Vaping illness has been a frequent topic in the news since August of 2019 when the Centers for Disease Control (CDC) began tracking cases. Formally called EVALI — e-cigarette, or vaping, product use–associated lung injury — the condition has affected thousands of vape product consumers, most of them under the age of 35. Many were hospitalized due to lung injuries and a small number of them died.
Medical tests revealed vitamin E acetate in the lung fluid of EVALI patients and the compound became closely linked with the disease. While vitamin E, also known as tocopheryl acetate, is generally safe and commonly used in dietary supplements and cosmetics, inhalation of the vapors hadn't previously been tested.
After the EVALI outbreak, scientific research, including a 2020 study published in the New England Journal of Medical Science, found that vitamin E is very harmful to lung tissue. Coconut oil and medium-chain triglycerides (MCT) were also found in the lung fluid of EVALI patients but not in significant numbers.
Here you'll learn more about MCT oil and whether it is unsafe to vape like Vitamin E acetate. You'll also learn which other substances may be harmful to vape, and how to shop for vapes safely.
What is MCT oil?
MCT oil is made from the fat contained in medium-chain triglycerides. Coconut oil and palm oil are two of the most common oils from which MCT is derived. Through a process called fractionation, MCT oil is separated from coconut or palm oil and concentrated.
Research is emerging on potential therapeutic usages of MCT oil, including as a weight loss aide. One 2008 study published in the American Journal of Clinical Nutrition found that MCT oil led to a greater rate of weight and fat mass loss than olive oil did. Another study, published in 2018 in the journal PLoS One, found that medium-chain triglycerides enhanced exercise endurance.
Some people have used MCT oil for its possible ability to manage blood sugar levels and reduce risk factors for heart disease. But the way individuals consume MCT oil could mean the difference between providing therapeutic benefits and harming the body. Powdered MCT oil may be relatively safe to add to coffee or smoothies, but is it safe to vape the substance?
Is it dangerous to vape MCT oil?
“The short answer: we don't know if it is dangerous or not,” according to Dr. Adie Rae, a neuroscientist and scientific adviser to Weedmaps.
There are, however, parallels between the vitamin E acetate involved in the EVALI cases and MCT oil. “Exactly like vitamin E acetate, MCT oil (from coconut) is safe to swallow and apply to your skin, which is why it is an FDA-approved substance. However, prior to the EVALI outbreak, these oils were never studied as inhalable substances in either humans or animals. The FDA could never have predicted that humans would be vaporizing these substances and breathing them,” Rae explained.

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Rae likened vaping MCT oil to spraying your lungs with super-heated cooking spray. It may not cause immediate damage, but EVALI showed that frequent vaping is tied to lung illness. Occasionally vaping MCT oil may or may not be harmful to the lungs. But CDC research has demonstrated that using a vape pen five or more times per day gives a consumer the greatest chances of developing a lung injury. As with all types of cannabis consumption, moderation is a key factor for a safe experience.
What other harmful vape additives should consumers avoid?
The safest thing to do is to avoid any additives whatsoever, according to Rae. “Shop for pens that only contain 100% pure cannabis oil, with no added substances of any kind, including added flavors and even added terpenes, which have been shown to be dangerous too.” In the EVALI outbreak, most people had purchased illicit or low-end vape pens or cartridges to which the vitamin E may have been added because it's similar in appearance to THC oil and would allow the manufacturer to produce more vape juice with less THC oil.
In addition to watching for flavors and terpenes, also be wary of vapes that contain nicotine and propylene glycol. One way to avoid encountering additives is to refrain from shopping on the black market where vape cartridges could be counterfeit. Instead, go to a licensed dispensary to make all your cannabis purchases.

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How do you shop for vapes safely?
Even if you are shopping at a licensed dispensary, you still need to do some research into the product you are purchasing. Since states don't always require ingredients to be listed on vape cartridges, certainty can be difficult. Even experienced budtenders may not know. Rae advises consumers to check brand websites and packaging carefully. You may just need to shop around a bit. “Usually, the brands that use 100% cannabis and no additives are very proud of this fact, and they go to great lengths to brag about it. These are the products you are looking for,” Rae said.
Some states, such as California and Colorado, have monitored or outlawed the use of MCT oil in vapes. “The prevalence of dirty and dangerous vape pens at unlicensed cannabis stores demonstrates how important it is to purchase cannabis goods from licensed retailers, which are required to sell products that meet testing and labeling standards,” said Lori Ajax, chief of California's Bureau of Cannabis Control. In December of 2019, the bureau seized more than 10,000 illegal vape pens from unlicensed cannabis retailers in Los Angeles. Though not illegal in California, MCT oil was found to be an undisclosed ingredient in the majority of the products seized.
Colorado's Marijuana Enforcement Division banned MCT oil as a vape additive effective January 1, 2021. Other states that have banned MCT oil in vaping products include Ohio, Michigan, Oregon, and Washington, with more likely to follow.
Bottom line on vaping MCT oil
There is currently not enough information about whether it is safe to vape MCT oil or not, but many states are taking precautions by banning the additive. When choosing any vaping product, shop at a licensed dispensary and consider consulting with your physician.
Major contributions from Dr. Adie Rae.