What Is AICAR?

1. How does AICAR work?

Cells use ATP to supply energy. AMP helps signal when energy availability is low, and AMP-activated protein kinase, or AMPK, helps coordinate the response. Depending on the tissue and conditions, that response can favor fuel use and reduce energy-consuming synthesis.

After AICAR enters a cell, the enzyme adenosine kinase can add a phosphate group to form ZMP. ZMP mimics some of AMP’s effects on AMPK. In Corton and colleagues’ experiments, AICAR activated this pathway in rat liver cells without requiring a change in their ATP, ADP or AMP concentrations.

The terminology can trip up a literature search. Some papers use “AICAR” for the riboside given experimentally; others use it for the phosphorylated ribotide, ZMP. Here, AICAR refers to acadesine, the administered nucleoside. The FDA substance record lists its chemical names and identity.

AMPK activation also does not explain every AICAR effect. The human muscle experiments below measured increased glucose uptake without detectable activation of the AMPK markers tested. Calling AICAR an AMPK activator is useful shorthand, but it cannot replace measurements of what happens in a particular tissue.

2. AICAR and endurance: the 44% mouse result

In the 2008 Cell paper by Narkar and colleagues, four weeks of AICAR treatment increased running endurance by 44% in sedentary mice. Researchers also measured changes in muscle genes involved in oxidative metabolism, the processes that use oxygen to release energy from fuel.

That result concerns performance in a mouse treadmill protocol. It cannot be translated into 44% more cycling power, a 44% higher VO₂ max or a corresponding improvement in race time. A time-to-exhaustion test and a fixed-distance time trial measure different things.

For anyone looking to improve athletic performance, the relevant participants are trained humans. Their baseline adaptations, training load and recovery would need to be accounted for in a controlled trial. The literature reviewed for this page did not establish such a human performance benefit.

3. What has AICAR done in human studies?

AICAR has a longer clinical history than many compounds sold for metabolic experimentation. The studies cover different populations and endpoints, so their results need to stay attached to the question each tested.

Glucose uptake increased, but the AMPK measurements did not

In the 2007 study, muscle uptake of the tracer 2-deoxyglucose increased approximately 2.1-fold with AICAR and 4.7-fold with bicycle exercise after three hours. Whole-body glucose disposal increased by a more modest 7% during an insulin-clamp experiment.

Researchers found no detectable increase in muscle AMPK activity or phosphorylation after AICAR at the sampled times. They did observe changes in another signaling pathway, ERK1/2. The experiment therefore supports an acute effect on glucose handling, without proving that AMPK caused it or that endurance improved.

The 2009 follow-up included six young men, eight older men and eight men with type 2 diabetes. At the lower infusion level, glucose-tracer uptake rose about 2.9-fold, 1.8-fold and 1.6-fold, respectively. The authors linked the blunted response to age rather than diabetes status. A result in young volunteers cannot automatically predict the response of an older person pursuing metabolic health.

The large heart-surgery trial did not show benefit

RED-CABG tested whether perioperative acadesine reduced death, nonfatal stroke or severe left-ventricular dysfunction requiring mechanical support. The trial stopped early for futility after randomizing 3,080 of a planned 7,500 participants.

The primary outcome occurred in 5.1% of the acadesine group and 5.0% of the placebo group. This was a cardiac-surgery trial, so it does not answer the endurance question. It does prevent the compound’s clinical history from being presented as proof of broad cardiovascular protection.

4. AICAR for fat loss, bodybuilding and longevity

Greater glucose uptake means that muscle took up more of the measured tracer under the experiment’s conditions. It does not establish increased daily calorie expenditure or a reduction in body fat. Likewise, burning a larger proportion of fat during a measurement period does not tell you how fat mass changes over weeks.

The human studies reviewed here do not provide a defensible fat-loss percentage, muscle-gain estimate or muscle-preservation claim during a cut. They also do not establish that pairing AICAR with tirzepatide or retatrutide improves body composition. That would require measurements of fat mass, lean mass and function against the same treatment without AICAR.

Longevity claims face a further problem: effects can differ by tissue and duration. In a 2015 mouse study by Guerrieri and van Praag, seven days of AICAR increased markers related to new brain cells and BDNF, a protein involved in neuronal function. At fourteen days, those benefits were no longer present, and researchers found increased expression of some inflammatory and cell-death-related genes.

That experiment does not prove brain harm in people. It does show why a favorable muscle signal cannot establish sustained benefits throughout the body. No human lifespan extension was demonstrated.

