Studies in Ipamorelin for Muscle Growth and Bone Density

by | Jan 25, 2023 | Research

Ipamorelin, also known as NNC 26-0161, is a pentapeptide with the amino acid sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2. Researchers suggest it may induce a peak in growth hormone (GH) synthesis by the pituitary gland via activating the growth hormone secretagogue receptors (GHS-Rs). In this respect, Ipamorelin is classified as a growth hormone secretagogue (GHS). It appears mimic the hunger hormone Ghrelin, which is considered a natural activator of the GHS-Rs.

Ipamorelin peptide appears to differentiate itself from other GHSs as a potentially more selective option that elevates GH levels without increasing other pituitary hormones, such as prolactin. Studies are still underway with this peptide within the context of postoperative ileus and speeding up the recovery of gastrointestinal function following damage.




Ipamorelin and Growth Hormonse Synthesis

Studies suggest that Ipamorelin may be a highly selective growth hormone secretagogue, which may be capable of increasing GH levels in animals by activating the GHS-R receptors.[1,2]

Research studies report that the effect may occur relatively quickly – as soon as 40 minutes after exposure, there appeared to be a peak in GH levels. Increasing GH levels may potentially have numerous potential impacts, such as preserving muscle and lean body mass, increasing energy levels, improving bone mineral density, and more. [3]


Ipamorelin and Gastrointestinal Functions

Ipamorelin has been studied for its potential to alleviate delayed gastric emptying and post-surgical ileus in animals. In rodents, the peptide may significantly accelerate the rate of gastric emptying through stimulating gastric contractility.[4] The route via which the peptide may act appears to be by activating a ghrelin receptor-mediated mechanism involving cholinergic excitatory neurons. The researchers reported that “Ipamorelin (0.014 µmol/kg intravenous) resulted in a significant acceleration (P < 0.05 vs vehicle-treated rat) of gastric emptying with 52% ± 11% of the meal remaining in the stomach compared to nonsurgical control animals with 44% ± 6%.


Ipamorelin and Appetite, Weight

Existing research suggests that Ipamorelin may increase appetite, reduce weight loss in the context of research studies in wasting disorders. This hypothesis is based on animal study findings. According to the researchers, these hypotheses are due to the apparent appetite-increasing characteristics of Ipamorelin.[5] The peptide appears to activate the receptors of the hunger hormone, which in turn may result in an increased food intake.

On the other hand, any growth hormone-increasing potential of Ipamorelin may also help reduce weight loss, especially protein loss. Studies posit that Ipamorelin may reduce muscle wasting in cortisol-exposed animals and help maintain a positive nitrogen balance.[6] The researchers conclude that “Accelerated nitrogen wasting in the liver and other organs caused by prednisolone [exposure] was counteracted by [influence] with either GH or its secretagogue Ipamorelin.

Another trial observes that Ipamorelin appears to negate the GH-inhibiting action of glucocorticoids in tested animals.[7] Animal studies suggest that Ipamorelin may also stimulate insulin secretion, another anabolic hormone that can help reduce muscle loss in wasting disorders.[8]


Ipamorelin and Bone

Growth hormones are considered a factor in maintaining optimal bone mineral density. Animal studies suggest that thanks to Ipamorelin’s alleged action on growth hormone synthesis and body weight, it may help maintain or even increase bone mass. One study on thirteen-week-old female Sprague-Dawley rats suggested that Ipamorelin exposure appeared to significantly increase bone mineral content after 12 weeks.[9] The increase was measured via a DEXA (dual-energy X-ray absorptiometry) scan and was significantly higher than the placebo group.

Another animal trial on rats treated with glucocorticoids reported that Ipamorelin has the potential to completely negate bone loss induced by glucocorticoids.[10] The scientists report that the periosteal bone formation rate increased four-fold in animals exposed to glucocorticoids and Ipamorelin in combination, compared with the group that received glucocorticoids alone.

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