The short answer on cardarine UK law is that it turns on a legal judgement under the Human Medicines Regulations 2012, which prohibit selling or supplying an unauthorised medicinal product, and that in sport the position is clearer: WADA added GW-501516, the laboratory name for cardarine, to the Prohibited List in 2009. The practical questions that follow are the same ones: what does "research use only" actually mean, and how can a buyer tell whether a bottle contains what the label says? This guide answers those questions using primary legislation, anti-doping statements and published studies of GW-501516. It is educational and is not medical or legal advice. Listings (laboratory research only, 18+): Cardarine (GW-501516) capsules compared.
Key takeaways
- Cardarine (GW-501516) is a PPAR-delta agonist, a laboratory compound that was developed as a drug candidate before development was discontinued. None of the sources used for this guide reports an approval.
- On the question of legal status in the UK, the starting point is the Human Medicines Regulations 2012: selling or supplying an unauthorised medicinal product is prohibited. Whether cardarine falls within that definition is a legal judgement, and no regulator statement naming cardarine is cited in this guide.
- The World Anti-Doping Agency (WADA) added GW-501516 to the Prohibited List in 2009; check the current list on the WADA website. UK Anti-Doping (UKAD) applies strict liability to athletes.
- "Research use only" is a label. The sources used for this guide do not show that it changes the legal position, and UKAD notes that sellers often add such wording to try to get around restrictions (in relation to SARMs).
- A Certificate of Analysis (CoA) is only useful when it names a laboratory, carries a batch number that matches the label, and shows identity and purity data.
- Research compounds sold by Free Muscle are supplied for laboratory research use only and are not for human consumption. They are not authorised as medicines by the MHRA, EMA or FDA, are not food supplements, and are sold only to adults aged 18 or over. Nothing on this page is medical or dosing advice.
Cardarine UK law: what the medicines regulations say
This is general information, not legal advice. Anyone with a specific question should speak to a solicitor or to the relevant regulator.
The starting point is primary legislation. Regulation 46(1) of the Human Medicines Regulations 2012 says that a person may not sell or supply, or offer to sell or supply, an unauthorised medicinal product. Regulation 46(3) separately prohibits possession where the person knows, or has reasonable cause to believe, that the product is intended to be sold or supplied. As at 2 October 2026 the legislation.gov.uk page shows this regulation as up to date.
The next question is what counts as a "medicinal product". The definition in regulation 2(1) (as originally made) covers any substance presented as having properties of preventing or treating disease in human beings, and any substance that may be used by or administered to humans with a view to restoring, correcting or modifying a physiological function by exerting a pharmacological, immunological or metabolic action. The text does not mention cardarine. Applying the definition to cardarine is therefore an inference and a matter of legal judgement, not a quotation from a regulator.
What can be said with confidence is how the compound's own history looks. GSK and Ligand developed GW-501516 as a possible treatment for dyslipidaemia, and phase II trials were under way in 2006 (Pelton, 2006). A later review reported that GSK announced further research would be discontinued because of rodent studies that linked the drug to widespread tumour development (Mackenzie and Lione, 2013). That review is a secondary source and the original developer reports are not cited here. A search of ClinicalTrials.gov (query for GW501516) returned three completed studies, none of them a performance study or an application for approval. The Free Muscle listings state that it is not authorised for human consumption in the UK or EU.
What UKAD says about similar products
UKAD's page on selective androgen receptor modulators (SARMs) states that no SARM has been approved for human consumption and that none can legally be marketed as such. It also notes that sellers often add wording such as "for research purposes only" or "not for human consumption" to try to get around restrictions, and that products labelled this way are not regulated for safety or composition. Cardarine is not a SARM and the page does not name it, so this is an analogy for how UK Anti-Doping views the wording, not a ruling on cardarine.
Cardarine and sport
A review and an analytical study record that WADA added GW-501516 to its Prohibited List in 2009; the review describes the reason as its assumed performance-enhancing properties (Pokrywka et al., 2014; Thevis et al., 2010). UKAD explains on its Prohibited List page that the list is updated each year with effect from 1 January, that athletes are strictly liable for anything found in their system whatever their intent, and that it is not a defence that a substance was missing from a product label. WADA published the 2026 List on 24 September 2025, in force from 1 January 2026. Anyone subject to anti-doping rules should check the current list at wada-ama.org.
For athletes and for anyone asking whether cardarine is legal in the UK, the practical reading is cautious. Whether it meets the definition of a medicinal product is a legal judgement (see above), and it was added to the anti-doping list in 2009; check the current list.
