THC Suppositories: The Medical Format Nobody Talks About

Spend enough time around medical cannabis patients and someone will bring up suppositories, usually with a promise attached: all of the relief and none of the high. A THC suppository is a real pharmaceutical format with decades of research behind it, but the chemistry is stranger than the promise.

Plain THC barely gets through the rectal wall. A modified form of THC does, and once it gets in, it behaves like THC.

Melting at body temperature

A suppository is a dosage form used to deliver medications by insertion into a body orifice, where it melts or dissolves. Rectal and vaginal versions are the common ones. The classic base is cocoa butter, also called theobroma oil, which is solid at room temperature and melts just below body temperature. Pharmacists also use polyethylene glycol, hydrogels and glycerinated gelatin.

The appeal is the blood supply. A drug absorbed through the rectum skips much of the liver's first pass, the round of breakdown that swallowed drugs go through before they reach the rest of the body. Wikipedia's entry on rectal administration puts the share bypassed at about two-thirds, because the middle and lower rectal veins drain into general circulation and only the upper one runs to the liver.

Doctors also reach for suppositories when the oral route fails. Wikipedia's entry notes that the rectal route helps people who cannot swallow or whose gut is not moving medication along, and that no dose is lost to vomiting. For THC, which is prescribed in pill form against chemotherapy nausea, that is a real advantage.

The route matters for THC in another way, too, because swallowed THC loses a lot on the way. Wikipedia's THC entry puts oral bioavailability, the share of a dose that reaches the blood, at 6% to 20%, against 10% to 35% when inhaled.

Plain THC barely gets through

The catch is that THC itself does not absorb well this way. When University of Mississippi chemist Mahmoud ElSohly patented a fix in 1990, his patent summed up earlier attempts bluntly: there was no absorption, consequently no bioavailability achieved via the rectal route using various suppository formulations. His own test of a plain THC suppository found neither THC nor its metabolite in any of the blood samples.

The fix was THC-hemisuccinate, or THC-HS, a water-soluble form of THC that the body converts back into THC. A compound like this is called a prodrug, and in medical research THC-HS has mainly been made into rectal suppositories. Rectal THC absorption depends almost entirely on that switch, which is why the research on this route is really research on THC-HS.

Home-infused oil, whether it starts from OG Kush or any other strain, contains plain THC and its raw acid, THCA, never THC-HS. OG Kush, a Chemdawg, Lemon Thai and Hindu Kush cross at 26% THC with citrus, earthy and pine notes that flowers in 55 to 65 days, makes a fine kitchen oil, but nothing in the research suggests the rectal route will absorb what it puts in that oil.

Human studies of the THC suppository

The human evidence is thin, and most of it involves THC-HS:

• Patent tests, 1990. Suppositories made with plain THC left no THC in the blood
• Spinal cord injury, 2007. Rectal THC-HS eased muscle spasticity about as much as oral THC did
• Healthy men, 2018. THC-HS suppositories produced 2.44 times the total THC exposure of a 10-milligram dronabinol capsule, the FDA-approved synthetic THC pill
• Gynecological cancer survivors, 2024. A preliminary study of 83 women found less sexual pain in the groups using cannabis suppositories

Most of these studies are tiny. The spinal cord study in the journal Spinal Cord enrolled 25 patients, but only eight subjects received rectal THC-HS, and seven finished that phase. Mean daily doses were 31 milligrams with oral THC and 43 with THC-HS. The authors concluded that patients needed at least 15 to 20 milligrams of THC a day for a therapeutic effect. The 2018 study gave 30 healthy men rising doses from 1.25 to 20 milligrams, then compared a 10-milligram suppository with a 10-milligram capsule in 12 more. It counted total THC, meaning free THC plus THC still in its prodrug form, and its authors reported that the suppositories were well tolerated with no safety issues.

