When Should You Not Take MCT Oil?

October 21, 2025 •

4 min read

According to research from WebMD, MCT oil is likely safe for most people in small doses, but can cause significant side effects at higher doses. Understanding when you should not take MCT oil is crucial for avoiding these potential risks, as its rapid absorption can be problematic for individuals with specific health conditions.

Quick Summary

This article outlines critical scenarios where MCT oil is not recommended, covering severe liver conditions, uncontrolled diabetes, certain metabolic disorders, and sensitivities that cause significant digestive upset. It provides important safety guidelines and explores potential interactions with specific medications.

Key Points

Avoid with Liver Disease: Do not take MCT oil if you have pre-existing liver conditions, as it can place an excessive metabolic burden on the organ and potentially cause further damage.
Caution with Diabetes: Individuals with uncontrolled diabetes should avoid MCT oil due to the risk of increased ketone production and complications like ketoacidosis.
Mitigate Digestive Issues: If prone to digestive upset, start with a very small dose (e.g., 1 teaspoon) and take MCT oil with food to reduce the risk of diarrhea, bloating, and cramps.
Check for Allergies: Those with allergies to coconut or palm oil must avoid MCT oil, as it is typically derived from these sources and can trigger allergic reactions.
Monitor Cholesterol: Be cautious if you have heart disease or high cholesterol, as some studies show MCT oil can increase triglycerides and affect lipid profiles.
Consult a Doctor First: Always speak with a healthcare professional before starting MCT oil, especially if you have chronic medical conditions or take other medications.

Who Should Avoid Taking MCT Oil?

While MCT oil has gained popularity for its purported health benefits, it is not suitable for everyone. Certain health conditions and physiological sensitivities can make MCT oil consumption risky or uncomfortable. Consulting a healthcare professional before adding any new supplement to your diet is always recommended, especially if you have pre-existing medical conditions.

Liver Disease

The most significant contraindication for MCT oil is liver disease. The liver is the primary organ responsible for metabolizing MCTs, and for individuals with conditions like cirrhosis, hepatitis, or fatty liver disease, the additional strain can be dangerous.

Increased burden: A compromised liver may struggle to process the concentrated fats in MCT oil, potentially exacerbating existing damage.
Hepatic damage: Studies suggest that in certain contexts, MCT oil can contribute to hepatic steatosis (fatty liver) and inflammation, even in seemingly healthy subjects when consumed in excess.
Parenteral nutrition: Special caution is advised for patients on parenteral (IV) nutrition with liver dysfunction, where excessive lipid intake, including MCTs, must be carefully managed.

Uncontrolled Diabetes

Individuals with uncontrolled diabetes, particularly those at risk for ketoacidosis, should avoid MCT oil.

Ketone production: MCTs can increase the production of ketones in the body. While this is a desired effect for those on a ketogenic diet, it can lead to complications for a diabetic person with already high ketone levels, a potentially life-threatening condition.
Fluctuating blood sugar: There is conflicting evidence regarding MCT oil's effect on blood sugar. Some studies suggest a potential benefit, while others indicate it could cause insulin response fluctuations. Given the risk, it is best to avoid it without strict medical supervision.

Digestive System Concerns

Digestive issues are the most common complaint among new MCT oil users.

Diarrhea and discomfort: The rapid absorption of MCTs can irritate the digestive tract, leading to significant gastrointestinal distress, including diarrhea, cramps, gas, and bloating. Starting with a high dose or taking it on an empty stomach drastically increases this risk.
Pre-existing conditions: People with conditions like Irritable Bowel Syndrome (IBS) or Crohn's disease may be more susceptible to these adverse effects.

Allergies and Sensitivities

Since most MCT oil is derived from coconut or palm kernel oil, individuals with known allergies to these products should avoid it. An allergic reaction can cause swelling, hives, or difficulty breathing and requires immediate medical attention.

Cardiovascular and High Cholesterol Conditions

The impact of MCT oil on cardiovascular health and cholesterol levels is complex and not fully understood.

