Journal September 16, 2026 7 min read

SLU-PP-332 vs AOD9604 (Fragment 176-191): what the research compares

A comparison of the published research on SLU-PP-332, a pan-ERR agonist, and AOD9604 (Fragment 176-191), a synthetic peptide fragment, covering what each is, what studies measured, and where evidence is stronger or absen

peptides-pro Editorial

SLU-PP-332 is a synthetic small-molecule agonist of the estrogen-related receptors (ERRα, ERRβ, ERRγ), also referred to as an exercise mimetic. AOD9604 (Fragment 176-191) is a synthetic peptide corresponding to the C-terminal fragment of human growth hormone (hGH), specifically residues 176–191, and is also known as Anti-Obesity Drug 9604. The evidence block does not provide a sequence, molecular formula, or molecular weight for either compound.

The published work on SLU-PP-332 centres on the ERR nuclear receptor family and its downstream regulation of mitochondrial metabolism and exercise-responsive transcription; the work on AOD9604 centres on its classification as a peptide therapy in sports medicine, with mechanisms and safety profiles discussed in that context.

Research Studies

SLU-PP-332 and ERR nuclear receptor activation

SLU-PP-332 is described as a well-established exercise mimetic and widely used chemical probe for ERR activation [2]. A comprehensive structure-activity relationship (SAR) analysis of the SLU-PP-332 scaffold integrated chemical synthesis, cell-based functional assays, downstream gene-expression profiling, and additional evaluations to elucidate the structural features governing potency, efficacy, selectivity, and drug-like properties [2]. The same paper notes that estrogen-related receptors are master regulators of mitochondrial metabolism and exercise-responsive transcription, and that only a limited number of synthetic agonists with suitable potency and drug-like properties have been reported [2].

SLU-PP-332 and in vitro metabolism

SLU-PP-332 and SLU-PP-915 were characterized using liquid chromatography-high resolution (tandem) mass spectrometry (LC-HRMS/MS), and their in vitro metabolic transformation products were prepared using human liver S9 fractions [1]. The study rationale noted that ERR agonists such as SLU-PP-332 and SLU-PP-915 are being investigated as exercise mimetics given their ability to trigger human physiological processes similar to those initiated by physical activity, which prompted consideration of these compounds as drugs potentially relevant for sports drug testing programs [1].

SLU-PP-332 and skeletal muscle from inactive women

A pilot study evaluated targeting of ERRs in myoblasts isolated from the skeletal muscle of inactive women, assessing metabolic and expression changes associated with ERR activation [5]. Twenty women undergoing hip arthroplasty for coxarthrosis were enrolled and divided into an active group (n = 10) and an inactive group (n = 10) based on self-reported physical activity [5]. The introduction stated that estrogen-related receptors have been suggested as a potential therapeutic target to counteract muscle decline associated with aging or inactivity, being known to regulate mitochondrial function and cellular respiration by up-regulating key factors in muscle responses to exercise [5].

SLU-PP-332 and doping-control analysis

A reference-only source reports that exercise mimetics mimic physical activity and prevent development and progression of chronic metabolic diseases, including obesity and Type 2 diabetes, and that the World Anti-Doping Agency (WADA) prohibits the use of exercise mimetics and metabolic modulators in sports; SLU-PP-332 is described as a small, synthetic ERRα/β/γ agonist [6]. This finding is reported as a fact from that paper and is not the focus of the present comparison.

AOD9604 (Fragment 176-191) and peptide therapy classification

AOD9604 (Anti-Obesity Drug 9604) is included among prominent approved and unapproved peptides marketed direct to patients in a review of peptide therapies for musculoskeletal injuries and athletic performance [3][4]. The review states that peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins, and that their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement [3][4]. It further notes that while numerous peptide drugs have undergone a rigorous approval process evaluating both safety and efficacy, a parallel "gray market" of unapproved compounds has emerged, operating largely outside regulatory oversight [3][4]. The objective of that work was to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 [3][4].

