What Is it MCT Oil? Benefits , Side Effects

MCT Oil

MCT oil is a semi-new product that has probably popped up on the shelves of your favorite health food stores and social media feeds.

With all the hype, you would think it’s liquid gold. So what is it? Well, here we will breakdown the research for you (so you don’t have to) and discuss the potential benefits, side effects, and the current uses of MCT. 

What Is MCT oil?

MCT stands for medium-chain triglycerides. You have probably heard of triglycerides before. Most likely, you saw this word on the results sheet on your last blood test and avoided looking at the actual number. Triglycerides are a grouping of fatty acids – one triglyceride has a glycerol backbone (made of carbon molecules, in addition to hydrogen atoms, and oxygen molecules) and three (tri) fatty acid tails. 

Triglycerides (TGs) are found in nature, coming in several forms. Short-chain triglycerides have less than 6 carbon molecules in each of the fatty acid tails attached to the glycerol backbone. Medium-chain TGs have 6-12 carbons, and long-chain triglycerides have 13-21 carbon molecules. 

There are several different types of MCTs classified by the chain length (number of carbons) of the attached fatty acids (FAs), and each type has slightly different properties. Here is a brief breakdown of the various forms of medium FAs. The numeral next to C indicates the number of carbon atoms.

Types of Medium Fatty Acids:

  • C6 (caproic acid or hexanoic acid) – this fatty acid contains 6 carbons and it metabolizes quickly in the body. However, this acid is apparently quite smelly so it is generally removed prior to creating commercially sold MCT oil. 
  • C8 (caprylic acid or octanoic acid) – C8 has a chain length of 8 carbon atoms and is one of the most common fatty acids in MCT oils sold. Caprylic acid may have anti-microbial and anti-fungal effects, especially when combined with other compounds (1, 16). The wildly popular Brain Octane Oil from BulletProof is a product of pure C8. 
  • C10 (capric acid or decanoic acid) – C10 is another common fatty acid found in bottles of MCT oil and may have anti-microbial and anti-fungal effects.
  • C12 (lauric acid or dodecanoic acid) – lauric acid is the slowest to metabolize out the FAs previously mentioned. Like C8 and capric acid, it also has possible antimicrobial effects, possibly decreasing the growth of harmful bacteria like C. difficle (1, 18). However, most studies involve observing the proposed effects in vitro (on Petri dishes) or are animal studies (mostly rats); the effects are rarely studied on humans.

As mentioned earlier, TGs (and thus MCTs) are a form of fat. Fat is a necessary part of our diet and is used for energy storage in the body. With current diet trends revolving around a certain high-fat diet (think keto), it’s no surprise MCT oil supplements such as MCT powder and liquid MCT oil are now commonly seen on store shelves.

However, MCTs are actually saturated fats, meaning there are no double bonds on the fatty acid chain. As we have been told repeatedly to limit saturated fat intake, why are people promoting this oil? What makes MCT so special?

How MCT Oil Metabolizes

The various forms of fat have different metabolic and absorption pathways once they are in the human body. For example, once long-chain triglycerides (LCTs) enter the small intestines, bile and pancreatic lipase are released. Bile coats the TGs making it easier for lipase to break down the LCTs so that they can be absorbed (in the form of chylomicrons) into the lymphatic system. LCTs enter the bloodstream, either headed to adipose tissue or the liver. 

Conversely, MCTs do not need to be broken down by the bile and pancreatic lipase. The medium-chain fatty acids are passively absorbed in the intestines and travel to the liver through the bloodstream, where they are broken down into ketone bodies, a form of energy (11). 

Now, normally your body only produces ketones when you have very little stored glucose, which is the brain’s favorite form of energy. However, after a long period of not eating carbohydrates (ex: starvation, fasting, uncontrolled diabetes, keto diet, etc.), your body will breakdown fat into ketones for energy.

As fat is the main source of energy in the keto diet, the quick metabolism of medium-chain fatty acids is the reason why MCT oil is frequently found on the ingredient list for many low-carb keto recipes. People following the keto diet must stay in a state of ketosis, meaning that their body is mainly using fat for energy. They measure this by testing their urine for the presence of ketone bodies.