5. Oral AICAR, half-life and dosage

Dixon and colleagues tested oral and intravenous administration in healthy men. The oral solution had less than 5% bioavailability. After intravenous administration, the terminal plasma elimination half-life was about 1.4 hours.

Those measurements concern a particular formulation, route and biological compartment. Plasma disappearance and intracellular ZMP activity are different measurements. A short plasma half-life cannot, by itself, determine the duration of an effect or a safe redosing interval.

There is no clinically validated human dose or cycle for endurance, fat loss or longevity in the evidence reviewed. Hospital infusion studies cannot establish the exposure produced by a subcutaneous injection. Capsule claims also need formulation-specific bioavailability data before anyone can infer an effective dose.

6. AICAR side effects: what was observed?

The 24-patient CLL trial reported increased uric acid, kidney impairment, temporary reductions in red blood cells or platelets, and transient infusion-related hypotension. The authors considered the low blood pressure clinically significant. Elevated uric acid was managed within the trial using allopurinol.

These were patients with relapsed or refractory leukemia receiving monitored intravenous treatment. Their adverse-event experience cannot supply a precise risk estimate for a healthy person using a different dose or route. It does supply documented concerns beyond the generic headache-and-nausea lists often attached to research compounds.

The earlier healthy-volunteer study described mild, transient adverse effects and good short-term tolerability. That finding and the oncology findings concern different exposures and populations. Neither establishes the safety of months of unsupervised use.

Chemical purity adds another layer of uncertainty. A certificate for a tested sample can support identity or purity, depending on the assay. It cannot establish clinical safety, and chemical purity alone does not establish sterility for an injectable product.

7. AICAR vs cardarine, SLU-PP-332 and MOTS-c

These compounds appear in the same discussions because researchers study connections to fuel use and exercise. Their molecular targets and evidence differ.

There is no established human head-to-head ranking for endurance or fat loss among these options in the evidence reviewed. Nor does a combination that changes gene expression in a laboratory establish an effective or safe human stack.

For a personal performance log, changing compounds, calorie intake and training volume together makes attribution difficult. Faster intervals could reflect training adaptation; a lower scale weight could include water or lean tissue. Those records can describe what happened without identifying what caused it.

8. AICAR in tested sport

The 2026 WADA Prohibited List explicitly names AICAR in section S4.4.1, alongside other metabolic modulators. It is prohibited in and out of competition. The restriction applies even though a human performance benefit has not been established in the studies discussed here.

An FDA substance identifier also should not be mistaken for permission to use a drug. The acadesine registry entry records its identity and an orphan designation for chronic lymphocytic leukemia. Neither entry establishes approval for endurance, fat loss or anti-aging treatment.

For evidence that could change the performance assessment, look for a controlled human study of a defined formulation, with measured drug exposure, a prespecified endurance or body-composition endpoint, and adverse-event reporting over repeated use.

9. AICAR FAQ

• Is AICAR a peptide or a SARM?

  Neither. Acadesine is a nucleoside analog. Its connection to energy metabolism and AMPK does not make it an amino-acid chain or a selective androgen receptor modulator.

• Does AICAR improve endurance in humans?

  The evidence reviewed here does not establish a human endurance benefit. The widely repeated 44% improvement comes from a mouse treadmill experiment, not a human race, cycling test or VO2 max measurement.

• Does AICAR burn fat?

  AICAR affects pathways involved in fuel use, but the reviewed human studies do not establish a body-fat reduction. Changes in glucose uptake or fuel oxidation cannot supply a percentage of fat lost.

• What is the recommended AICAR dosage?

  No clinically validated dose or cycle is established for endurance, bodybuilding, fat loss or longevity. Intravenous research protocols for other conditions cannot validate a subcutaneous regimen or capsule dose.

• What is AICAR's half-life?

  Dixon and colleagues reported a terminal plasma half-life of about 1.4 hours after intravenous administration in healthy men. That value does not establish the duration of intracellular effects or a dosing interval for other formulations.

• Does oral AICAR work?

  A human study found less than 5% bioavailability for an oral solution. A capsule or enhanced-delivery product would need its own absorption and efficacy data.

• Can AICAR replace cardio?

  No human evidence reviewed here establishes that it reproduces the cardiovascular, muscular and skill adaptations from training. A change in one metabolic pathway cannot establish those combined outcomes.

• Is AICAR banned in sport?

  Yes. The 2026 WADA Prohibited List names AICAR under S4.4.1, metabolic modulators. It is prohibited both in and out of competition.

10. Sources