If your horse competes under USEF or FEI rules, cannabinoids are prohibited and the dosing question does not arise. USEF has treated a positive cannabinoid test as a violation since 2019, CBD included. FEI’s 2026 list carries CBD and CBDA as Controlled Medication.
→Read nextThe full rules picture
If that does not apply to you, here is why the dosing question is harder than it looks.
The scaling intuition, and why it fails
The natural approach is arithmetic. If a certain amount suits a 25kg dog, multiply by twenty for a 500kg horse.
That reasoning fails for four reasons, and the first is the most concrete.
Practicality. A consumer pet tincture holds a few hundred milligrams. Scaling by body weight would mean multiple bottles per dose. Nobody manages a horse that way, on cost or on practicality, and a product that would require it is simply the wrong product.
Dose does not scale linearly with body weight across species. How an animal handles a compound depends on metabolic rate, body composition and organ function, not only mass. Larger animals do not simply need proportionally more of everything, and treating body weight as a straight multiplier is a well-known way to get veterinary dosing wrong.
Horses have an unusual digestive system. A hindgut fermenter with a very large caecum and colon, adapted for continuous forage. How an oil-based product behaves in that system is not the same as how it behaves in a dog, and it is not well characterised.
The evidence base does not support a figure. There is no established veterinary dosing standard for CBD in horses. Anyone giving you a milligrams-per-kilogram number is offering a convention, and often one supplied by whoever wants to sell you the bottle.
Why we are not giving you a number
Two reasons, and we would rather state them than hedge.
We do not make an equine product. Publishing a dosing figure for a 500kg animal we do not supply and cannot test against would be irresponsible, and it would be an easy thing to do because nobody would check.
There is no standard to publish. A number invented on a website gets copied and eventually gets used. The honest answer is less satisfying and it is the correct one.
If you need a figure for your horse, that is a conversation with an equine vet who can examine the animal and knows what else it is on.
What to ask your vet
- “Does my horse compete under any rules that prohibit this?” First, because it may end the conversation.
- “Given what my horse is on, is there an interaction concern?” Horses on long-term medication, particularly for a chronic condition, are the population where this matters most.
- “Is there a legitimate equine product, and what would you look for in one?”
- “What would you monitor, and what would make you want to stop?”
- “Is there something that would do more for what I am actually worried about?” Usually there is. Equine pain management and joint medicine have real tools.
What to check on any equine product
If you go ahead with a product built for horses, the verification is the same as anywhere else.
- Total CBD stated, and the volume, so a concentration can be calculated
- A third-party certificate available for the product you are buying, covering potency, THC and contaminants
- The laboratory is not the brand
- Dosing guidance that references body weight rather than “one scoop”
→Read nextHow to read a lab report
For a competing horse, none of that helps, because CBD itself is the prohibited substance under USEF rules. A clean certificate confirms the product is what it claims. It does not make it permitted.
Do not extrapolate to a donkey
Worth a line here because owners with mixed yards do exactly this.
Donkeys metabolise a number of drugs differently from horses, and dosing a donkey from horse guidance is a recognised way to get it wrong. It applies well beyond CBD.
→Read nextCBD for donkeys, mules and ponies
The short version
The short version
- If your horse competes, cannabinoids are prohibited and the dosing question does not arise.
- You cannot scale a dog dose up by body weight. Dose does not work that way across species.
- A consumer pet tincture would require multiple bottles per dose, which tells you it is the wrong product.
- There is no established veterinary dosing standard for CBD in horses.
- We do not make an equine product and will not publish a figure for one.
- Do not apply horse guidance to a donkey.