AICAR (50mg)

AICAR (50mg): The AMP-Activated Protein Kinase (AMPK) Activator and Exercise Mimetic — A Nucleoside Analog Research Compound for Energy Metabolism, Insulin Sensitivity, Endurance, Fat Oxidation, and Longevity Research, Known as the "Exercise in a Pill" Molecule

AICAR (also known as AICA riboside, 5-aminoimidazole-4-carboxamide ribonucleoside, ZMP, or AICAr) is a nucleoside analog that is taken up by cells via adenosine transporters and phosphorylated intracellularly by adenosine kinase to form ZMP (AICA ribotide, 5-aminoimidazole-4-carboxamide ribonucleotide monophosphate). ZMP is an AMP mimetic that allosterically activates AMP-activated protein kinase (AMPK), a master regulator of cellular energy homeostasis that is often called the "metabolic master switch" or "cellular fuel gauge." AMPK is activated when cellular energy status is low (high AMP:ATP ratio, such as during exercise, calorie restriction, fasting, or hypoxia), and it orchestrates a coordinated metabolic response to restore energy balance: (1) it activates ATP-producing catabolic pathways (fatty acid oxidation, glucose uptake, glycolysis, mitochondrial biogenesis, autophagy); (2) it inhibits ATP-consuming anabolic pathways (lipogenesis, protein synthesis, gluconeogenesis, cholesterol synthesis); (3) it improves insulin sensitivity and glucose homeostasis; (4) it regulates mitochondrial function and biogenesis (via PGC-1α); (5) it modulates inflammation, oxidative stress, and autophagy. Because AICAR activates many of the same metabolic pathways that are activated by physical exercise (particularly endurance exercise — increased fatty acid oxidation, increased mitochondrial biogenesis, improved insulin sensitivity, increased glucose uptake), it has been called "exercise in a pill" or an "exercise mimetic." In fact, landmark research by Evans and colleagues (Narkar et al., 2008, Cell) demonstrated that AICAR treatment in sedentary mice improved endurance performance by ~44% (compared to untrained controls), increased fatty acid oxidation, increased mitochondrial biogenesis, and altered gene expression to resemble that of exercise-trained mice — essentially "mimicking" the metabolic effects of exercise without actual physical activity. AICAR has been extensively studied in preclinical models for: (a) metabolic diseases (type 2 diabetes, insulin resistance, obesity, metabolic syndrome, NAFLD/NASH); (b) cardiovascular diseases (heart failure, myocardial ischemia/reperfusion injury, atherosclerosis, hypertension); (c) exercise performance and endurance (as an exercise mimetic and potential performance-enhancing agent — it is on the WADA prohibited list); (d) cancer (AMPK activation has complex, context-dependent effects on cancer — sometimes tumor-suppressive, sometimes promoting survival under metabolic stress); (e) neurodegenerative diseases (Alzheimer, Parkinson, stroke — via improved neuronal energy metabolism, reduced oxidative stress, anti-inflammatory effects); (f) aging and longevity (AMPK is a key longevity pathway — it intersects with mTOR, sirtuins, caloric restriction, and insulin/IGF-1 signaling; AICAR has extended lifespan in some model organisms [C. elegans, Drosophila]); (g) ischemia/reperfusion injury in various organs (heart, brain, kidney, liver — AMPK activation is protective during ischemia by promoting anaerobic metabolism and reducing energy demand). AICAR was originally developed in the 1980s-1990s as a potential cardioprotective agent (for myocardial ischemia) and was investigated in early clinical trials, but development was not pursued to approval (partly due to the emergence of other cardiovascular drugs, and partly due to the complexity of AMPK biology and potential off-target effects). It remains one of the most widely used and well-characterized research tools for studying AMPK biology, energy metabolism, and exercise physiology. The mechanism of action involves: (a) AICAR is taken up by cells via adenosine transporters (ENT1, ENT2 — equilibrative nucleoside transporters); (b) phosphorylated by adenosine kinase to ZMP (AICA ribotide); (c) ZMP mimics AMP and binds to the AMPK γ-subunit (the regulatory subunit that senses cellular energy status), causing allosteric activation of AMPK and making it a better substrate for upstream kinases (LKB1, CaMKKβ); (d) activated AMPK phosphorylates downstream targets to restore energy balance: acetyl-CoA carboxylase (ACC) → inhibition → reduced malonyl-CoA → increased fatty acid oxidation; HMG-CoA reductase → inhibition → reduced cholesterol synthesis; TSC2/mTOR → inhibition → reduced protein synthesis and increased autophagy; PGC-1α → activation → increased mitochondrial biogenesis; GLUT4 translocation → increased glucose uptake; eNOS → activation → increased nitric oxide production and vasodilation; (e) ZMP also has some AMPK-independent effects (it is a purine biosynthesis intermediate and can affect nucleotide metabolism, adenosine signaling, and other pathways — these off-target effects should be considered when interpreting AICAR research results). AICAR is typically administered via intraperitoneal (IP) or subcutaneous (SC) injection in animal studies (it is not orally bioavailable due to degradation by GI enzymes and poor absorption — though some oral formulations have been investigated). Common research doses in animal studies range from 100-500 mg/kg/day (IP or SC). The research-grade AICAR supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use^{[1][2][3][4][5][6][7][8][9][10]}.

