CBD & Hemp Oil for Horses — What Our Tarleton State University Research Found

If your horse paws, kicks at the wall, or winds up in the stall, you're probably looking for something that genuinely helps settle them — without sedating them or breaking the rules. Full-spectrum hemp (CBD) oil has become one of the most popular natural options horse owners reach for, and at HempMy Pet we've done something almost no other brand has: we funded an independent, four-part research program on our own oil at Tarleton State University. This page walks through what that research actually found — including the parts that didn't work — plus how hemp works in your horse's body, the competition rules you need to know, and how to give it well.

What the Research Found — and What It Didn't

Most equine CBD brands point at someone else's research. We funded our own, and we're going to tell you about all of it rather than only the flattering parts. HempMy Pet's equine work was carried out at the Tarleton State University Equine Center (part of the Texas A&M University System) under Dr. Kimberly Guay, Ph.D., P.A.S., using our full-spectrum Equine Formula — 5000 mg of full-spectrum CBD in cold-pressed virgin olive oil — against an olive-oil control.

It is one research program with four separate datasets, not a single study:

Dataset	Horses	Design	What was measured
Dose	8 (4 mares, 4 geldings)	Single oral dose, 0.3 vs 0.6 mg/kg	Plasma CBD, feed & water intake, heart rate
Feed	7 geldings	Switchback, 5 days, 2-week washout	Serum CBD, glucose, insulin, NEFA, intake, heart rate
Behavior	8	Single dose and 5-day daily, 0.3 vs 0.6 mg/kg	Stereotypic behaviors by video ethogram
Transport	6	7-day dosing, 3-hour haul, high ambient heat	Cortisol, blood lactate, body temperature

The behavioral result — this is the strong one

In stalled horses, a single oral dose significantly reduced stereotypic stress behaviors (P = 0.03). At the higher serving level, recorded aggression events fell from 113 to 26 and pawing from 69 to 27 compared with control. Those are the behaviors horse people actually watch for in a stall — pawing, pinned ears, going after the wall or a neighbor.

One detail matters more than it looks: the benefit came from a single dose. When the same horses were given the oil daily for five days, the researchers found no behavioral difference from control. The pharmacokinetics agree — more on timing below.

The transport result — reported straight

In a three-hour transport trial conducted in high ambient temperatures, physiological stress markers — cortisol, blood lactate, and body temperature — did not differ significantly between horses given full-spectrum CBD and controls (cortisol P = 0.646; lactate P = 0.560; rectal temperature P = 0.347).

We'd rather say that plainly than dress it up. The behavioral arm of this program is where the significant finding lives, and that is the claim we stand behind.

Tolerability and timing — the quietly useful part

• No adverse effects at either dose. In the researchers' own words, the single oral dose "resulted in no adverse effects in horses at neither 0.3 nor 0.6 mg/kg."
• Heart rate unchanged — 40.53 ± 5.64 bpm on control vs 40.26 ± 4.87 on CBD (P = 0.885), both inside the normal resting range of 25–48 bpm.
• No effect on blood glucose or NEFA by treatment — values moved with time of day, not with CBD.
• Predictable clearance. Plasma CBD peaked roughly 1 to 4 hours after dosing and returned to baseline by 16 to 24 hours (P < 0.001 for hour).
• No accumulation across days of dosing (P = 0.199) — directly relevant to competition withdrawal, and a question almost no brand can answer with data.
• Horses on CBD spent longer at their first meal — 271.4 vs 135.2 minutes (P = 0.002), replicated in a second dataset (275.9 vs 176.2 minutes, P = 0.0108).
• Dose response was real — the higher serving produced significantly higher plasma CBD than the lower (P = 0.005), with no difference between mares and geldings (P = 0.407).

Read as a whole, this is a tolerability-and-behavior result, not a stress-hormone result — and for an owner deciding whether to put something in a very expensive animal, that is arguably the more useful of the two.

Where these numbers come from. The behavioral and transport findings are published abstracts in the Journal of Animal Science, linked below. The dose, feed-intake, heart-rate, blood-chemistry and pharmacokinetic figures come from the Tarleton study reports on file at HempMy Pet and have not been separately published in a peer-reviewed journal. We'd rather label that than blur it.

