After years of being a favorite dietary supplement among bodybuilders and ultra-low-carb dieters, MCT oil has made a major mainstream splash with praise from celebs like Emma Stone and Kourtney Kardashian. Fans say the food-derived oil can torch body fat, speed up metabolism, fire up energy, even fend off diseases like type 2 diabetes. But before you start stirring this stuff into your morning coffee, health experts want you to know that the perks are far from proven—and that side effects are possible. Here’s a closer look at what MCT oil really is, and how the science on this best-selling supplement is shaping up so far.
What is MCT oil?
OK, let’s start with a super quick chemistry lesson: MCT stands for medium-chain triglyceride; it’s a type of dietary fat that occurs naturally in foods like coconut and cheddar cheese. Compared with the long-chain triglycerides (LCTs) you get from sources like olive oil and avocados, MCTs have a simpler molecular structure, explains registered dietitian nutritionist Jerlyn Jones, owner of The Lifestyle Dietitian.
The main difference between the groups is in their number of carbon atoms. MCTs—which include lauric acid, capric acid, caprylic acid, and others—contain a chain of six to 12 carbon atoms, while long-chain triglycerides contain 12 or more. Because MCTs are shorter than LCTs, the body digests them a little differently. “Other fats are broken down with the help of enzymes from the pancreas,” says Jones, who is also a spokesperson for the Academy of Nutrition and Dietetics. Meanwhile, “MCTs are broken down more efficiently.”
In short, the fatty acids of MCTs enter the bloodstream more quickly. That speedy effect forms the basis of many health claims around MCT oil, including accelerated weight loss, more energy, and healthier cholesterol levels.
MCT oil is sold as a dietary supplement in liquid, powder, and capsule form. Is MCT oil the same as coconut oil? Not quite. The product is made by crystallizing coconut or palm kernel oil, then extracting just the triglycerides—a commercial process known as fractionation, says Caroline Apovian, MD, co-director for the Center for Weight Management and Wellness at Brigham and Women’s Hospital. So while coconut oil is partly made up of MCTs, an MCT supplement is way more potent.
How is MCT oil used?
Many people take MCT oil in capsule form, swallowing it with water like any other pill. Others opt for a liquid or powdered form they can add to foods and drinks—MCT oil is odorless and flavorless, so it mixes well into smoothies and coffee, Jones says. MCT oil is one of three key ingredients in “keto coffee” (aka Bulletproof coffee), which also includes grass-fed butter.
Some home cooks use MCT oil in recipes like salad dressings and no-bake energy bites. Cooking with MCT oil generally isn’t recommended, Jones notes. Its low smoke point means that above 300°F degrees or so, the fat can oxidize, altering its chemical structure and resulting in an off taste.
Health benefits of MCT oil
To date, there hasn’t been a ton of good-quality scientific research to prove or disprove the health claims surrounding MCT oil. While some small studies suggest that MCT supplements may be associated with certain health benefits, larger investigations are needed to fully understand the effects on human health—especially over longer periods of time, Dr. Apovian says. Here’s how the evidence stacks up so far:
Claim 1: MCT oil speeds weight loss
A few small, short-term studies have found that substituting MCTs for other oils or butter may help decrease body fat and lead to greater weight loss, possibly by upping the body’s rate of energy expenditure. MCT oil is popular with people on super-low-carb keto diets. Research on people following an intermittent-fasting regimen suggests that because MCTs are metabolized quickly, they can help you get into or remain in a fat-burning stage called ketosis. Still, the jury’s out on whether MCT oil can help with long-term weight management, or in conjunction with other patterns of eating.
In one small study, 31 people following a calorie-restricted diet were told to consume roughly 5 teaspoons of MCT oil or 5 teaspoons of olive oil each day. After 16 weeks, those in the MCT group lost about 3.5 pounds more on average, and saw greater reductions in body fat, as well. “MCT [may be] beneficial for body composition,” Dr. Apovian says. But again, “more long-term studies are needed.”
Claim 2: MCT oil improves cholesterol
Some fans insist that the high amount of saturated fat in MCT oil won’t raise levels of bad cholesterol (like butter can) because MCT oil is digested differently. But don’t bank on that, cautions researcher Michael Skilton, PhD, a professor of nutrition and cardiometabolic health at Australia’s University of Sydney. In a recent review published in the Journal of Nutrition, Dr. Skilton’s team concluded that when people trade unsaturated fats like olive oil for an MCT supplement, “switching to MCT will, on average, lead to worse blood cholesterol levels,” he says—particularly when it comes to triglycerides in the blood. This tracks with previous studies of MCT food sources such as coconut oil, which has been shown to increase good (HDL) and bad (LDL) cholesterol alike.
Claim 3: MCT oil supports gut health
In hospitals, some patients living with gastrointestinal disorders—especially conditions that interfere with fat absorption—receive MCT oil for nutrition, as MCTs are more easily metabolized. But that’s not the same as saying MCT oil can optimize gut function in healthy people, Dr. Apovian says. Although preliminary research on animals suggests that MCTs may improve the makeup of the gut microbiome by increasing the number of healthy bacteria in the intestines—at least in baby pigs—human evidence so far is lacking.