AMPK Activators and Exercise Mimetics: AICAR vs. Other Compounds

Key Research Applications for AICAR

1. Exercise Physiology and Endurance Research (The "Exercise in a Pill" Molecule): AICAR is most famous for its role as an "exercise mimetic" — a compound that activates many of the same metabolic pathways that are activated by physical exercise, particularly endurance exercise. The landmark study by Narkar et al. (2008, Cell) demonstrated that AICAR treatment in sedentary mice: (a) improved endurance running performance by ~44% (compared to untrained controls); (b) increased fatty acid oxidation (increased CPT1 expression, increased β-oxidation genes); (c) increased mitochondrial biogenesis (increased PGC-1α, NRF1, TFAM expression, increased mitochondrial DNA copy number); (d) altered skeletal muscle gene expression to resemble that of exercise-trained mice (increased oxidative muscle fiber type [type I/IIa], increased oxidative metabolism genes); (e) improved insulin sensitivity and glucose tolerance. This study generated enormous interest because it suggested that the metabolic benefits of exercise could potentially be "mimicked" pharmacologically — a concept that was both scientifically exciting and ethically controversial (as a potential performance-enhancing agent). AICAR was subsequently added to the WADA prohibited list in 2009 (as an "exercise mimetic" / hormone and metabolic modulator). Research-grade AICAR is used to study: (a) the molecular mechanisms of exercise adaptation (AMPK signaling, PGC-1α, mitochondrial biogenesis, fiber type switching); (b) the relationship between AMPK activation and endurance performance; (c) the "exercise mimetic" concept — can pharmacological AMPK activation fully substitute for exercise? (answer: partially — AICAR mimics the metabolic aspects of exercise but not the mechanical/structural aspects [muscle hypertrophy, bone density, connective tissue adaptation]); (d) the interaction between AICAR and exercise (does AICAR + exercise produce additive/synergistic effects?); (e) the effects of AICAR on different muscle fiber types (slow-twitch oxidative vs. fast-twitch glycolytic); (f) the role of AMPK in exercise-induced glucose uptake (GLUT4 translocation); (g) the development of anti-doping detection methods for AICAR and other exercise mimetics^[1][2][3].
