ERR Pan-Agonist · Exercise Mimetic · Oral Capsule · Protocol Guide

SLU-PP-332: The Honest Exercise Mimetic Guide

SLU-PP-332 is an oral small molecule that switches on the estrogen-related receptors (ERR), the genetic program your muscles run during aerobic exercise. The biology is genuinely interesting. The catch is the size of the gap: every result so far is from mice and cells. There is no human data at all.

FDA Status: Investigational, 503A Compounded
Pharmacy: Optimal Balance Pharmacy (503A licensed)
Medical Service: RxPepsDirect, physician-supervised
Access: 28 U.S. States

Our promise: There is no human evidence for SLU-PP-332. None. Every published study is in mice or cultured cells, and the lead studies come from the academic group that invented the molecule. This guide treats that as the headline, not a footnote.

Medically reviewed by Dr. Jonathan Snipes, MD. Last reviewed June 8, 2026.

On this page

Quick Protocol

SLU-PP-332

Oral capsuleERR agonist exercise mimetic

When: Flexible. Many users take it earlier in the day, and some pair the dose with their training window.
Food: No established food requirement. There is no human pharmacokinetic data to optimize around.
How often: Once daily.
Duration: Kept short and supervised. Re-evaluate with your prescriber before extending.
Cycling: No trial-derived cycling guidance exists because there are no human trials. Course length is a physician decision.

Why this timing matters

SLU-PP-332 activates the estrogen-related receptors (ERRalpha, beta, gamma), switching on a slice of the gene program muscle runs during aerobic exercise. It acts on transcription rather than a hormonal pulse, so timing is flexible. The honest caveat: all of this is demonstrated only in mice and cells, and the molecule has limited oral bioavailability in animals, so human exposure from an oral capsule is unknown.

Before your first dose

Take one 250 mcg capsule by mouth as directed by your prescriber.
No reconstitution, no injection, and no measuring. The capsule is ready to take.
Pick a consistent time each day. Earlier in the day is a common choice.
If you train, you may pair the dose with your workout window, though human timing data does not exist.
Store as directed on the pharmacy label and observe the Beyond Use Date.

Watch for

There is no human evidence for SLU-PP-332: zero trials, no human pharmacokinetics, no human safety data, and no FDA approval. Every benefit is extrapolated from mouse and cell studies.
SLU-PP-332 has limited oral bioavailability in animals, so an oral capsule may produce no perceptible benefit in a person. That would be consistent with the evidence.
Anti-doping laboratories have characterized SLU-PP-332 and its metabolites and framed it as a compound with doping potential. Athletes subject to testing should treat it as high risk and confirm status with their governing body before use.
SLU-PP-332 is not a substitute for exercise. The whole-body benefits of training are not reproduced by a partial gene program.

What to expect

Week 1-2: No reliable felt effect expected. SLU-PP-332 acts on a gene-expression program, not on a receptor that produces an immediate sensation.
Week 2-4: If anything translates to humans, this is the window to watch perceived exercise capacity and recovery. Track honestly; there is no placebo-controlled human data to separate signal from belief.
Week 4-8: A sensible point to reassess with your prescriber. Seeing nothing meaningful is fully consistent with the absence of human evidence.
Week 8-12: Course decision point. Because long-term human safety is uncharacterized, shorter supervised courses are the conservative default.

Commonly stacked with

BPC-157: Tissue repair through a separate pathway. A common pairing when training is limited by injury and recovery is the goal. Independent mechanisms, no timing conflict.
NAD+: Mitochondrial and metabolic support through a different mechanism. Complementary on paper, though human data on the combination does not exist.

Section 01

What SLU-PP-332 Actually Is

SLU-PP-332 is a synthetic small molecule, not a peptide. It was designed by chemists at Saint Louis University and the Burris lab (the SLU in the name stands for Saint Louis University) and first described in 2023. Its job is narrow and specific: it activates the estrogen-related receptors, a family of three orphan nuclear receptors called ERRalpha, ERRbeta, and ERRgamma. These receptors are master switches for mitochondrial metabolism and for the genes muscle turns on in response to aerobic exercise.

That is why SLU-PP-332 gets called an exercise mimetic. In the original work, a single dose triggered an ERRalpha-dependent gene program in mouse muscle that looks like the program triggered by an acute bout of aerobic exercise, and treated mice ran farther and longer than untreated mice. Follow-up work in obese mice showed increased energy expenditure, more fat oxidation, and less fat mass. The mechanism is real and the animal data is consistent.

