By Marley Lien-Gonzalez and Piper Klemm

In a recent US Equestrian article, Dr. Stephen Schumacher reiterated the Federation’s strict zero-tolerance stance on CBD use and downstream metabolites in competition horses, emphasizing that “just because something’s natural or organic doesn’t mean it’s safe or effective.” But as many horse owners and veterinarians point out, there’s still little concrete science behind those rules. This raises an important question: what do we actually know about CBD and its metabolites in equines?

Is testing positive for minuscule quantities of CBD derivatives a broad problem in our sport? After testing more than 10,000 samples in 2024, USEF has reported 9 findings in all of which were for CBD metabolites, and zero CBD positive tests in 2024. What effect do CBD derivatives have on a horse and how do they impact show performance? What is the rationale behind banning pharmacologically inactive downstream derivative breakdown compounds that can sit in a horse’s fatty tissue and microscopically test positive for over six weeks? 

What USEF Says About CBD

I had read the USEF press releases on CBD as they came out. From reading these articles, I understood that “CBD, both natural and synthetic forms, are likely to effect the performance of a horse due to its reported anxiolytic effects. This substance is no different than legitimate therapeutics that effect mentation and behavior in horses. It is for these reasons that USEF prohibits CBD and all related cannabinoids.” 

Simple enough… although it should be “affect”, but grammar is literally the least of the current issues with the Federation. 

They continue, “Because CBD is known to act on the central and peripheral nervous systems, it is a prohibited substance under FEI, Horseracing Integrity and Safety Authority, and US Equestrian rules, and no medication report forms may be accepted to justify its use.  

It’s important to note that neither of these press releases from US Equestrian contains citations, but upon request, USEF produced two sources: 

• https://rmtcnet.com/wp-content/uploads/2019-02-RMTC-Cannabidiol-Bulletin.pdf
• https://pmc.ncbi.nlm.nih.gov/articles/PMC9308437/

I followed up by reading the sources. With USEF having such a black and white ruling on CBD derivatives, it would seem they’d contain pretty clear documentation on how the substance affects behavior in horses. Right?

What the Research Really Shows

The first link, a bulletin from 2019, states, “No research exists regarding similar effects in horses. These effects could occur because the horse does have cannabinoid receptors.” 

The second link, a peer-reviewed scientific article, states “Cannabinoid receptors (CBRs) have been identified in invertebrates and in almost all vertebrate species in the central and peripheral nervous system as well as in immune cells, where they control neuroimmune homeostasis.”

This study out of Poland was published in 2022, but the USEF CBD rules were passed in 2019. The 2022 study is a preliminary one. It contains no information on the effect that CBD or any derivatives have on horses. The research is all about receptors, which is data we do need to move forward, but it does not make the claims USEF put in their press release. 

At this time, I have not found any hard data that supports the CBD claims from the USEF press release.

The current rules not only state that CBD itself is a violation of the drugs and medications policy, but also the pharmacologically inactive metabolites that are produced downstream from the breakdown process, which last in a horse’s bloodstream over a month after exposure. These metabolites are only identified as ‘metabolites’ in their communications and press releases, not by name, timing, or breakdown structure.  

No data provided by USEF gives a rationale for pharmacologically inactive compounds such as 7-carboxy-cannabidiol, being on the list. These compounds are not known or suspected to give any competitive advantage, and their ability to ‘hide’ in fatty tissue allows them to stay in the bloodstream for weeks, well beyond any amount of time that could have any competitive advantage. 

Contrary to USEF’s interpretation, CBD in equines is not “known to act on the central and peripheral nervous system.” The article simply states that horses do have CBD receptors in their skin under normal conditions.

Big Decisions Coming From Little Data

Despite the first article stating clearly that there is no CBD research or evidence regarding similar effects in horses, USEF says it is ”likely to affect the performance of a horse due to its reported anxiolytic effects.” There is no performance evidence in any direction of CBD or any derivatives in equines. Reported effects do not appear to be reported anywhere. 

I believe USEF’s claims are exaggerated and not based on any credible evidence. The leap of logic misinforms the membership as to where current science is. Neither article mentions nor discusses CBD derivatives, and there have been no known effects from these derivatives.

To state simply, USEF had zero scientific data or proof and no peer-reviewed publications, article abstracts, or conference presentations when they made their policies currently in the rulebook regarding the pharmacologically inactive derivatives of CBD. Instead of using the over $5 million annually collected in drug and medication fees to do research that would help all over 83,000 competing members understand how to be better stewards and caretakers for their horses, they rushed to immediately establish a zero-tolerance protocol that did not rely on science, member needs, practicality in a horse show environment, or common sense. 

Expert Insight from Dr. Wakshlag 

We asked Professor Joseph J. Dr. Wakshlag, Ph.D., DVM, MS, ACVN, ACVSMR, a research professor at the Cornell University College of Veterinary Medicine, to estimate how much a comprehensive study on equine musculoskeletal pain issues or behavior would cost, and he stated a grant $100,000-$200,000 price range.

