The OSYRIS Metabolic category is the largest in the catalog with 6 primary compounds (plus cross-listings). These compounds fall into three distinct pharmacological approaches:

Approach 1: Incretin Receptor Agonism

The incretin progression is OSYRIS's most distinctive offering. No other vendor provides all three agonism levels (single, dual, triple) plus amylin agonism in research-grade format. This enables systematic subtractive pharmacology: testing each level under identical conditions to isolate the contribution of each additional receptor.

The key insight: Each receptor adds qualitatively different metabolic effects, not just more of the same:

• GLP-1 alone: appetite suppression + insulin secretion + gastric slowing
• + GIP: adipose tissue insulin sensitization + potential bone protection + anti-nausea
• + Glucagon: hepatic fat oxidation + thermogenesis + energy expenditure increase

Cagrilinitide represents a fourth pathway (amylin) that modulates appetite through brainstem circuits distinct from GLP-1's hypothalamic mechanisms. It's studied both alone and in combination with GLP-1 agonists.

Approach 2: Direct Fat Metabolism

AOD-9604 takes a completely different approach to metabolic research. Rather than modulating appetite through receptor signaling, it directly stimulates fat breakdown (lipolysis) and inhibits fat formation (lipogenesis) in adipose tissue. It's the C-terminal fragment of growth hormone — the specific piece responsible for GH's fat-metabolizing effects, isolated from all other GH activities.

What makes this approach distinct: AOD-9604 doesn't affect appetite, insulin, glucose, or IGF-1. It's a direct intervention on fat tissue metabolism through beta-3 adrenergic receptors. This makes it a clean tool for studying fat metabolism independent of appetite and glucose variables.

Approach 3: Exercise-Mimetic Metabolism

SLU-PP-32 and MOTS-C (cross-listed from Longevity) represent pharmacological tools for studying exercise-induced metabolic adaptation without physical activity:

• SLU-PP-32 activates ERR (estrogen-related receptors) — nuclear receptors that drive exercise-induced gene expression programs including mitochondrial biogenesis and fatty acid oxidation.
• MOTS-C activates AMPK — the cell's energy sensor that triggers the metabolic cascade normally activated by exercise.

Different targets (ERR vs AMPK), same research question: which exercise benefits are mediated by each specific pathway?

The Metabolic category has the widest range of evidence quality in the OSYRIS catalog:

Strongest evidence: GLP-1 (S), GLP-2 (T) — backed by extensive Phase 3 clinical trials with thousands of participants. These have the most robust human data of any compounds OSYRIS sells.

Moderate evidence: GLP-3 (R) — Phase 2 clinical data (smaller sample sizes, shorter duration). AOD-9604 — Phase 2 trial data (safety confirmed, efficacy equivocal). Cagrilinitide — Phase 2 data in combination studies.

Early evidence: SLU-PP-32 — preclinical with limited published data. MOTS-C — growing preclinical data from one primary laboratory.

Researchers should calibrate their expectations to the evidence level of each compound.