Rad 140 INJ: What Researchers Need to Know in 2026

RAD-140 has been one of the most studied selective androgen receptor modulators (SARMs) of the past decade — but most of that research has centered on oral administration. The injectable formulation changes certain variables that matter for research design: bioavailability kinetics, peak plasma concentration, dosing precision, and the elimination of first-pass hepatic metabolism. This article covers what researchers need to understand about RAD-140 INJ specifically, how injectable pharmacokinetics differ from oral, and where the compound sits in the current scientific literature.

What Is RAD-140 INJ?

RAD-140 INJ is the injectable oil-suspension formulation of Testolone — the same non-steroidal SARM originally developed by Radius Health, delivered subcutaneously or intramuscularly rather than orally. RAD-140’s core pharmacological profile — a reported anabolic-to-androgenic ratio of approximately 90:1, selective binding to androgen receptors in skeletal muscle and bone, and reduced androgenic activity at prostate and hepatic tissue — remains the same regardless of delivery route. What changes with injectable administration is the pharmacokinetic curve: absorption rate, time to peak plasma concentration, and avoidance of hepatic first-pass metabolism.

Why Researchers Choose Injectable Over Oral

1. Bypassing first-pass metabolism. Oral RAD-140 passes through the GI tract and liver before reaching systemic circulation. Injectable formulations enter the bloodstream directly — the full administered dose reaches target receptors without hepatic attrition, reducing liver stress in extended research protocols.

2. Controlled release kinetics. Oil-suspended injectables produce slower absorption from the injection site, resulting in a more sustained plasma concentration curve versus the peak-and-trough of daily oral dosing.

3. Dosing precision. Volumetric dosing via syringe allows more precise calibration than capsule or liquid oral formats.

Research Overview

Key studies informing injectable RAD-140 research include neuroprotective data from Jayaraman et al. (2014, Endocrinology), showing RAD-140 activation of MAPK/ERK and PI3K/Akt pathways in neuronal tissue at levels comparable to testosterone. This signal is receptor-mediated and delivery-route agnostic. (PubMed: 24384845)

Radius Health Phase I/II oncology trials (NCT02971761) used oral administration in HR+/HER2- breast cancer patients at 50–150 mg/day, establishing human safety data for the oral route. Injectable pharmacokinetics in humans remain extrapolated from preclinical data.

Additional research: PubMed — RAD-140 | Google Scholar

Community Discussion

The research community on r/PEDs and r/sarmssourcetalk broadly reports on injectable RAD-140: faster onset of noticeable effects, reduced digestive sensitivity, and preference for the precision injectable dosing affords. Post-injection pain from the oil carrier is the most noted drawback, largely resolved by warming the vial and injecting slowly.

Potential Benefits Studied

• Enhanced bioavailability: First-pass bypass means more of the administered dose reaches androgen receptors in target tissues.
• Reduced hepatic burden: Bypassing enterohepatic circulation lowers metabolic liver load versus equivalent oral doses.
• Skeletal muscle anabolism: Same ~90:1 anabolic-to-androgenic selectivity as oral RAD-140.
• Sustained plasma concentration: Oil depot effect produces a flatter, more consistent plasma curve than oral peak-and-trough.
• Neuroprotective signaling: MAPK/ERK and PI3K/Akt pathway activation — receptor-mediated and route-independent.

Dosage & Administration

Community-documented injectable RAD-140 protocols typically use 5–15 mg per injection subcutaneously or intramuscularly, on every-other-day or three-times-weekly schedules. Injectable doses are generally 20–30% lower than oral equivalents due to improved bioavailability. Standard cycle length: 8–12 weeks. HPG axis suppression applies equally — post-cycle bloodwork and PCT planning are standard. All dosing data is from published literature and community documentation for research reference only.

Where to Find It

Combat Research carries RAD-140 INJ (injectable Testolone) formulated for research applications. The oral formulation is also available: RAD-140 10mg.

Conclusion

RAD-140 INJ offers a pharmacokinetically distinct research tool — same mechanism as oral Testolone, with bypassed first-pass metabolism, improved bioavailability, and a more sustained plasma concentration curve. For researchers where precision and hepatic load are protocol variables, the injectable formulation provides a meaningful option worth exploring with appropriate research design and monitoring.

Disclaimer

This article is for educational and research purposes only. RAD-140 is not approved by the FDA for human use. Nothing on this page constitutes medical advice. Combat Research products are intended for laboratory and research use only.