MCTs

MCTs, or medium-chain triglycerides, are a subset of triglycerides in which the fatty acid chains are shorter than those of long-chain triglycerides, typically six to twelve carbon atoms. The most common forms used commercially are caprylic acid (C8) and capric acid (C10); caproic acid (C6) is less common, and lauric acid (C12) is sometimes treated as a longer chain variant. They occur naturally in coconut oil, palm kernel oil, and dairy fats and are widely sold as MCT oil.

MCTs differ from long-chain triglycerides in their absorption and metabolism. They are more water-soluble and are absorbed directly into the portal circulation, delivering fatty acids to the liver where they are rapidly oxidized for energy. They require less bile for emulsification and, unlike long-chain fats, do not rely on the carnitine shuttle to enter mitochondria, making them a quick energy source. On low-carbohydrate diets they can increase circulating ketone bodies.

Uses include medical nutrition therapy for fat malabsorption or pancreatic insufficiency, where MCTs help meet energy needs. In general nutrition, MCT oil is used as a calorie-dense supplement and as an ingredient in ketogenic diets or sports nutrition. Evidence for sustained weight loss or performance benefits is mixed and varies by individual.

Safety and considerations: Common side effects include gastrointestinal symptoms such as diarrhea, abdominal cramps, and nausea, especially with rapid dose increases. MCTs do not supply essential fatty acids, so a varied fat intake is still needed. Long-term safety appears acceptable at moderate doses, but high intake may affect lipid profiles and is not recommended without medical supervision.