The position for the other compounds we stock, side by side: Are SARMs legal in the UK? 2026 guide
What "research use only" means, and what it does not
Free Muscle's position is that research compounds are sold for laboratory research use only, to customers aged 18 or over, and are not medicines or food supplements. The listings state research use only and that the product is not authorised for human consumption in the UK or EU. The listings publish no dosing schedules. UKAD notes, in relation to SARMs, that sellers often add "for research purposes only" wording to try to get around restrictions.
The wording is a label. The definition in regulation 2(1) of the Human Medicines Regulations 2012 (as originally made) refers to how a substance is presented and to what it may be used by or administered to humans for. Whether a research-use-only label changes how that definition applies to cardarine is a legal judgement, and no source used for this guide answers it.
What the published research says
This section summarises the published literature and official statements. It describes what happened to the named study populations, in the named designs, and nothing here should be read as a claim about any product.
Human studies
A small randomised trial that its authors described as the first report of a PPAR-delta agonist given to people enrolled healthy volunteers who were hospitalised and sedentary for two weeks, with six people on placebo and nine in each of two treatment groups (Sprecher et al., 2007). In that trial of healthy volunteers (Sprecher et al., 2007), HDL cholesterol was higher in both treatment groups, while it fell by 11.5% in the placebo group. The authors called it a small study, and triglycerides only trended downward.
A two-week double-blind trial in moderately overweight men, with six people per group, reported lower fasting triglycerides (30%), apolipoprotein B (26%), LDL cholesterol (23%) and insulin (11%), with HDL cholesterol unchanged, plus a 20% fall in liver fat (Risérus et al., 2008). A randomised double-blind crossover trial in 13 dyslipidaemic men with central obesity, using six-week treatment periods, found lower triglycerides and apoB-100 and higher HDL cholesterol (Ooi et al., 2011). A randomised, placebo-controlled 12-week trial in 268 patients with low HDL cholesterol reported HDL cholesterol increases of up to 16.9%, triglycerides lower by 16.9% and LDL cholesterol lower by 7.3% (Olson et al., 2012).
Limits matter here. The abstracts of these trials report blood lipids, liver fat, insulin and muscle gene expression; none reports body weight, fat loss or athletic performance as an outcome. The longest treatment period stated was 12 weeks, so they say nothing about long-term safety, and the doses and schedules are in the papers themselves. A reviewer concluded that it is still not known whether PPAR-beta/delta agonists would be different enough from existing treatments to justify use in treating dyslipidaemia or type 2 diabetes, and described the path forward as undefined (Billin, 2008). The Sprecher abstract states that GW-501516 was given orally; the other abstracts do not state the route. These trials were in the named volunteers and patients under trial conditions, and their results cannot be assumed to apply to any capsule sold as a research compound, or to anyone else, because those papers say nothing about the composition or quality of other products.
Cell and animal studies
In primary cultured human muscle cells, GW-501516 increased AMPK phosphorylation, fatty acid transport and oxidation, and glucose uptake (Krämer et al., 2007). That is cell culture only. In mice, the abstract reports that a PPAR-beta/delta agonist combined with exercise training increased oxidative muscle fibres and running endurance (Narkar et al., 2008). A metabolomic study in Kunming mice reported greater running endurance and a higher share of succinate dehydrogenase-positive muscle fibres after GW-501516 (Chen et al., 2015). Nothing in these papers shows that mouse results carry over to people.
Safety findings and counter-evidence
The cancer literature is mixed. In Apc(Min/+) mice, deleting PPAR-delta reduced intestinal adenoma growth and blocked the tumour-promoting effect of GW-501516, and activation raised VEGF in colon carcinoma cells; the authors flagged concern for patients at high risk of colorectal cancer (Wang et al., 2006). In mice carrying an APC mutation, GW-501516 enhanced colorectal tumorigenesis while an antagonist suppressed it (Liu et al., 2019). In a KRAS-mutant pancreatic model (the abstract reports PPAR-delta up-regulation in precancerous lesions in humans and mice), GW-501516 strongly accelerated progression from precancerous lesions to pancreatic cancer (Liu et al., 2022).
