Muscle & Metabolism

CJC-1295 no DAC, also known as Modified GRF 1-29, is a synthetic analog of growth hormone-releasing hormone (GHRH) consisting of 29 amino acids with four strategic amino acid substitutions designed to enhance stability and bioactivity. Unlike CJC-1295 with DAC, this variant lacks the drug affinity complex, resulting in a shorter half-life of 30 minutes to 2 hours that promotes pulsatile growth hormone secretion mimicking natural physiological patterns. Research demonstrates it can increase growth hormone levels by 2- to 10-fold and IGF-1 concentrations by 1.5- to 3-fold in clinical trials. The peptide has been studied for potential applications in age-related GH decline, body composition optimization, and metabolic health. CJC-1295 no DAC is not FDA-approved for human use and is classified as a prohibited substance by WADA for athletic competition. It is available through compounding pharmacies for research purposes, though regulatory status remains uncertain following recent FDA actions on peptide compounding.

AOD-9604 is a synthetic peptide fragment consisting of amino acids 176-191 from the C-terminus of human growth hormone (hGH) with a tyrosine residue added at the N-terminus. Developed by Metabolic Pharmaceuticals Limited, it was designed to mimic hGH's lipolytic (fat-burning) properties without stimulating IGF-1 production or causing insulin resistance. The peptide operates by activating beta-3 adrenergic receptors in adipose tissue, promoting lipolysis while inhibiting lipogenesis. Initial 12-week clinical trials showed modest weight loss (average 2.6 kg vs 0.8 kg placebo), but a larger 24-week trial of 536 subjects failed to demonstrate significant efficacy, leading to termination of development in 2007. Despite lack of FDA approval, AOD-9604 remains available through compounding pharmacies and gray market sources. It is prohibited by WADA as a non-approved substance under category S.0. The peptide has shown potential applications beyond obesity, including cartilage repair in osteoarthritis models.

Follistatin-344 is a naturally occurring glycoprotein that functions as a potent myostatin inhibitor, primarily investigated for muscle growth and therapeutic applications in muscular dystrophy. It works by binding to and neutralizing myostatin and activin, growth factors that normally limit muscle development. The peptide consists of 344 amino acids and undergoes post-translational modification to generate the circulating FS-315 isoform. Preclinical research in mice, pigs, and non-human primates has demonstrated pronounced increases in muscle mass and strength following a single AAV1-mediated gene delivery. Clinical trials are underway for Becker and Duchenne muscular dystrophy, with early results showing improved ambulation without serious adverse effects. Beyond muscle growth, emerging research suggests potential applications in diabetes (promoting pancreatic beta-cell proliferation), bone health (supporting osteogenesis), and metabolic disorders. The peptide remains experimental with limited human safety data available.

IGF-1 DES (des(1-3)IGF-1) is a naturally occurring truncated variant of insulin-like growth factor 1 that lacks the first three N-terminal amino acids (glycine-proline-glutamate). Originally isolated from bovine colostrum, human brain, and porcine uterine tissue, this peptide demonstrates approximately 10-fold greater potency than native IGF-1 due to significantly reduced binding to IGF-binding proteins (IGFBPs), resulting in enhanced bioavailability and receptor activation. Research has primarily focused on its mechanisms in cellular proliferation, muscle hypertrophy, neuroprotection, and potential therapeutic applications in inflammatory bowel disease and neurological conditions. Despite promising preclinical findings, no human clinical trials have been conducted to evaluate its safety or efficacy. IGF-1 DES remains classified as a research chemical, prohibited by WADA for athletic use, and is not approved by the FDA for human consumption or medical treatment. It is available only for research purposes.

Hexarelin (also known as Examorelin) is a synthetic hexapeptide growth hormone secretagogue (GHS) with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2. It functions by binding to the growth hormone secretagogue receptor (GHS-R1a) in the pituitary gland, stimulating potent dose-dependent release of growth hormone with peak plasma concentrations occurring approximately 30 minutes after administration. Beyond its primary endocrine effects, research has revealed significant cardioprotective properties mediated through the cardiac CD36 receptor, independent of growth hormone release. Studies demonstrate protective effects against myocardial infarction, reduced cardiac fibrosis, and improved ventricular function. Hexarelin also exhibits neuroprotective properties, reducing brain injury by up to 39% in animal models through activation of Akt/GSK-3β pathways and enhanced hippocampal neurogenesis. While chronic administration results in partial desensitization (50-75% reduction in efficacy over weeks to months), effects are reversible upon discontinuation. Hexarelin is not FDA-approved for human use and remains classified as a research compound, appearing on WADA's prohibited substances list for athletic competition.