So does a THC suppository get you high? It can. In the spinal cord study, psychological side effects were one of the main reasons people dropped out, and the 2018 team suggested only that the slower rise in blood levels may soften the high. The same team tracked THC-COOH, the metabolite urine tests look for, in their volunteers' blood, so a THC suppository can also produce a positive drug test. When a plain THC suppository produces no high, the likeliest reason is that very little THC reached the blood.

CBD suppositories and the vaginal route

Cannabis suppository products are also sold for vaginal use, often with CBD. The largest study we found followed women using a hemp-derived, broad-spectrum, high-CBD (100 mg) vaginal suppository for period pain, comparing 77 users with 230 women who managed their symptoms as usual. The CBD group reported less frequent and less severe symptoms and needed fewer painkillers, and most reported at least moderate improvement.

That 2024 study in npj Women's Health was a survey without a placebo, and participants got the product free from its manufacturer, which also helped with recruiting. We found no published human data on how much THC or CBD the vaginal wall actually absorbs.

Rectal CBD looks worse. In a 2022 study in Frontiers in Veterinary Science, six beagles received 100 milligrams of CBD rectally, and their blood levels stayed below the point the lab could measure. The researchers advised against the route. A CBD suppository may still act locally, where it is inserted, but that is a different claim from reaching the blood.

The rectal route has one small human signal. In a 2026 pilot trial in the journal Biomedical Papers, 16 men aged 24 to 49 with chronic pelvic pain used rectal suppositories containing 100 milligrams of CBD plus hyaluronic acid nightly for 30 days, and 13 of them reported improvement with no adverse events. The trial had no control group, so it shows that the product was tolerated more than it shows that it works.

The unexamined day is a wasted opportunity. Reflect on what you did, what you learned, and how you can improve.

John Dewey

Rules for dispensary and hemp products

In legal states, THC suppositories sit on dispensary shelves under state cannabis rules. Hemp-derived CBD suppositories sold online face a federal change. According to a Congressional Research Service report updated in September 2026, the new hemp definition excludes final hemp-derived cannabinoid products that contain greater than 0.4 milligrams combined total per container of THC and similar cannabinoids, and most of the new rules take effect on December 11, 2026. A full-spectrum CBD suppository with traces of THC in every unit will need to fit under that cap to keep counting as hemp.

Homemade suppositories and infused oil

Homemade versions circulate online, made by melting cannabis-infused coconut oil or cocoa butter into molds. We would leave them alone, for five reasons:

• Absorption. Infused oil carries plain THC, the form the 1990 patent found did not absorb rectally, so most of it is probably wasted
• Dosing. Nobody can say how much THC each homemade suppository holds
• Melting. Coconut oil turns liquid above about 25 °C (77 °F), so a coconut-oil suppository can soften on a warm day before it is ever used
• Irritation. Suppositories that inflame the lining can, with chronic use, cause rectal stricture, a narrowing of the rectum
• Condoms. Oil-based homemade versions used vaginally can weaken latex condoms, as our THC lube guide explains

If you make infused oil, keep it in the kitchen, where our guide to cooking with cannabis walks through coconut oil step by step. For the oil itself, Purple Punch Auto, a Purple Punch and BF Auto Critical cross, lists 22% THC with 1% CBD, a happy, relaxing effect and a baked apple pie flavor, ready 65 to 70 days from seed.

A real format with a narrow evidence base

THC suppositories work only when the THC is built for the route. Plain THC barely crosses the rectal wall, while the prodrug THC-HS produced 2.44 times the exposure of an oral capsule in one study and can still bring a high and a positive drug test. CBD suppositories have one encouraging, company-supported survey for period pain, and rectal CBD stayed below measurable levels in dogs. Hemp versions also have to fit under the 0.4-milligram THC cap from December 11.

Check which form of THC a product uses before you pay for it. Barney's Farm has been developing premium cannabis genetics since the 1980s, with over 40 Cannabis Cup wins. Explore our full seed catalog and find strains bred for every climate and skill level.