CBD and horses: banned at shows, 161-hour half-life

Every year the Fédération Équestre Internationale (FEI) publishes a list of substances prohibited in horses. The list has two categories, and the French equestrian federation (FFE) sums up the difference: "banned substances" are prohibited at all times, in competition and in the stable, while "controlled medication" is allowed during veterinary treatment and prohibited in competition.

The 2026 list, in force since 1 January 2026, divides cannabis between the two categories:

The label "Specified substance" implies no lesser seriousness. At the top of the list, the FEI explains that it applies to substances more likely to have been ingested for a reason unrelated to performance, such as contaminated feed.

In practice, the classification matters. A full-spectrum "CBD" oil or pellet also contains THC, up to 0.30% when the product complies with French law. The FEI treats that THC as a substance banned at all times, whether or not the horse is under treatment. A CBD isolate avoids the issue if the batch analysis confirms it; our article on CBD isolate explains what a certificate guarantees.

The rules for human athletes differ. The World Anti-Doping Agency prohibits THC and the other cannabinoids and leaves CBD off its list, as our article on the WADA 2026 list explains.

Shows held in France outside FEI rules follow the list of prohibited substances for horses set by the decree of 2 May 2011. That list is drawn up by pharmacological class, for example substances acting on the nervous system, with no molecule named, and CBD does not appear in it. According to the FFE, you need a vet's help to interpret it.

Vets approved by the French Anti-Doping Agency (AFLD) carry out the tests. These can happen in competition at any level, during training, or wherever the horse is kept. After a positive result, the AFLD can bar the owner or trainer from entering the horse and ban them from taking part in FFE events.

The FFE makes a further point about supplements in general: no regulation guarantees that a supplement is free of prohibited substances. That holds for a "natural" herbal product too.

The most precise figures come from a pharmacokinetic study of oral CBD in horses, published in 2023 in Frontiers in Veterinary Science as a resource for anti-doping laboratories. Six horses were given a CBD paste at 3 mg per kilo twice a day for 15 days. After the final dose, the mean terminal half-life of CBD in the blood was 161 hours, with a standard deviation of 43 hours.

With a 161-hour half-life, the blood concentration takes nearly 7 days to fall by half, and another 7 days to halve again. The authors attribute this slow elimination to CBD spreading widely into the horse's tissues.

The curve is a theoretical calculation and cannot tell you when a test would turn negative. That depends on the laboratory's detection limit, which the FEI does not publish for CBD. Cannabidiol is also absent from the FEI's published list of detection times. The FEI stresses that a detection time differs from a withdrawal time, which the vet sets with a safety margin. The study's own authors conclude that CBD should be given to sport horses with caution.

Research in horses has mostly looked at how CBD is absorbed, eliminated and tolerated. No study was designed to measure an effect on a disease.

The 2025 trial, published in the American Journal of Veterinary Research, gave the two oils to the same horses one after the other. CBDA reached the blood far better, peaking at 103 ng/ml against 12 ng/ml for CBD. The authors conclude that CBDA deserves further study; they claim no benefit for the horse. This acid form is described on our page on CBDA.

Each of these studies followed a handful of horses for a few weeks, and none establishes a dose or an indication. Dogs have been studied slightly more, and some animals showed a rise in a liver enzyme; our article on CBD for dogs summarises those trials.

Under European law, what a product promises decides its category. Once presented as curing or preventing an animal disease, it is a veterinary medicine and cannot be sold without a marketing authorisation. To our knowledge, France has authorised no CBD-based veterinary medicine. A product sold as complementary feed may not claim to prevent, treat or cure a disease. The references for both regulations are in the article on CBD for dogs cited above, and the one on CBD for cats applies the same framework.

The Ministry of Agriculture notice of 20 May 2026 on CBD foods deals with human food and food supplements and says nothing about animal feed. For any use, a hemp product must stay under the 0.30% Δ⁹-THC threshold, which our article on the legal THC level explains.

Speak to your equine vet first, above all if the horse is under follow-up for a health problem or entered in competition. Stiffness, unusual nervousness or a loss of form may have a medical cause that a product would hide. If a trial is still being considered, check five points:

1. Look at the show calendar: with a half-life of nearly 7 days, a few days' break before the event falls short.
2. Choose an isolate to avoid THC, which the FEI bans at all times and which a full-spectrum product carries.
3. Ask for the batch's certificate of analysis, showing the CBD content and a Δ⁹-THC line reading "not detected". Our guide to reading a certificate covers each line, and the laboratory page describes the methods.
4. Look for a concentration stated in mg per ml or per gram, so you can work out a dose in mg per kilo of body weight.
5. Make sure the label promises no care: such a promise marks a product sold outside the law.