Peptides Studied for Longevity & Anti-Aging

Tesamorelin (tesamorelin acetate) is a synthetic 44-amino-acid analog of human growth hormone-releasing hormone (GHRH) and the only FDA-approved medication for reducing excess abdominal fat in HIV-infected adults with lipodystrophy, marketed as Egrifta. It stimulates endogenous GH and IGF-1 production. Egrifta WR, a new weekly-reconstitution formulation, was FDA-approved in March 2025. Phase 3 trials demonstrated significant visceral fat reduction with a generally well-tolerated safety profile over 26 weeks of therapy.

SS-31 (Elamipretide) is a mitochondria-targeted tetrapeptide that selectively concentrates in the inner mitochondrial membrane, binding to cardiolipin and stabilizing cristae structure. It is being developed by Stealth BioTherapeutics for mitochondrial diseases, heart failure, and age-related mitochondrial dysfunction. It has undergone multiple Phase I–III clinical trials, including the TAZPOWER trial for Barth syndrome.

Exenatide is a 39-amino-acid GLP-1 receptor agonist (MW ~4186.6 g/mol) originally derived from exendin-4, a peptide found in the saliva of the Gila monster (Heloderma suspectum). It was the first GLP-1 receptor agonist approved by the FDA, with Byetta (twice-daily injection) approved in April 2005 and Bydureon (once-weekly extended-release) approved in January 2012, both for type 2 diabetes. Exenatide shares approximately 53% sequence homology with human GLP-1 and is resistant to DPP-4 degradation.

Human growth hormone (hGH, somatotropin) is a 191-amino acid protein produced by the anterior pituitary gland. Recombinant human growth hormone (rhGH, somatropin) is FDA-approved for numerous indications including pediatric and adult growth hormone deficiency, Turner syndrome, short stature from small for gestational age (SGA), Prader-Willi syndrome, chronic kidney disease, idiopathic short stature, and short bowel syndrome (Zorbtive). It is one of the most extensively studied hormones in medicine. Off-label use for anti-aging and performance enhancement is widespread but not approved, and GH is banned by WADA in sport.

Glucagon is a 29-amino-acid peptide hormone (MW ~3482.8 g/mol) produced by pancreatic alpha cells that serves as the primary counter-regulatory hormone to insulin. It is FDA-approved for the emergency treatment of severe hypoglycemia and as a diagnostic aid for GI radiographic examination. Multiple formulations are available: traditional reconstituted injection (GlucaGen), intranasal powder (Baqsimi, approved 2019), and ready-to-use auto-injector (Gvoke, approved 2019), representing significant advances in emergency usability.

HGH 191AA refers to recombinant human growth hormone (somatropin) — a 191-amino acid, single-chain polypeptide (MW ~22,124 g/mol) identical in sequence to endogenous pituitary growth hormone. It is FDA-approved for growth hormone deficiency in children and adults, Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, and HIV-associated wasting. In the peptide community, "191AA" distinguishes legitimate somatropin from the older 192-amino acid variant (somatrem, which had an extra methionine and higher immunogenicity).

Somatropin is recombinant human growth hormone (rHGH), a 191-amino-acid protein identical to naturally produced pituitary GH. Unlike secretagogues (which stimulate GH release), somatropin IS the direct hormone. FDA-approved for multiple indications including growth hormone deficiency, Turner syndrome, and chronic renal insufficiency in children.

Vasoactive Intestinal Peptide (VIP) is a 28-amino-acid neuropeptide (MW ~3326.8 g/mol) widely distributed in the central and peripheral nervous systems, lungs, and gastrointestinal tract. It is a potent vasodilator, bronchodilator, and immunomodulator. The synthetic form aviptadil (RLF-100) was investigated for COVID-19-associated acute respiratory distress syndrome (ARDS) and has been studied in pulmonary arterial hypertension. VIP is also used diagnostically in VIPoma identification.

Glutathione is a tripeptide (Glu-Cys-Gly, MW ~307.3 g/mol) and the most abundant intracellular antioxidant in mammalian cells. It is critical for Phase II detoxification, free radical scavenging, immune function, and cellular redox homeostasis. Injectable (SC/IV) glutathione bypasses the poor oral bioavailability (~3%) issue and achieves clinically meaningful plasma levels. It has been studied for conditions ranging from non-alcoholic fatty liver disease to Parkinson disease.

Injectable L-Carnitine is a naturally occurring amino acid derivative (MW ~161.2 g/mol) that facilitates the transport of long-chain fatty acids across the mitochondrial inner membrane for beta-oxidation. While oral L-carnitine has poor bioavailability (5-18%), subcutaneous injection achieves near-100% bioavailability, making it a significantly more effective delivery method. It is FDA-approved in IV form (Carnitor) for primary carnitine deficiency and dialysis patients. SC injectable use for fat oxidation enhancement is off-label but widely used in metabolic optimization clinics.