What SLU-PP-332 has not done is be tested in a single human being. There is no clinical trial, no published human pharmacokinetics, no human safety data, and no FDA approval for any use. Everything claimed about endurance, fat loss, or metabolic health in people is an extrapolation from mouse and cell studies. That is the single most important fact on this page.

ERR subtypes targeted (alpha, beta, gamma); highest potency at ERRalpha

2023

Year SLU-PP-332 was first characterized (ACS Chem Biol)

Human trials completed or published to date

503A

Pathway for U.S. compounded access under physician prescription

Section 02

Who It Is Actually For

Because there is no human trial, every row in this table is a hypothesis drawn from the animal mechanism, not a tested indication. The honest framing matters more here than on almost any other guide we publish.

Profile	Primary Motivation	Evidence Basis	Fit
Endurance and Exercise Capacity Seeker	Improve aerobic capacity and fat oxidation	Mouse running-endurance data. No human data.	Hypothesis Only
Recovery / Limited-Mobility User	Capture exercise-like adaptations when training is limited by injury	Mechanistically plausible, animal-only, never trialed for this use.	Exploratory
Metabolic / Body-Composition User	Fat loss, energy expenditure, glycemic support	Obese-mouse metabolic data. No human metabolic data.	Speculative
Longevity / Biohacking User	Mitochondrial and aging-pathway benefits	Extrapolated from cell and animal mitochondrial work.	Speculative
Athlete Subject to Anti-Doping Testing	Performance support during training	Already flagged by anti-doping labs as a doping-potential compound.	High Risk, Confirm First

Profile

Endurance and Exercise Capacity Seeker

Primary Motivation

Improve aerobic capacity and fat oxidation

Evidence Basis

Mouse running-endurance data. No human data.

Fit

Hypothesis Only

Profile

Recovery / Limited-Mobility User

Primary Motivation

Capture exercise-like adaptations when training is limited by injury

Evidence Basis

Mechanistically plausible, animal-only, never trialed for this use.

Fit

Exploratory

Profile

Metabolic / Body-Composition User

Primary Motivation

Fat loss, energy expenditure, glycemic support

Evidence Basis

Obese-mouse metabolic data. No human metabolic data.

Fit

Speculative

Profile

Longevity / Biohacking User

Primary Motivation

Mitochondrial and aging-pathway benefits

Evidence Basis

Extrapolated from cell and animal mitochondrial work.

Fit

Speculative

Profile

Athlete Subject to Anti-Doping Testing

Primary Motivation

Performance support during training

Evidence Basis

Already flagged by anti-doping labs as a doping-potential compound.

Fit

High Risk, Confirm First

Section 03

How SLU-PP-332 Works

SLU-PP-332 is a pan-agonist of the ERR family, with its strongest activity at ERRalpha. When it binds these receptors, it drives a transcriptional program centered on mitochondrial biogenesis, oxidative phosphorylation, and fatty acid oxidation. In animals, that program overlaps with the one acute aerobic exercise produces.

ERRalpha-Dependent Gene Program

In mouse muscle, SLU-PP-332 induced an acute aerobic-exercise gene signature that depended specifically on ERRalpha, including Ddit4, a gene that acute exercise switches on. Knock out the receptor and the endurance benefit disappears, which is how the researchers tied the effect to the target.

Mitochondrial and Fat-Oxidation Drive

In a skeletal-muscle cell line, SLU-PP-332 increased mitochondrial function and cellular respiration. In obese mice it raised energy expenditure and fatty acid oxidation. The throughline is metabolism: the molecule pushes cells toward burning fuel oxidatively.

Oxidative Fiber Shift

Treated mice showed an increase in type IIa oxidative muscle fibers, the fatigue-resistant fiber type endurance training favors, alongside improved running distance and duration. This is a structural adaptation, not just an acute signal.

Autophagy via TFEB

A separate cardiac study found ERR agonists induce TFEB, a master regulator of the autophagy-lysosome recycling pathway. This is part of why the receptor family is being explored for heart failure and aging, all of it still in animal and cell models.

Section 04

What the Evidence Shows

This is the section that decides whether SLU-PP-332 is right for you, because the entire evidence base is preclinical. Here is the actual published record, in order, with the species made explicit every time.