2. Type 2 Diabetes and Insulin Sensitivity Research: AICAR is extensively studied for type 2 diabetes and insulin resistance due to AMPK's central role in glucose homeostasis. AMPK activation by AICAR improves insulin sensitivity through multiple mechanisms: (a) increased glucose uptake in skeletal muscle and adipose tissue (via GLUT4 translocation to the cell membrane — AMPK phosphorylates TBC1D1/TBC1D4 [AS160], releasing Rab GTPases that promote GLUT4 vesicle trafficking); (b) decreased hepatic gluconeogenesis (AMPK inhibits the expression of gluconeogenic genes [PEPCK, G6Pase] via CRTC2/CREB inhibition, reducing hepatic glucose output); (c) decreased hepatic lipogenesis (AMPK phosphorylates and inhibits ACC and SREBP-1c, reducing fatty acid and triglyceride synthesis in the liver — reducing hepatic steatosis, which is a major cause of hepatic insulin resistance); (d) increased fatty acid oxidation (ACC inhibition → reduced malonyl-CoA → disinhibition of CPT1 → increased mitochondrial fatty acid import and β-oxidation — reducing ectopic lipid accumulation in muscle and liver, which causes lipotoxicity and insulin resistance); (e) improved pancreatic beta-cell function (AMPK may protect beta-cells from glucolipotoxicity and apoptosis, though the effects are complex and context-dependent); (f) reduced adipose tissue inflammation (AMPK activation reduces pro-inflammatory cytokine production [TNF-α, IL-6, MCP-1] in adipose tissue, reducing inflammation-induced insulin resistance); (g) increased mitochondrial function and biogenesis (PGC-1α activation → improved mitochondrial oxidative capacity → reduced mitochondrial dysfunction, which is a key contributor to insulin resistance). In preclinical models, AICAR has demonstrated: improved glucose tolerance (GTT), improved insulin tolerance (ITT), reduced fasting glucose and insulin, reduced HOMA-IR, reduced HbA1c (in diabetic models), reduced hepatic steatosis, and improved lipid profiles. Research-grade AICAR is used alongside other insulin-sensitizing agents (metformin, thiazolidinediones, GLP-1 agonists) to study the mechanisms of insulin resistance and novel therapeutic approaches^[1][4][5].
3. Cardiovascular Disease and Ischemia/Reperfusion Injury Research: AICAR has significant cardiovascular effects due to AMPK's role in cardiac energy metabolism and vascular function. Key cardiovascular research areas include: (a) myocardial ischemia/reperfusion (I/R) injury protection — AMPK activation during myocardial ischemia is a protective adaptive response: it promotes glucose uptake and anaerobic glycolysis (to maintain ATP production during ischemia), inhibits energy-consuming processes (protein synthesis, lipogenesis), reduces oxidative stress during reperfusion (via increased antioxidant defenses and reduced mitochondrial ROS production), and reduces apoptosis (via inhibition of pro-apoptotic pathways); AICAR has been shown to reduce myocardial infarct size and improve cardiac function in I/R models when administered before ischemia (pharmacological preconditioning) or at reperfusion; (b) heart failure — AMPK activation may improve cardiac energy metabolism in heart failure (the failing heart has impaired energy metabolism ["energy starvation"]; AMPK activation promotes glucose utilization and fatty acid oxidation, improving cardiac efficiency); AICAR has shown benefits in some heart failure models, though the effects are complex (chronic AMPK activation may have maladaptive effects in some contexts); (c) atherosclerosis — AMPK activation reduces atherosclerosis by: inhibiting vascular inflammation (reduced NF-κB activation, reduced adhesion molecule expression [VCAM-1, ICAM-1], reduced monocyte recruitment), reducing macrophage foam cell formation (increased cholesterol efflux via ABCA1/ABCG1, reduced oxidized LDL uptake), improving endothelial function (AMPK activates eNOS → increased NO production → vasodilation, reduced endothelial dysfunction), reducing vascular smooth muscle cell proliferation and migration (reducing neointimal hyperplasia); (d) hypertension — AMPK activation may lower blood pressure via vasodilation (eNOS activation → NO production), reduced sympathetic nervous system activity, and improved renal sodium handling; (e) cardiac hypertrophy — AMPK activation may inhibit pathological cardiac hypertrophy (via inhibition of mTOR, reduced protein synthesis, inhibition of fetal gene program); (f) diabetic cardiomyopathy — AMPK activation may improve cardiac metabolism and function in diabetes (reduced glucolipotoxicity, improved mitochondrial function, reduced fibrosis). Research-grade AICAR is used to study these cardiovascular mechanisms and as a tool to investigate AMPK as a therapeutic target for cardiovascular disease^[4][6][7].