The Ketogenic diet is not the only reason why people use MCT oil. Due to their properties of passive absorption, many individuals with digestive issues take this form of fat. I’ll go into more detail later on. 

MCT Oil Sources

Now, where do MCTs naturally come from?

The most common sources of MCT are coconut oil and palm kernel oil (palm oil), but they are also found in dairy products, and breast milk. However, these sources also contain LCTs. So the medium-chain triglyceride oil you buy is not just regular coconut oil or palm oil. This bottled liquid comes from naturally occurring MCTs that are extracted from coconut and palm oil, through a process called fractionation. 

7 Health Benefits of MCT Oil

Here I will briefly touch on the proposed health benefits of MCT, based on current research, not the model-thin social media influencer you follow claiming this substance is a fat-burning miracle oil.

1. May Help Control Appetite 

One of the proposed health benefits of supplementing with MCT oil is that it helps control your appetite. 

Long-chain fatty acids are stored easily, compared to their medium-length counterparts. If LCTs are consumed excessively, it can cause unhealthy weight gain. Excessive fat storage can lower the body’s response to leptin, which kind of acts as an anti-hunger hormone, and insulin (7). 

One study observed the impact medium-length TGs had on appetite in overweight men. Researchers found that supplementing MCT with meals may cause the satiety-related hormone (leptin) to increase, thus decreasing appetite and curbing post-meal cravings (14).

However, this had a small number of participants and more research must be done.

2. May Aid Weight Loss

Another suspected health benefit of MCT oil (and one often promoted in advertisements) is that this oil aids weight loss. Now, what do the professionals say? 

A meta-analysis published in the Journal of the Academy of Nutrition and Dietetics suggests that having a diet higher in MCTs versus LCTs may cause a slight weight reduction and an increased energy expenditure (more calories burned). They also found that total body fat and waist circumference were slightly reduced with supplementation of MCFAs (6).

Another study (tested on mice) showed that high doses of MCT triggered an increase in a hormone (GLP-1), which is secreted in the intestines and is shown to increase satiety, thus decreasing random cravings throughout the day. It also showed MCT did not greatly increase GIP. As GIP is associated with fat accumulation, lower concentrations may cause weight loss.

The study also showed that the mice given a diet high in medium-chain fats gained less weight than the mice eating more LCTs; this could be due to decreased intake and or the higher likelihood that LCTs will be stored as fat. Both gained more weight than those eating a controlled diet (a low-fat diet) (7).

There could be several reasons why medium-chain TGs may help with weight loss but more research must be done for conclusive evidence.

3. May Increase Energy Level

This potential MCT oil benefit is understudied. Some individuals claim that this fatty fuel source gives them a boost of energy. While MCT oil consumption may not provide you enough additional energy to combat all fatigue and cure your afternoon slump, this medium-chained FA group has been shown to increase the level of cellular energy (energy expenditure) in some studies (6).

4. Lower Risk of Heart Disease

Now how can high amounts of fat decrease one’s risk of heart disease? Well, first of all, fat is part of a healthy diet. However, many people consume too many grams of fat along with generally unhealthy diets, usually resulting in high body weight, large waist circumference, inflammation, and other health conditions that could lead to heart disease.

Let’s first take a look at body composition. Being obese or overweight puts someone at a higher risk for having heart disease later on in life. As you read earlier, one of the potential benefits of medium-length TGs is that they may help individuals lose weight and decrease fat accumulation (6). If someone is able to lose weight, then it may reduce their risk of heart-related issues.

Additionally, having high cholesterol and TG levels generally puts someone at a higher risk of heart disease. An older study found that overall, levels of total cholesterol decreased more when the participants’ diet was supplemented with a combo of MCT, flaxseed oil, and phytosterols, compared to the diets supplemented with olive oil. The researchers concluded that medium-length TGs, along with other types of fat, could lower cardiovascular risks (13).