It is unknown to average members how much of their various dues USEF spends on lawsuits, but it seems like this would be good to have for all members and potentially a cost savings for them. 

“If I gave my horse CBD for a trailer ride, and then I decided to compete with them three weeks later, I might still test positive based on the metabolites of what I was giving,” said Wakshlag. 

Given the variation in metabolisms in various horses, Wakshlag said it could be possible for a horse to still test positive for CBD derivatives six weeks after exposure. In our conversation, Wakslag emphasized that even if effects are present, the real question is how much of each compound would be needed to have an impact on a thousand-pound horse—and that we currently lack pharmacokinetic data or evidence to answer that.

What preliminary research has been able to show us is that 0.1-3 milligrams of CBD per kilogram of body weight is not enough to activate a response. A biological effect in horses is going to require a higher quantity. “We really haven’t done the clinical studies that are necessary to better understand it. We don’t understand the dose all that well. All we know is we probably need more of it,” says Dr. Wakshlag. 

USEF’s drug rules for CBD derivatives aren’t based on any proven effects in horses. According to Dr. Wakshlag, no one knows what dose of CBD could cause a behavioral change—it would likely take a large amount, and even then, the effect isn’t confirmed.

What Other Current Studies Tell Us

Recent research underscores how limited our understanding of CBD and its metabolites in horses still is.

• The Horseman’s Journal reported that the equine metabolite 7-carboxy-cannabidiol “should best be considered an atypical finding and not a regulatory matter.” This is largely because metabolites remain under-researched, and modern drug testing equipment is highly sensitive to trace compounds.

• Williams et al. (2022) studied how CBD supplements move through the horse’s body (pharmacokinetics). Their findings suggest that a 0.35 mg/kg dose is too low to have any clinical effect, while a 2.0 mg/kg dose—though well tolerated—still may not produce measurable results. The researchers emphasize that more pharmacokinetic studies are needed to determine safe and effective CBD use in horses.

• Cohen et al. (2021) explored oral CBD supplementation and found that doses of 0.3 mg/kg and 0.6 mg/kg caused no abnormal changes in heart rate or feed intake over 24 hours. However, these low doses also didn’t show any clear behavioral or physiological effects, further highlighting the need for additional research.

The Bigger Issue: No Regulation or Clarity

There are no equine supplement laws, so no CBD or CBD derivative products are FDA-regulated. According to Dr. Wakshlag, “The amounts that most people are giving in little hemp cookies or pastes are really negligible, and probably aren’t going to be beneficial. So we have to understand dosing and the horse a little bit better for sure.”

Are we so misinformed that CBD could be good and therapeutic for national show horses? That’s another piece we miss when we don’t do the research. Current research shows an improvement in seizures in humans with epilepsy and a horse related study would yield more knowledge either way to attend to equine seizures. You don’t have to walk far into the barns at any given show to see a horse habitually cribbing, which has many underlying issues. 

This Williams et al. (2022) study describes “The clinical case report described a 22-year-old mare suffering from chronic crib-biting and wind-sucking, and the successful outcome of four weeks of therapy with CBD. This is the first report of the successful therapeutic use of phytocannabinoids in equine behavioural disorders.”

What We Could Have Learned by Now

With proactive leadership, we could already have dozens of scientific studies and credible data on these topics if research had begun back in 2019. While science takes time, six years is more than enough to generate meaningful results, publish peer-reviewed papers, and share findings at conferences where other researchers could collaborate and build on the work.

Instead of choosing to create a learning environment to benefit all members, it appears that USEF is choosing punishment. Instead of having an environment of growth and the ability to learn new topics and contribute to all horse welfare through correctly done peer-reviewed research, USEF chose to spend down their drug and medication endowment on punishment and lawsuits. 

Lawsuits do not help horses. Research helps horses. 

Make Your Voice Heard

If you believe USEF should prioritize funding research over legal action, take a moment to share your perspective. Email feedback@usef.org and board@usef.org, or reach out directly to any staff or board members you know. Members may not have a formal vote, but your feedback still matters. Make your voice heard and advocate for science-driven policy that truly supports horse welfare. 

We’ve provided an email template below to use as a reference for communication outreach:

Subject: Request for More Investment in Equine Research

Dear USEF Board and Staff,

As a member, I’m writing to express my concern about how USEF allocates funds from drug and medication fees. I believe these resources would be far better spent on scientific research that improves equine welfare and informs evidence-based policy.

It’s time for USEF to prioritize research, transparency, and collaboration with the scientific community so members can have confidence that rules are grounded in credible data. I urge the organization to direct funding toward studies that help us better understand substances like CBD and their true effects on horses.

Thank you for your attention to this important issue.

Sincerely,
[Your Name]
[Your USEF Member Number, if applicable]