Hormonal Peptides in Plain Language
The OSYRIS Hormonal category currently focuses on melanocortin biology — a receptor system in the brain and body that regulates pigmentation, appetite, sexual function, and stress response through five receptor subtypes (MC1R-MC5R).
PT-141 — the sole current product — is a melanocortin receptor agonist that acts in the central nervous system, targeting MC3R and MC4R receptors in the hypothalamus. Unlike peripheral-acting compounds, PT-141 works through brain signaling pathways — specifically dopaminergic and oxytocinergic circuits.
PT-141 is notable for having an FDA-approved pharmaceutical equivalent (Vyleesi/bremelanotide), which provides validated human pharmacological data that informs preclinical research design.
What's in the OSYRIS Hormonal Category
| Compound | Target | Mechanism |
|---|---|---|
| PT-141 | MC3R, MC4R (brain) | Central melanocortin agonism |
Related melanocortin compounds in other categories:
- Melanotan 2 (Aesthetics) — non-selective MC1R-MC5R, pigmentation focus
- KPV (Immune) — α-MSH fragment, NF-κB inhibition (receptor-independent)
Planned expansion: Kisspeptin, HCG, Oxytocin (not yet available)
Where to Go Next
Choose Your Next Step
Move from the beginner overview into the category guide, collection page, or broader peptide primer depending on how deep you want to go next.
Hormonal Category Guide
See how PT-141, melanocortin biology, and adjacent hormonal pathways fit together in the broader category context.
Hormonal Collection
Browse PT-141 and follow future hormonal-category expansions from the main collection page.
What Are Research Peptides?
Start with the broad primer on what peptides are, how they are studied, and why RUO context matters.
Frequently Asked Questions
Questions About What Are Hormonal Peptides?
The Hormonal category currently focuses on melanocortin-mediated research (PT-141). Additional compounds are planned for future expansion.
It crosses the blood-brain barrier and activates MC3R/MC4R melanocortin receptors in the hypothalamus, triggering downstream dopaminergic signaling. This is a central (brain) mechanism, not a peripheral one.
A pharmaceutical version (Vyleesi) is FDA-approved. OSYRIS PT-141 is research-grade for laboratory use only.
PT-141 is more selective for MC3R/MC4R (brain receptors). Melanotan 2 activates MC1R-MC5R non-selectively (including pigmentation). PT-141 was derived from MT-II.
Yes. MC4R agonism affects appetite and energy expenditure, making PT-141 relevant to metabolic studies beyond its primary hormonal category.
Kisspeptin, HCG, and Oxytocin are under evaluation. Subscribe to product notifications on the collection page.
Keep Following the Research Trail
PT-141 — Melanocortin Signaling and the Central Nervous System
PT-141 (bremelanotide) melanocortin receptor research. MC3R/MC4R, CNS mechanism, energy homeostasis. PubMed citations.
Hormonal Peptides — Melanocortin Signaling and Beyond
Guide to sexual and hormonal health research peptides. Melanocortin receptors, CNS mechanisms, MC4R biology. Current catalog and pipeline.
What Are Research Peptides?
What are research peptides? A plain-language introduction covering peptide biology, how they're made, categories, quality, and regulatory context.