The honest summary up front: mouse data are striking, human data do not exist, and community results are split between "this works as described" and "I felt absolutely nothing." That split tracks closely with route of administration — injectable users describe effects more consistently than oral-capsule users — and that pattern has a published mechanistic explanation.
Research-context information only. SLU-PP-332 is an investigational small-molecule pan-agonist of the estrogen-related receptors (ERRα/β/γ) developed at Saint Louis University. It is not approved by the FDA and has not entered human clinical trials. Effects reported below come from published preclinical studies and self-reported community sources. This article reports what has been documented, not what should be done. Consult a licensed physician for personal medical decisions.
Route. The published preclinical dosing was IP injection. The Billon 2025 paper introducing SLU-PP-915 (PMID 41421047) explicitly states the parent SLU-PP-332 "lacks oral bioavailability" — they developed SLU-PP-915 as the orally active sibling because of that limitation. Oral capsules and tablets sold as SLU-PP-332 may produce no systemic exposure.
Dose. Mouse studies used 25 mg/kg IP BID. Allometric scaling to a human is contested and untested. Community injectable doses cluster well below the scaled equivalent.
Training stimulus. SLU-PP-332 is described as an exercise mimetic, but in mice the strongest effects came when the compound was paired with a treadmill protocol. Whether the compound produces benefits in sedentary humans has not been tested.
Week 1 — Subclinical Transcriptional Changes
In mice, gene-expression changes were measurable within days. Mitochondrial biogenesis transcripts (PGC-1α targets), fatty acid oxidation genes, and DDIT4 — an acute aerobic exercise gene — were upregulated within hours of a single IP dose (Billon et al., ACS Chem Biol 2023, PMID 36988910).
Most users report nothing at all in week 1. That is consistent with the mouse data: transcriptional changes precede phenotypic changes by weeks, and at the cellular level mitochondrial biogenesis takes time to translate into measurable energy-system improvements.
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Weeks 2–4 — First Phenotypic Signals
In the DIO mouse study (Billon et al., J Biol Chem 2023, PMID 37739806), measurable weight and adiposity changes appeared in the first 2 weeks of 25 mg/kg IP BID dosing and accelerated through week 4.
Community reports on injectable SLU-PP-332 cluster around weeks 2–3 for noticeable changes:
Better cardio capacity at familiar workloads — running paces feel easier, longer sets without fatigue
Reduced perceived exertion at the same heart rate
Modest fat-loss signals (waistline, scale) at maintenance calories
Community reports on oral capsules and tablets at the same timeline are split. Most commonly: nothing. Some users report mild appetite changes or perceived energy shifts — both of which are non-specific and could be placebo or could indicate partial absorption that's not been formally characterized.
Month 1 — Where the Mouse Data Peak
The 28-day endpoint of the published metabolic syndrome study showed:
~12% body weight loss in DIO mice on 25 mg/kg IP BID (Billon 2023, PMID 37739806)
~10× less fat gain on the same high-fat diet vs vehicle controls
Improved glucose tolerance
Increased resting energy expenditure
Treated mice ran ~70% longer and ~45% farther in treadmill tests (Billon 2023, PMID 36988910)
Community-reported month-1 results from injectable users at modest community doses describe 1–3 lb of fat loss per month with stable training, alongside subjective cardio improvements. That is a fraction of what the mouse data would predict if the compound translated 1:1, but allometric scaling rarely works that cleanly and community doses are below the mouse-equivalent scale.
Months 2–3 — Where Mouse Data End
There is no published preclinical data beyond ~30 days of continuous SLU-PP-332 dosing. The cardiac heart-failure work (Xu et al., Circulation 2023, PMID 37961903) tested chronic dosing in pressure-overload models and reported sustained efficacy without overt toxicity, but that was a disease model, not normal mice.
Community reports at months 2–3 are sparse because most users either drop the compound (if oral and they felt nothing) or run a defined cycle of 4–8 weeks. The few extended-use reports describe a plateau in fat-loss rate and stable endurance gains — consistent with what would be expected from a metabolic intervention plus calorie balance.
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Factors That Affect Results
Factor
Impact on Results
Route (injectable vs oral)
The single biggest variance driver. Injectable produces measurable systemic exposure; oral parent SLU-PP-332 may not.
Concurrent training
Mouse data showed amplified effects with treadmill exercise. Sedentary use likely produces blunted phenotypic changes.
Caloric deficit
SLU-PP-332 increases output, not appetite suppression. Without a deficit, fat loss is modest.
Dose
Mouse 25 mg/kg BID does not translate cleanly. Community doses are usually below the scaled equivalent.
