AICAR vs SLU-PP-332
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Acadesine, AICA riboside
AICAR is not a peptide at all. It is a small nucleoside (a building block related to the purine pathway) that cells convert into ZMP, a molecule that mimics AMP and switches on AMPK, the cell's energy sensor. It became famous in 2008 when a Salk Institute study showed sedentary mice on AICAR ran 44% further, earning it the "exercise in a pill" label. Human data tell a much less exciting story: it was tested as an intravenous drug (acadesine) for heart surgery and leukemia, the big heart trial failed, and nothing is approved.
Also: Exercise in a Pill, ERR Agonist SLU-PP-332
SLU-PP-332 is a small synthetic molecule, not a peptide, that turns on the estrogen-related receptors (ERRalpha, beta and gamma), the master switches behind much of the body's response to endurance exercise. Researchers call it an 'exercise mimetic' because in mice it boosts mitochondria, shifts muscle toward fatigue-resistant fibers, improves stamina and trims fat without the animal moving more. It was made as a lab tool to study exercise biology. There are no human trials.
Key Comparison Insights
- Both peptides belong to the Metabolic category, suggesting similar primary applications.
- AICAR has stronger research evidence (Human Trials) compared to SLU-PP-332 (Animal Studies).
Detailed Comparison
| Attribute | AICAR | SLU-PP-332 |
|---|---|---|
| Category | Metabolic | Metabolic |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Once inside cells, AICAR is phosphorylated to ZMP (AICAR monophosphate), which behaves like AMP and activates AMP-activated protein kinase (AMPK). AMPK is the master switch cells flip when energy runs low: it pushes glucose uptake and fat oxidation up and energy-costly processes like fat and protein synthesis down. In mouse muscle, AMPK activation by AICAR turned on a set of oxidative, endurance-type genes overlapping with those controlled by PPAR-delta. The catch is that ZMP is not a clean AMPK switch: it also affects other AMP-sensitive enzymes and the adenosine system, which is why acadesine was originally developed as an "adenosine regulating agent" for the heart. Effects in mice also do not automatically translate to people. A 2011 human study found that IV AICAR during an insulin clamp caused vasodilation (higher heart rate, lower blood pressure) but no direct effect on glucose uptake. | ERRs are nuclear receptors that, when active, switch on genes for mitochondrial biogenesis, fatty acid burning and the Krebs cycle, which is the same transcriptional program endurance training normally turns on. SLU-PP-332 is a pan-ERR agonist, most potent at ERRalpha (roughly 98 nM), and it pushes this metabolic gene program directly through the receptor rather than through actual physical effort. In skeletal muscle cells it raises mitochondrial function and cellular respiration, and in mice it increases oxidative type IIa muscle fibers. The net proposed effect is the 'feeling' of having exercised at the gene-expression level, hence the exercise-mimetic label. This is a pharmacological hypothesis being tested, not an established clinical effect. |
| Common Dosing | No established dose; human data are IV infusions only Single infusions or short cycles in trials | 250 mcg - 1 mg daily 1-2x daily |
| Administration | Intravenous infusion in human trials; intraperitoneal injection in mice | Oral (tablets/capsules) most common, subcutaneous injection less common |
| Typical Duration | Single infusions or short cycles in human trials; 4 weeks in the mouse endurance study | 4-8 weeks typical community protocols |
| Best Time to Take | No evidence-based timing in healthy people | Morning, or split morning and afternoon |
Possible Side Effects May vary by individual |
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| Research Summary | The headline study is Narkar and colleagues (Cell, 2008): four weeks of AICAR at 500 mg/kg/day by injection in untrained mice induced metabolic genes and increased running endurance by 44%. That paper is the source of nearly all the hype, and it was in mice at a huge dose. Human work is a different picture. As acadesine, it went into the RED-CABG phase 3 trial (JAMA 2012), giving 0.1 mg/kg/min IV for 7 hours around bypass surgery. The trial was stopped for futility after 3,080 patients: the primary outcome was 5.1% with acadesine versus 5.0% with placebo, so no benefit. A phase I/II study in relapsed chronic lymphocytic leukemia (Van Den Neste et al., Cancer Chemotherapy and Pharmacology) set the maximum tolerated single IV dose at 210 mg/kg; at 315 mg/kg two of three patients had dose-limiting toxicity (tumor lysis syndrome and kidney injury), and hyperuricemia was a recurring problem that required allopurinol. There are no human trials showing AICAR improves endurance, body composition, or longevity in healthy people. It is also one of the more catchable doping agents: anti-doping labs use carbon isotope ratio testing to separate injected AICAR from the body's natural AICAR. | The headline preclinical study, by Billon and colleagues in ACS Chemical Biology in 2023, showed SLU-PP-332 triggers an ERRalpha-dependent acute aerobic exercise gene response in muscle and enhances running endurance in mice. Follow-up work reported that treated mice gained more fatigue-resistant oxidative muscle fibers, ran longer, and lost fat mass without increasing their voluntary activity, plus improvements in metabolic markers in obesity models. More recent medicinal-chemistry papers, including work captured in PMC in 2025, have optimized the chemical scaffold to better dissect ERR signaling and improve drug-like properties. All of this is in cells and rodents. There are no published human clinical trials of SLU-PP-332, it is not approved for any use, and long-term safety in people is unknown. Because ERR signaling touches many tissues, the human risk-benefit picture is genuinely unstudied, and any 'exercise in a capsule' marketing runs far ahead of the data. |
Frequently Asked Questions: AICAR vs SLU-PP-332
What is the difference between AICAR and SLU-PP-332?
AICAR is a metabolic peptide that aicar is not a peptide at all. it is a small nucleoside (a building block related to the purine pathway) that cells convert into zmp, a molecule that mimics amp and switches on ampk, the cell's energy sensor. it became famous in 2008 when a salk institute study showed sedentary mice on aicar ran 44% further, earning it the "exercise in a pill" label. human data tell a much less exciting story: it was tested as an intravenous drug (acadesine) for heart surgery and leukemia, the big heart trial failed, and nothing is approved. SLU-PP-332 is a metabolic peptide that slu-pp-332 is a small synthetic molecule, not a peptide, that turns on the estrogen-related receptors (erralpha, beta and gamma), the master switches behind much of the body's response to endurance exercise. researchers call it an 'exercise mimetic' because in mice it boosts mitochondria, shifts muscle toward fatigue-resistant fibers, improves stamina and trims fat without the animal moving more. it was made as a lab tool to study exercise biology. there are no human trials. The main differences lie in their mechanisms of action and clinical applications.
Which is better, AICAR or SLU-PP-332?
Neither is universally "better" - the choice depends on your specific goals. AICAR is typically used for metabolic purposes, while SLU-PP-332 is used for metabolic. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can AICAR and SLU-PP-332 be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using AICAR and SLU-PP-332 together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.