Other groups reported the opposite. Neither GW-501516 nor a related ligand (GW0742) increased cell growth in five human cancer cell lines or increased Akt phosphorylation, VEGF or COX2 in any of them, and liver, colon and colon polyps from treated mice showed no change in Akt phosphorylation, VEGF or COX2; the authors concluded that the ligands do not potentiate tumorigenesis (Hollingshead et al., 2007). A study using a different ligand, GW0742, found less chemically induced colon carcinogenesis in mice, and notes that a PPAR-beta ligand has been reported to increase small-intestinal tumours in Apc(min/+) mice (Marin et al., 2006). Because that study used GW0742, it cannot be read as a statement about GW-501516. The longest treatment period stated in the human trial abstracts was 12 weeks, and none reports a cancer outcome, so the question stays open.
Case reports and market surveillance
A case report described a 43-year-old man who presented to hospital after using cardarine together with the SARM ostarine, with markedly raised liver enzymes and severe muscle breakdown; the abstract reports that he fully recovered (Kintz et al., 2021). Another described gynaecomastia and hypogonadotropic hypogonadism in a 40-year-old man who had taken supplements found to contain cardarine, RAD-140 and MK-677 plus undisclosed hormones; symptoms resolved on stopping (Chong et al., 2024). Both involved more than one substance, so cardarine alone cannot be blamed. Anecdotal reports from forums or reviews are not evidence and are not used in this guide.
On quality, European official medicines control laboratories reported 324 samples (354 results) from 14 laboratories in 13 countries, most of the samples coming from illegal distribution. Cardarine was among the top five molecules reported; 65% of the seized products were represented as medicines and 24% as dietary supplements. From the limited quantitative data reported, the authors assumed that most samples contained active doses and that some were overdosed (Barrios et al., 2025).
How to judge quality: the Certificate of Analysis explained
A Certificate of Analysis is a laboratory document that reports what was measured in a specific batch. It is evidence about that batch, not a guarantee about every bottle ever sold. The table below is a general checklist and not a description of any Free Muscle report. It sets out what a reader should look for. For a longer walkthrough, see the guide on how to read a Certificate of Analysis.
| What to check | What it tells you | Red flag |
|---|---|---|
| Named laboratory | Who carried out the analysis, and whether it is independent of the seller | No laboratory named, or a name that cannot be traced to a real testing business |
| Batch number | That the report refers to the same batch as the label on the bottle in hand | No batch number, or a number that does not match the printed label |
| Identity by mass spectrometry or similar | That the main compound has the expected molecular identity | Identity not reported at all, or only a purity percentage with no identity data |
| Purity by HPLC | HPLC (high-performance liquid chromatography) separates a sample into its components, so the report shows the share that is the target compound | A purity figure with no chromatogram, or a figure that looks rounded or identical across unrelated products |
| Test date | That the analysis is recent enough to relate to the current production run | No date, or a date that predates the batch |
| Product name and form | That the report describes the same product name and form as the listing | A generic report that could apply to any product |
| Method and units | What was measured and how results are expressed | Units missing or inconsistent, or no method stated |
A CoA describes only the sample tested, so batch matching is not optional. The research on illegal products cited above shows why this scepticism is reasonable (Barrios et al., 2025).
How batch testing works at Free Muscle
Every Free Muscle batch of research compounds is assayed for identity and purity by Janoshik Analytical, an independent laboratory. More background on the laboratory is in the article what is Janoshik Analytical.
The Certificate of Analysis for a batch, including a cardarine batch, is sent on request. To ask for one, email the batch number printed on the product label together with the product name. The process is described on the lab tests page. Because the request is keyed on the batch number, the report a customer receives can be checked against the bottle in hand using the table in the previous section.
A CoA from the seller is still a vendor claim, and this article has not inspected any individual report. Apply every check in the table when a report arrives.
How to order from Free Muscle, step by step
- Choose the listing. The two listings covered in this guide are Cardarine GW-501516 5mg, 60 capsules and Cardarine GW-501516 10mg, 60 capsules. Read the full listing text, including the research-use-only statement.
- Add to basket and check out. Review the order summary before paying. Research compounds are sold only to customers aged 18 or over.
- Delivery. Delivery within the UK is free and tracked, in plain packaging. Standard UK delivery takes 2 to 5 working days. Orders placed before 2pm UK time, Monday to Friday, are processed the same working day. Details are on the shipping page.
- Check the label on arrival. The batch number is printed on the label. Keep a note of it together with the product name, as both are needed to request the CoA.
- Request the CoA. Email the batch number and product name, as described on the lab tests page above.
- Returns. Unopened items in their original packaging can be returned within 30 days under the 30-day guarantee. Apparel returns follow the refund policy.
