Cardarine (GW-501516) vs RAD-140 (Testolone)

Mechanism

Cardarine is a selective peroxisome proliferator-activated receptor delta (PPARd) agonist, not a SARM (it does not bind the androgen receptor). PPARd activation in skeletal muscle upregulates genes for fatty acid oxidation (CPT1B, PDK4, ACOX1), shifting fuel substrate from glycolysis toward beta-oxidation, effectively increasing endurance capacity and fat utilization. It increases oxidative type I (slow-twitch) muscle fiber proportion, enhances mitochondrial biogenesis via PGC-1a coactivation, reduces circulating triglycerides and LDL, and increases HDL cholesterol. PPARd activation also reduces macrophage-mediated inflammation through NF-kB suppression.

Standard Dosing

Research indicates 10-20 mg daily orally for 8-12 weeks. Clinical trials (metabolic syndrome) used 2.5-10 mg/day.

Timing

Once daily, 1-2 hours before exercise for acute endurance benefit. Half-life approximately 16-24 hours. Consistent daily dosing.

Cycle Duration

8-12 week cycles. No HPG suppression, so PCT is not required. However, long-term safety is unknown and cycling is prudent.

Side Effects

• CANCER RISK: Accelerated tumor development in multiple organs observed in 2-year rodent study at all doses tested
• Headache
• Nausea
• Diarrhea
• Potential liver effects at high doses

Contraindications

• Active or history of cancer (CRITICAL — see notes on carcinogenicity)
• Pregnancy and breastfeeding
• Individuals under 21
• Liver disease

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Mechanism

RAD-140 is a potent nonsteroidal SARM with high oral bioavailability and selectivity for muscle and bone AR over prostate. It acts as a full agonist at the AR in muscle tissue, promoting nitrogen retention and protein synthesis via mTOR/p70S6K pathway activation. RAD-140 also demonstrates neuroprotective properties, acting against beta-amyloid-induced neurotoxicity through AR-mediated MAPK/ERK signaling. Preclinical data show greater anabolic potency than testosterone propionate at equivalent doses with significantly reduced prostate stimulation.

Standard Dosing

Research indicates 10-20 mg daily orally for 8-12 weeks. Phase 1 clinical trial (oncology) identified 100 mg as the maximum tolerated dose.

Timing

Once daily, consistent timing. Very long half-life (~60 hours) means stable plasma levels even with once-daily dosing. Morning preferred.

Cycle Duration

8-12 week cycles. PCT mandatory due to significant HPG axis suppression.

Side Effects

• Significant testosterone suppression
• Hepatotoxicity (multiple published case reports of drug-induced liver injury)
• HDL suppression and LDL elevation
• Aggression and mood changes
• Hair shedding (androgenic effect despite 'selective' designation)
• Insomnia
• Headache

Contraindications

• Pre-existing liver disease
• Androgen-sensitive cancers
• Cardiovascular disease (LDL elevation concern)
• Pregnancy and breastfeeding
• Individuals under 21
• Athletes subject to anti-doping testing

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