Runners are increasingly turning to CBD to help manage soreness, sleep, and pre-race nerves. But not every product on the shelf is safe, accurately labeled, or appropriate for athletes who may face drug testing. Knowing what to look for helps marathoners protect both their health and eligibility.

First, runners should understand the anti-doping landscape. Cannabidiol itself is no longer prohibited by the World Anti-Doping Agency (WADA), but all other cannabinoids, including THC, remain banned in-competition. Regulators and national anti-doping bodies warn that many “CBD” products contain trace THC or other cannabinoids, which can still trigger a positive test. For athletes subject to testing, products labeled CBD isolate or broad-spectrum (with verified non-detectable THC) are generally safer choices than full-spectrum oils.

Independent third-party testing is non-negotiable. A reputable CBD brand provides a recent certificate of analysis (COA) from an accredited lab for every batch. Consumer health resources such as Harvard Health and Healthline stress that COAs should confirm the advertised CBD potency, verify THC levels, and screen for heavy metals, pesticides, and residual solvents. This is crucial because multiple studies have found that a majority of retail CBD products are mislabeled, with many containing more or less CBD than claimed and, in some cases, undisclosed THC or contaminants. Athletes should be able to scan a QR code or visit a website to see batch-specific lab results; if they cannot, it is a red flag.

Label clarity is another key marker of quality. Serious runners should look for products that clearly state the total milligrams of CBD per bottle and per serving, the type of extract (isolate, broad-spectrum, or full-spectrum), ingredient lists, and suggested use. Research on supplement quality shows that vague labels and exaggerated performance claims are common warning signs for poorly regulated products. For endurance athletes, sugar content and other additives also matter, especially when CBD is delivered in gummies or beverages that might be used alongside gels and sports drinks.

Safety and medical interactions cannot be ignored. Reviews from agencies and medical journals note that CBD can cause side effects such as fatigue, gastrointestinal upset, and—at higher doses—elevations in liver enzymes. It may also interact with common medications by competing for liver enzymes that metabolize drugs. Marathoners using prescription anti-inflammatories, blood pressure medications, or other chronic therapies should speak with a sports physician or pharmacist before adding CBD to their routine, especially if they plan daily use during a training cycle.

Finally, brand transparency matters. Companies that cater to athletes typically offer clear education about dosing, anti-doping considerations, and safety, and they make it easy to contact customer support with questions. When a brand is open about sourcing, extraction methods, and testing protocols, runners can have more confidence that they are getting what they pay for.

For marathon athletes, quality CBD is not about trendy packaging or bold promises. It is about verifiable purity, accurate labeling, thoughtful formulation, and honest communication—so any potential benefits for recovery or sleep do not come at the expense of health or eligibility.

Learn More: Comparing CBD Options for Athletes: What Oils, Edibles and Topicals Each Do Best