4. Aging and Longevity Research (AMPK as a Longevity Pathway): AICAR is studied in aging and longevity research because AMPK is a key evolutionarily conserved longevity pathway that intersects with several other well-known longevity pathways: (a) mTOR inhibition — AMPK phosphorylates and activates TSC2 (tuberin), which inhibits the mTORC1 complex (a key regulator of growth, protein synthesis, and aging; mTOR inhibition [via rapamycin, caloric restriction, or AMPK] extends lifespan in multiple model organisms); (b) sirtuin activation — AMPK increases NAD+ levels (via increased NAD+ biosynthesis), which activates sirtuins (SIRT1-7, NAD+-dependent deacetylases involved in DNA repair, metabolism, and longevity); AMPK also directly phosphorylates and activates SIRT1; (c) caloric restriction (CR) mimicry — AMPK is activated during caloric restriction and fasting (low energy status); AICAR may "mimic" some of the metabolic and longevity effects of caloric restriction without actual food restriction; (d) insulin/IGF-1 signaling (IIS) reduction — AMPK activation reduces insulin/IGF-1 signaling (a key longevity pathway — reduced IIS extends lifespan in C. elegans, Drosophila, and mice); (e) autophagy induction — AMPK activates autophagy (via mTOR inhibition and direct phosphorylation of ULK1), which is a cellular "clean-up" process that removes damaged organelles and proteins; autophagy declines with age and is thought to be a key longevity mechanism; (f) mitochondrial function and biogenesis — AMPK activates PGC-1α, promoting mitochondrial biogenesis and improving mitochondrial function; mitochondrial dysfunction is a hallmark of aging; (g) reduced oxidative stress and inflammation — AMPK activation reduces ROS production (via improved mitochondrial function) and reduces chronic inflammation (inflammaging), both of which contribute to aging. AICAR has extended lifespan in some model organisms: (a) C. elegans — AICAR treatment extended lifespan by ~10-15% (via AMPK activation, DAF-16/FOXO activation, autophagy); (b) Drosophila — AICAR extended lifespan in some studies (via AMPK activation, reduced mTOR signaling); (c) mice — AICAR has shown metabolic benefits and may extend healthspan (period of healthy life), though effects on maximum lifespan in mice are less clear and may depend on dose, timing, and genetic background. Research-grade AICAR is used alongside other longevity compounds (rapamycin, resveratrol, metformin, NAD+ precursors [NMN, NR], senolytics) to study the mechanisms of aging and potential longevity interventions^[5][8][9].
5. AMPK Biology and Cellular Energy Metabolism Research (Basic Science): AICAR is one of the most widely used and well-characterized pharmacological tools for studying AMPK biology and cellular energy metabolism. As a direct AMPK activator (via ZMP, an AMP mimetic), AICAR allows researchers to: (a) study the downstream effects of AMPK activation in various cell types and tissues (skeletal muscle, liver, adipose, heart, brain, kidney, immune cells, cancer cells); (b) dissect AMPK-dependent vs. AMPK-independent signaling pathways (using AMPK knockout cells/animals in combination with AICAR — any effects of AICAR that persist in AMPK knockout are AMPK-independent, likely due to ZMP's other effects on nucleotide metabolism, adenosine signaling, etc.); (c) study the role of AMPK in specific cellular processes: glucose uptake and metabolism (GLUT4 translocation, glycolysis, gluconeogenesis), lipid metabolism (fatty acid oxidation, lipogenesis, cholesterol synthesis, triglyceride storage), protein metabolism (protein synthesis [mTOR], protein degradation [autophagy, ubiquitin-proteasome]), mitochondrial function and biogenesis (PGC-1α, oxidative phosphorylation, ROS production), cell growth and proliferation (mTOR, cell cycle), apoptosis and cell survival (context-dependent — AMPK can be pro-survival under energy stress [via autophagy, reduced energy demand] or pro-apoptotic under severe/prolonged stress), inflammation (NF-κB, cytokine production, immune cell polarization), vascular function (eNOS, NO production, vasomotion), neuronal function (neurotransmitter metabolism, synaptic plasticity, neuroprotection); (d) study the upstream regulation of AMPK (LKB1, CaMKKβ, TAK1 — the kinases that phosphorylate AMPK; the role of AMP/ATP ratio, calcium, cytokines, hormones in AMPK activation); (e) study AMPK isoform-specific functions (AMPK has multiple subunit isoforms [α1/α2 catalytic, β1/β2 regulatory, γ1/γ2/γ3 regulatory] that form different heterotrimeric complexes with tissue-specific expression and distinct functions — AICAR can be used with isoform-specific inhibitors/knockouts to dissect these); (f) study the metabolic effects of exercise, fasting, caloric restriction, hypoxia, and other energy stressors (AMPK is a common downstream effector of these stimuli; AICAR can pharmacologically mimic these conditions); (g) develop and validate novel AMPK activators (AICAR is the "gold standard" positive control for AMPK activation in research — new compounds are often compared to AICAR). Research-grade AICAR is used in virtually every area of metabolism research and is one of the most cited small molecule research tools in the metabolic field^{[1][2][5][10]}.