Study	Model	Key Finding	Strength
Billon 2023 (ACS Chem Biol) [1]	Cells and mice	Identified SLU-PP-332 as an ERR pan-agonist; induced an ERRalpha-dependent acute-exercise gene program, increased type IIa fibers, and enhanced running endurance in mice.	Foundational, Preclinical
Billon 2024 (JPET) [2]	Diet-induced obese mice	Increased energy expenditure and fatty acid oxidation, reduced fat mass, and improved insulin sensitivity in metabolic-syndrome models.	Animal Metabolic
Losby 2024 (Mol Pharmacol) [3]	Cardiomyocytes and rodent cells	ERR agonists induce autophagy through TFEB, a mechanism relevant to heart failure and aging. Mechanistic, cell-level.	Mechanistic, Preclinical
Billon 2025 (JPET) [4]	Mice	Built SLU-PP-915 because SLU-PP-332 lacks oral bioavailability; the orally active successor matched its exercise-mimetic activity by mouth in mice.	Highlights the Oral Gap
Moller 2026 (Rapid Commun Mass Spectrom) [5]	Human liver fractions, in vitro	Characterized SLU-PP-332 metabolites for anti-doping detection, explicitly framing it as a compound with doping potential.	Anti-Doping Flag
de Souza-Lima 2026 (Rev Med Chil) [6]	Systematic review	Reviews the pan-ERR agonist field and concludes the strategy is promising but states plainly that clinical trials are still needed to confirm efficacy and safety in humans.	Review, Calls for Trials

Study

Billon 2023 (ACS Chem Biol) [1]

Model

Cells and mice

Key Finding

Identified SLU-PP-332 as an ERR pan-agonist; induced an ERRalpha-dependent acute-exercise gene program, increased type IIa fibers, and enhanced running endurance in mice.

Strength

Foundational, Preclinical

Study

Billon 2024 (JPET) [2]

Model

Diet-induced obese mice

Key Finding

Increased energy expenditure and fatty acid oxidation, reduced fat mass, and improved insulin sensitivity in metabolic-syndrome models.

Strength

Animal Metabolic

Study

Losby 2024 (Mol Pharmacol) [3]

Model

Cardiomyocytes and rodent cells

Key Finding

ERR agonists induce autophagy through TFEB, a mechanism relevant to heart failure and aging. Mechanistic, cell-level.

Strength

Mechanistic, Preclinical

Study

Billon 2025 (JPET) [4]

Model

Mice

Key Finding

Built SLU-PP-915 because SLU-PP-332 lacks oral bioavailability; the orally active successor matched its exercise-mimetic activity by mouth in mice.

Strength

Highlights the Oral Gap

Study

Moller 2026 (Rapid Commun Mass Spectrom) [5]

Model

Human liver fractions, in vitro

Key Finding

Characterized SLU-PP-332 metabolites for anti-doping detection, explicitly framing it as a compound with doping potential.

Strength

Anti-Doping Flag

Study

de Souza-Lima 2026 (Rev Med Chil) [6]

Model

Systematic review

Key Finding

Reviews the pan-ERR agonist field and concludes the strategy is promising but states plainly that clinical trials are still needed to confirm efficacy and safety in humans.

Strength

Review, Calls for Trials

Section 05

Realistic Expectations

We cannot give you a human timeline because there are no human studies to draw one from. What follows is framed honestly as a reasonable-monitoring schedule, not a promise of results. If you and your prescriber decide to proceed, this is the lens to evaluate it through.

Wk 1-2

No Reliable Felt Effect

SLU-PP-332 acts on a gene-expression program, not on a receptor that produces an immediate sensation. Expect to feel nothing obvious early. In animals the effects are metabolic and structural, the kind of change that would accrue quietly rather than announce itself.

Wk 2-4

Watch, Do Not Assume

If anything translates to humans, this is the window to start paying attention to perceived exercise capacity and recovery. Track it honestly, because expectation effects are powerful and there is no placebo-controlled human data to separate signal from belief.

Wk 4-8

Reassess With Your Prescriber

A sensible point to check in. If you are seeing nothing meaningful, that is fully consistent with the absence of human evidence and is a reason to stop, not to push the dose higher.

Wk 8-12

Course Decision Point

Decide with your prescriber whether to continue, pause, or stop. Because long-term human safety is entirely uncharacterized, shorter, supervised courses are the conservative default.