AOD9604 (Fragment 176-191) and regulatory status

The same review includes AOD-9604 among unapproved peptides and discusses its regulatory status alongside other compounds in that category [3][4]. The evidence block does not provide specific approval dates, jurisdictional decisions, or detailed regulatory pathways for AOD9604 beyond its inclusion in the unapproved category.

ERR activation as an exercise mimetic strategy

A reference-only source reports that physical inactivity contributes to the development of chronic diseases, and that activation of orphan nuclear receptors estrogen-related receptors (ERRα/β/γ) has emerged as a molecular strategy to mimic exercise-induced benefits; the aim of that work was to systematically review the current evidence on the physiological, molecular, and clinical aspects of this approach [8]. This finding is reported as a fact from that paper and is not the focus of the present comparison.

SLU-PP-915 and aerobic exercise capacity

A reference-only source reports that estrogen receptor-related receptors (ERRα, ERRβ, and ERRγ) are orphan nuclear receptors that regulate genes involved in mitochondrial biogenesis, oxidative phosphorylation, fatty acid oxidation, and the Krebs cycle, and that ERRs are essential for skeletal muscle adaptation to aerobic exercise and represent promising targets; the paper describes an orally active ERR agonist, SLU-PP-915, and its enhancement of aerobic exercise capacity [9]. This finding is reported as a fact from that paper and is not the focus of the present comparison.

Comparison of evidence types

The table below summarises the types of evidence available for each compound based on the sources provided. It does not rank the compounds or imply superiority.

Aspect	SLU-PP-332	AOD9604 (Fragment 176-191)
Class	Synthetic small-molecule pan-ERR agonist (ERRα/β/γ) [1][2][6]	Synthetic peptide fragment of hGH (residues 176–191) [3][4]
Primary pathway/receptor family	Estrogen-related receptors (ERRα, ERRβ, ERRγ) [1][2][5]	Not specified in the evidence block beyond peptide classification [3][4]
In vitro metabolism data	Characterised by LC-HRMS/MS; metabolic transformation products prepared with human liver S9 fractions [1]	Not reported in the evidence block
SAR analysis	Comprehensive SAR of the scaffold reported [2]	Not reported in the evidence block
Human cell/tissue studies	Myoblasts from skeletal muscle of inactive women (n=20 total) [5]	Not reported in the evidence block
Regulatory/doping context	Considered relevant for sports drug testing programs; WADA prohibits exercise mimetics [1][6]	Listed among unapproved peptides in a review of peptide therapies [3][4]
Review coverage	Included in reviews of ERR activation as exercise mimetic strategy [8]	Included in review of approved and unapproved peptide therapies [3][4]

Where the evidence is stronger for one compound

For SLU-PP-332, the evidence block includes primary research articles describing in vitro metabolism [1], structure-activity relationships [2], and a pilot study in human myoblasts from inactive women [5], as well as reference-only sources on doping-control analysis [6] and ERR activation as an exercise mimetic strategy [8]. For AOD9604 (Fragment 176-191), the evidence block includes review articles that discuss its classification as a peptide therapy and its regulatory status [3][4], but does not include primary research articles reporting specific mechanisms, metabolic pathways, or clinical outcomes for this compound. The literature represented here therefore provides more detailed mechanistic and metabolic data for SLU-PP-332 than for AOD9604.

What is simply not known

The evidence block does not provide sequence, molecular formula, or molecular weight for either compound. It does not report pharmacokinetic parameters, dosing regimens, or clinical efficacy endpoints for either compound. For AOD9604, no primary studies on mechanism of action, receptor binding, or metabolic effects are included in the evidence block. For SLU-PP-332, the pilot study in myoblasts from inactive women [5] reports metabolic and expression changes but the evidence block does not provide the full results or statistical outcomes. No head-to-head studies comparing SLU-PP-332 and AOD9604 are present in the evidence block. No conclusions about relative potency, safety, or efficacy can be drawn from the available sources.

If you are reading this for personal health reasons

This material is sold for laboratory research only. We do not provide dosing or medical guidance. Anyone considering a compound for themselves should speak to a licensed clinician.