How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
MCT oil
MCT oil: replacing other fats with MCTs leads to a small weight loss (0.51 kg on average) and eating slightly less at the next meal. No sports performance gains, and a slight increase in triglycerides.
Benefits
- Weight: across 13 trials (749 people), replacing other fats with MCTs led to an additional weight loss of 0.51 kg and a waist circumference reduction of 1.46 cm, with slightly less fat under the skin and around the organs.
- Next meal: across 11 trials, people eat slightly less at the meal following MCTs than after other fats; taken as a liquid at breakfast, they reduced daily intake (7904 vs. 9531 kJ) in 29 people.
- Upper body fat: in 24 overweight men, 4 weeks of an MCT-rich diet led to a loss of 0.67 kg of upper body fat, compared to 0.02 kg with olive oil.
- Type 2 diabetes: in 40 overweight people, 18 g per day for 90 days replacing corn oil reduced weight, waist circumference, and insulin resistance.
- Frail elderly people: in 64 nursing home residents, 6 g per day for 3 months improved a leg movement test by 48.1% and daily autonomy by 7.5%, compared to another oil.
- Alzheimer's disease: across 12 studies (422 participants), MCTs slightly increase ketone bodies and slightly improve cognition on a combined measure, in patients in the early stages of the disease.
Precautions
Stomach: with 30 mL three times a day during a ketogenic diet, abdominal pain was more frequent and severe than with sunflower oil, in 28 adults. Triglycerides: across 7 studies, MCT oil increases triglycerides by 0.14 mmol/L. Cholesterol: compared to oils rich in unsaturated fats, MCT oil increases total cholesterol and LDL; compared to other saturated fats, it tends to decrease them. Limitations: weight: the effect is small, many trials lack quality information, and the meta-analysis detected a commercial bias. Review of 14 studies: inconclusive results on body composition, energy expenditure, and satiety. Hunger: across 17 studies, MCTs change neither the feeling of hunger nor appetite hormones. Sports: one review concludes they do not improve performance; taken before exertion (about 25 g), they did not spare muscle glycogen in 7 trained cyclists. A sports exception: 6 g per day with maltodextrin for 2 weeks prolonged intense exertion from 17.6 to 23.5 minutes, with large variations from one person to another. Energy expenditure: in 19 overweight men, it increased less with MCTs in the heavier ones. Lipids: in 28 insulin-resistant obese men, 20 g per day for 4 weeks changed nothing in the lipoprotein profile. Memory in healthy elderly people: 4 trials out of 6 see an improvement in working memory, but too few studies for a meta-analysis. Ketosis: on a ketogenic diet, MCTs did not achieve ketosis significantly faster.
Recommended dosage
6 to 20 g per day in most trials, replacing another oil; up to 30 mL three times a day in a ketogenic diet trial.
How to take it
- Instead of, not in addition to: trials replace another fat (olive, corn, or sunflower oil) with MCTs, and the meta-analysis on weight refers to replacement.
- Form: in one trial, daily intake only decreased with MCTs taken in liquid form.
- C8 or C10: caprylic acid (C8) is about three times more ketogenic than capric acid (C10), and the response is about twice as strong without a meal.
- Dose and duration: from 6 g per day for 2 weeks to 18 g per day for 90 days depending on the trials.
- Sports: expect nothing from them; added to a sugary drink during exercise, they did not improve a 100 km cycling time trial.
Did you know?
MCTs make people eat slightly less at the next meal without curbing hunger: across 17 studies, neither the sensation of appetite nor hunger hormones change.
What the studies say
This systematic review and meta-analysis, including 17 studies and 291 participants, explored the effects of MCTs on satiety and dietary intake. It revealed a statistically significant and moderate reduction in ad libitum energy intake following acute or chronic consumption of MCTs compared to long-chain triglycerides (LCTs). However, few effects were noted on subjective feelings of appetite or appetite-related hormones, suggesting that MCTs reduce energy intake through other mechanisms yet to be elucidated.
Maher T, Clegg ME. — Critical reviews in food science and nutrition (2021) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more