Why is SR-9009 oral bioavailability so low?

SR-9009 undergoes extensive first-pass metabolism in the liver, resulting in only ~2% reaching systemic circulation orally. This is why sublingual administration (holding under the tongue for 60+ seconds) or subcutaneous injection are preferred routes for meaningful blood levels.

Does SR-9009 suppress testosterone?

No. SR-9009 is not a SARM and does not interact with androgen receptors. It modulates Rev-ErbA circadian rhythm receptors. No PCT is needed, and it can be safely stacked with SARMs without adding suppression.

How does SR-9009 compare to Cardarine (GW-501516)?

Both enhance endurance and fat loss but through different mechanisms. SR-9009 modulates circadian genes and mitochondrial function, while GW-501516 activates PPARdelta. GW-501516 has much better oral bioavailability. They can be stacked for synergistic effects.

Research & Educational Use Only. This protocol guide is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before beginning any research protocol.

Rev-ErbA Agonist Evidence Grade: C (Animal Data)

SR-9009 (Stenabolic) Protocol Guide

SR-9009 (Stenabolic) is a Rev-ErbA agonist developed at Scripps Research Institute. It is not a SARM but is often grouped with them. It modulates circadian rhythm genes, enhancing mitochondrial function, fat oxidation, and endurance. Despite impressive animal data, it has extremely poor oral bioavailability (~2%). This protocol covers various administration routes.

Protocol Overview

Compound: SR-9009 (Stenabolic)
Category: Rev-ErbA Agonist (Metabolic Modulator)
Mechanism: Activates Rev-ErbA alpha and beta nuclear receptors, modulating circadian rhythm gene expression. Increases mitochondrial count, enhances oxidative metabolism, reduces fat storage, and improves exercise endurance
Half-Life: 4 hours
Form: Oral liquid, sublingual, or injectable
Route: Sublingual preferred (oral bioavailability ~2%)
Frequency: 3-4x daily (split due to short half-life)
Cycle Length: 8-12 weeks

Dosing Protocol

Protocol	Dose	Frequency	Route	Duration
Oral (Low Bioavail.)	20-30 mg	3-4x daily (split)	Oral	8-12 weeks
Sublingual	10-20 mg	3x daily (split)	Sublingual (hold 60s)	8-12 weeks
Injectable	10 mg	2x daily	Subcutaneous	8-12 weeks

Expected Timeline

Week 1-2

Increased wakefulness and energy during active hours. Improved sleep quality. Subtle increase in exercise endurance.

Week 3-4

Noticeable fat loss, especially with caloric deficit. Cardio endurance significantly improved. Recovery between sessions improves.

Week 5-6

Peak metabolic effects. Reduced body fat with preserved lean mass. Cholesterol markers may improve (LDL reduction noted in studies).

Week 7-8

Continued fat oxidation. Exercise capacity remains elevated. No hormonal suppression (non-SARM).

Week 9-12

Sustained benefits without tolerance buildup. Can run longer cycles as it is non-hormonal and non-suppressive.

Side Effects & Monitoring

Common Side Effects

Wakefulness / difficulty sleeping if dosed too late
Injection site irritation (injectable form)
Mild headaches
Slightly increased heart rate during exercise

Precautions

Extremely poor oral bioavailability (~2%) - sublingual or injectable preferred
Does not suppress testosterone - no PCT needed
Frequent dosing required due to 4-hour half-life
Not a SARM despite being marketed alongside them
Banned by WADA for athletic competition

Related Tools & Resources

Dosing Calculator Reconstitution Calc Bloodwork Planner Stack Checker

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