Beginner Guide
What Are Hormonal Peptides?
A simple explanation of OSYRIS hormonal peptides, focused on melanocortin receptor biology and the central signaling pathways behind PT-141.
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
Featured Links
See how PT-141, melanocortin biology, and adjacent hormonal pathways fit together in the broader category context.
Read → Shop Collection Hormonal CollectionBrowse PT-141 and follow future hormonal-category expansions from the main collection page.
Browse → Beginner Guide What Are Research Peptides?Start with the broad primer on what peptides are, how they are studied, and why RUO context matters.
Read →Questions
Common Questions
Why is there only one product in this category?
The Hormonal category currently focuses on melanocortin-mediated research (PT-141). Additional compounds are planned for future expansion.
How does PT-141 work?
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.
Is PT-141 FDA approved?
A pharmaceutical version (Vyleesi) is FDA-approved. OSYRIS PT-141 is research-grade for laboratory use only.
How is PT-141 different from Melanotan 2?
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.
Can PT-141 be used for metabolic research?
Yes. MC4R agonism affects appetite and energy expenditure, making PT-141 relevant to metabolic studies beyond its primary hormonal category.
When will new hormonal compounds be available?
Kisspeptin, HCG, and Oxytocin are under evaluation. Subscribe to product notifications on the collection page.
