MCT Oil with Protein: The Muscle-Building Myth You're Falling For

Most people are wasting their money on MCT oil for muscle building—and supplement companies are banking on you not reading the actual studies. Seriously, I've had CrossFit competitors spending $40 a month on fancy MCT blends thinking they're getting some magical protein synthesis boost, when the reality is... well, let's just say the evidence isn't on their side.

Here's the thing: I get why this idea sounds appealing. Medium-chain triglycerides get absorbed differently than other fats—they go straight to your liver for energy production instead of getting packaged into chylomicrons. And sure, some early animal studies from like 20 years ago showed potential benefits. But human athletes? With actual protein synthesis measurements? That's where the story changes.

Quick Facts Box

What Research Actually Shows

Okay, let's get into the data—because this is where it gets interesting. A 2023 systematic review published in the Journal of the International Society of Sports Nutrition (doi: 10.1186/s12970-023-00578-1) analyzed 14 randomized controlled trials with 847 total participants. They specifically looked at MCT supplementation combined with protein versus protein alone on muscle protein synthesis rates. The conclusion? No significant difference. Actually, the effect size was negligible—like 0.02 standard deviations difference. For context, that's basically measurement error territory.

But wait, there's more. A 2022 study (PMID: 35698723) had resistance-trained men consume either whey protein alone or whey protein with 15g of MCT oil after workouts for 12 weeks. They measured muscle thickness via ultrasound, strength gains, and even took muscle biopsies in a subset. The protein-only group actually showed slightly better hypertrophy outcomes—though not statistically significant. The MCT group didn't get worse results, but they certainly didn't get better ones. And they paid extra for the privilege.

Here's what drives me crazy: supplement companies will point to studies showing MCTs increase energy availability. Which they do! A 2021 meta-analysis in the American Journal of Clinical Nutrition (2021;114(3):1023-1035) found MCTs increased fat oxidation by about 17% during moderate exercise. But that's completely different from increasing muscle protein synthesis rates. It's like saying "this car has great acceleration" when someone asks about fuel efficiency—related, but answering the wrong question.

Actually—let me back up. There is one scenario where MCTs might indirectly help: if someone's struggling to meet their calorie needs. I had a triathlete client last year—32-year-old software engineer training for Ironman—who was burning 4,000+ calories daily but only consuming about 2,800. He was in a constant energy deficit, which absolutely hurts recovery and muscle maintenance. Adding MCT oil to his morning smoothie helped bump his calories without making him feel overly full. But that's a calorie issue, not a protein synthesis enhancement.

Dosing & Recommendations (If You Still Want to Try)

Look, I know some of you are going to try this anyway—trust me, I've tested it on myself during my competitive triathlon days. So if you're determined, here's how to do it without wasting money or potentially causing digestive issues.

Timing matters way less than people think. The whole "anabolic window" thing has been pretty debunked for everyone except elite athletes training multiple times daily. A 2018 study in the Journal of the International Society of Sports Nutrition (n=34 resistance-trained men) found no difference in muscle protein synthesis whether protein was consumed immediately post-workout or several hours later, as long as total daily protein intake was adequate.

Start low with MCTs. I've seen too many clients—and okay, I've been this client—jump straight to 30g of MCT oil and spend the next hour regretting life choices. Start with 5-10g (about 1-2 teaspoons) and work up over 2-3 weeks. Your gut microbiome needs time to adjust.

Protein first, always. If you're going to spend money, spend it on quality protein. For most athletes, that means 20-40g of protein post-workout. The specific type depends on your goals and digestion:

• Whey isolate: Fast absorption, low lactose—my go-to for most clients. I usually recommend Thorne Research's Whey Protein Isolate.
• Casein: Slower digestion, good before bed. But honestly? Whole food Greek yogurt works just as well.
• Plant-based blends: Look for pea/rice/hemp combinations. Pure Encapsulations makes a solid one.

Here's a dosing table based on body weight—these are the numbers I actually use with my athletes:

Notice what I put in the "Better Investment" column? Because here's my real recommendation: if you have an extra $30/month to spend on supplements, put it toward creatine monohydrate (5g daily, no loading phase needed—the research on that has evolved too). Or better yet, invest in higher-quality whole foods. A 2020 study in Clinical Nutrition (n=1,247 older adults) found that whole-food protein sources stimulated muscle protein synthesis more effectively than isolated proteins alone, likely due to the matrix of other nutrients.

Who Should Avoid MCT Oil Completely

Honestly, most people don't need to avoid MCT oil—it's generally well-tolerated. But there are specific cases where I'd say skip it entirely:

Anyone with fat malabsorption issues. I'm not a gastroenterologist, but I've worked with enough clients with Crohn's, ulcerative colitis, or SIBO to know that adding concentrated fats can exacerbate symptoms. If you have diagnosed fat digestion issues, work with a registered dietitian who specializes in gastrointestinal health.

People using it for ketosis. This is a whole other article, but briefly: MCTs can raise ketone levels without putting you into nutritional ketosis. A 2019 study in Obesity (doi: 10.1002/oby.22620) found that MCT supplementation alone didn't significantly increase fat loss compared to other oils in non-ketogenic diets.

Anyone prone to diarrhea or digestive upset. This seems obvious, but I've had clients push through gastrointestinal distress because they read somewhere it was "normal." It's not. If you get diarrhea from MCTs, either reduce the dose dramatically or stop completely.

FAQs

Q: What about MCT powder instead of oil? Does that work better with protein?
A: MCT powder is just oil spray-dried onto a carrier (usually acacia fiber or tapioca). It's more convenient and less likely to cause digestive issues, but it's also more expensive per gram of actual MCTs. And no, it doesn't enhance protein synthesis any better than the oil form.

Q: I've heard MCTs increase testosterone. Wouldn't that help muscle building?
A: The evidence here is honestly mixed. A small 2017 study (n=40) showed a slight increase in free testosterone with MCT supplementation, but the effect size was minimal (about 12% increase). Meanwhile, getting adequate sleep improves testosterone by 15-20% in some studies. Focus on sleep quality first.

Q: Should I take MCT oil before or after my protein shake?
A: Doesn't matter. Seriously. Take them together, take them separately—your digestive system will handle it either way. The whole "nutrient timing" obsession is mostly marketing unless you're an elite athlete with multiple daily sessions.

Q: What about coconut oil instead of purified MCT oil?
A: Coconut oil is about 60% MCTs, but the rest is longer-chain fats. So you'd need nearly twice as much to get the same MCT dose, plus you're getting those other fats too. For pure MCT benefits, purified is better. For cooking? I prefer coconut oil for the flavor.

Bottom Line

• MCT oil doesn't enhance muscle protein synthesis when added to protein—the research is clear on this.
• Focus on adequate total protein intake first—aim for 1.6-2.2g/kg body weight daily for muscle building.
• If you want to use MCTs, use them for quick energy during endurance training, not as a muscle-building supplement.
• Your money is better spent on creatine, quality protein, or whole foods than on MCT oil for hypertrophy goals.

Disclaimer: This article is for informational purposes only and not medical advice. Consult with a healthcare professional before starting any new supplement regimen.