Sermorelin is a synthetic 29-amino-acid peptide (MW ~3357.9 g/mol) corresponding to the first 29 amino acids of naturally occurring growth hormone-releasing hormone (GHRH). It was previously FDA-approved as Geref for the diagnosis and treatment of growth hormone deficiency in children, though the product was voluntarily discontinued for commercial reasons — the FDA confirmed in 2013 it was not withdrawn for safety reasons. It preserves the body's natural GH feedback loop via somatostatin, making it safer than exogenous HGH. The 1997 JCEM trial remains the most substantial evidence for its effects in adults, demonstrating improvements in IGF-1, body composition, and well-being over 5 months.

MK-677 (Ibutamoren) is a potent, long-acting, orally-active, non-peptide ghrelin receptor (GHS-R1a) agonist that stimulates growth hormone release without injections. Unlike injectable GH peptides such as GHRP-6 or Ipamorelin, MK-677 can be taken orally and maintains elevated GH and IGF-1 levels for up to 24 hours. It has been studied in several human clinical trials for GH deficiency, muscle wasting, bone density, and sleep quality, but is not FDA-approved for any indication.

Hexarelin is a synthetic hexapeptide growth hormone secretagogue that binds to the ghrelin receptor (GHS-R1a). It is considered one of the most potent GHRPs available, stimulating greater GH release than GHRH alone. However, it causes relatively rapid receptor desensitization compared to milder GHRPs like ipamorelin, limiting cycle duration to 4-8 weeks. It also has notable cardioprotective properties independent of GH release.

NAD+ is a fundamental coenzyme present in all living cells that serves as a critical electron carrier in metabolic reactions and a substrate for enzymes including sirtuins, PARPs, and CD38. NAD+ levels decline approximately 50% between ages 40 and 60. While not a peptide, NAD+ and its precursors (NMN, NR) are frequently discussed in peptide communities. IV NAD+ infusions are popular at anti-aging clinics, though large-scale human efficacy trials are limited.

Epidermal Growth Factor (EGF) is a 53-amino acid protein discovered by Stanley Cohen, who shared the 1986 Nobel Prize in Physiology or Medicine for this work. EGF plays a fundamental role in cell growth, proliferation, and differentiation. In medicine, recombinant human EGF (rh-EGF) is used in wound healing products and is approved in several countries (South Korea, Cuba, China) for diabetic foot ulcers and other wound indications. In cosmetics, it is marketed as oligopeptide-1 or sh-oligopeptide-1 for anti-aging. The wound healing evidence is strong; cosmetic anti-aging evidence is more limited.

Thymulin (FTS) is a 9-amino-acid zinc metallopeptide (sequence: pyroGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, MW ~858 g/mol) secreted exclusively by thymic epithelial cells. It requires zinc binding for biological activity and plays a central role in T-cell differentiation and maturation. Thymulin serum levels decline with age and thymic involution, and it has been investigated as an immunomodulator in immunodeficiency states and aging.

Noopept (GVS-111, omberacetam) is a synthetic dipeptide derivative (N-phenylacetyl-L-prolylglycine ethyl ester, MW ~318.4 g/mol) developed at the Russian Academy of Sciences. It is not a true peptide but a peptidomimetic prodrug of the endogenous neuropeptide cycloprolylglycine. Noopept is approved in Russia for treatment of cognitive disorders of vascular and traumatic origin, but has not undergone rigorous clinical evaluation by Western regulatory standards.

AICAR (5-aminoimidazole-4-carboxamide ribonucleoside) is a cell-permeable nucleoside analog (MW ~258.2 g/mol) that is phosphorylated intracellularly to ZMP, which directly activates AMP-activated protein kinase (AMPK). As an exercise mimetic, it triggers many of the same metabolic adaptations as physical exercise — including enhanced glucose uptake, fatty acid oxidation, mitochondrial biogenesis, and improved insulin sensitivity — without requiring muscular contraction. It has been studied in Phase II/III trials for cardiac ischemia and is banned by WADA as a metabolic modulator.

Thymalin is a polypeptide complex isolated from calf thymus glands, developed by Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology. It has been used clinically in Russia since the 1980s for immunodeficiency states and as an anti-aging intervention. A landmark 6-year study by Khavinson et al. (2003) showed thymalin + epithalamin treatment reduced mortality by 4.1x in elderly patients compared to controls. Thymalin is proposed to restore thymic function and T-cell immunity that declines with age.

GHK is a naturally occurring tripeptide first isolated from human plasma. It declines significantly with age. Even without copper complexation, GHK demonstrates gene-regulatory activity affecting over 4,000 genes related to tissue repair, immune function, and anti-inflammatory responses.