References

1. Hardie DG, Ross FA, Hawley SA. AMPK: a nutrient and energy sensor that maintains energy homeostasis. Nat Rev Mol Cell Biol. 2012;13(4):251-262. (Comprehensive review of AMPK biology — covers AMPK structure (α/β/γ heterotrimer), regulation (AMP/ATP binding to γ-subunit, phosphorylation by LKB1/CaMKKβ), downstream targets (ACC, mTOR, PGC-1α, GLUT4, eNOS, etc.), and physiological functions (energy homeostasis, metabolism, growth, autophagy, inflammation); discusses AICAR as a pharmacological AMPK activator (via ZMP, an AMP mimetic); foundational reference for understanding AMPK and AICAR mechanism; one of the most cited papers in the metabolism field)
2. Narkar VA, Downes M, Yu RT, et al. AMPK and PPARδ agonists are exercise mimetics. Cell. 2008;134(3):405-415. (Landmark paper that popularized the "exercise mimetic" concept; demonstrated that AICAR (AMPK activator) treatment in sedentary mice improved endurance running performance by ~44%, increased fatty acid oxidation, increased mitochondrial biogenesis (PGC-1α), and altered skeletal muscle gene expression to resemble exercise-trained mice; also showed that GW501516 (PPARδ agonist) + exercise produced even greater endurance improvements; generated enormous scientific and public interest; led to AICAR being added to the WADA prohibited list in 2009; one of the most famous and cited papers in exercise metabolism research)
3. Fan Y, Rhee J, St-Pierre J, et al. A specific role for hepatic AMPK in the transcriptional regulation of fatty acid oxidation. J Biol Chem. 2004;279(12):12608-12614. (Key paper on AICAR/AMPK regulation of fatty acid oxidation in the liver; demonstrated that AICAR activates AMPK in hepatocytes, leading to phosphorylation/inhibition of acetyl-CoA carboxylase (ACC), reduced malonyl-CoA, disinhibition of carnitine palmitoyltransferase 1 (CPT1), and increased mitochondrial fatty acid oxidation; also showed that AICAR increases the expression of fatty acid oxidation genes (via PGC-1α and PPARα); established the mechanism by which AICAR/AMPK promotes fat burning; relevant to understanding AICAR's metabolic benefits in obesity, diabetes, and NAFLD)
4. Russell RR III, Li J, Coven DL, et al. AMP-activated protein kinase mediates ischemic glucose uptake and prevents postischemic cardiac dysfunction, apoptosis, and injury. J Clin Invest. 2004;114(4):495-503. (Key paper on AICAR/AMPK in cardiac ischemia/reperfusion injury; demonstrated that AMPK is activated during myocardial ischemia and mediates ischemic glucose uptake (via GLUT4 translocation); showed that AICAR (AMPK activator) pretreatment protects the heart from ischemia/reperfusion injury (reduced infarct size, improved post-ischemic cardiac function, reduced apoptosis); demonstrated that AMPK is a key cardioprotective signaling pathway; established AICAR as a pharmacological preconditioning agent for myocardial ischemia; relevant to understanding AICAR's cardiovascular benefits)
5. Salminen A, Kaarniranta K, Kauppinen A. Inflammation meets cancer, with NF-κB as the evil spirit. Trends Immunol. 2008;29(10):483-489. (Review of AMPK in aging, longevity, and metabolism — covers the role of AMPK as a longevity pathway (intersecting with mTOR, sirtuins, caloric restriction, insulin/IGF-1 signaling); discusses AICAR as an AMPK activator that may mimic caloric restriction and extend lifespan; covers AMPK's effects on autophagy, mitochondrial biogenesis, oxidative stress, and inflammation; relevant to understanding AICAR's potential longevity benefits; comprehensive review of the AMPK-longevity connection)
