What is Cardarine?
Cardarine, also GW-501516, is often mentioned in the same breath as SARMs but is not one. It is an agonist at the PPAR-delta receptor, a switch in energy metabolism. It was originally developed by GlaxoSmithKline for metabolic disease.
In the community Cardarine is known mainly for its endurance and fat-burning profile. Equally important is an honest read of the animal data, see below.
Comparison
Exercise mimetics in the lexicon
Which switch each entry targets, as stated in the TPD lexicon. Tap a card to open its entry.
Simplified. In the mouse study AICAR (AMPK) worked even without training, GW1516 (PPAR-delta) only together with training. Ostarine is a SARM and is shown for comparison. 1
How it works
Through the PPAR-delta receptor Cardarine switches on programs in muscle cells tied to fat burning and oxidative metabolism. In animal models this shifted energy use toward fat and increased endurance performance.
Cardarine does not act on the androgen receptor, so it does not suppress the testosterone axis. It is hormonally neutral, which fundamentally separates it from the SARMs.
Where it acts
Where Cardarine acted in studies
Tap a point or a card. Colour = PPAR-delta, grey = observed.
Targets in the ChEMBL database8
Compound ChEMBL CHEMBL38943: one recorded mechanism, Agonist.
- Gene
- PPARD
- UniProt
- Q03181
- ChEMBL
- CHEMBL3979
- Action
- Agonist
How to take it
Oral, usually once daily.
- One dose per day is generally enough, some split because of the half-life.
- Often taken before training.
- With some water, with or without food.
Dosing
Dosing
Dosing, titration and syringe
Loading the dosing information …
- Getting started and stepping up, drawn as a staircase
- Units on the U-100 syringe for every step
- How long one vial lasts
What the research shows
The best-known study (Narkar, 2008) showed in mice that GW1516 together with training markedly increased the number of oxidative muscle fibers and endurance performance, a classic exercise-mimetic result.
The other side: GlaxoSmithKline stopped development after long-term animal studies at high doses showed increased tumors in several organs. That is the central reason Cardarine never reached approval. Human long-term safety data are missing. Anyone using Cardarine should know these animal data and not talk them away.
Study results
What the trials measured
Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.
Blood lipids after 12 weeks3
268 people with low HDL, largest reported change from baseline
Values from the abstract, three dose levels against placebo. The abstract gives the largest change per value but no placebo values.
Metabolism after 2 weeks2
Overweight men, 6 per group, change from baseline
Values from the abstract. HDL stayed unchanged. The PPAR-alpha comparator only lowered triglycerides. Very small groups over a short time.
Endurance and muscle fibres in mice1
4 weeks, treadmill test, 9 animals each
Values from the full text. GW1516 alone did not raise endurance in untrained mice, not even after up to 5 months. Only AICAR worked without training.
Research status
Where the research stands
ClinicalTrials.gov lists three trials with GW501516, all from 2003 to 2006 and completed. The phase 2 trial is counted here. A metabolic study with 13 men is entered as phase 4 although GW501516 was never approved. Another trial has neither a phase nor an end date. As of 26 Oct 2026. 7
- Preclinical Mice: more endurance only together with training
- Phase 1 no registered trial
- Phase 2 1 trial, 1 completed
- Phase 3 no registered trial
- Approval not yet
Show all 1 phase 2 trial on a timelineHide timeline
NCT00158899 · 424 participants, started Aug 2004, primary endpoint reached Jun 2006.
Registry entry ↗ · Results not yet in PubMed
Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026.
Side effects
- Central point: increased tumor rate in long-term animal studies at high doses, the reason for the development stop.
- Short term, users report few acute effects, which is exactly what hides the real risk.
- No solid long-term human safety data.
Practice
-
The animal tumor data are real, take them seriously rather than ignoring them.
-
If at all, then low and not over long periods.
-
Banned and detectable in official competition.
Storage
Store dry, cool and protected from light, out of reach of children. Keep the original container closed and mind the expiry date.