Comparing listings: strengths and pack sizes
Cardarine UK pack sizes are simple to compare: strength per capsule multiplied by the number of capsules gives the total amount of the compound in the bottle. It is a statement about the contents of the pack, not about how anything should be used.
| Listing | Strength per capsule | Capsules | Total per bottle |
|---|---|---|---|
| Cardarine GW-501516 5mg | 5mg | 60 | 5 x 60 = 300 mg |
| Cardarine GW-501516 10mg | 10mg | 60 | 10 x 60 = 600 mg |
Check the strength per capsule against the product name, the capsule count against the quoted total, and the batch number on the label against the CoA, because strength and purity are properties of a batch and not of a product name.
Readers who want background on the neighbouring compound class can read the explainer what are SARMs or browse the SARMs collection. Cardarine is not a SARM (see the UKAD caveat above).
Frequently asked questions
Is cardarine legal in the UK?
UK law prohibits selling or supplying an unauthorised medicinal product (Human Medicines Regulations 2012, regulation 46); whether cardarine meets the definition is a legal judgement. No source used for this guide reports an authorisation of cardarine as a medicine. In short, cardarine UK law depends on whether a product meets the definition of a medicinal product, so the answer is a legal judgement and not a plain yes or no. This is general information, not legal advice.
Has any UK regulator made a statement about cardarine by name?
No regulator statement naming cardarine is cited in this guide, because none of the sources used for it names cardarine. The UKAD page covers SARMs, which are a different class, and it is used here only as an analogy for the "research use only" wording. This is general information, not legal advice.
Is GW-501516 on the WADA Prohibited List?
WADA added GW-501516 to the Prohibited List in 2009 (Pokrywka et al., 2014); the current list must be checked on the WADA website and the UKAD pages.
What does research use only mean?
It means the product is sold for laboratory research and not for human consumption. It is a label, and the sources used here do not show that it changes the legal position. Free Muscle's position is that research compounds are not medicines or food supplements. This is general information, not legal advice.
How can I tell whether a GW-501516 listing is trustworthy?
Look for a named independent laboratory, a batch number on the label that matches the report, identity and purity data and a recent test date. The table in the quality section lists the red flags.
How do I get the Certificate of Analysis for a Free Muscle batch?
Email the batch number printed on the label together with the product name. The lab tests page has the details.
Who tests Free Muscle batches?
Every batch of research compounds is assayed for identity and purity by Janoshik Analytical, an independent laboratory.
How long does UK delivery take?
Standard UK delivery takes 2 to 5 working days, it is free and tracked, and it arrives in plain packaging. Orders placed before 2pm UK time, Monday to Friday, are processed the same working day.
Can I return an order?
Unopened items in their original packaging can be returned within 30 days. See the guarantee page.
Is there an age limit?
Yes. Research compounds are sold only to customers aged 18 or over.
What is the difference between the 5mg and 10mg listings?
Both listings hold 60 capsules. The first has 5mg per capsule, 300 mg in total, and the second has 10mg per capsule, 600 mg in total.
Sources
- Sprecher DL, Massien C, Pearce G, et al. Triglyceride:high-density lipoprotein cholesterol effects in healthy subjects administered a peroxisome proliferator activated receptor delta agonist. Arterioscler Thromb Vasc Biol. 2007;27(2):359-65. doi PMID 17110604
- Risérus U, Sprecher D, Johnson T, et al. Activation of peroxisome proliferator-activated receptor (PPAR)delta promotes reversal of multiple metabolic abnormalities, reduces oxidative stress, and increases fatty acid oxidation in moderately obese men. Diabetes. 2008;57(2):332-9. doi PMID 18024853
- Ooi EM, Watts GF, Sprecher DL, Chan DC, Barrett PH. Mechanism of action of a peroxisome proliferator-activated receptor (PPAR)-delta agonist on lipoprotein metabolism in dyslipidemic subjects with central obesity. J Clin Endocrinol Metab. 2011;96(10):E1568-76. doi PMID 21816786