Section 06

Dosing Protocol

There is no established human dose for SLU-PP-332, because there has never been a human study to set one. The practical dosing below is a conservative starting point your RxPepsDirect physician sets and adjusts. It is not derived from a human trial, and we are not going to pretend otherwise.

Context	Dose	Route / Frequency	Evidence Basis
Preclinical Reference	Animal dosing only	Mouse studies, mg/kg, not human-translatable	Animal Only
RxPepsDirect Standard	1 capsule (250 mcg)	Oral, once daily, as directed	Clinical Practice
Adjustment	Per physician	Oral, frequency and duration set by prescriber	Individualized
Stacking With Exercise	Same 250 mcg capsule	Oral, alongside (not instead of) training	Sensible Default

Context

Preclinical Reference

Dose

Animal dosing only

Route / Frequency

Mouse studies, mg/kg, not human-translatable

Evidence Basis

Animal Only

Context

RxPepsDirect Standard

Dose

1 capsule (250 mcg)

Route / Frequency

Oral, once daily, as directed

Evidence Basis

Clinical Practice

Context

Adjustment

Dose

Per physician

Route / Frequency

Oral, frequency and duration set by prescriber

Evidence Basis

Individualized

Context

Stacking With Exercise

Dose

Same 250 mcg capsule

Route / Frequency

Oral, alongside (not instead of) training

Evidence Basis

Sensible Default

SLU-PP-332 ships as an oral capsule, so there are no needles, no syringes, and no units to draw. You take one 250 mcg capsule by mouth as directed by your prescriber. Timing is flexible because the compound acts on a gene program rather than aligning to a hormonal pulse. Many users take it earlier in the day, and some pair the dose with their training window, but the data to optimize timing in humans simply does not exist yet.

Section 07

Ready to Start

Needles, syringes, or reconstitution steps

503A

Licensed pharmacy (Optimal Balance), physician-supervised

Overnight

FedEx shipping, capsules ready to take

Section 08

Safety and Side Effects

The honest safety statement is short: there is no human safety data for SLU-PP-332. In animal studies it was tolerated without obvious toxicity, but animal tolerability does not establish human safety, and no formal toxicology in people has been done. Everything below is precautionary.

Consideration	Detail	Action
No human safety data	Tolerability is known only from rodent studies	Treat as investigational. Use only under physician supervision.
Metabolic and cardiovascular effects	ERR agonism touches energy metabolism and cardiac pathways	Share your full cardiac and metabolic history with your prescriber.
Pregnancy / lactation	No safety data	Avoid.
Anti-doping tested athletes	Already characterized by anti-doping labs as a doping-potential agent	Confirm status with your governing body before use. Treat as high risk.

Consideration

No human safety data

Detail

Tolerability is known only from rodent studies

Action

Treat as investigational. Use only under physician supervision.

Consideration

Metabolic and cardiovascular effects

Detail

ERR agonism touches energy metabolism and cardiac pathways

Action

Share your full cardiac and metabolic history with your prescriber.

Consideration

Pregnancy / lactation

Detail

No safety data

Action

Avoid.

Consideration

Anti-doping tested athletes

Detail

Already characterized by anti-doping labs as a doping-potential agent

Action

Confirm status with your governing body before use. Treat as high risk.

Section 09

Stacking

Pairs Reasonably With

Actual exercise
The single most evidence-backed pairing. SLU-PP-332 is studied as an exercise mimetic, not an exercise replacement. Pairing it with training is the only combination grounded in how the molecule was designed.
BPC-157
Tissue repair through a separate pathway. A common pairing when training is limited by injury and recovery is the goal. Independent mechanisms, no timing conflict.
NAD+
Mitochondrial and metabolic support through a different mechanism. Complementary on paper, though human data on the combination does not exist.

Avoid or Use Caution

Replacing exercise entirely
Not a stack, a substitution, and the evidence does not support it. The whole-body benefits of training are not reproduced by a partial gene program in a capsule.
Pregnancy / lactation
No safety data. Avoid.
Competition while drug-tested
Anti-doping labs have already built detection methods for SLU-PP-332. Combining it with a testing obligation is a sanction risk.

Section 10

Pricing

Pharmacy: Medication

$3.00 per 250 mcg capsule. Compounded and shipped by Optimal Balance Pharmacy, a 503A licensed compounding pharmacy. Oral capsules, ready to take, FedEx overnight.