Generally, saturated fats like high-fat dairy products (butter, full-fat yogurt, whole milk), meats, and fried foods are limited in a heart-health diet, while healthy fats, such as unsaturated fats, are encouraged. Coconut oil is also a saturated fat (why it is solid at room temperature), and coconut oil is a main source of medium-chain fats. Coconut oil has a high content of lauric acid (C12) and polyphenols, which can act as antioxidants.

One study looked at the effects extra virgin coconut oil had on cholesterol levels and body mass in patients with coronary artery disease. They found that patients given pure coconut oil each day showed decreases in weight, BMI, waist circumference, and an increase in HDL (your good cholesterol) compared to those on a normal, healthy diet. No significant differences were found in TG and LDL (“bad” cholesterol) levels (2).

In general, it is recommended you get your fat sources from lean foods and incorporate healthy fats like omega-3s and polyunsaturated fats into your daily diet. Great food sources include fish, nuts, and oils. However, in the coming years, MCT products could become apart of lowering one’s risk of cardiovascular disease and heart disease treatment, depending on more conclusive results from research. 

5. Treating Alzheimer’s 

There is some research suggesting that MCT oil could treat Alzheimer’s Disease (AD) and dementia by improving cognitive function. 

Brain cells prefer to use glucose as fuel, but they can use ketones, as these byproducts can cross the blood-brain barrier. Research has found that in the early stages of AD, glucose usage in the brain is reduced. So ketones (and thus MCTs) may be an alternative energy source in these cases, possibly improving cognitive function and slowing the progression of AD (12).

A literature review concluded that including MCTs in the diet of those at risk for Alzheimer’s may be beneficial for brain function. However, they also stated more human studies must be conducted before this type of fatty acid can be used as a standard treatment for AD and improving cognition (12).

Another study tested the effects of an MCT-based keto diet on patients with AD. However, this study was small, and even though their results suggested that a keto diet may enhance cognitive performance, they could not make a solid conclusion (10). 

So before we can use medium-chain TGs for improving cognitive health, more research must be done. 

6. May Increase Endurance

Another suggested benefit of MCT oil is that it could increase the exercising capacity of athletes. 

One study done on mice found that MCT supplementation helped increase endurance by increasing the function and production of mitochondria – the cells that are necessary to create energy (15). A second study found that MCT with maltodextrin may increase fat oxidation and duration of exercise (9). An older study showed those supplementing with medium-chain FAs had longer durations of exercise than those supplementing with LCTs (8). 

On the other hand, a study showed that MCT supplementation increased energy expenditure and aided weight loss but did not increase the exercise capacity of participants (3). 

Again, research shows that more studies must be done before endurance athletes rush to the supplement store to enhance their athletic performance.

7. Treatment for Diseases 

Medium TGs are commonly used for treating malabsorption issues (in particular fat malabsorption) in the GI tract. 

The pancreas is an organ in the body that produces many substances including insulin and pancreatic enzymes. These enzymes are necessary for proper digestion. Malabsorption of fat can cause gastrointestinal distress and steatorrhea, which is the term for frothy, loose stools.

If the pancreas is damaged or is not working well, like in pancreatitis or cystic fibrosis, the body cannot properly digest or utilize some nutrients. If this organ is damaged, its ability to make pancreatic lipase, an enzyme that breaks down fat, may be hindered. With little lipase, the body can not breakdown most forms of fat nor can the intestines absorb the fat molecules. As MCTs are absorbed passively, they are used as a primary fat source for these patients (we all need dietary fat!) without triggering pain or other not so fun side-effects other forms of fat like LCTs would cause (11). 

Issues of the liver and gallbladder can also negatively impact fat uptake by the body. The liver creates bile then sends it to the gallbladder, which then secretes it into the gastrointestinal tract to help with fat digestion. Not enough bile for fat digestion can cause gastrointestinal distress and malabsorption. 

 Just like protein and carbs, fat is a very important nutrient for our bodies, and over time, if the body is not receiving enough fat due to impaired absorption, malnutrition may occur.