See all of HempMy Pet's clinical research →

New research: what a 2026 controlled trial found on CBD, metabolism, and insulin in ponies →

Watch: The Equine CBD Study

Researcher Credentials

This research was conducted independently by Tarleton State University — part of the Texas A&M University System — using HempMy Pet's full-spectrum hemp CBD oil.

What Full-Spectrum Hemp Can Support in Horses

Owners most often turn to full-spectrum hemp oil to help with:

• Stall behavior & nerves — pawing, pacing, and stall aggression in high-strung horses. This is where our Tarleton research found a significant effect.
• Calm around handling — new environments, farrier and vet visits, and unfamiliar routines.
• Joint & mobility comfort — everyday support for senior horses, hard-working performance horses, and stiff joints.
• Skin, coat & hoof — the omega fatty acids naturally present in hemp support healthy coat and condition.

Horses Whose Owners Wrote to Us

The research above is one kind of evidence. These are the other kind — seven horses documented by their own owners, two of them written up week by week. Individual experiences, not typical results.

Read All Equine Testimonials & Case Studies →

Hemp, CBD & Competition Rules — The Full Detail

This matters and most sellers skip it: cannabidiol (CBD) and other cannabinoids are prohibited substances under FEI and USEF competition rules. Under FEI rules cannabidiol is a Banned Substance, and USEF lists cannabinoids among its forbidden substances. If you compete in regulated disciplines, do not give hemp or CBD inside your organization's withdrawal window, and always check the current rule before a show — governing bodies revise these lists.

Our Tarleton pharmacokinetic data is genuinely useful context here. Plasma CBD peaked roughly 1 to 4 hours after an oral dose, returned to baseline by 16 to 24 hours, and did not accumulate across consecutive days of dosing (P = 0.199) — meaning there is no reservoir building up in the horse to clear later.

But do not treat those numbers as a withdrawal time. They come from a small research group using our specific formula and a specific analytical method; detection thresholds at a testing lab are not the same thing as our measured clearance curve, and the requirement is set by your governing body, not by us or by our researchers. Read your organization's published withdrawal guidance, allow a margin, and talk to your veterinarian before a competition season.

For pleasure horses, retired horses, and daily at-home wellness, none of this applies — it is simply a supplement decision to make with your vet.

How Hemp Works in Your Horse's Body

Horses — like all mammals — have an endocannabinoid system (ECS), a network of receptors that helps regulate mood, comfort, and balance. The cannabinoids in full-spectrum hemp interact with this system to support a horse's natural sense of calm — working with your horse's body rather than sedating it. Because our oil is full-spectrum, the CBD, minor cannabinoids (CBG, CBC), and terpenes work together — an effect researchers call the "entourage effect" — rather than relying on isolated CBD. For background on how CBD from hemp works, see Cornell University's veterinary overview.

Why does stress behavior matter beyond the annoyance of it? Chronic stress can weaken the immune system over time and is linked to real health problems in horses — respiratory changes, gastrointestinal upset, and injury (see Padalino et al., 2015). A horse that settles in the stall is doing more than being easier to be around.

How to Choose Quality Hemp for Horses

Full-Spectrum, Never Isolate

Full-spectrum keeps the natural range of cannabinoids and terpenes intact, which most owners and researchers prefer over isolated CBD. We only make full-spectrum — the same oil used in the Tarleton research.

Read the COA

Equine hemp is an unregulated space, so third-party lab results matter. A trustworthy brand publishes a Certificate of Analysis confirming cannabinoid content and that the oil is clean — free of pesticides, heavy metals, and solvents — with THC under the legal 0.3% limit. Every HempMy Pet batch is third-party tested; you can read the results.

Organic & Colorado-Grown

Hemp is a phytoremediator — it pulls whatever is in the soil into the plant — so where and how it's grown genuinely matters. We breed and grow our own hemp on our Colorado farm using organic practices and manufacture under human-grade standards, never sourcing from overseas. That control is what made it possible to hand a university a known, consistent product to test.

HempMy Pet's CBD Oil for Horses

5000mg Full-Spectrum CBD Olive Oil. Our most potent formula, made for large animals — 5000mg of full-spectrum hemp extract in gentle, palatable cold-pressed organic olive oil. This is the exact formula Tarleton State University used. The high concentration suits a horse's size, and olive oil is easy to top-dress onto feed. Third-party lab tested, grown on our Colorado farm. $199. Shop the 5000mg CBD Oil for Horses →

This same formula works for large dogs over 75 lbs — see our full hemp for dogs lineup if you have both, or save with a bundle.

