You’ve probably heard that MCT oil enhances the Keto diet. Taking MCTs is said to help with weight loss, ketone production, energy levels, and even preventing the infamous Keto flu.
Is it true? Is MCT oil an essential Keto supplement?
Well, it might not be essential, but MCT oil doeshave a raft of science-backed benefits behind it. We’ll cover those benefits after we introduce the star of the article.
MCT oil stands for medium-chain triglyceride oil. It’s typically made from coconuts, but palm kernel oil, whole milk, and butter also contain MCTs.
MCTs have a unique ability to travel to the liver and boost ketone production.[*] To understand why this occurs, we need to unpack the term “medium-chain triglyceride.”
Triglycerides are how plants and animals store fatty acids. When you eat something with fat, you’re consuming triglycerides. Triglycerides are also how fat is transported, via the bloodstream, to different tissues in the body. Eating a diet high in calories, refined sugars, and/or processed carbohydrates may lead to excess triglyceride production in the liver and unwanted fat deposition. This can be reflected as “high triglycerides” on a lipid (cholesterol) panel at your doctor’s office.
Triglycerides can be made of three types of fatty acids: short-chain fatty acids, medium-chain fatty acids, and long-chain fatty acids. The short, medium and long prefixes refer to the number of carbon atoms in the fatty acid molecule.[*]
Medium-chain fatty acids—the building blocks of medium-chain triglycerides (MCTs)—have 6 to 12 carbon atoms. That’s why the four types of MCTs are labeled from C6 to C12:
4 Types of MCTs
- C6: caproic acid
- C8: caprylic acid
- C10: capric acid
- C12: lauric acid
Look for MCT oils made with caprylic acid (C8) or capric acid (C10). Caproic acid (C6) is rarely used due to its bad taste, while lauric acid (C12) doesn’t have the same ketogenic properties as other MCTs.[*]
Ketogenic properties? Yes, when you consume MCT oil, the MCTs travel rapidly to the liver for ketone production.[*] The resulting elevation in ketones—your backup brain fuel—is likely responsible for any cognitive benefits one may experience while supplementing MCTs.
Thinking about supplementing with MCT oil? The following potential benefits might convince you.
Several studies suggest that MCTs promote fat loss.[*][*][*] In one study published in the American Journal of Clinical Nutrition, overweight people taking MCT oil lost more weight than counterparts taking olive oil.
A few mechanisms may explain why MCT oil helps folks lose fat.
First, MCT oil has been shown to increase fullness hormones like leptin and peptide YY.[*] When you're full, you're less likely to overeat and pack on the pounds.
Consuming MCTs also appears to increase energy expenditure—the rate at which you burn calories. This may be mediated by shifts in the gut microbiome.[*]
Finally, MCT oil increases fat-burning in the liver. That’s how ketones and energy are produced.
The brain normally runs entirely on glucose. But in a state of ketosis, the burden shifts to ketones.
Elevating ketones—with the Keto diet, MCT oil, or both—appears to have brain benefits in a variety of situations. Consider the following:
- Elderly people performed better on cognitive tests after consuming a single meal containing MCTs.[*] No Keto diet required.
- MCT supplementation improved memory in those with Alzheimer’s disease.[*]
- An MCT-based ketogenic diet has proven effective for controlling epilepsy in children.[*]
- Adding MCTs to a Keto diet improved behavior in autistic children.[*]
These benefits may not be entirely driven by ketones. MCTs themselves can also cross the blood-brain barrier to (potentially) improve cognition and brain function.[*]
The transition from carbs to Keto isn’t always a smooth one. Many people experience a cluster of symptoms known collectively as Keto flu.
Some of these symptoms (like headaches) may stem from the brain’s inability to transition from glucose to ketones for energy. By elevating ketones, MCT oil may ease this transition.[*]
Since MCTs don’t require bile for digestion, they require fewer steps to be oxidized (burned) by the liver than long-chain fats. In other words, MCTs are converted to energy faster.
MCT oil may also enhance exercise performance, but the evidence is mixed. One mouse study found that MCTs boosted swimming capacity[*], but human studies haven’t shown endurance improvements.[*]
The MCTs capric acid, caprylic acid, and lauric acid have been documented to have antimicrobial effects against bacteria, yeast, and viruses.[*]
One such yeast is Candida albicans, a common cause of thrush, intestinal, and vaginal fungal infections. The MCTs in coconut oil inhibit the growth of this pathogen.[*]
To be clear, most of the research on this topic is test tube or animal research. It’s not ready for primetime yet.
The main reported side effect of MCT oil is digestive distress. Consuming too much too quickly can cause diarrhea, gas, bloating, and abdominal pain.
Very high doses of MCT oil (50% of daily calories) have also been shown to increase liver fat in mice.[*] Keep in mind, however, that these doses are 5 to 10 times higher than the recommended upper limit for humans.[*]
If you want to take MCT oil, start slow with a teaspoon per day and work your way up from there. This will help mitigate any laxative effects.
Most people stabilize at a tablespoon or two per day, but the safe upper limit for bowel tolerance is 4 to 7 tablespoons per day.[*]
For a more digestible option, try MCT oil powder (It has the same nutritional value).
When shopping for MCT oil, look for products made with C8 (caprylic acid) and C10 (capric acid). These are the most ketogenic MCTs, and the most studied for their benefits.[*]