Its also been said that medium TGs may decrease irritation in other gastrointestinal disorders including celiac disease, short bowel syndrome, and IBD (5, 11). 

I won’t touch on the specifics here, but other studies suggest MCTGs may have numerous benefits in addition to the ones listed above. These include improving gut health by increasing the good bacteria, treating autism, and having possible antimicrobial benefits (1, 18). It may also affect insulin levels (possibly improving blood sugar levels), which could help pre-diabetic and diabetic patients (4). However, like the potential benefits discussed above, more research must be completed. 

Although this popular dietary supplement has numerous benefits associated with its name, the bottom line is that we have much more to learn about this form of TGs.

MCT and Keto Diet

For a quick refresher, the ketogenic diet is a high-fat, low-carb diet, consuming less than 50 grams of carbs per day. 

The keto diet was originally used (and still is) as a treatment for epilepsy. Although the exact mechanism of how the keto diet helps epilepsy is somewhat unknown, it is thought that the ketones inhibit the activity of neurotransmitters (the little guys that send signals to your brain), which may protect neurons and decrease the convulsant activity which causes seizures. Pretty cool, right?!

I hinted at this earlier, but the reason why MCT is such a common ingredient in the ketogenic diet is due to its quality as an (almost) instant energy source, thus creating ketone bodies, hence energy. Followers of the keto diet can measure their body’s ketone levels by testing their urine; having a positive ketone body reading is a sign that keto followers are in ketosis.

MCT oil is a convent way for keto dieters to add fat to many recipes without changing the taste of food. 

How to Take MCT Oil

Making MCT oil

Now there are several ways to incorporate this type of fat into one’s daily diet. None of these ideas involve taking a tablespoon of pure MCTs. Although pure MCT oil does not have much flavor by itself, these ideas will provide a more pleasant taste. 

One option is to make a homemade salad dressing that uses MCT as a base. The ingredient list for a yummy, fat bomb salad topping generally includes mayonnaise or avocado for a boost of creaminess, olive oil, and spices, in addition to the MCT. Make a large batch of a high-fat dressing for a convenient way to increase your daily fat intake. 

Another option is to make keto butter coffee, a.ka. Bulletproof coffee. For those of you who have no idea what I am talking about, no, this coffee will not make you invincible. Bulletproof coffee was created by Dave Asprey, an entrepreneur, and self-proclaimed “biohacker”. 

This recipe involves blending pure MCT oil (more specifically, C8 oil, which he calls Brain Octane) and grass-fed butter or grass-fed ghee (clarified butter from grass-fed cows) to your morning coffee. After blending it with a milk frother, keto coffee looks more like a latte than a regular cup of coffee. It’s basically a fat bomb with a dose of caffeine, not your typical first cup of coffee in the morning. Try adding a splash of vanilla for a pleasant taste.

I tried drinking Bulletproof coffee for a week, out of curiosity, and it defiantly has an interesting taste, but afterward, I had a slight upset stomach. While many keto dieters choose to drink this butter coffee first thing in the morning on an empty stomach as part of their daily routine, this may cause some digestive discomfort for those of us not following the keto lifestyle or the keto newbies.

If this is the case, one way that eased my digestive discomfort was to eat something with the coffee, like a banana or bowl of cereal.

A great way to start your morning (other than drinking butter coffee) is to mix MCT to your morning smoothie or post-workout protein shake. Simply mix a tablespoon of MCT oil (less or more, depending on your needs) to your favorite recipe! A different way to add MCT products into your diet is to include a teaspoon or a tablespoon to your matcha tea. These are quick and convenient ways to increase your total fat intake.

You can always use coconut oil and palm oil for cooking and baking for a little dose of MCTs; my personal favorite oil to bake with is coconut as it adds more flavor. However, cooking with pure MCT oil is not a great way to use the oil as the medium-chain TGs have a low smoke point (5). So stick to a healthy cooking oil like avocado or olive oil when cooking the next family dinner!

