Peptide Comparisons
Commonly confused or commonly paired peptides, side by side: how they work, what they're studied for, and where the evidence stands.
- BPC-157 vs TB-500BPC-157 is a 15-amino-acid fragment of a protein found in gastric juice, studied mostly in animals for gut, tendon, and ligament healing. TB-500 is derived from thymosin beta-4, a protein that regulates actin and cell migration, and is studied for tissue repair more broadly. Neither has substantial human trial data. Because their proposed mechanisms differ, they are often combined as the Wolverine stack, but a controlled rat study of Achilles tendon healing found the combination gave no additional benefit over either peptide alone.
- Semaglutide vs TirzepatideBoth are approved once-weekly injections for type 2 diabetes and obesity. Semaglutide activates the GLP-1 receptor; tirzepatide activates both the GIP and GLP-1 receptors. In the SURMOUNT-5 head-to-head trial in adults with obesity, average weight loss at 72 weeks was 20.2% with tirzepatide versus 13.7% with semaglutide.
- Tirzepatide vs GLP-3 RTirzepatide is an approved dual agonist of the GIP and GLP-1 receptors. GLP-3 R is an investigational triple agonist that also activates the glucagon receptor, which is thought to add energy expenditure. Their results come from separate trials rather than a direct comparison, and GLP-3 R is not an approved drug.
- Semaglutide vs GLP-3 RSemaglutide is an approved GLP-1 receptor agonist. GLP-3 R is an investigational single molecule that activates the GLP-1, GIP, and glucagon receptors. GLP-3 R is not approved, and the two have been studied in separate trials rather than head to head.
- CJC-1295 vs IpamorelinThey raise growth hormone through different receptors. CJC-1295 is a GHRH analog, acting on the growth hormone-releasing hormone receptor; ipamorelin is a ghrelin mimetic (GHRP) acting on the ghrelin receptor. Because the two pathways are complementary, they are commonly paired.
- Sermorelin vs TesamorelinBoth are GHRH analogs. Sermorelin is the first 29 amino acids of natural GHRH; it was once FDA-approved but was discontinued by its manufacturer. Tesamorelin is a stabilized full-length GHRH analog that is FDA-approved to reduce excess abdominal fat in people with HIV-associated lipodystrophy.
- Ipamorelin vs GHRP-6Both are ghrelin receptor agonists that trigger growth hormone release. GHRP-6 strongly increases appetite and can raise cortisol and prolactin. Ipamorelin is described as more selective, with little effect on those hormones in the studies that introduced it.
- CJC-1295 vs SermorelinBoth are GHRH analogs. Sermorelin is cleared within minutes. CJC-1295 is modified to resist breakdown, and the version with DAC binds albumin in the blood, extending its action to days.
- Semax vs SelankBoth are synthetic peptides developed in Russia and usually given intranasally. Semax is derived from a fragment of ACTH and is studied for cognition and stroke recovery. Selank is derived from tuftsin, an immune peptide, and is studied mainly for anxiety.
- Melanotan II vs PT-141Both act on melanocortin receptors. PT-141 (bremelanotide) was developed from melanotan II and is FDA-approved for low sexual desire in premenopausal women. Melanotan II is unapproved and is known mainly for tanning, alongside sexual and appetite effects.
- GHK-Cu vs BPC-157GHK-Cu is a naturally occurring copper-binding tripeptide, studied largely in topical skin and wound-healing research. BPC-157 is a synthetic gastric-derived peptide studied by injection and orally in animal models of tissue injury.
- Testosterone Cypionate vs Testosterone EnanthateThe same hormone with slightly different esters. Cypionate's ester is a little longer, but their release profiles are very similar and they are generally treated as interchangeable. Cypionate is the more common formulation in the US.
- Clomiphene vs EnclomipheneClomiphene is a mixture of two isomers: enclomiphene, which blocks estrogen's feedback on the brain and raises the body's own testosterone production, and zuclomiphene, which has estrogen-like activity and a much longer half-life. Enclomiphene is that first isomer on its own and is not FDA-approved.
- AOD-9604 vs HGH Fragment 176-191AOD-9604 is a modified version of the hGH fragment 176-191, the part of growth hormone associated with fat breakdown, with an added amino acid at one end. Both were studied for fat loss; AOD-9604's clinical trials did not show meaningful weight loss.
- Anastrozole vs ExemestaneBoth are aromatase inhibitors approved for breast cancer. Anastrozole is non-steroidal and binds the enzyme reversibly. Exemestane is steroidal and binds it irreversibly, permanently disabling each enzyme molecule it hits.
- NAD+ vs NMNNMN is a direct precursor that cells convert into NAD+. In peptide contexts NAD+ is typically injected or infused, while NMN is usually taken orally. Both are studied for age-related decline in NAD+ levels.
- MOTS-c vs SS-31 (Elamipretide)Both target mitochondria in different ways. MOTS-c is a peptide encoded in mitochondrial DNA that acts as a metabolic signal, activating AMPK. SS-31 (elamipretide) is a synthetic peptide that binds cardiolipin in the inner mitochondrial membrane, and it has been tested in human trials for mitochondrial disease.