MCT oil: what it is, what the evidence shows, and how to choose one
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- Pure C8 (caprylic acid) MCT oil. Best for: People on a ketogenic eating plan who want the most ketone-raising form. See options on Amazon
- C8 and C10 MCT oil blend. Best for: Everyday use in coffee, dressings and smoothies. See options on Amazon
- Organic coconut-sourced MCT oil. Best for: Buyers who want an organic product made only from coconut. See options on Amazon
- MCT oil powder. Best for: Shakes, coffee and travel, where liquid oil is messy. See options on Amazon
What is MCT oil?
MCT stands for medium-chain triglycerides. Cleveland Clinic describes MCTs as fats whose chains have 6 to 12 carbon atoms, while long-chain triglycerides have more than 12. MCT oil is a dietary supplement, often made by distilling coconut oil, and Cleveland Clinic notes it is a more concentrated source of MCTs than the foods that contain them.
Those foods include coconut meat and oil, palm kernel oil, butter, cheese, milk, yogurt and breast milk. The body handles MCTs differently from longer fats: Cleveland Clinic explains that MCTs go straight to the liver to be turned into usable energy, while long-chain fats travel through the lymphatic system first.
MCT oil vs coconut oil
Coconut oil is not the same thing as MCT oil. A 2021 review in Frontiers in Nutrition gives coconut oil's makeup as under 10% C8, 5 to 6% C10 and 41 to 42% C12 (lauric acid). Most MCT oils are refined to keep the C8 and C10 fractions. In one study the review describes, coconut oil alone did not significantly raise blood ketones compared with a sunflower oil control.
MCT oil benefits: what the research shows and does not show
Remember that the FDA does not approve dietary supplements for safety and effectiveness before they are sold. Companies are responsible for their own products. So treat label promises with care and look at what studies actually found.
- Weight. A 2015 meta-analysis of 13 randomized trials with 749 adults found that replacing long-chain fats with MCTs was linked to a small extra drop in body weight (about 0.51 kg) and in waist size (about 1.46 cm). The authors called the effects modest, noted commercial bias in the studies, and asked for larger independent trials. Cleveland Clinic likewise says more research is needed.
- Fullness. Cleveland Clinic says MCT oil may trigger fullness hormones, and one study linked it to eating less overall.
- Ketones. The 2021 review found C8 is the main ketone-raising part of MCT oil, with a total ketone effect about three times that of C10 and six times that of C12.
- Energy and brain claims. Cleveland Clinic says MCTs may give a short energy lift, but claims about diabetes, Alzheimer's disease, blood sugar and inflammation are speculative, and researchers have not shown concrete evidence.
- Blood lipids. The meta-analysis found no differences in blood lipids between MCTs and long-chain fats.
In short, MCT oil is a fat that may help a little with fullness when it replaces other fats. It is not a fat burner.
How to choose an MCT oil
| Type | What it is | Who it fits | Trade-off |
|---|---|---|---|
| C8 (caprylic) MCT oil | Oil made of the C8 fraction | People following a ketogenic eating plan who want the most ketone-raising form | Same stomach side effects; no proven extra health benefit |
| C8/C10 blend | Mix of caprylic and capric acids | General kitchen use in dressings or drinks | Less ketone effect per spoon than pure C8 |
| MCT oil powder | MCT oil combined with other ingredients | Shakes, coffee and travel | Cleveland Clinic notes powders add dairy proteins, carbohydrates, fillers and sweeteners |
| Coconut oil | Whole oil, mostly C12 | Cooking | Low in C8, so it is not a substitute for MCT oil |
Read the label. Look for an oil that states which fatty acids it contains (C8, C10 or both) and in what share. A vague "MCT blend" may include more C12. Check the source oil (coconut or palm kernel) if that matters to you, and look for an organic seal if you want organic MCT oil. Choose a bottle with a measured pump or use a measuring spoon so you can keep servings small.
MCT oil side effects and who should be careful
The most common side effects are in the gut. Cleveland Clinic lists abdominal pain, nausea, vomiting and diarrhea with large doses. The 2021 review describes one study in which 3 of 7 people had abdominal discomfort and diarrhea after about 23 g of MCTs, and notes that people who are not used to MCTs are more likely to have trouble.