Now, MCT comes in the form of oil and a powder form. The type of MCT you chose is up to your preferences. For the MCT powder, you can easily add a scoop to your coffee, smoothie, shake, oatmeal, snack, or whatever satisfies your sweet tooth for a boost of fat. Make sure to read the instructions on the product’s packaging before using it. Store both the oil form and MCT powder at room temperature. 

Now, what is a serving of pure MCTs? Serving sizes may vary between 1 tsp., a few tablespoons, or a scoop depending on the product. Generally, if you are new to MCT consumption, it is a good idea to only add a small amount, like 1-2 tsp., to your favorite beverage or food, and slowly incorporate more (11). This slow incorporation will help your body adjust to the high-fat supplement, decreasing the risk of any digestive discomfort. 

Remember that although medium-length FAs are generally not stored in the body as they quickly metabolize into ketones, too much MCT oil could lead to fat accumulation in your liver, which would be an adverse effect. Before taking, look at the dosage information on the package and talk to your healthcare provider about the frequency of use. 

Before running to health food stores and buying MCT supplements such as MCT oil powder for your smoothies and other beverages, talk to your doctor and dietitian to see if MCT may be beneficial for your health. MCT is not known to cause many adverse effects, the most common ones being gastrointestinal distress (i.e., nausea, vomiting, diarrhea, stomach pain, etc.). 

However, it is always a great idea to ask your dietitian and doctor for individual medical advice, especially if you are taking medication or have a medical condition like liver disease. Your healthcare providers can also recommend high-quality MCT oil products as the U.S. Food ad Drug Administration (FDA) does not regulate dietary supplements. 

Final Word

In recent years MCT products have become popular dietary supplements. A large part of the increase in MCT use is due to the popularity of the keto lifestyle. However, as this article shows, there is a lot of research emerging regarding the potential benefits of pure MCTs.

For those of you who skimmed through this article, in summary, MCT oil does not magically burn fat, cause a greater energy expenditure, or increase your metabolic rate to the point where you are burning 2000 more calories a day, or help you lose 20 pounds in a week. 

Unfortunately, this oil will not give you the body composition of endurance athletes overnight. And unfortunately, it probably won’t provide complete mental clarity, boost your brain power, and cure those diagnosed with cognitive disorders like AD and dementia. 

However, many studies point towards the positive effects of MCTs on brain health, heart health, and fat loss, which is very promising. For those following the ketogenic lifestyle, it may be a source of quality fat that may help boost production of ketones and keep the body in ketosis. Who knows, maybe in a few years, MCT products will be a standard intervention for weight loss, weight management, as well as prevention of cardiovascular disease and cognitive disorders.

The bottom line is that although research has found some positive effects, many more studies must be completed before the real benefits of MCT can be promoted.