Medical Service: Physician Consultation

$39 medical visit fee. Intake consultation including history review, contraindication screening, protocol design, prescription writing, and follow-up. Billed by RxPepsDirect for the medical service only.

Section 11

Legal Access in 28 States

503A Licensed Pharmacy

Optimal Balance Pharmacy, U.S. licensed

Physician Prescription Required

Compounded medication, Rx only

Investigational Compound

Preclinical only, no FDA approval

Off-Label, Legal Practice

Standard and legal in U.S. medicine

SLU-PP-332 is an investigational compound. It has not been studied in humans and is not FDA-approved for any indication. In the United States it is available through 503A patient-specific compounding under a physician prescription. The 503A pathway is the documented legal route for compounded access. RxPepsDirect prescribers serve patients in 28 states. Athletes subject to testing should note that anti-doping authorities are already tracking this compound.

Section 12

Community Q&A

Is there any human data on SLU-PP-332?

No. There are zero human trials. Every published result is from mice or cultured cells, and the foundational studies come from the lab that designed the molecule. Treat all human benefits as hypothesis, not fact.

Does SLU-PP-332 replace exercise?

No. In mice it turned on some of the same genes acute aerobic exercise turns on and improved running endurance. That is not the same as replacing the cardiovascular, neurological, and musculoskeletal benefits of training, and it has never been tested in a person. Best thought of as a tool studied alongside exercise, not a substitute.

Is it banned for drug-tested athletes?

Treat it as high risk. Anti-doping laboratories have already characterized SLU-PP-332 specifically and built methods to detect it and its metabolites. Exercise mimetics fall under the metabolic-modulator category that anti-doping programs watch closely. Confirm with your governing body before use.

Why a capsule instead of an injection?

SLU-PP-332 is a small molecule, not a peptide, so it is taken by mouth. The honest caveat: the original molecule has limited oral bioavailability in animals, which is exactly why its developers built an orally active successor, SLU-PP-915. How much of an oral SLU-PP-332 capsule reaches the bloodstream in a human is unknown.

How long is a course?

There is no trial-derived course length, because there are no trials. RxPepsDirect courses are kept short and supervised, with your prescriber reassessing before any extension, precisely because long-term human safety is uncharacterized.

Section 13

The RxPepsDirect Model

Pharmacy: Optimal Balance, 503A Licensed

Optimal Balance Pharmacy compounds your SLU-PP-332 under a patient-specific prescription, USP <797> standards, and federal 503A oversight, dispensed as oral capsules.

Medical Service: RxPepsDirect Physicians

A licensed physician reviews your history, screens for contraindications, designs your protocol, and writes your prescription. RxPepsDirect bills the $39 medical visit fee for this service.

Transparent Safety Communication

This guide leads with the fact that SLU-PP-332 has zero human data, flags its oral bioavailability problem, notes the anti-doping attention, and frames every benefit as preclinical extrapolation. We do not hide limitations to make a sale.

Legal Access in 28 States

Every shipment is a compounded prescription medication filled by a 503A licensed pharmacy under a physician prescription.

References

Billon C, Sitaula S, Banerjee S, et al. Synthetic ERRalpha/beta/gamma Agonist Induces an ERRalpha-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chem Biol. 2023. PMID: 36988910
Billon C, Schoepke E, Avdagic A, et al. A Synthetic ERR Agonist Alleviates Metabolic Syndrome. J Pharmacol Exp Ther. 2024. PMID: 37739806
Losby M, Hayes M, Valfort A, et al. The Estrogen Receptor-Related Orphan Receptors Regulate Autophagy through TFEB. Mol Pharmacol. 2024. PMID: 39168657
Billon C, Appourchaux K, Cote I, Burris TP. An orally active estrogen receptor-related receptor agonist, SLU-PP-915, enhances aerobic exercise capacity. J Pharmacol Exp Ther. 2025. PMID: 41421047
Moller T, Krug O, Thevis M. In Vitro Metabolism and Analytical Characterization of SLU-PP-332 and SLU-PP-915: Novel Pan-ERR Agonists With Doping Potential. Rapid Commun Mass Spectrom. 2026. PMID: 41588687
de Souza-Lima J, Astrosa-Martin BD, Galaz-Rodriguez CA, et al. Pharmacological Activation of ERRalpha/beta/gamma as an Exercise Mimetic: Potential Therapeutic Applications. Rev Med Chil. 2026. PMID: 42024694

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