Metabolic Investigational

SLU-PP-332

Also known as: Exercise Pill, ERR Agonist

An ERR receptor agonist that mimics the molecular effects of endurance exercise — increases fatigue-resistant muscle fibers and running endurance in animal models.

Popularity B
Class ERRα/γ Agonist (Small Molecule)
Half-Life Not fully characterized in humans
Form Powder (research grade)
Jump to Dosing ↓
Athletic man in a modern home gym holding a small glass vial with vibrant purple
Research-Backed User Reports Sourced Updated Mar 2026
// Overview

What is SLU-PP-332?

SLU-PP-332 is a small molecule agonist of estrogen-related receptors alpha and gamma (ERRα/ERRγ) developed by researchers at Washington University in St. Louis (SLU). Published in 2023, it has generated significant interest as a potential “exercise mimetic” — a compound that activates the same metabolic pathways as endurance exercise.

In animal studies, SLU-PP-332 treatment increased fatigue-resistant muscle fibers, enhanced running endurance, and improved metabolic markers without any change in physical activity. Treated mice ran significantly longer and farther than controls, demonstrating genuine exercise-mimicking effects.

ERR receptors are master regulators of mitochondrial biogenesis and oxidative metabolism in muscle. SLU-PP-332 activates these receptors to upregulate the same gene networks that endurance training naturally triggers, including programs for fatty acid oxidation, mitochondrial respiration, and muscle fiber type switching.

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// How It Works

How SLU-PP-332 Works

SLU-PP-332 activates estrogen-related receptors (ERRs) to mimic exercise adaptations:

  1. ERRα/ERRγ activation — These nuclear receptors are master regulators of mitochondrial biogenesis and oxidative metabolism. Exercise naturally upregulates ERR activity; SLU-PP-332 does the same pharmacologically.
  2. Muscle fiber type switching — Promotes conversion of fast-twitch glycolytic fibers (Type IIb) toward slow-twitch oxidative fibers (Type I), increasing fatigue resistance — the same adaptation seen with endurance training.
  3. Mitochondrial biogenesis — Upregulates PGC-1α and downstream mitochondrial genes, increasing mitochondrial density and oxidative capacity in skeletal muscle.
  4. Fatty acid oxidation — Enhances the muscle's ability to burn fat as fuel, improving metabolic flexibility and endurance capacity.
// Dosage Protocols

Dosage Information (User-Reported)

Disclaimer: Dosage information is compiled from user reports and published research. This is not medical advice. Consult a healthcare professional before use.
Level Dose Frequency Duration
Animal Studies ~50 mg/kg Twice daily (oral, in mice) 4-8 weeks
Human Equivalent Not established TBD TBD

What to Expect

Note

SLU-PP-332 is very early-stage. Limited human anecdotal data exists.

Animal Data

Mice showed increased running endurance within 2-4 weeks of dosing. Muscle fiber composition shifted toward fatigue-resistant types. No significant adverse effects observed.

Community Reports

Early adopters report improved endurance and reduced exercise fatigue, but data is extremely limited and uncontrolled.

Common Stacks

MOTS-c

Dual Exercise Mimetic

Both activate exercise-related metabolic pathways through different mechanisms — AMPK + ERR receptor activation

Cardarine (GW501516)

Endurance Stack

PPARδ agonist pairs with ERR agonist for complementary endurance and fat oxidation pathways

Creatine

Performance Foundation

Provides ATP buffer for enhanced high-intensity performance alongside SLU-PP-332's endurance effects

// Preparation

Reconstitution & Storage

Research use only. Typically dissolved in DMSO for in vitro studies or prepared in vehicle solutions for animal dosing. Not established for human administration.

Storage: Store at -20°C desiccated. Protect from light and moisture.
// Safety Profile

Side Effects & Safety

Potential Side Effects

  • ! Very limited human safety data
  • ! Animal studies showed good tolerability at tested doses
  • ! Potential for hormonal interactions (ERR receptors are related to estrogen receptor family)
  • ! Long-term effects unknown

Contraindications

  • ⚠ Not established for human use — investigational only
  • ⚠ Pregnancy or breastfeeding
  • ⚠ Hormone-sensitive conditions (theoretical concern due to ERR receptor family)
  • ⚠ No clinical safety data available

Legal & Regulatory Status

Not FDA-approved. Very early-stage research compound. Available from select research chemical vendors. Not a controlled substance. Not intended for human consumption.

// Research

Published Research

// Related Compounds

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This content is for informational and educational purposes only. SLU-PP-332 is sold for research purposes. Never Natty does not condone or encourage the use of any substance in violation of any laws. Consult a healthcare professional before using any compound discussed on this site.