Peptide directory

Protirelin is synthetic thyrotropin-releasing hormone (TRH). Historically used as a diagnostic pituitary-thyroid challenge agent. Current U.S. public labeling on DailyMed reflects a compounded product, and PubChem notes protirelin is not currently available in an FDA-approved product.

PT-141 (bremelanotide, brand name Vyleesi) is a nonselective melanocortin receptor agonist and the only peptide in this batch with a current FDA therapeutic label. It is approved for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. It acts centrally on melanocortin signaling — not as a vasodilator.

PTD-DBM is a synthetic, cell-penetrating competitor peptide engineered to disrupt the CXXC5-Dishevelled (Dvl) protein-protein interaction. By displacing CXXC5 — a negative feedback regulator of Wnt — it reactivates Wnt/β-catenin signaling and downstream wound-healing and follicle-regeneration programs. No human clinical data identified.

Retatrutide (LY3437943) is a once-weekly synthetic peptide and the most-advanced "triple G" agonist in development. A single molecule activates all three of GLP-1R, GIPR, and GCGR. As of 2026 it remains investigational, with peer-reviewed phase 2 obesity data and company-reported phase 3 readouts in type 2 diabetes; no marketed label exists yet.

Selank is a synthetic tuftsin analog (Thr-Lys-Pro-Arg-Pro-Gly-Pro) marketed in Russia as a 0.15% intranasal drop. It functions as an anxiolytic neuropeptide without a single universally accepted receptor mechanism. It is not FDA or EMA approved.

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) — an analog of an ACTH fragment, but devoid of hormonal activity. Marketed in Russia as a 0.1% (general use) and 1% (stroke) intranasal drop. Used for neuroprotection, stroke recovery, cognitive disorders, optic-nerve disease, and adaptation under stress.

Sermorelin is a synthetic analog of the first 29 amino acids of human growth hormone-releasing hormone (GHRH(1-29)NH2). It was FDA-approved as Geref for both GH-reserve diagnostic testing and pediatric growth hormone deficiency treatment; the FDA documented that the products were later withdrawn from sale, but not for reasons of safety or effectiveness.

SLU-PP-332 is an experimental small molecule (not a peptide). Primary reports describe it as a synthetic agonist of ERRα/β/γ, with highest potency for ERRα. Follow-on medicinal chemistry emphasizes that the parent compound lacks oral bioavailability, motivating development of orally active follow-up agonists. There is no approved human use.

SNAP-8 (acetyl octapeptide-3) is an eight-amino-acid extension of Argireline, marketed as a topical cosmetic anti-wrinkle peptide. It is not an approved therapeutic drug. The proposed mechanism is interference with SNARE-complex assembly at the neuromuscular junction, conceptually mirroring botulinum-toxin biology at a much weaker, topical scale.

Syn-AKE is the cosmetic ingredient dipeptide diaminobutyroyl benzylamide diacetate — a waglerin-1 inspired peptide designed to antagonize muscular nicotinic acetylcholine receptors. It is a topical cosmetic active, not an approved drug.

Syn-Coll is palmitoyl tripeptide-5, a palmitoylated cosmetic signaling peptide positioned as anti-aging and collagen-supporting. The strongest publicly visible evidence is mechanistic and ex vivo rather than large clinical outcome trials.

TB-500 — as flagged by the FDA — refers specifically to the thymosin beta-4 fragment LKKTETQ, not full-length thymosin beta-4. The two are frequently conflated in marketing material, but the FDA states it lacks human exposure data for fragment-containing drug products. No approved human medicine exists.

Tesamorelin is a synthetic growth hormone-releasing factor analog, FDA-approved as Egrifta SV and Egrifta WR formulations for reduction of excess abdominal fat in HIV-infected adults with lipodystrophy. The two formulations are explicitly not substitutable. It is not a general weight-loss drug.

Thymalin is a polypeptide extract from calf thymus tissue marketed in Russia and Belarus as an immunostimulant. It is a peptide complex rather than a single defined short peptide; not FDA or EMA approved.

Thymosin alpha-1 (thymalfasin / Zadaxin) is a synthetic 28-amino-acid peptide identical to the endogenous form. International monographs describe use in chronic hepatitis B and as an immunomodulator. It is NOT FDA-approved — the FDA's 2024 compounding briefing explicitly states no Tα1 drug products are approved in the U.S.

Tirzepatide is the active ingredient in Mounjaro and Zepbound. It is an FDA-approved synthetic peptide that activates both GIP and GLP-1 receptors. The current Zepbound label covers chronic weight management and moderate-to-severe obstructive sleep apnea in adults with obesity; Mounjaro is approved for type 2 diabetes. Tirzepatide products were first approved in the U.S. in 2022.

Tripeptide-29 is a collagen-like Gly-Pro-Hyp tripeptide used in cosmetic anti-wrinkle and firmness products. The direct mechanistic evidence base is thin — claims rest on the collagen-mimetic motif and related collagen-tripeptide biology rather than human studies of the molecule itself.

Triptorelin is a GnRH agonist FDA-approved as TRELSTAR for advanced prostate cancer. Non-U.S. labeling extends use to endometriosis, fibroids, hormone-responsive breast cancer, infertility protocols, and central precocious puberty (Decapeptyl).

Vialox is generally described as pentapeptide-3, a temple-viper inspired topical anti-wrinkle cosmetic active. It is a competitive antagonist at postsynaptic acetylcholine receptors at the cosmetic-level dose.

Vilon is a synthetic Lys-Glu thymic dipeptide from the Russian peptide-bioregulator literature, the same tradition that produced Thymalin and related compounds. The evidence base is much less standardized and less internationally regulated than for approved endocrine peptides.

VIP is an endogenous neuropeptide with broad vasoactive, pulmonary, gastrointestinal, and immunomodulatory functions. The main synthetic therapeutic analog in the literature is aviptadil (Zyesami). It remains investigational in the U.S. rather than FDA-approved.