Mixed results: Some studies suggest that MCTs can improve blood lipids, while others show increases in certain types of cholesterol.
Increased triglycerides: A systematic review found that MCT oil can cause a small but significant increase in triglycerides, a risk factor for heart disease.

Comparison Table: MCT Oil Risks by Health Condition


Health Condition	Primary Risk Factor	Key Considerations
Liver Disease	Exacerbates existing damage, potential fat accumulation in the liver.	Processing places a high burden on a compromised liver; avoid entirely.
Uncontrolled Diabetes	Increased ketone production, risk of ketoacidosis.	Requires strict medical supervision; avoid without professional guidance.
Digestive Sensitivity	Significant gastrointestinal discomfort, diarrhea.	Risk increases with high doses or consumption on an empty stomach.
Allergies to Coconut/Palm	Allergic reaction symptoms, including hives and swelling.	Check product origin and packaging carefully; avoid if allergic.
Heart Disease Risk	Potential for increased triglycerides and mixed cholesterol effects.	Long-term effects still require more research; caution is advised.

Practical Steps to Avoid Complications

For those who do not have a pre-existing medical condition that contraindicates use, following proper procedures can prevent common side effects.

Start with a Low Dose

To allow your body to adapt, begin with a very small amount, such as 1 teaspoon per day. Gradually increase the dosage over time, paying close attention to your body's response. Most studies use 1 to 5 tablespoons daily, but exceeding 4-7 tablespoons is generally not recommended due to increased gastrointestinal issues.

Take with Food

Consuming MCT oil with food helps slow its absorption and reduces the likelihood of digestive upset. Adding it to a smoothie, mixing it into a salad dressing, or taking it with a meal can make it easier on the stomach.

Monitor Your Body's Response

If you experience any adverse effects, such as persistent diarrhea or stomach pain, reduce your intake or stop taking the supplement altogether. Severe symptoms, including a serious allergic reaction, require immediate medical attention.

Conclusion

MCT oil is a potent supplement that offers potential benefits for certain individuals, but its unique metabolic pathway makes it unsuitable for others. The most critical contraindication is pre-existing liver disease, where the supplement can place a dangerous strain on the organ. Uncontrolled diabetes also poses a significant risk due to potential issues with ketone levels. For many, the most common issue is simple digestive discomfort, which is often dose-dependent and can be managed by starting slow and taking the oil with food. Before incorporating any new supplement into your regimen, especially one with known contraindications, it is essential to consult with a qualified healthcare professional. They can assess your individual health status, review your medical history, and provide personalized guidance on whether MCT oil is a safe and appropriate choice for you.

Resources

WebMD: Medium Chain Triglycerides (MCTs): A comprehensive overview of MCT uses, side effects, precautions, and safety concerns, including specific warnings for those with liver problems and diabetes.

Frequently Asked Questions

No, it is highly recommended that you do not take MCT oil if you have liver problems, such as cirrhosis or fatty liver disease. Since MCTs are processed by the liver, they can place a heavy strain on an already compromised organ, potentially causing serious complications.

Yes, MCT oil can cause significant gastrointestinal distress, most notably diarrhea. This is often a result of consuming too much too quickly, or taking it on an empty stomach. The rapid absorption can irritate the gut lining.

Individuals with uncontrolled diabetes should avoid MCT oil. Because it can cause a buildup of ketones in the body, it can be problematic for those at risk for ketoacidosis. Always consult a doctor if you have diabetes before considering MCT oil.

While often used for weight management, MCT oil is calorie-dense. Consuming it in large quantities without adjusting your overall caloric intake can lead to weight gain. Moderation is key to avoid this effect.

For many, taking MCT oil on an empty stomach can increase the risk of digestive issues like diarrhea and nausea. It is generally recommended to start with a small dose and take it with food to improve tolerance.

Since most MCT oils are derived from coconut or palm kernel oil, you should avoid MCT oil if you have an allergy to either of these ingredients. An allergic reaction could include hives, swelling, or difficulty breathing.

The effects of MCT oil on cardiovascular health are mixed. Some research indicates a potential for an increase in triglycerides, while effects on total and LDL cholesterol can vary depending on the comparative diet. Those with heart conditions should be cautious and seek medical advice.