  1. Bae YS, Rhee MS. Short-Term Antifungal Treatments of Caprylic Acid with Carvacrol or Thymol Induce Synergistic 6-Log Reduction of Pathogenic Candida albicans by Cell Membrane Disruption and Efflux Pump Inhibition. Cell Physiol Biochem. 2019;53(2):285-300. doi: 10.33594/000000139. PMID: 31334617. 
  2. Cardoso, Diuli A et al. “A coconut extra virgin oil-rich diet increased HDL cholesterol and decreases waist circumference and body mass in coronary artery disease patients”. Nutricion hospitalaria vol. 32,5 2144-52. 1 Nov. 2015, doi:10.3305/nh.2015.32.5.9642 
  3. Clegg, M. (2010) Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance, International Journal of Food Sciences and Nutrition, 61:7, 653-679, DOI: 10.3109/09637481003702114 
  4. Han, Jian Rong et al. “Effects of dietary medium-chain triglyceride on weight loss and insulin sensitivity in a group of moderately overweight free-living type 2 diabetic Chinese subjects.” Metabolism: clinical and experimental vol. 56,7 (2007): 985-91. doi:10.1016/j.metabol.2007.03.005 
  5. Hultin, Ginger. “Is MCT Oil a Miracle Supplement or Just Another Fad?” Food & Nutrition Magazine, 28 July 2017, foodandnutrition.org/january-february-2016/mct-oil-miracle-supplement-just-another-fad/. 
  6. Mumme, Karen, and Welma Stonehouse. “Effects of medium-chain triglycerides on weight loss and body composition: a meta-analysis of randomized controlled trials.” Journal of the Academy of Nutrition and Dietetics vol. 115,2 (2015): 249-63. doi:10.1016/j.jand.2014.10.022 
  7. Murata, Yuki et al. “Medium-chain triglyceride diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with long-chain triglyceride diet.” American journal of physiology. Endocrinology and metabolism vol. 317,1 (2019): E53-E64. doi:10.1152/ajpendo.00200.2018 
  8. Nosaka, Naohisa, et al. “Effect of Ingestion of Medium-Chain Triacylglycerols on Moderate- and High-Intensity Exercise in Recreational Athletes.” Journal of Nutritional Science and Vitaminology, vol. 55, no. 2, 2009, pp. 120–125., doi:https://doi.org/10.3177/jnsv.55.120. 
  9. Nosaka, Naohisa et al. “Medium-chain Triglycerides with Maltodextrin Increase Fat Oxidation during Moderate-intensity Exercise and Extend the Duration of Subsequent High-intensity Exercise.” Journal of oleo science vol. 67,11 (2018): 1455-1462. doi:10.5650/jos.ess18112 
  10. Ota, Miho et al. “Effects of a medium-chain triglyceride-based ketogenic formula on cognitive function in patients with mild-to-moderate Alzheimer’s disease.” Neuroscience letters vol. 690 (2019): 232-236. doi:10.1016/j.neulet.2018.10.048 
  11. Shah, Neha, and Berkeley Limketkai. “The use of medium-chain triglycerides in gastrointestinal disorders”. Practical gastroenterology. Feb. 2017, med.virginia.edu/ginutrition/wp-content/uploads/sites/199/2014/06/Parrish-February-17.pdf. 
  12. Sharma, A., Bemis, M., & Desilets, A. R. (2014). Role of Medium Chain Triglycerides (Axona®) in the Treatment of Mild to Moderate Alzheimer’s Disease. American Journal of Alzheimers Disease & Other Dementiasr, 29(5), 409-414. doi:10.1177/1533317513518650
  13. St-Onge, Marie-Pierre et al. “Consumption of a functional oil rich in phytosterols and medium-chain triglyceride oil improves plasma lipid profiles in men.” The Journal of nutrition vol. 133,6 (2003): 1815-20. doi:10.1093/jn/133.6.1815 
  14. St-Onge, M-P et al. “Impact of medium and long chain triglycerides consumption on appetite and food intake in overweight men.” European journal of clinical nutrition vol. 68,10 (2014): 1134-40. doi:10.1038/ejcn.2014.145 
  15. Wang, Ying et al. “Medium Chain Triglycerides enhances exercise endurance through the increased mitochondrial biogenesis and metabolism.” PloS one vol. 13,2 e0191182. 8 Feb. 2018, doi:10.1371/journal.pone.0191182 
  16. Watanabe, Takamasa et al. “Systematic Analysis of Selective Bactericidal Activity of Fatty Acids against Staphylococcus aureus with Minimum Inhibitory Concentration and Minimum Bactericidal Concentration.” Journal of oleo science vol. 68,3 (2019): 291-296. doi:10.5650/jos.ess18220 
  17. “What Is MCT Oil? MCT Oil Uses, Benefits, Sources & More: Acme-Hardesty.” Acme-Hardesty, 16 Nov. 2018, www.acme-hardesty.com/overview-mct-oil-medium-chain-triglycerides/. 
  18. Yang, Hsiao-Ting et al. “Lauric Acid Is an Inhibitor of Clostridium difficile Growth in Vitro and Reduces Inflammation in a Mouse Infection Model.” Frontiers in microbiology vol. 8 2635. 17 Jan. 2018, doi:10.3389/fmicb.2017.02635 
23 Shares:
Leave a Reply

Your email address will not be published. Required fields are marked *

You May Also Like