Cycle length
Most reports are 4–8 weeks; longer cycles have no published or self-reported safety/efficacy data.
Sleep + recovery
Mitochondrial biogenesis is sensitive to recovery state. Poor sleep blunts adaptation.
By Use Case
Endurance/aerobic capacity research. This is where the strongest preclinical signal is, and where injectable community reports are most consistent. Expect 2–3 weeks before perceived cardio changes; mouse-scale effects (70%+ improvements) are not realistic at community doses.
Fat loss as a primary goal. Mouse data are dramatic but driven by the combination of increased resting energy expenditure plus continued food intake. In humans, fat loss is dominated by calorie balance — SLU-PP-332 may modestly help, but is not a retatrutide or tirzepatide substitute for appetite control.
Glucose tolerance / metabolic markers. Mouse data showed improved glucose tolerance. Whether HbA1c moves meaningfully in humans — and at what dose, route, and duration — is untested.
Muscle hypertrophy. Not the right tool. SLU-PP-332 shifts fiber composition toward type IIa oxidative; it does not drive hypertrophy. For muscle/body recomposition tools, the muscle peptide cluster is a better starting point.
When to Adjust Protocol
No effect after 4 weeks on oral capsules. Most likely explanation: oral bioavailability is low or zero. Switching to injectable is the only way to test whether the compound itself is doing anything for that user.
Effect plateaus after 6–8 weeks. Consistent with most metabolic interventions — initial response, then adaptation. Most community protocols cycle off at 8 weeks for that reason.
Side effects that warrant stopping. No human safety data exist, but if cardiac-rhythm changes, persistent fatigue, sleep disruption, or unexplained labs appear, discontinuation is the standard self-experimentation default. See SLU-PP-332 Side Effects for the documented adverse-event picture.
Frequently Asked Questions
How long until SLU-PP-332 works?
Mouse studies showed measurable changes in metabolic gene expression within days and visible body composition changes within 2–4 weeks at 25 mg/kg IP twice daily (Billon 2023, [PMID 37739806](https://pubmed.ncbi.nlm.nih.gov/37739806/)). Community reports on injectable SLU-PP-332 cluster at 2–3 weeks for endurance changes; reports on oral capsules are inconsistent because the parent compound lacks oral bioavailability.
Does SLU-PP-332 work in humans?
There is no published human data on SLU-PP-332 — no Phase 1 trial, no pharmacokinetic study, no efficacy data. All confidence in the 'it works' claim derives from mouse studies. Community self-reports are anecdotal and split.
What weight loss results have people reported?
Self-reported community results vary widely. Injectable users on AnabolicMinds and Reddit commonly describe 1–3 lb of fat loss per month at modest community doses, often alongside cardio. Oral capsule users frequently report no change at all — consistent with the published bioavailability concerns.
Why do oral SLU-PP-332 results vary so much?
The Billon 2025 paper introducing SLU-PP-915 ([PMID 41421047](https://pubmed.ncbi.nlm.nih.gov/41421047/)) explicitly notes that the parent compound SLU-PP-332 lacks oral bioavailability. If the molecule isn't absorbing systemically, the user effectively took a placebo. That is the most likely explanation for the split community results on oral capsules and tablets.
What does research describe about endurance gains without training?
Mouse data suggest yes — treated mice ran ~70% longer than vehicle controls without altered training (Billon 2023, [PMID 36988910](https://pubmed.ncbi.nlm.nih.gov/36988910/)). Whether the same effect occurs in humans, and at what doses, has not been tested.
Research Supplies for SLU-PP-332
Hand-picked storage, injection, and recovery supplies paired with SLU-PP-332 protocols.
Billon C, et al. Synthetic ERRα/β/γ agonist induces an ERRα-dependent acute aerobic exercise response and enhances exercise capacity. ACS Chem Biol. 2023. PMID: 36988910.
Billon C, et al. A synthetic ERR agonist alleviates metabolic syndrome. J Biol Chem. 2023. PMID: 37739806.
Xu W, et al. Novel pan-ERR agonists ameliorate heart failure through enhancing cardiac fatty acid metabolism and mitochondrial function. Circulation. 2023. PMID: 37961903.
Billon C, et al. An orally active estrogen receptor-related receptor agonist, SLU-PP-915, enhances aerobic exercise capacity. J Pharmacol Exp Ther. 2025. PMID: 41421047.
This article is for educational and informational purposes only. It is not medical advice and should not be used to diagnose, treat, or prevent any condition. Consult a licensed healthcare provider before using any peptide or research compound.