- Liver and heart. Cleveland Clinic says long-term use may lead to fat buildup in the liver, and its dietitian would not recommend MCT oil for people with fatty liver disease or heart disease, because MCTs are still fats.
- Medicines and conditions. The FDA advises talking with a doctor, pharmacist or registered dietitian before you start any supplement, since some supplements interact with medicines or affect lab tests.
- Bad reaction. If you react badly, stop it, get medical care if needed, and report it to the FDA.
How to use MCT oil
- Start low. The review cites researchers who recommend starting with 5 g of MCTs in the morning and working up slowly. Follow your product's label and ask your doctor or pharmacist about the right amount for you.
- Mix it in. Cleveland Clinic suggests stirring the oil into dressings, soups or broths, or drizzling it over vegetables, and using powder in shakes or smoothies. Cleveland Clinic cautions against chugging MCT oil.
- Mind the meal. If you take C8 for ketones, the review found a high-carbohydrate meal blunted the effect; in one study adding 50 g of glucose cut it by 63%.
- Swap, do not add. MCT oil still carries the calories of fat. The weight studies replaced other fats with it rather than adding it on top.
If you want a mixable form, see our MCT oil powder guide.
What to look for when you buy
Pure C8 (caprylic acid) MCT oil
Best for: People on a ketogenic eating plan who want the most ketone-raising form
A 2021 review found C8 has about three times the ketone effect of C10. A label that says 100% C8 tells you exactly what you are getting.
Watch out: Ketones are not a health benefit in themselves, and C8 can still cause cramps and diarrhea if you take too much.
See options on AmazonC8 and C10 MCT oil blend
Best for: Everyday use in coffee, dressings and smoothies
This is the most common kind of MCT oil. Choose one that lists the C8 and C10 share so you know it is not mostly C12.
Watch out: Less ketone effect per serving than pure C8; start small to avoid stomach upset.
See options on AmazonOrganic coconut-sourced MCT oil
Best for: Buyers who want an organic product made only from coconut
MCT oil is often distilled from coconut oil. An organic seal and a stated coconut source tell you how it was made.
Watch out: Organic does not change how the oil works or its side effects.
See options on AmazonMCT oil powder
Best for: Shakes, coffee and travel, where liquid oil is messy
Cleveland Clinic says powder works better in shakes and smoothies than the oil.
Watch out: Powders add dairy proteins, carbohydrates, fillers and sweeteners, per Cleveland Clinic; check the label if you avoid dairy or sugar.
See options on AmazonQuestions people ask
- Is MCT oil good for you?
- In small amounts it is likely safe for most healthy people, according to a Cleveland Clinic dietitian, but the evidence for benefits is modest. It is still a fat, and it is not advised for people with fatty liver disease or heart disease.
- What are the side effects of MCT oil?
- Mostly stomach problems: abdominal pain, nausea, vomiting and diarrhea with large doses. Cleveland Clinic also notes that long-term use may lead to fat buildup in the liver.
- Is MCT oil the same as coconut oil?
- No. Coconut oil is mostly C12 and contains under 10% C8, according to a 2021 review. MCT oil is refined to keep the shorter C8 and C10 fats.
- Does MCT oil help with weight loss?
- Only a little, if at all. A meta-analysis of 13 trials found about 0.51 kg more weight loss when MCTs replaced long-chain fats, and the authors called for larger, independent studies.
- How much MCT oil should I take?
- There is no set daily amount. Researchers cited in a 2021 review recommend starting with 5 g and building up slowly. Follow your product's label and ask a doctor, pharmacist or dietitian.
Sources
- Is MCT Oil Worth the Hype? (health.clevelandclinic.org), Cleveland Clinic
- Effects of medium-chain triglycerides on weight loss and body composition: a meta-analysis of randomized controlled trials (pubmed.ncbi.nlm.nih.gov), Journal of the Academy of Nutrition and Dietetics (PubMed)
- The Ketogenic Effect of Medium-Chain Triacylglycerides (frontiersin.org), Frontiers in Nutrition
- FDA 101: Dietary Supplements (fda.gov), U.S. Food and Drug Administration