, et al. Antagonism of ghrelin receptor reduces food intake and body weight gain in mice. Gut. 2003;52(7):947-952.

As you can see from the chart above, the rodents injected with the highest dose of [D-Lys-3]GHRP-6 not only ended up eating less, but they carried less fat and more muscle. So that’s the really interesting thing – at least in rodents, [D-Lys-3]GHRP-6 actually seems to be anabolic/anti-catabolic, because while the total bodyweight of the rodents in the highest [D-Lys-3]GHRP-6 group was lower than the placebo (saline) group, their skeletal muscle was about 9% higher, and they had over 10% less fat pad mass.

I don’t know how this will shake loose in humans, and haven’t heard of anyone trying [D-Lys-3]GHRP-6 as a diet compound. But it’s interesting, to say the least, as most appetite inhibitors tend to live in the stimulant family, and this seems to operate by purely metabolic effects.

The expected loss of circulating natural growth hormone that we can expect from this compound doesn’t seem enough to tilt the scales towards a catabolic state, and in fact, it appears to have exactly the opposite effect.

Suggested Reading:

1. Korbonits M, Goldstone AP, Gueorguiev M, Grossman AB (2004). “Ghrelin–a hormone with multiple functions”. Frontiers in neuroendocrinology 25 (1): 27–68. doi:10.1016/j.yfrne.2004.03.002. PMID 15183037.

2. Laferrère B1, Abraham C, Russell CD, Bowers CY. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. 2005 Feb;90(2):611-4.

3. Peñalva A1, Baldelli R, Camiña JP, Cerro AL, Micic D, Tamburrano G, Dieguez C, Casanueva FF.J Physiology and possible pathology of growth hormone secretagogues. Pediatr Endocrinol Metab. 2001;14 Suppl 5:1207-12; discussion 1261-2.

4. Maletínská L1, Matyšková R, Maixnerová J, Sýkora D, Pýchová M, Spolcová A, Blechová M, Drápalová J, Lacinová Z, Haluzík M, Zelezná B. The Peptidic GHS-R antagonist [D-Lys(3)]GHRP-6 markedly improves adiposity and related metabolic abnormalities in a mouse model of postmenopausal obesity. Mol Cell Endocrinol. 2011 Aug 22;343(1-2):55-62. doi: 10.1016/j.mce.2011.06.006. Epub 2011 Jun 17.

5. Asakawa A, Inui A, Kaga T, et al. Antagonism of ghrelin receptor reduces food intake and body weight gain in mice. Gut. 2003;52(7):947-952.