MCT Oil vs Olive Oil: Fats, Ketones and Which to Use
MCT oil vs olive oil is less a contest than a question of jobs. MCT oil is a refined supplement oil made almost entirely of medium-chain fats, mainly caprylic (C8) and capric (C10) acids, and it is the oil people take for a quick rise in blood ketones. Extra virgin olive oil is a whole food fat, dominated by the long-chain monounsaturated fat oleic acid, and it belongs in the kitchen. Each does something the other cannot. This guide sets out what is actually in each bottle, what human studies found on ketones and body weight, the digestive side effect that catches many first-time MCT users, why MCT oil is not a frying oil, and how to decide which one — or both — earns a place in your routine.
For our own oil, see our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml).
The Short Answer
- MCT oil is made of medium-chain triglycerides, mostly C8 and C10. In one classic formulation tested by Vandenberghe and colleagues in 2017, that meant 55% C8 and 35% C10; ordinary coconut oil in the same study contained only 3% C8 and 5% C10.
- Olive oil is a long-chain oil. The International Olive Council's trade standard allows oleic acid to make up 55–85% of its fatty acids.
- MCT oil reliably raises blood ketones in healthy adults; C8 is the most ketogenic of the medium-chain fats in Canadian metabolic studies. Olive oil does not produce that acute rise.
- In a 16-week trial in the American Journal of Clinical Nutrition, people on a weight-loss programme using MCT oil ended 1.67 kg lighter than those using olive oil. A 2015 meta-analysis found a smaller average difference of about half a kilogram. Neither oil is a weight-loss product.
- Digestive upset, including abdominal pain, is the side effect most associated with MCT oil, especially in larger doses or without food.
- MCT oil is not a frying oil; at least one major manufacturer advises against frying with it because of its low smoke point. Extra virgin olive oil handles ordinary home cooking well.
MCT Oil vs Olive Oil at a Glance
MCT oil is better for a fast, measurable rise in blood ketones; extra virgin olive oil is better for cooking, dressing and eating as food. MCT oil is a refined supplement made from medium-chain fats, mainly C8 and C10. Olive oil is pressed from the fruit and is mostly oleic acid. Many people who use MCT oil also cook with olive oil.
| Factor | MCT oil | Extra virgin olive oil |
|---|---|---|
| What it is | A refined oil of medium-chain triglycerides, usually made from coconut or palm kernel oil | Oil pressed mechanically from olives, unrefined |
| Main fats | Caprylic acid (C8) and capric acid (C10), both saturated | Oleic acid (a long-chain monounsaturated fat), 55–85% under the IOC standard |
| Effect on blood ketones | Raises them within hours in healthy adults | No comparable acute rise |
| Flavour | Neutral, almost tasteless | Fruity, grassy, often bitter and peppery |
| High-heat cooking | Not suitable for frying | Suitable for normal home sautéing, roasting and shallow frying |
| Common side effect | Digestive upset, especially with larger doses | None specific at normal food amounts |
| Typical use | A spoonful in coffee, a shake or a dressing | Everyday cooking, dressing and finishing food |
What MCT Oil Actually Is: C8, C10 and Where They Come From
Medium-chain triglycerides are fats built from fatty acids six to twelve carbon atoms long. A 2026 review in Nutrients by Heidt and colleagues describes how commercial MCT oil is made: caprylic (C8) and capric (C10) acids are esterified with glycerol, chemically or with enzymes, to give a high-purity oil [1]. Those fatty acids are typically obtained from coconut or palm kernel oil. It is a manufactured ingredient rather than something pressed directly from a fruit or seed.
The proportions vary by brand. The classic formulation in Vandenberghe and colleagues' 2017 study in Current Developments in Nutrition was 55% C8 and 35% C10 [2]; NOW Foods' MCT oil label lists 50% caprylic and 30% capric acid, from coconut or palm kernel oil. Some products are pure C8.