Claim 4: MCT oil reduces inflammation
Laboratory research done in test tubes and on animals hints at the possibility that MCT oil could lower inflammatory markers. That may be because MCTs are less likely to be stored as fat tissue, which is linked with inflammation, Dr. Apovian says. Given that inflammation can increase a person’s risk for developing certain chronic diseases, such as heart disease and diabetes, many in the scientific community are excited about the potential of MCT oil on this front. Still, studies in humans are needed to figure out whether the oil can actually control inflammation—and to what long-term effects.
Claim 5: MCT oil lowers diabetes risk
Type 2 diabetes occurs when the body is unable to properly use the hormone insulin, which is key to healthy blood-sugar levels. Studies so far have yielded mixed findings on whether MCT oil might improve the body’s sensitivity to insulin. In a 2019 study Dr. Apovian and team published in the journal PLoS One, 22 volunteers swapped MCTs for some of their usual dietary fat. After six weeks, the group’s insulin sensitivity jumped by a significant 12% on average. “It’s encouraging, but more research is needed,” Dr. Apovian says.
Claim 6: MCT oil boosts energy
Many proponents claim that because MCTs are metabolized more efficiently than LCTs, the fats result in a quick burst of energy that can power up a workout and put more pep in your step. This is another claim to file under “plausible but unproven”: Preliminary research conducted in test tubes and on animals suggests that MCTs may set off cellular changes that could heighten physical endurance, but scant research on people means it’s too soon to say whether the theory holds up in real life.
Claim 7: MCT oil makes you mentally sharper
Because MCT converts readily to a usable form of energy, many fans say it’s good brain fuel. Early research offers a bit of support for this theory. British scientists found that young adults who took an MCT supplement daily scored higher on cognitive tests after two to three weeks. Other thinking suggests that MCTs may improve symptoms of dementia and Alzheimer’s disease—one theory being that the brain may use the energy from MCTs more easily than it uses more common energy from carbs. A Clinical Nutrition study of 53 adults with mild to moderate Alzheimer’s disease showed that those who took daily MCT supplements scored better on cognitive tests after one month.
Risks of taking MCT oil
For most people, taking MCT oil for short periods is generally safe, according to research in Food and Chemical Toxicology. But acute side effects are possible, and more studies on MCT’s health effects beyond a year or two are still needed, Jones says. The following issues may be a concern:
- Weight gain: A tablespoon of MCT oil contains roughly 120 calories and 14 grams of fat. If you’re adding it to your diet instead of using it as a replacement for other fat sources, the extra calories could result in extra pounds, Jones says.
- Cardiovascular conditions: “MCT oil is a saturated fat,” Jones says. By increasing LDL cholesterol, too much saturated fat can raise a person’s risk of experiencing heart attack or stroke. The specific effects of MCT oil on heart health still aren’t well understood. In the meantime, the American Heart Association recommends getting no more than 5-6% of your daily calories from saturated fat, including the kind found in red meat and French fries.
- Digestive problems: For some people, taking too much MCT oil can lead to stomach pain, cramping, gassiness, bloating, and diarrhea, according to research published in Practical Gastroenterology. Experts think that because MCT is metabolized without enzymes, the fat for some people can overtax the digestive system.
How much MCT is found in foods?
As mentioned earlier, MCTs do occur naturally in foods—often in combination with other fats, Dr. Apovian says. Here’s a closer look at the percentages of MCTs found in each serving of common foods:
Coconut oil: 55% MCT (7.4 grams per 1 tablespoon)
Palm kernel oil: 54% MCT (7.3 grams per 1 tablespoon)
Full-fat yogurt: 0.3% MCT (0.77 grams per 1 cup)
Whole milk: 0.3% MCT (0.67 grams per 1 cup)
Butter: 8% MCT (1.18 grams per 1 tablespoon)
Cheddar cheese: 8% MCT (0.77 grams per 1-ounce slice)
Bottom line: Is MCT oil good for you?
The science is still evolving on whether MCT oil delivers on its popular claims of enhancing weight loss, increasing endurance, boosting brainpower, and reducing risk of diseases such as type 2 diabetes. Studies so far have been small and limited to short periods of time. Long-term impacts of MCT oil—which could include adverse effects on heart health, given that MCT oil is a form of saturated fat—aren’t yet clear. If you do want to try an MCT oil dietary supplement, chat with your healthcare provider to figure out whether the product makes sense with your overall diet and personal health situation.
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Sharon Liao is a freelance writer and editor specializing in health, nutrition, and fitness. She lives in Redondo Beach, California.
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This article was reviewed for accuracy in November 2021 by Angela Goscilo, MS, RD, CDN, manager of nutrition at WW. The WW Science Team is a dedicated group of experts who ensure all our solutions are rooted in the best possible research.