Medium-chain Triglycerides (MCTs) – Uses, Side Effects, And More

MCT Oil – fats with many beneficial actions – for weight loss, for healing, for muscle mass and energy

Medium-chain triglycerides (MCT) are used as a supplement under the name MCT oil. They are widespread among athletes who want to reduce excess fat, but at the same time have energy and maintain muscle mass.

In fact, the popularity of these fats took off after their use to treat various more serious diseases. MCTs are absorbed differently in the body compared to other types of fats, and this contributes to their many positive effects.

What are MCTs?

The abbreviation stands for Medium-chain Triglycerides, or medium-chain triglycerides. The name comes from the way the carbon atoms are arranged in a chemical structure.

MCT-containing oil is a light yellow translucent liquid (at room temperature) that has no odor.

What does MCT oil contain?

Medium-chain triglycerides can be found in the form of a dietary supplement – MCT oil. It is created either chemically in a laboratory from the natural sources of this type of fat – coconut and palm oils.

MCTs are molecules consisting of 3 chains of saturated fatty acids, each containing 6-12 carbon atoms.

What do you need to know about MCTs?


MCTs are currently used by many athletes to aid athletic performance, but supplementation with them originally began for medicinal purposes. Medium-chain triglycerides are a source of fat used to help treat various diseases. MCTs provide quick energy for the body and are less likely to be stored in fat depots.

They are used as a supplement by athletes to reduce body fat and preserve muscle mass. If MCT oil is added to the diet, a thermogenic effect is created.

What is MCT oil used for and what health benefits does it bring?

In medicine – for the treatment of various diseases, which we will list below in the article. In sports circles – in the fight against excess body fat and as a quick source of energy. That’s why lately many nutritionists, athletes, bodybuilders, etc. include medium-chain triglycerides in their supplement kit.

How do MCTs work?

We’ve seen that medium-chain triglycerides have a different structure than other types of fat, and this is why they are metabolized differently in the body. Their absorption and mode of action are more similar to carbohydrates (the body’s first preferred fuel) than fats.

Once in the body, MCTs are transported directly to the liver where they are broken down and release energy, creating many ketones. These are burned for energy immediately after ingestion and thus conserve muscle glycogen.

Medium-chain triglycerides are the preferred supplement when muscle mass preservation is the goal – the ketone bodies that are released when they are broken down in the liver are used for energy before the amino acids in the muscles.

Proven and potential benefits in humans

Medium-chain triglycerides have several proven benefits in humans:

  • Obesity – MCTs are used in the fight against obesity because their intake and breakdown are characterized by greater energy expenditure.

As there were suspicions that MCTs could have a negative impact on the cardiovascular system, various studies had to be conducted.

One study involved 31 subjects, both men and women, aged 19-50 years and with a body mass index of 27-33. They completed a 16-week controlled weight loss program and were divided into two groups: those consuming MCT fats and those consuming olive oil. The results favored the MCT-taking group.

Several studies confirm the results that MCT actually helps burn fat. The effect was significantly stronger in overweight individuals and minimal in individuals with a low percentage of subcutaneous fat.

  • Appetite suppression – 25 grams of MCTs with breakfast significantly suppresses appetite for the rest of the day. In this case, MCTs are used as a substitute for popular vegetable fats. A detailed test was done on 19 adults with average physical activity (10 hours per week) and a normal diet without purposeful calorie restriction. Daily caloric intake was lowered by 594 calories.

The effects were rapid and short-lived. It is not clear what the overall effect on the body would be with long-term intake.

  • Cholesterol – the intake of medium-chain triglycerides affects cholesterol levels by increasing “good” but also “bad” cholesterol. In this case, the good cholesterol increased significantly more, but more research is needed on the extent to which MCTs improve the ratio between HDL-C and LDL-C.

At this stage, 18 grams of MCT daily for 90 days was found to significantly raise total cholesterol by 12% and bad cholesterol by 17% in diabetics.

