"SLU-PP-332 vs retatrutide" is searched as if the two were rival weight-loss peptides. Only one is a peptide, and only one has been given to people. The comparison worth making is therefore between two records of very different depth: a set of mouse and laboratory papers on one side, a published phase 2 trial and a phase 3 programme on the other. This page sets them side by side and converts the circulating amounts into syringe units.
The full record for each is on SLU-PP-332 dosage and retatrutide dosage. SLU-PP-332's other common comparison, with a peptide that is also called an exercise mimetic, is SLU-PP-332 vs MOTS-c.
Side by side
| SLU-PP-332 | Retatrutide | |
|---|---|---|
| What it is | Small molecule, C18H14N2O2, MW 290.3 (PubChem CID 5338394) | Peptide, injected under the skin |
| Target | Estrogen-related receptors ERRα, β, γ (strongest at ERRα) | GIP, GLP-1 and glucagon receptors |
| Registry records (ClinicalTrials.gov, 2026-11-10) | 0 | 33 (21 completed) |
| PubMed records (2026-11-10) | 10, none dosing a person | Published phase 1b and phase 2 trials (2022, 2023) |
| Closest weight finding | Less fat-mass gain in obese mice (2024) | −24.2% mean weight at 12 mg weekly, 48 weeks (2023) |
| Human dose on record | None | 0.5 to 12 mg once weekly in trials |
| Label anywhere | None | None; Eli Lilly has not yet filed |
What the SLU-PP-332 record holds
All ten PubMed records for SLU-PP-332, read by title and abstract on 2026-11-10, fall into five kinds:
| Kind of study | Records | What was done |
|---|---|---|
| Mice | 5 | Endurance and muscle fibres (2023), obesity and metabolic syndrome (2024), heart failure under pressure overload (2024), 21-month-old mice's kidneys (2023), comparison with SLU-PP-915 (2026) |
| Test-tube metabolism for doping control | 2 | Metabolites mapped in human liver fractions (2026) |
| Human cells in a dish | 1 | Muscle cells isolated from inactive women (2025) |
| Chemistry | 1 | Chemical optimisation of the molecule (2026) |
| Review | 1 | Systematic review of pan-ERR agonists (2026), which ends that clinical trials are needed |
The founding paper describes it as a pan-ERR agonist with "sufficient pharmacokinetic properties to be used as an in vivo chemical tool" that increased oxidative muscle fibres and exercise endurance in mice (Billon et al., ACS Chemical Biology 2023). The 2024 obesity paper reports that in diet-induced obese and ob/ob mice it mimicked exercise-induced benefits on whole-body metabolism and decreased fat mass. The developers' 2026 paper states that SLU-PP-332 "lacks oral bioavailability" and introduces SLU-PP-915 as an orally active successor, still in mice.
The mouse amounts were 30 or 50 mg/kg by intraperitoneal injection, often twice daily, as read on this site's SLU-PP-332 vs MOTS-c page on 2026-10-17. A per-kilogram mouse amount does not convert to a human dose by multiplication.
What the retatrutide record holds
Retatrutide's record starts where SLU-PP-332's stops. The phase 1b trial in 72 people with type 2 diabetes measured a half-life of about 6 days (Urva et al., The Lancet 2022). The phase 2 obesity trial gave 338 adults once-weekly injections for 48 weeks and reported mean weight changes of −8.7%, −17.1%, −22.8% and −24.2% at 1, 4, 8 and 12 mg, against −2.1% on placebo; gastrointestinal events were the most common adverse events and were dose-related (Jastreboff et al., NEJM 2023). The phase 3 TRIUMPH trials are registered and partly reported by Eli Lilly in company releases, set out on the retatrutide dosing schedule.
That is not the same as an approval. Retatrutide sold in research vials is not Lilly's product, and no label exists to describe its use.
The figures in circulation
| Figure | Source | Note |
|---|---|---|
| SLU-PP-332 250 mcg to 1 mg a day, mostly by mouth | Vendor pages (this site's SLU-PP-332 page, 2026-09-18) | No human study; developers state no oral bioavailability |
| SLU-PP-332 30–50 mg/kg, intraperitoneal | Mouse studies | Not a human dose |
| Retatrutide 2 mg weekly, rising every 4 weeks | TRIUMPH starting step, per Lilly | Trial protocol |
| Retatrutide 4, 9 or 12 mg weekly | TRIUMPH maintenance arms, per Lilly | Trial protocol |
A daily oral figure and a weekly injected one cannot be set against each other as milligrams: the routes differ, the targets differ, and for SLU-PP-332 there is no measurement of how much of an oral amount reaches the blood in anyone.
Both in syringe units
For injectable vials only. On a U-100 syringe, units = mg ÷ mg/mL × 100.
| Amount | 5 mg/mL (10 mg + 2 mL) | 10 mg/mL (10 mg + 1 mL) |
|---|---|---|
| SLU-PP-332 0.25 mg | 5 | 2.5 |
| SLU-PP-332 0.5 mg | 10 | 5 |
| SLU-PP-332 1 mg | 20 | 10 |
| Retatrutide 2 mg | 40 | 20 |
| Retatrutide 4 mg | 80 | 40 |
| Retatrutide 12 mg | 240 (>1 syringe) | 120 (>1 syringe) |
The water volumes for retatrutide are on reconstituting retatrutide; any vial and volume can be worked in the retatrutide calculator.
What is not established
No study has given SLU-PP-332 to a person, so its effect, safety and dose in humans are unknown; whether oral capsules deliver any of it is unknown. No study has combined it with retatrutide. Retatrutide's trial results apply to Lilly's molecule in screened, monitored participants, not to research-market vials. Nothing on this page is a dose or a suggestion to use either compound.
Sources and dates
Opened 2026-11-10: PubChem compound record CID 5338394 (formula and weight); the ClinicalTrials.gov v2 API searches for SLU-PP-332 (0) and for retatrutide as an intervention (33, status counts); the PubMed search for SLU-PP-332 (10 records) and the abstracts of Billon et al., ACS Chem Biol 2023 (PMID 36988910), J Pharmacol Exp Ther 2024 (PMID 37739806), J Pharmacol Exp Ther 2026 (PMID 41421047), Front Physiol 2025 (PMID 40692696), PMIDs 41850449, 37961903, 37717940 and 42024694, and, for retatrutide, Urva et al., Lancet 2022 (PMID 36354040) and Jastreboff et al., NEJM 2023 (PMID 37366315). The mouse amounts and the vendor figures are as read on this site's sibling pages on the dates given. Units are arithmetic by this site. Corrections go to the contact page.