Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
Cardarine (GW501516) is a PPAR-delta agonist that shifts fuel metabolism from glucose to lipids, dramatically increasing endurance and fat oxidation. While providing massive performance benefits (endurance enhancement impossible naturally), it does not affect hormones or build muscle. Critical concern: abandoned in clinical trials due to rapid cancer development in animal studies. No hormonal suppression or PCT required. Rated 6 due to significant performance enhancement but capped below steroids as it lacks anabolic effects.
Overview
A PPAR-delta agonist that shifts fuel source from glucose to lipids. Provides massive boosts in endurance and fat oxidation but was abandoned in clinical trials due to cancer concerns.
Important Warnings
- •CRITICAL: Abandoned in clinical trials due to cancer development in animal studies
- •Long-term human safety data does not exist
- •Use at your own significant risk
Purpose & Use Cases
Endurance Enhancement
Dramatically increases cardiovascular endurance and stamina.
Fat Oxidation
Shifts metabolism to preferentially burn fat for fuel.
Lipid Improvement
Can improve cholesterol profiles significantly.
Benefits
- Massive endurance increase
- Enhanced fat burning
- Improved cholesterol profile
- No hormonal suppression
- No stimulant effects
- Works immediately
Good to Know
It is a PPAR-delta agonist, NOT a SARM
Cardarine is constantly sold and stacked alongside SARMs, but it does not touch the androgen receptor. It activates PPAR-delta, a metabolic nuclear receptor. That means no androgenic activity, no aromatization, no testosterone suppression and no PCT, but also zero direct muscle-building effect. It is a pure endurance/fat-oxidation drug, not an anabolic.
The cancer controversy: honest framing
GSK ran 2-year (104-week) carcinogenicity studies in rats and mice and saw tumors develop across multiple organ systems (liver, stomach, tongue, skin, bladder, ovaries, uterus, testes) at doses reported as low as ~3 mg/kg/day, and abandoned the program in 2007. Two caveats cut both ways: even ~3 mg/kg/day is roughly 200mg/day for an adult, still well above a typical human physique dose (10-20mg), and the abstracts were never published in full, but the mechanism (PPAR-delta driving angiogenesis, GLUT1 expression and cell proliferation) is biologically plausible and a 2018 study showed it accelerated colorectal cancer growth in mice. Bottom line: there is no long-term human safety data, so the real human risk is genuinely unknown rather than proven safe or proven lethal.
Why users like it: no crash, no shutdown
Unlike stimulant fat burners, Cardarine is not a stimulant: no jitters, tremors, elevated heart rate or insomnia, and it works from the first dose. The trade-off users accept for that clean endurance boost is the unresolved carcinogenicity question, which is why many knowledgeable users avoid it entirely or keep cycles very short.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 10 – 10 mg/day |
| Intermediate | 10 – 15 mg/day |
| Advanced | 15 – 20 mg/day |
Strictly adhere to low doses and short cycle lengths due to cancer concerns.
Side Effects
Cancer Risk
rareAnimal studies showed rapid cancer development. Human risk unknown but concerning.
Keep doses low and cycles short. Many choose to avoid entirely.
Rhabdomyolysis / Liver Enzyme Elevation (high-dose)
rareA published clinical case report documented severe rhabdomyolysis and liver enzyme elevation (AST >2,500 U/L, ALT >900 U/L, CPK >86,000 U/L) in a user who took 20mg/day for 4 days on top of roughly two months of prior use. Confounding factors (exertion, possible co-ingestants) mean causation isn't fully isolated, but it is a real documented toxicity signal at higher doses.
Do not exceed typical doses (10-20mg/day) or attempt acute "loading." Seek medical care for dark/brown urine, severe muscle pain, or unusual fatigue.
General Mitigation Strategies
Limit cycle length to 6-8 weeks maximum. Use lowest effective dose and avoid exceeding ~20mg/day (higher acute doses are linked to a documented rhabdomyolysis/liver-enzyme case). Many users avoid this compound entirely due to cancer concerns from animal studies.
Post Cycle Therapy (PCT)
Not hormonal. No PCT required.
How It Works
Cardarine activates PPAR-delta, a nuclear receptor that regulates lipid metabolism. This shifts the body's preferred fuel source from glucose to fatty acids, dramatically increasing fat oxidation and endurance capacity.
Fundamentals
Reference on the practices relevant to Cardarine: how they are done and where they go wrong. Not a recommendation to use it.
Detection Times
The unmetabolized parent GW501516 clears quickly (case-report literature puts it at no more than ~5 days), but anti-doping labs actually screen for its long-lived sulfone/sulfoxide metabolites: a published detection study found the GW1516 sulfone metabolite measurable in urine via LC-MS/MS for up to 40 days after a single 15mg oral dose (Sobolevsky & Dikunets, 2012). Separately, a clinical poisoning case found the unmetabolized parent drug undetectable in urine 10 days after stopping ~2 months of repeated use (confirmed via hair analysis), consistent with fast parent-compound clearance. Fast parent clearance does not mean a short real detection window, WADA screens for the metabolites directly both in- and out-of-competition.
Legal Status
Research chemical / not for human consumption (USA).
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
GW501516 (Cardarine) is explicitly prohibited at all times as a metabolic modulator under S4.5 (Metabolic Modulators) on the WADA Prohibited List.