Ipamorelin

MK677 and Ipamorelin are both selective agonists of the ghrelin receptor. Ipamorelin is a peptide analogue of ghrelin whereas MK677 is an unusual molecule that doesn’t fit into any specific category (it isn’t a peptide). These two compounds, while affecting a similar receptor, have different properties and produce different biochemical results. Many people are interested in the differences between MK677 vs Ipamorelin. Below is a look at how these compounds differ as well as how they are alike.

MK677 vs Ipamorelin

MK677, also known as Ibuatmoren and Oratrope, is an orally active, non-peptide, selective agonist of the ghrelin receptor. MK677 shares no structural similarities with ghrelin and therefore no structural similarities with Ipamorelin. Research shows that MK677 increases the secretion of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) without affecting cortisol levels. It is currently under investigation for the treatment of growth hormone deficiency, muscle wasting, bone wasting, and appetite stimulation. MK677 has a long half-life and once-daily dosing in most trial settings.

Ipamorelin is a peptide analogue of ghrelin that stimulates the secretion of GH. It is among the most selective of ghrelin analogs with research revealing no effect on ACTH, prolactin, follicle-stimulating hormone, luteinizing hormone, thyroid stimulating hormone, or cortisol levels. Ipamorelin has been investigated in the treatment of GH deficiency, muscle wasting, and post-surgical ileus. It has also been the subject of numerous clinical trials for its ability to increase bone strength and mineralization.

Tesamorelin and Ipamorelin are both peptide-based therapeutics that belong to the class of growth hormone-releasing peptides (GHRPs). They are used for different purposes and have distinct receptor binding properties, but because they both affect natural growth hormone (GH) levels, they have similar effects in many respects. Both peptides have seen renewed research interest, however, thanks to a boom in the weight loss field led by peptide compounds like semaglutide and liraglutide. While both Tesamorelin and Ipamorelin are associated with changes in body composition, fat mass, and lean body mass, there is a great deal more to what these peptides can do.

Tesamorelin vs. Ipamorelin: Properties

Tesamorelin is approved for the treatment of HIV-associated lipodystrophy. This very narrow approval belies the peptide’s wider use as an agent for altering body composition. Research indicates that Tesamorelin can reduce fat mass, boost muscle and bone mass, improve peripheral nerve regeneration, and may even be useful in the treatment of mild cognitive impairment.

Ipamorelin, which underwent phase II clinical trials for the treatment of postoperative ileus, is known to be the most selective ghrelin receptor (aka growth hormone secretagogue receptor/GHSR) agonist yet discovered. It increases plasma growth hormone levels in animals but has no effect on prolactin, follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, or adrenocorticotropic hormone levels. The astounding specificity of Ipamorelin makes it a highly useful peptide for studying the effects of increased GH levels with confounding results by elevating levels of other hormones.

Sermorelin vs Ipamorelin: Structure and Route of Administration

Sermorelin is made up of the first 29 amino acids from the much larger, naturally occurring GHRH peptide. It is the smallest fraction of GHRH than retains all of the properties of the parent molecule. Weighing in at 3357.9 g/mol, Sermorelin is a relatively large, heavy peptide that must be injected sub-cutaneous to be absorbed. It is not orally bioavailable. As a result of its large size, Sermorelin has a more significant three-dimensional structure than Ipamorelin and is thus is a little less stable in terms of storage half-life.

Source: PubChem

Ipamorelin is substantially smaller than Sermorelin at just 5 amino acids and 711.868 g/mol. It is a derivative of GHRP-1, which is itself a derivative of met-enkephalin. Though the most common route of administration for Ipamorelin is via sub-cutaneous injection, the peptide is also orally active and can even be absorbed though the nasal mucosa.

