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MCT Oil Diarrhea: What Causes It and What You Can Do to Stop It

By Fitoru | 04 December 2019
woman sitting in a toilet holding her tummy

First you read about the weight-loss benefits of the ketogenic diet. Then you heard all the buzz about bulletproof coffee. So after doing a little research of your own, you decided to dip your toe into this brave new world and embark on your own keto diet odyssey on a river of coffee, grass-fed butter, and MCT oil. But after your first cup of high-fat deliciousness, the energy high gives way to a sudden urge to run not around the block but around the bathroom. Yes, you have officially fallen victim to MCT oil diarrhea.

But what’s causing this more than slightly annoying affliction? And what—save giving up the MCT oil completely—can be done to stop it?

Thankfully, you’ve come to the right place. Because we’ve got the answers to both these questions.

But first, let’s set the stage by getting to know a little bit more about this relative newcomer to the dietary supplement world, like where it comes from and what its health benefits might be.

What Is MCT Oil?

Unlike flaxseed and olive oil, which are produced by simply extracting the oil from the flax plant seeds or olive tree fruits, you can’t go out and squeeze a nut, seed, or fruit and end up with MCT oil.

On the contrary, MCT oil must be refined from other oils. And not just any other oils. In fact, the medium-chain triglycerides that make up MCT oil—caprylic acid and capric acid—are found in only a few foods:

  • Coconut oil
  • Palm kernel oil
  • Cow, goat, and breast milk

But, by far, the richest sources of MCTs are coconut and palm kernel oil, and thus these sources are most often used in the production of MCT oil. However, most MCT oil is produced using coconut oil, which contains the most MCTs of any source.

So how do you turn coconut oil into MCT oil?

In the Beginning, There Was Coconut Oil…

Over half of coconut oil is made up of MCTs, but the other 40 or so percent is composed of long-chain triglycerides, or LCTs. These long-chain fatty acids are the reason coconut oil remains solid at room temperature—they have a higher melting point than other forms of fat.

However, if you heat coconut oil past this melting point and then allow it to cool down again, you can easily separate the LCTs from the MCTs.

And, thus, MCT oil is born.

Before we go on, there’s one thing we want to point out.

We mentioned earlier that MCT oil contains caprylic acid and capric acid. Yet the MCTs in coconut oil are actually made up of three types of medium-chain fatty acids: caprylic, capric, and lauric acid. 

However, lauric acid is made up of longer chains of carbon atoms than both caprylic acid and capric acid, so most of it gets removed with the long-chain fatty acids during processing.

While lauric acid has been found in studies to possess strong antimicrobial properties, it doesn’t possess the type of fast-acting energy and weight-loss boons as caprylic and capric acids do. If it’s fat burning you’re after, lauric acid shouldn’t be missed too much. The large amounts of capric acid and caprylic acid that make up MCT oil (though different brands contain different ratios of each) have certain characteristics that make this oil one of the hottest health trends on the market today.

Health Benefits of MCT Oil

One of the most interesting aspects to MCT oil is that, while it may be relatively new on the dietary supplement scene, it’s been used in hospitals for decades to treat patients with malabsorptive disorders.

This is because, unlike the long-chain triglycerides found in coconut oil, medium-chain triglycerides can be digested and absorbed by the body without the aid of either enzymes or bile salts.

This almost effortless digestion and absorption is one of the qualities that makes MCT oil so popular among athletes and people following the keto diet. Because not only are the medium-chain fatty acids in MCT oil converted almost immediately into energy—instead of being stored as body fat—but they’re also converted easily into ketones.

Although ketones help keep your body in the fat-burning state known as ketosis, this effect is more pronounced when using MCT oils that are particularly high in caprylic acid.

In addition, studies have also discovered that MCT oil helps decrease lactate levels—an important consideration for anyone wanting to get more out their workouts.

But while the ability to convert into ketones, help maintain ketosis, and even decrease workout-limiting levels of lactate certainly explains what makes the use of MCT oil popular among people interested in fat loss and maintaining healthy body weight, these factors aren’t the only benefits offered by this special blend of fatty acids.

In fact, a number of studies have demonstrated that MCT oil may help protect against heart disease via its positive effects on blood sugar and cholesterol and improve gut health due to its ability to boost levels of good bacteria. 

What’s more, MCT oil has even been found to offer potential health benefits for patients with Alzheimer’s disease by providing a readily available source of energy for brain cells that may help support brain function.

