SR-9009, designated Stenabolic, is a synthetic Rev-ErbA agonist developed at the Scripps Research Institute by Professor Thomas Burris. It is not a SARM — it does not interact with the androgen receptor. Instead, SR-9009 targets Rev-Erb-alpha and Rev-Erb-beta, nuclear receptors that regulate circadian rhythm gene expression, lipid metabolism, inflammatory response, and mitochondrial biogenesis. It is commonly sold alongside SARMs due to its complementary role in endurance and fat metabolism research.

SR-9009 activates Rev-ErbA nuclear receptors, which function as transcriptional repressors of genes involved in gluconeogenesis, lipogenesis, and adipocyte differentiation. In preclinical models, SR-9009 administration increased mitochondrial count in skeletal muscle, enhanced oxidative metabolism, reduced plasma triglycerides and total cholesterol, decreased fat mass, and — most dramatically — increased exercise endurance capacity by approximately 50% in sedentary mice. The compound essentially reprograms the metabolic machinery of cells toward a state resembling that of a trained endurance athlete, independent of actual exercise.

The research literature emphasizes SR-9009's effects on exercise capacity, fat oxidation, and metabolic efficiency. It is particularly noted for reducing stored body fat without caloric restriction, increasing the ratio of energy expenditure to energy intake, and improving lipid profiles. Anti-inflammatory effects via macrophage reprogramming have also been documented.

SR-9009 is best suited for researchers focused on endurance optimization, fat loss, and cardiovascular metabolic improvement. Because it does not engage the androgen receptor, it produces no hormonal suppression and is appropriate for researchers of any experience level. It is frequently stacked with Cardarine (GW-501516) for compounded endurance effects, or with SARMs like Ostarine during cutting protocols to accelerate fat loss while preserving lean tissue.

SR-9009 has a notably short half-life of approximately 4–6 hours, which is its primary practical limitation. Optimal research protocols require dosing 3–4 times daily to maintain stable plasma levels. Oral bioavailability has been a subject of debate in the literature — early pharmacokinetic studies in rodents suggested limited oral absorption, though subsequent research and widespread anecdotal evidence support meaningful oral activity in practice, particularly in liquid suspension formulations. There is zero testosterone suppression and no PCT requirement. No significant hepatotoxicity or adverse effects have been documented at standard research doses. Typical protocols range from 20–30mg daily (divided into 3–4 doses) for 8–12 weeks.