Source: PubChem

Ipamorelin vs Sermorelin: Lean Body Mass

Both Sermorelin and Ipamorelin favor the development of lean body mass over fat mass, but Sermorelin is the more potent of the two. This arises from the fact that Sermorelin is both a growth stimulator and a fat burner while Ipamorelin is a more general growth stimulator. That is not to say that Ipamorelin isn’t effective, it is, but ipamorelin isn’t as strictly favorable of lean body mass deposition as Sermorelin. This difference arises from the fact that Ipamorelin is a ghrelin analogue and ghrelin favors food intake in general. Its growth hormone boosting properties shift the overall balance away from fat deposition and toward lean body mass deposition, but the Ipamorelin peptide is best thought of as a general weight boosting peptide while Sermorelin is best thought of as a more exclusive booster of lean body mass. In fact, Sermorelin is often referred to as a lipolytic or fat-burning peptide.

Both peptides stimulate the development of bone and other connective tissue, but Ipamorelin appears to have the advantage in this realm. In fact, ipamorelin is so effective in boosting bone density and mineralization that it has been investigated as a potential treatment for corticosteroid-induced bone loss as well as osteoporosis[7], [8].

When it comes to muscle growth, Sermorelin is probably the big winner, though this can be debated endlessly. Sermorelin not only boosts muscle hypertrophy and hyperplasia, it reduces fat mass and thus causes a shift in body chemistry toward lean body weight. In other words, Sermorelin will always favor the production of lean body mass even if diet is not perfectly geared toward muscle development. Ipamorelin, on the other hand, is more of a mixed bag. It will always cause muscle growth, but ipamorelin may channel some of those calories into fat deposition as well.

What Is Ipamorelin?

In the world of anti-aging research, a handful of peptides have become superstars. Ipamorelin is one of those peptides. This short peptide is just five amino acids in length, but is one of the most selective growth hormone secretagogue receptor agonists known. This means that ipamorelin research has been shown to help build lean body mass and fight obesity without having unwanted effects on other aspects of the body like hair growth or decreased sexual function[1].

Ipamorelin is a peptide, which means it is made of the same amino acid building blocks found in all proteins. Ipamorelin falls into the subcategory of anti-aging peptides as well as into the subcategory of fat-burning peptides. In animal studies, it has been shown to effectively fight the signs of aging while benefiting muscle growth, bone health, and GI system function.

Because of its relative lack of secondary effects, ipamorelin is often referred to as the gentle growth hormone releasing peptide. This is because, when compared to other peptides like Sermorelin or GHRP-6, Ipamorelin tends to only affect the growth hormone axis. This makes it particularly useful in research exploring the isolated effects of growth hormone secretagogue agonists.

Ipamorelin vs GHRP-2

Many people think that ipamorelin and GHRP-2 are the essentially the same thing. After all, both cause an increase in the secretion of growth hormone (GH). In reality, ipamorelin and GHRP-2 are very different peptides and the fact that they cause GH hormone release is the only thing they really share in common. Below is summary of ipamorelin vs GHRP-2 that outlines the similarities, differences in their respective research studies.

Both ipamorelin and GHRP-2 cause the pituitary gland to release more growth hormone by binding to the growth hormone secretagogue receptor. This means that both peptides are analogues of ghrelin. Ghrelin, a naturally occurring peptide produced in the gastrointestinal tract, is often referred to as the hunger hormone as it stimulates eating behavior. It does so much more than that though.Growth Hormone Releasing Hormone (GHRH).Stimulation of the growth hormone secretagogue receptor (GHS-R) has effects on learning, memory, the sleep-wake cycle (diurnal cycle), reward behavior, glucose metabolism, and even taste sensation. Most importantly, stimulating this receptor impacts energy balance in the body, helping to shift the body from catabolism (the breakdown of stored energy) to anabolism (the storage of energy and the repair and building of muscle and other tissue). This shift occurs via the stimulation of GH release. GHS-Rs are found on both the hypothalamus and the pituitary gland, which means that peptides like ipamorelin and GHRP-2 have a two-pronged approach for stimulating growth hormone release. The first is via direct stimulation of the pituitary gland where GH is stored and the second is via the release of GHRH, which has its own receptors on the pituitary gland for stimulating GH release.