So now you know about the health benefits of MCT oil, but what about that unpleasant side effect that brought you here?

We’re going to get into that now. 

But be warned—this is where things get complicated.

Ways to Stop MCT Oil Diarrhea

What Causes MCT Oil Diarrhea?

When it comes to MCT oil and diarrhea, a short search of the Internet will offer up more than a few stories of people’s personal experiences with what they affectionately call “disaster pants.” There are even entire forums dedicated to the topic.

Yet you’re also likely to run into at least a few health care professionals declaring that all this is bunk, and that MCT oil is no more likely than any other oil to cause diarrhea because people who are hospitalized with malabsorption receive MCT oil day in and day out without any problems. In fact, many of them actually see their diarrhea improve with MCT oil.

But unless hundreds, if not thousands, of people are consistently having diarrhea with other types of oils and just aren’t talking about it, you have to think something else is going on here.

And you’d be right.

What’s more, even though studies on the subject are about as mixed as the varying reports you find on the Internet—with some saying issues are more likely to be seen in people who take MCT oil on an empty stomach or eat large amounts of dietary fat and others finding no correlation whatsoever—a report in Nutrition Issues in Gastroenterology indicates that an association has indeed been documented between excessive consumption of MCT oil and upset stomach, cramping, bloating, and diarrhea (1).

So what’s going on?

When it comes to MCT oil, two things seem to be to blame: the quick uptake of the oil and the nature of triglycerides.

Although the easy digestibility of MCT oil is what makes it so great for fat burning and energy, bypassing the digestive process altogether can actually end up irritating the GI tract. And when the GI tract is irritated, it responds by trying to rid itself of the irritant.

In addition, all triglycerides, including those found in MCT oil, contain glycerol. If that word sounds familiar, it’s because glycerol is sometimes known by a different name: glycerin. 

As in the suppository.

Glycerin is what’s called a hyperosmotic laxative. This means it has the ability to draw water into the colon from the surrounding tissues, which in turn softens the stool and increases peristalsis in the colon.

Because MCT oil is rich in glycerol, it, too, has this ability—which can be great if you tend to suffer from constipation but not so much if you don’t.

Luckily, however, there are things you can do to stop the diarrhea from happening in the first place.

How to Stop MCT Oil Diarrhea

You know those exercise neophytes who walk into a gym for the first time, their latest New Year’s resolution pinging around their brains, grab the heaviest weight, and immediately proceed to blow a tendon?

The same approach to MCT oil can get you into similar—though admittedly less painful—trouble.

So if you’re new to MCT oil, don’t start with the maximum recommended dosage. Instead, begin with a teaspoon and work your way up gradually.

Sounds simple, we know. But following this one bit of advice should give your system plenty of time to adjust.

However, even a teaspoon of MCT oil is too much for some people, so if you’re still having trouble, you can try lowering the dose even further, or even dividing the dose throughout the day.

It’s also important to remember that following a ketogenic diet or drinking bulletproof coffee can complicate things.


Because a keto diet is already fat heavy, and adding the additional (and unique) fat found in MCT oil can aggravate your GI tract even more.

And bulletproof coffee throws even more potential complications into the mix.

For one thing, caffeine is a stimulant, and one of the things it’s known to stimulate is the colon. What’s more, people tend to drink bulletproof coffee upon arising. And dumping that much fat into a GI tract that’s been at rest over the course of the night can be a recipe for disaster.

In fact, the double whammy of caffeine and heavy fat first thing in the morning is a common theme running through many of the “disaster pants” stories on the Internet.

So if you’re currently following the keto diet or trying your hand at bulletproof coffee or—possibly not the wisest choice—doing both at the same time and starting low and slow with MCT oil isn’t working, you may have to make some choices.

For example, you may find that adding coconut oil to your bulletproof coffee instead of MCT oil and taking your MCT oil with meals works better.

However, some people are simply intolerant of MCT oil.

So if you’ve tried lowering your dose or taking it with meals and you’re still having side effects with MCT oil, don’t ignore your body. After all, it’s only looking out for you.


  1. I took mct oil first thing in morning 1 tablespoon then one in my coffee.i had not eaten for 12 hours and didnt eat for another 10hours.About 2 hours after my meal had terrible stomach cramps and only thing had different was mct oil.Was it to much for first time and coz no food

    1. Hi Gregory! It could be because of your tolerance to MCT Oil. Start from a small dosage then gradually increase your MCT intake.


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