Exercise Mimetics
Type Mechanism / biological process
Primary compounds SLU-PP-332
Overview
Exercise mimetics target the transcriptional programs activated by endurance exercise without requiring physical activity. The key distinction from older compounds (AICAR, Cardarine, SR9009): direct nuclear targeting of the terminal transcriptional effectors rather than upstream kinases.
Evolution of Exercise Mimetics
| Compound | Target | Problem |
|---|---|---|
| AICAR | AMPK | Skews toward Type IIb glycolytic fibers |
| Cardarine (GW501516) | PPARδ | Caused cancer — abandoned |
| SR9009 | Rev-Erbα/β | Circadian disruption, poor oral bioavailability |
| SLU-PP-332 | ERR α/β/γ | First direct nuclear targeting; cancer risk theoretical |
ERR — The Endurance Transcription Factors
Estrogen-related receptors (ERRα, ERRβ, ERRγ) are the nuclear receptors that directly activate PGC-1α transcriptional programs:
| Isoform | EC₅₀ | Tissue | Function |
|---|---|---|---|
| ERRα | 98 nM | Muscle, adipose | Mitochondrial biogenesis, endurance |
| ERRβ | 215 nM | CNS, embryonic | Stem cell pluripotency |
| ERRγ | 340 nM | Heart, kidneys | Cardiac oxidative metabolism |
ERRα is the master regulator of muscle endurance capacity — it orchestrates the entire oxidative phosphorylation program.
SLU-PP-332’s Mechanism
- Direct ERR agonism → PGC-1α activation → mitochondrial biogenesis
- Full ETC upregulation: Complex I–V genes all upregulated
- Antioxidant upregulation: SOD1 +131%, SOD2 +45%, Catalase +61%, GPX1 +71%
- Cardioprotection: Rescues ejection fraction in heart failure without hypertrophy (E2F1 suppression)
- Works during immobilization: Signal is transcriptional, not mechanical
Metabolic Outcome
In DIO mice (50 mg/kg/day × 4 weeks):
| Metric | Result |
|---|---|
| Fat mass | −20% |
| Fasting glucose | −30% |
| Insulin sensitivity | +50% |
| Treadmill running distance | +50% |
| Food intake | No change |
Mechanism of fat loss: SLU-PP-332 doesn’t suppress appetite. Fat loss comes from massively increased oxidative metabolism — fatty acids are burned, not just mobilized.
Stacking with Retatrutide
The synergy is mechanistically precise:
- Retatrutide (GCGR) → hepatic lipolysis → free fatty acids released into circulation
- SLU-PP-332 (ERR) → primes muscle mitochondria to incinerate those fatty acids
- Result: Fatty acids are not just mobilized — they are actually oxidized
This is why the combination produces more fat loss than either alone without increasing appetite (appetite is suppressed by Retatrutide’s GLP-1 axis, not driven by the GCGR axis).
MOTS-c — AMPK-First Exercise Mimetic
MOTS-c converges on AMPK via a different route from SLU-PP-332 (ERR/PGC-1α):
| SLU-PP-332 | MOTS-c | |
|---|---|---|
| Primary target | ERRα/β/γ → PGC-1α | Folate cycle → AICAR → AMPK |
| Downstream | Transcriptional mitochondrial biogenesis | Epigenetic reprogramming, GLUT4 translocation |
| Myostatin effect | Indirect (via overall metabolism) | Direct (CK2-PTEN-mTORC2-AKT-FOXO1) |
| Half-life | Not peptide (small molecule) | <2 hours (requires injection) |
| Oral | Yes (bioavailable) | No (SubQ/IM only) |
Together: SLU-PP-332 builds the engine (ERR/PGC-1α → more mitochondria); MOTS-c optimizes the fuel and protects muscle (AMPK + myostatin inhibition). Complementary exercise mimetic pair.
MOTS-c also prevents β-cell senescence (2025 SNU) and signals via NRG1-ErbB4 for cardiac protection — benefits SLU-PP-332 does not address.
Required Support Stack
| Add | Rationale |
|---|---|
| GHK-Cu | Upregulates SOD/catalase/GPX — handles increased mitochondrial ROS |
| NAD+ precursors | SIRT1 (involved in PGC-1α deacetylation) is NAD+-dependent |
| Glutathione | Direct antioxidant buffer for mtROS |
| Creatine | Buffers ATP from newly expanded mitochondrial pool |
Cancer Risk Note
ERRα is overexpressed in aggressive breast/prostate cancers. However, SLU-PP-332 activates ERR (pro-growth in this context) while Cardarine blocked apoptosis (the lethal part). The risk is theoretical, not confirmed — but cycling is mandatory.
Links
- SLU-PP-332 (anchor compound)
- MOTS-c — AMPK-first complementary exercise mimetic
- GLP-1 GIP Glucagon — metabolic overlap with Retatrutide
- Peptides MOC
Source: Washington University / UF research · Gemini Deep Research · PeptideDosages.com 2026-03-20