How Much CBD Oil to Give a Horse

Horses need far more than dogs given their size. The Tarleton work compared two oral serving levels — roughly 0.3 and 0.6 mg of CBD per kg of body weight — and the higher level produced significantly higher blood concentrations (P = 0.005) and was the level at which the behavioral change was recorded. There was no difference in response between mares and geldings (P = 0.407).

As always, start low and go slow. Because the right amount depends on your horse's weight and what you're supporting, see the product page for serving guidance, and confirm the amount with your veterinarian — especially if your horse is on other medications.

When to Give It — Timing Matters More Than Loading Up

This is where our own research changed our advice. The significant behavioral result came from a single oral dose, not from a daily course — when horses were dosed daily for five days, the researchers recorded no behavioral difference from control.

The pharmacokinetics point the same way: plasma CBD peaks about 1 to 4 hours after dosing, returns to baseline by 16 to 24 hours, and does not build up across days (P = 0.199). There is no loading period to observe, because there is nothing accumulating.

Practically: for a known stressor, top-dress a measured serving onto feed roughly one to four hours beforehand rather than starting a course days in advance. Olive oil is palatable, so most horses take it without fuss.

Is Hemp Safe and Legal for Horses?

Hemp-derived products containing less than 0.3% THC are federally legal under the 2018 Farm Bill and are non-intoxicating — they will not get your horse "high." In the Tarleton dose work, the researchers reported no adverse effects at either serving level, with heart rate, blood glucose, and NEFA unchanged by treatment. As responsible guidance, introduce it gradually, keep competition rules in mind, and consult your veterinarian before starting, especially for horses on medication or with health conditions.

Frequently Asked Questions

Does CBD or hemp oil calm horses?
In HempMy Pet's Tarleton State University research, a single oral dose of full-spectrum CBD significantly reduced stereotypic stress behaviors in stalled horses (P = 0.03), with recorded aggression falling from 113 to 26 events and pawing from 69 to 27. In a separate transport trial from the same program, physiological stress markers — cortisol, lactate, and body temperature — did not differ significantly from control. The behavioral finding is the one we stand behind.

Did the study show CBD lowers cortisol in horses?
No. In the published transport abstract, cortisol did not differ significantly between the CBD and control groups (P = 0.646), and neither did blood lactate or body temperature. We used to describe this differently and have corrected it. The significant finding from this research program is behavioral, not hormonal.

When should I give my horse CBD before a stressful event?
Roughly one to four hours beforehand, which is when plasma CBD peaked in the research. The behavioral benefit was recorded from a single dose — dosing daily for five days showed no difference from control, and CBD did not accumulate across days (P = 0.199), so there is no loading period to observe.

Can I give my horse hemp or CBD before a competition?
No — CBD and cannabinoids are prohibited under FEI and USEF rules. Don't use inside your organization's withdrawal window, and check current regulations before competing. Plasma CBD returned to baseline by 16 to 24 hours in the research and did not accumulate across days, but your governing body sets the withdrawal requirement, not us.

How much CBD oil should I give my horse?
The research compared roughly 0.3 and 0.6 mg of CBD per kg of body weight; the higher level produced significantly higher blood concentrations and was where the behavioral change was seen. Start low and go slow, see the product page for serving guidance, and confirm with your veterinarian.

Is hemp safe for horses?
The researchers reported no adverse effects at either serving level, with heart rate, blood glucose, and NEFA unchanged by treatment. Hemp-derived products under 0.3% THC are non-intoxicating and federally legal. Introduce gradually and consult your vet if your horse is on medication.

Press Coverage of the Research

The Tarleton program was covered when it was announced in 2022:

• Texas A&M — background on the research program as it got under way.
• IVC Journal — plain-language summary, August 2022.
• dvm360 — trade coverage, 2022.

A note in the interest of being straight with you: the 2022 IVC Journal and dvm360 pieces both describe the transport phase as having reduced stress hormones, following our own press release at the time. The peer-reviewed transport abstract does not support that — cortisol, lactate and body temperature showed no significant difference. We have corrected our claims on this page rather than leave the stronger version standing, and we're linking the coverage anyway rather than quietly dropping it.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. CBD is a prohibited substance under FEI and USEF competition rules — observe withdrawal times. Always consult your veterinarian before starting any new supplement, especially if your horse is taking medication or has a health condition.