  • Body composition, energy expenditure – medium-chain triglycerides have proven benefits in improving body composition, treating obesity, increasing energy expenditure.
  • Treatment of Alzheimer’s and other diseases – MCTs are used in the treatment of obesity, cystic fibrosis, fat metabolism disorder, Alzheimer’s disease, liver disease, diarrhea, eating disorders, digestive problems due to partial surgical removal of the stomach, etc. The interesting thing about Alzheimer’s disease is that the medium-chain triglycerides provide bonus energy for the brain and can protect it from the disease-forming structures.
  • Ketogenesis – Using 10 grams of MCTs daily helps the body enter a state of ketogenesis more quickly. So far, the results have been confirmed in overweight individuals and on a low-calorie diet that does not exceed even 1000 calories per day.

Proven and potential benefits in laboratory animals

A study conducted in 2011 found that MCT use in rats could successfully reduce body fat. However, after a long period of use, no changes may be observed due to the animals’ ability to adapt to new metabolic states.

A surprisingly strong anti-inflammatory effect of MCTs has also been found in rats, of which there is so far no evidence of a similar effect in humans.

Unproven impacts and evidence of no effect

In the period of studying the impact of MCTs, there were doubts that they did not impact on the treatment of metabolic syndrome. Therefore, a number of studies have been done to refute this doubt. The conclusion is that the fight against metabolic syndrome can be successful when medium-chain triglycerides are included in the menu.

One study in China found that a long-term intake of 18 grams of MCT daily improved insulin resistance by 17% according to the HOMA-IR index. However, there was no effect on fasting blood glucose levels, so no definite effect of these fatty acids on diabetics has been confirmed.

Medium-chain triglycerides are recommended as a pre-workout agent to increase endurance and regulate fatigue. In fact, there is no evidence that MCTs are superior to long-chain fats or carbohydrates. The positive effect may come from the extra calories. More research is needed to establish the benefits of MCTs .

Are there any established side effects and contraindications to taking MCTs?

Medium-chain triglycerides are safe. Use of MCT oil in some people may cause diarrhea, vomiting, irritability, stomach discomfort, or gas. This all depends on the individual’s body and the amount taken.

These side effects can be reduced or eliminated if MCT is added to the diet. According to some sources , more information is needed on whether and in what amounts to take by pregnant women and nursing mothers. They are not thought to be suitable for people suffering from diabetes and cirrhosis of the liver.

What doses are recommended and how is it taken?

The intake of MCT as a supplement (MCT oil) should be tailored to individual needs, physical activity and overall diet. It is recommended to start with a lower dose and gradually increase to 3 times a day, 15 ml.

Of course, everything is individual. It can be taken before and after exercise as well as with meals.

There are no definite guidelines on whether and to what extent MCTs can be used for heat treatment. At this stage, it has been confirmed that coconut oil is significantly modified by prolonged and repeated heat treatment , and that the fatty acids in it start to exhibit carcinogenic properties. Of course, a case beyond normal cooking use is considered.

More research is needed to establish whether there is a limit to the intake of medium-chain triglycerides and whether side effects are possible over time, but the benefits are well established and verified:

  • improvement of body composition;
  • treatment for obesity;
  • increase in energy expenditure;
  • increased thermogenesis;
  • increase in strength.

What to combine MCT with?

Medium-chain triglycerides combine successfully with other fatty acids such as CLA. Preliminary results suggest that the two fatty acids act synergistically in suppressing appetite and may have long-term effects on obesity.

For positive effects on cholesterol, MCTs can be successfully combined with omega-3 fatty acids, with fish or krill oil being most recommended.

Where can we find MCTs?

Medium-chain triglycerides can be found as a stand-alone product or as part of coconut oil.

Coconut oil is the best source of MCTs, with medium-chain triglycerides making up over 60% of the composition.

MCTs can be found as a self-heating product, and NOW Foods currently offers MCT Oil – 946 ml, the advantages of this product are the glass packaging and the dark color of the glass which preserve the stability of the fatty acids.

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