Peptide Therapy, Graded By the Same Evidence Standard as Everything Else
Peptide therapy attracts more marketing hype, and more vague sourcing, than almost anything else in this field. Every guide below states plainly what has actually been studied in humans, what is still animal or cell-culture data, and what each compound's regulatory status is. New to the category? Start with What Are Peptides below.
Signals First, Symptoms Second
Peptides are signaling molecules. Some act on receptors on the cell surface, and others work inside the cell or the mitochondria, but all of them change cellular metabolism, mitochondrial function, inflammation, or repair processes downstream. That's the same cell-signaling-to-clinical-phenotype chain every guide on this site is organized around. The full reasoning behind that approach is on the Cellular Medicine page.
CJC-1295, Hexarelin, Ipamorelin, Sermorelin, and Tesamorelin
Peptides that stimulate the body's own growth hormone release rather than replacing growth hormone directly.
CJC-1295
A long-acting GHRH analog often paired with a growth-hormone-releasing peptide to amplify pulsatile GH secretion.
Read the Guide GH SecretagogueHexarelin
A potent early growth-hormone secretagogue with an unusual second mechanism: in animal and cell studies, it binds a separate heart-tissue receptor (CD36) and protects heart cells in ways that appear independent of growth hormone. These are promising signals of potential human benefit, and human heart studies are the next step.
Read the Guide GH SecretagogueIpamorelin
A selective ghrelin-receptor agonist studied for a cleaner side-effect profile than older growth-hormone-releasing peptides.
Read the Guide GHRH AnalogSermorelin
One of the original growth-hormone-secretagogue peptides, still used today for a more physiologic secretion pattern.
Read the Guide GHRH AnalogTesamorelin
The same active compound as FDA-approved Egrifta, approved for reducing excess belly fat in adults with HIV-associated lipodystrophy, with a strong body-composition trial base. Typical clinic uses are off-label.
Read the GuideBPC-157, TB-500, and GHK-Cu
Peptides studied for tendon, gut, skin, and soft-tissue repair, with evidence ranging from a randomized human trial of topical GHK-Cu to promising animal research that sets up the next round of human studies.
BPC-157
A gastric peptide fragment with a large and consistent body of animal research on tendon, ligament, and gut repair. These findings are promising signals of potential human benefit, which is why well-designed human studies are warranted.
Read the Guide RepairTB-500
A thymosin beta-4 fragment studied for tissue repair, and the identity question that determines which body of research actually applies to it.
Read the Guide Skin & CollagenGHK-Cu
A copper-binding tripeptide with a randomized, double-blind human trial showing reduced wrinkle depth and volume with a topical serum. Human studies of injectable GHK-Cu have not been done yet, so this guide focuses on topical use.
Read the GuideKPV, MOTS-c, VIP, SS-31, and Thymosin Alpha-1
Peptides that map directly onto specific levels of the Cellular Medicine framework: inflammation, mitochondrial function, and immune regulation.
KPV
An alpha-MSH-derived tripeptide with a well-defined anti-inflammatory mechanism and promising lab and animal research in gut and systemic inflammation. Human treatment studies are the next step.
Read the Guide MitochondrialMOTS-c
A mitochondrial-derived peptide encoded inside the mitochondrial genome itself. In people, higher natural levels track with better metabolic health and exercise capacity, and treatment trials of MOTS-c itself are the next step.
Read the Guide Immune ModulatorVIP
A neuropeptide with a well-established anti-inflammatory and immune-regulating mechanism and promising early human studies in sarcoidosis and chronic inflammatory illness.
Read the Guide Mitochondrial MembraneSS-31 (Elamipretide)
A cardiolipin-binding peptide that targets the mitochondrial inner membrane directly, FDA approved in 2025 as Forzinity for Barth syndrome, a rare genetic mitochondrial disease. Other uses, including aging research, are investigational.
Read the Guide Immune ModulatorThymosin Alpha-1
A thymic immune-modulating peptide with randomized trial data in hepatitis B, lung cancer, and liver cancer, and approval in more than 30 countries, though not yet in the US.
Read the GuideSemax, Selank, and Epitalon
Three peptides studied for cognition, stress, and aging. Each has a well-characterized mechanism in animal models, with human data that is still early and is graded that way in each guide.
Semax
A neuroactive peptide studied for cognition, neuroprotection, and stress resilience, with substantial mechanistic research and an emerging human evidence base.
Read the Guide NeuroSelank
An anxiolytic peptide studied for stress regulation, GABA-related signaling, and cognitive effects.
Read the Guide LongevityEpitalon
A short peptide studied for telomerase activity, pineal and circadian signaling, and lifespan in animal models.
Read the GuidePT-141 and Kisspeptin
Two peptides that act on desire and arousal in the brain rather than blood flow in the body, one with real FDA approval and real controversy attached to its evidence, the other unapproved but backed by a genuine randomized human trial.
PT-141 (Bremelanotide)
The only FDA-approved sexual-wellness peptide, approved as Vyleesi for low sexual desire in premenopausal women. It works on melanocortin receptors in the brain rather than on blood flow, and other uses, including in men, are off-label.
Read the Guide HPG AxisKisspeptin
A key upstream regulator of the reproductive hormone axis, with randomized human studies showing effects on sexual brain processing and desire. Larger trials are the next step.
Read the GuideCommon Questions
From the Blog
Peptides Aren't Magic. They're Messengers: How peptides work as signals that bind receptors, and why results vary from person to person.
Have a Question, or Want to Find a Clinic?
If you're already a patient, bring this up with your care team at your next visit. If you're not a patient yet and want to ask a question first, or find one of our clinics, reach out directly.