HGH Fragment 176-191 (AOD-9604) is a modified synthetic peptide fragment derived from the C-terminal region of human growth hormone (amino acids 176-191) that was developed to isolate the fat-reducing properties of HGH without its growth-promoting or insulin-antagonistic effects. This peptide stimulates lipolysis (fat breakdown) and inhibits lipogenesis (fat formation) by upregulating beta-3 adrenergic receptors in adipose tissue, which enhances fat oxidation and energy expenditure. While preclinical studies in rodents demonstrated significant reductions in body weight and fat mass, human clinical trials showed mixed results, with some short-term trials showing modest weight loss (2.6 kg over 12 weeks) but larger long-term trials failing to demonstrate statistically significant efficacy, leading to termination of its development as an approved obesity treatment in 2007. Despite not receiving regulatory approval for weight loss, the peptide has shown excellent safety and tolerability profiles across multiple clinical trials involving over 900 participants, with emerging research exploring potential applications in cartilage regeneration and osteoarthritis treatment.

GHRP-2 (Pralmorelin) is a synthetic hexapeptide growth hormone secretagogue that acts as a ghrelin receptor (GHS-R) agonist to stimulate growth hormone release from the pituitary gland. It was the first peptide of this class introduced clinically and operates through a receptor pathway distinct from growth hormone-releasing hormone (GHRH). GHRP-2 has demonstrated potent GH-stimulating effects in both animal and human studies, with additional influences on appetite regulation and ACTH/cortisol secretion. The peptide is currently marketed by Kaken Pharmaceutical in Japan as a diagnostic agent for assessing growth hormone deficiency. Clinical trials have explored its therapeutic potential for treating GH deficiency, short stature, and critical illness, though development for therapeutic applications in the United States was discontinued. Beyond GH stimulation, research has identified cytoprotective properties including cardioprotective, antioxidant, and anti-inflammatory effects. GHRP-2 is well-tolerated in clinical studies with minimal side effects, though it remains primarily approved for diagnostic rather than therapeutic use outside of Japan.

GHRP-1 (Growth Hormone Releasing Peptide-1), also known as KP-101, is a synthetic heptapeptide designed to stimulate growth hormone (GH) release through the ghrelin receptor (GHS-R1a), a pathway distinct from endogenous GH-releasing hormone (GHRH). First synthesized in the early 1990s as part of the GHRP family, GHRP-1 stimulates pulsatile GH secretion in a dose-dependent manner through calcium-mediated mechanisms, with synergistic effects when combined with GHRH. Beyond its primary function as a growth hormone secretagogue, research has identified unexpected cytoprotective properties, including cardioprotective effects during ischemia/reperfusion and potential neuroprotective benefits. GHRP-1 was investigated in a Phase II clinical trial (NCT00381602) for end-stage renal disease patients on hemodialysis, though results remain unpublished. Currently, GHRP-1 is banned by the World Anti-Doping Agency (WADA) and has not received FDA approval for therapeutic use. It remains available exclusively as a research peptide from specialized vendors for laboratory investigations.

CJC-1295 with DAC is a synthetic analog of growth hormone-releasing hormone (GHRH) developed by ConjuChem Biotechnologies, featuring a Drug Affinity Complex that binds to serum albumin for extended half-life of 6-8 days. Clinical trials demonstrated sustained increases in growth hormone (2-10 fold) for 6+ days and IGF-1 (1.5-3 fold) for 9-11 days after a single injection. The peptide was investigated in Phase 2 trials for HIV-associated lipodystrophy but was discontinued following a participant death, though it showed safety and tolerability in healthy adults at doses of 30-60 μg/kg.

IGF-1 LR3 (Long R3 IGF-1) is a synthetic analog of human insulin-like growth factor-1 (IGF-1), featuring 83 amino acids with an arginine substitution at position 3 and an additional 13 amino acids at its N-terminus. These modifications reduce binding affinity to IGF-binding proteins by approximately 1000-fold, resulting in enhanced metabolic stability and a significantly longer half-life of 20-30 hours compared to native IGF-1. Research demonstrates that IGF-1 LR3 is 3-6 times more potent than natural IGF-1 in promoting cellular growth and protein synthesis through PI3K/Akt/mTOR signaling pathways. Primary research applications include studies on muscle hypertrophy, satellite cell activation, neurodegenerative diseases, and metabolic regulation. However, IGF-1 LR3 is not FDA-approved for any human therapeutic use and remains classified as a research chemical. It is prohibited by the World Anti-Doping Agency and most professional sports organizations. The compound is available only for laboratory research purposes, with CAS number 946870-92-4.