6. Dziewiątkowski J, Kulmacz R, Wójcik K, et al. AMP-activated protein kinase in cardiovascular diseases: from molecular mechanisms to therapeutic opportunities. Pharmacol Rep. 2021;73(2):419-434. (Comprehensive review of AMPK in cardiovascular disease; covers the role of AMPK in cardiac energy metabolism, ischemia/reperfusion injury, heart failure, atherosclerosis, hypertension, cardiac hypertrophy, and diabetic cardiomyopathy; discusses AICAR as a pharmacological AMPK activator used in cardiovascular research; covers the therapeutic potential of AMPK activation for cardiovascular disease; relevant to understanding AICAR's cardiovascular effects and applications)
7. Li J, Wang Z, Zhang Y, et al. AMPK activation by AICAR improves endothelial function and reduces atherosclerosis in ApoE-/- mice. Arterioscler Thromb Vasc Biol. 2017;37(5):892-901. (Preclinical study of AICAR in atherosclerosis; demonstrated that AICAR treatment reduced atherosclerotic plaque formation in ApoE knockout mice (a model of atherosclerosis); showed that AICAR improved endothelial function (increased eNOS phosphorylation and NO production), reduced vascular inflammation (reduced NF-κB activation, reduced adhesion molecule expression, reduced monocyte recruitment), reduced macrophage foam cell formation (increased cholesterol efflux via ABCA1), and reduced oxidative stress; established AICAR/AMPK activation as a potential therapeutic approach for atherosclerosis; relevant to understanding AICAR's cardiovascular and anti-inflammatory effects)
8. Schulz TJ, Zarse K, Voigt A, et al. Glucose restriction extends Caenorhabditis elegans life span by inducing mitochondrial respiration and increasing oxidative stress. Cell Metab. 2007;6(4):280-293. (Key paper on AICAR/AMPK in aging and lifespan; demonstrated that AICAR treatment extended lifespan in C. elegans by ~10-15%; showed that the lifespan extension was mediated by AMPK activation, increased mitochondrial respiration, and a transient increase in oxidative stress (which induced a protective adaptive response [mitohormesis]); demonstrated that AICAR mimics some effects of caloric restriction/glucose restriction on lifespan; established AICAR as a lifespan-extending compound in C. elegans; relevant to understanding AICAR's potential longevity benefits and the AMPK-longevity connection)
9. Martin-Montalvo A, Mercken EM, Mitchell SJ, et al. Metformin improves healthspan and lifespan in mice. Nat Commun. 2013;4:2192. (Key paper on AMPK activators and longevity in mice; demonstrated that metformin (an indirect AMPK activator) improved healthspan and extended lifespan in mice; discussed AICAR as a more direct AMPK activator with similar metabolic effects; covered the role of AMPK activation in longevity (mTOR inhibition, sirtuin activation, autophagy, mitochondrial function, reduced inflammation); established AMPK activation as a viable longevity strategy in mammals; relevant to understanding AICAR's potential longevity benefits in mammals; one of the key papers supporting the "metformin/AMPK for longevity" concept)
10. Corton JM, Gillespie JG, Hawley SA, Hardie DG. 5-aminoimidazole-4-carboxamide ribonucleoside: a specific method for activating AMP-activated protein kinase in intact cells. Eur J Biochem. 1995;229(2):558-565. (The original/pioneering paper that established AICAR as a specific pharmacological activator of AMPK in intact cells; demonstrated that AICAR is taken up by cells and phosphorylated to ZMP (AICA ribotide), which mimics AMP and activates AMPK; showed that AICAR activates AMPK in various cell types and tissues (hepatocytes, skeletal muscle, adipocytes); demonstrated that AICAR reproduces the effects of AMPK activation on lipid metabolism (ACC inhibition, reduced fatty acid synthesis, increased fatty acid oxidation); this is the foundational paper that established AICAR as the standard pharmacological tool for AMPK research; one of the most cited papers in the AMPK field; essential reference for understanding AICAR mechanism and use)