- Olson EJ, Pearce GL, Jones NP, Sprecher DL. Lipid effects of peroxisome proliferator-activated receptor-delta agonist GW501516 in subjects with low high-density lipoprotein cholesterol: characteristics of metabolic syndrome. Arterioscler Thromb Vasc Biol. 2012;32(9):2289-94. doi PMID 22814748
- Krämer DK, Al-Khalili L, Guigas B, et al. Role of AMP kinase and PPARdelta in the regulation of lipid and glucose metabolism in human skeletal muscle. J Biol Chem. 2007;282(27):19313-20. doi PMID 17500064
- Narkar VA, Downes M, Yu RT, et al. AMPK and PPARdelta agonists are exercise mimetics. Cell. 2008;134(3):405-15. doi PMID 18674809
- Chen W, Gao R, Xie X, et al. A metabolomic study of the PPARδ agonist GW501516 for enhancing running endurance in Kunming mice. Sci Rep. 2015;5:9884. doi PMID 25943561
- Pelton P. GW-501516 GlaxoSmithKline/Ligand. Curr Opin Investig Drugs. 2006;7(4):360-70. PMID 16625823
- Billin AN. PPAR-beta/delta agonists for Type 2 diabetes and dyslipidemia: an adopted orphan still looking for a home. Expert Opin Investig Drugs. 2008;17(10):1465-71. doi PMID 18808307
- Mackenzie LS, Lione L. Harnessing the benefits of PPARβ/δ agonists. Life Sci. 2013;93(25-26):963-7. doi PMID 24184294
- Wang D, Wang H, Guo Y, et al. Crosstalk between peroxisome proliferator-activated receptor delta and VEGF stimulates cancer progression. Proc Natl Acad Sci U S A. 2006;103(50):19069-74. doi PMID 17148604
- Liu Y, Deguchi Y, Tian R, et al. Pleiotropic effects of PPARD accelerate colorectal tumorigenesis, progression, and invasion. Cancer Res. 2019;79(5):954-969. doi PMID 30679176
- Liu Y, Deguchi Y, Wei D, et al. Rapid acceleration of KRAS-mutant pancreatic carcinogenesis via remodeling of tumor immune microenvironment by PPARδ. Nat Commun. 2022;13(1):2665. doi PMID 35562376
- Marin HE, Peraza MA, Billin AN, et al. Ligand activation of peroxisome proliferator-activated receptor beta inhibits colon carcinogenesis. Cancer Res. 2006;66(8):4394-401. doi PMID 16618765
- Hollingshead HE, Killins RL, Borland MG, et al. Peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) ligands do not potentiate growth of human cancer cell lines. Carcinogenesis. 2007;28(12):2641-9. doi PMID 17693664
- Kintz P, Gheddar L, Paradis C, et al. Peroxisome proliferator-activated receptor delta agonist (PPAR-δ) and selective androgen receptor modulator (SARM) abuse: clinical, analytical and biological data in a case involving a poisonous combination of GW1516 (cardarine) and MK2866 (ostarine). Toxics. 2021;9(10). doi PMID 34678947
- Chong S, Woolnough CA, Koyyalamudi SR, Perera NJ. Reversible gynecomastia and hypogonadism due to usage of commercial performance-enhancing supplement use. JCEM Case Rep. 2024;2(8):luae148. doi PMID 39145153
- Thevis M, Möller I, Thomas A, et al. Characterization of two major urinary metabolites of the PPARdelta-agonist GW1516 and implementation of the drug in routine doping controls. Anal Bioanal Chem. 2010;396(7):2479-91. doi PMID 19946680
- Pokrywka A, Cholbinski P, Kaliszewski P, et al. Metabolic modulators of the exercise response: doping control analysis of an agonist of the peroxisome proliferator-activated receptor δ (GW501516) and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). J Physiol Pharmacol. 2014;65(4):469-76. PMID 25179079
- Barrios MM, Deconinck E, Vanhee C, et al. SARMs, metabolic modulators and growth hormone secretagogues in suspected illegal medicines, bought as sport performance enhancers: a retro- and prospective study within the GEON. Drug Test Anal. 2025;17(10):2078-2085. doi PMID 40551438
- Human Medicines Regulations 2012, regulation 46 and regulation 2 (as made). legislation.gov.uk
- UK Anti-Doping. About SARMs; What's banned in sport: the Prohibited List; 2026 Prohibited List: Summary of Changes. ukad.org.uk summary of changes
- World Anti-Doping Agency. Prohibited List. wada-ama.org
- ClinicalTrials.gov, search for GW501516, accessed 2 October 2026. API query
Notice. This article is published by Free Muscle, which sells the research compounds discussed. Research compounds sold by Free Muscle are supplied for laboratory research use only and are not for human consumption. They are not authorised as medicines by the MHRA, EMA or FDA, are not food supplements, and are sold only to adults aged 18 or over. Nothing on this page is medical or dosing advice. This is general information, not legal advice.