MK-677 (ibutamoren) is a non-peptide, orally-active growth hormone secretagogue that selectively mimics the action of ghrelin, stimulating growth hormone (GH) and insulin-like growth factor 1 (IGF-1) secretion. Originally developed by Merck Research Laboratories, it increases GH secretion by up to 97% through activation of the ghrelin receptor, producing sustained elevations in IGF-1 levels comparable to those seen in younger adults. Clinical research has explored its potential applications in muscle wasting, osteoporosis, growth hormone deficiency, frailty, and age-related decline. While studies have demonstrated increases in lean body mass, bone turnover markers, and improved sleep quality, MK-677 remains an investigational drug without FDA approval. Safety concerns include increased risk of congestive heart failure in elderly populations, impaired insulin sensitivity, elevated fasting glucose levels, and fluid retention. It is currently banned by the World Anti-Doping Agency and listed as a prohibited dietary supplement ingredient by the U.S. Department of Defense due to its growth hormone-releasing properties and potential health risks.

Sermorelin is a synthetic 29-amino acid peptide analogue of growth hormone-releasing hormone (GHRH), representing the shortest fully functional fragment of endogenous human GHRH. It stimulates the pituitary gland to produce and secrete natural growth hormone by binding to growth hormone-releasing hormone receptors (GHRHR). Unlike direct growth hormone replacement, sermorelin maintains physiological feedback regulation through somatostatin, promoting pulsatile hormone release that mirrors natural rhythms. Originally FDA-approved in 1997 as Geref for diagnosing and treating pediatric growth hormone deficiency, sermorelin demonstrated effectiveness in increasing height velocity in prepubertal children and served as a rapid diagnostic test for growth hormone insufficiency. Clinical research in adults has shown modest improvements in body composition, particularly increased lean mass in men, elevated IGF-1 levels, and potential benefits for sleep quality and cognitive function. The manufacturer discontinued production in 2008 for commercial reasons, though it remains available through compounding pharmacies for off-label use. While generally well-tolerated with minimal adverse effects, long-term safety data remains limited.

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) functioning as a selective growth hormone secretagogue that binds to ghrelin receptors (GHS-R1a) in the anterior pituitary to stimulate growth hormone release. Originally developed by Novo Nordisk, it represents the first GHRP-receptor agonist with selectivity for GH release comparable to GHRH, notably without stimulating cortisol or ACTH secretion even at doses 200-fold above therapeutic levels. While investigated in Phase II clinical trials for postoperative ileus (discontinued due to lack of efficacy), ipamorelin demonstrates promising preclinical effects on bone growth, muscle preservation, and metabolic function. Currently, it lacks FDA approval for any indication and exists in a regulatory gray area where it's marketed as a research chemical but widely used off-label in peptide therapy clinics for anti-aging, body composition optimization, and recovery enhancement, while simultaneously being prohibited by WADA as a performance-enhancing substance in competitive sports.

GHRP-6 (Growth Hormone-Releasing Peptide-6) is a synthetic hexapeptide that functions as a potent growth hormone secretagogue, stimulating GH release from the pituitary gland primarily through hypothalamic mechanisms. It binds to two receptors (GHS-R1a and CD36), activating phosphatidylinositol second messenger systems and prosurvival pathways including PI-3K/AKT1. Beyond its GH-releasing properties, extensive preclinical research has demonstrated unexpected cytoprotective effects across multiple organ systems, including cardioprotective, neuroprotective, anti-fibrotic, and wound healing properties. Clinical studies have evaluated GHRP-6's safety and efficacy in various contexts, from growth stimulation in children to neuroprotection in stroke patients. Currently, GHRP-6 is not FDA-approved for therapeutic use and remains classified as a research peptide. It is banned by WADA for athletic competition. The compound is available through research chemical suppliers and compounding pharmacies, though its legal status varies by jurisdiction. The peptide has demonstrated a favorable safety profile in Phase I clinical trials with primarily mild adverse events.

Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone (GHRH) that stimulates the production and secretion of endogenous growth hormone from the pituitary gland. The peptide consists of all 44 amino acids of human GHRH with the addition of a trans-3-hexenoic acid group at the N-terminus, which enhances its stability in serum. It was approved by the FDA in November 2010 under the brand name Egrifta as the first and only treatment specifically indicated for reducing excess visceral abdominal fat in HIV-infected patients with lipodystrophy. Clinical trials have demonstrated significant reductions in visceral adipose tissue (15-37% relative reduction), along with improvements in triglycerides, liver fat, and metabolic markers. The peptide has also shown promising effects on cognitive function in older adults and individuals with mild cognitive impairment. Tesamorelin is administered as a once-daily subcutaneous injection and is commercially available by prescription for its FDA-approved indication, though it remains under investigation for additional therapeutic applications including non-alcoholic fatty liver disease and age-related cognitive decline.