CBD for cats: absorbed 7 times less than in dogs

Five published studies have given CBD to healthy cats, three of them against a placebo. None involved sick cats. The groups are small, and at least four studies were funded by pet-product manufacturers: Ellevet Sciences, Canopy Growth and Mars Petcare.

ALT (alanine aminotransferase) is a liver enzyme. A rise in a blood test signals that the liver is under strain, and vets monitor it during any long course of treatment.

The Deabold trial gave the same product, at the same dose, to 8 dogs and 8 cats. The result is clear: peak blood CBD reached 301 ng/mL in dogs and 43 ng/mL in cats. Total exposure over the day, measured by the area under the curve, was 1,297 versus 164 ng·h/mL.

Lower absorption does not mean the dose should go up. First, the form of the product changes everything. A 2025 review in the Journal of Feline Medicine and Surgery reports, depending on the study, peaks of 42 ng/mL with a fish-oil base and 465 ng/mL with a paste. Food matters too: 463 ng/mL in fed cats against 269 ng/mL in fasted cats, at the same dose.

Second, cats process cannabinoids through different pathways from humans. The same review describes hydroxylation at positions 6 and 4' in cats, where humans mainly produce a derivative hydroxylated at position 7. More broadly, cats clear many phenolic compounds poorly: they lack the UGT1A6 enzyme, inactivated in every member of the cat family, which explains their sensitivity to paracetamol. No study has shown that this deficit affects CBD. It simply illustrates why data from dogs or humans do not carry over to cats.

Third, individual differences are large. In the Lyons trial, the coefficient of variation of blood levels exceeded 100% at some sampling times: cats given the same dose had very different blood levels.

In the healthy cats of these trials, the effects reported stayed mild. In the Deabold trial, across 1,344 observations over twelve weeks, the researchers recorded 476 episodes of excessive licking (35.4%) and 339 of head shaking (25.2%). In the Kulpa trial, CBD oil mainly caused drooling and about an hour of drowsiness, which cleared without treatment. Vomiting and diarrhoea were attributed to the MCT carrier oil rather than to CBD.

The liver is the thing to watch. One cat in the Deabold trial kept ALT above the normal range for the whole trial. In the first Coltherd trial, ALT in the CBD group was 1.44 times higher than on placebo at four weeks, and two cats from that group were withdrawn from the long study for suspected cholangitis, an inflammation of the bile ducts. The 26-week trial did not find this difference.

THC is the best-documented danger. In the Kulpa trial, oils containing THC caused more neurological effects and behaviour changes than the CBD oil. The 2025 review also notes that combining CBD and THC made these effects last longer. An oil sold for humans may contain THC up to the legal limit of 0.3%, so knowing the measured level matters as much as the CBD dose.

In humans, CBD alters how some medicines act by slowing the liver enzymes that clear them. This mechanism, covered in our article on CBD and drug interactions, has not been studied in cats. A cat already on treatment is therefore the case where the vet's opinion counts most.

A CBD product that claims a therapeutic effect for an animal, against pain for example, is a veterinary medicine. Anses points this out: such a product must be authorised by Anses or by the European Commission, on criteria of quality, safety and efficacy. No veterinary medicine containing CBD is authorised in France.

As an exception, a vet may prescribe a human medicine when no suitable veterinary medicine exists: this is the "cascade" of article L5143-4 of the French Public Health Code. For pain in dogs and cats, the veterinary medicines agency (ANMV) has pointed out that authorised medicines exist, which rules out CBD by that route.

On the food side, the French agriculture ministry's notice of 20 May 2026 calls for the withdrawal of CBD foodstuffs intended for humans, as they lack novel food authorisation. It does not deal with pet products. Our update on CBD regulation in 2026 explains this regime. For horses, which also fall under racing rules, see CBD in equines.

Bring precise information, not a brand name. Your vet will need:

• the cat's weight, age and current treatments;
• the product's real concentration, in mg of CBD per mL;
• the measured Δ⁹-THC level, and the absence of other cannabinoids such as HHC;
• the list of excipients: carrier oil, flavourings, sweeteners.

A rough figure shows why an oil made for humans is a poor fit. The lowest dose in the trials, 2 mg/kg, comes to 8 mg for a 4 kg cat, or 0.16 mL of a 5% oil, less than a fifth of a millilitre. This calculation is not a dosage: it shows that a few drops either way change the dose completely.

A product's data can be checked on its certificate of analysis: our guide explains how to read a certificate of analysis, and the laboratory page describes the measurement methods. For dogs, the reference points and limits are different: see our article on CBD for dogs and the veterinary framework.