That is why MCT oil and coconut oil are not interchangeable. In the same Vandenberghe study, the coconut oil tested contained just 3% C8 and 5% C10 [2]. Most of coconut oil is lauric acid (C12), which is far less ketogenic than C8, as the studies below show. Our comparison of olive oil vs coconut oil covers the jar-of-coconut-oil side of that story.
Olive oil sits at the other end of the chain-length scale. Its main fat, oleic acid, has eighteen carbon atoms and one double bond, and extra virgin olive oil also carries polyphenols and flavour compounds that refined oils lose. Our guide to what extra virgin olive oil is explains the grade.
Why MCT Oil Raises Ketones and Olive Oil Does Not
Medium-chain fats are absorbed quickly and travel mainly through the portal vein straight to the liver, where they are broken down rapidly and some of the result is turned into ketones, as the Heidt review summarises [1]. Long-chain fats such as oleic acid take a slower route through the lymphatic system and are not converted to ketones in the same burst.
The research group of Stephen Cunnane at the Université de Sherbrooke in Canada has measured this directly. In Vandenberghe and colleagues' 2017 crossover study, nine healthy adults took two 20 ml doses of each test oil in skimmed milk; pure C8 was the most ketogenic, raising plasma ketones by a day-long average of 295 µmol/L above the milk-only control [2]. In St-Pierre and colleagues' 2019 follow-up in Frontiers in Nutrition, C8 was about three times more ketogenic than C10 and about six times more than C12, and the ketone response was roughly twice as high when the dose was taken without a meal [3].
Over longer use the effect is real but mild. Courchesne-Loyer and colleagues gave eight healthy adults on their normal diet an MCT supplement for four weeks, building from 20 g to 30 g a day in four doses; on the final study day, plasma ketones peaked at 476 µmol/L and averaged 290 µmol/L [4]. That is just below the 0.5 mmol/L (500 µmol/L) threshold Harvey and colleagues used to define nutritional ketosis [5].
Olive oil does not do this. On a ketogenic diet, any fat helps supply energy while carbohydrate is kept low, but long-chain oils do not produce MCT oil's quick rise. In Harvey and colleagues' 2018 randomised trial of 28 adults starting a ketogenic diet, those given 30 ml of MCT oil three times a day had higher beta-hydroxybutyrate than those given sunflower oil as the long-chain control [5]. Whether that rise does anything useful for a healthy person is a separate, largely open question.
What the Weight Studies Found
The study most people mean when they search this comparison is St-Onge and Bosarge's 2008 trial in the American Journal of Clinical Nutrition [6]. Forty-nine overweight adults followed a 16-week weight-loss programme with weekly counselling and took 18–24 g a day of either MCT oil or olive oil; 31 completed it. The MCT group finished with a body weight 1.67 kg lower than the olive oil group.
That result deserves both its due and its limits. It was a small trial with substantial drop-out, the difference was modest, and everyone was also following a calorie-controlled programme. A companion paper from the same trial, in the Journal of the American College of Nutrition, reported that MCT oil did not worsen metabolic risk factors compared with olive oil [7] — a fair point in MCT oil's favour, since it is a saturated fat.
The wider evidence points the same way, only more gently. Mumme and Stonehouse's 2015 meta-analysis in the Journal of the Academy of Nutrition and Dietetics pooled 13 randomised trials with 749 participants that compared MCTs with long-chain fats; MCTs reduced body weight by an average of 0.51 kg [8]. The authors called the effect potentially modest and asked for larger, independent studies.
The honest reading: swapping some long-chain fat for MCT oil may make a small difference within a weight-loss diet. It is not a fat-burning product, and olive oil is not fattening by comparison — both supply energy, and adding either on top of your usual diet simply adds calories.
The Side Effect to Know About: Digestive Upset
The most commonly reported downside of MCT oil is digestive. In Harvey and colleagues' 2018 trial, abdominal pain occurred more often and more severely in the group taking 30 ml of MCT oil three times a day than in the sunflower oil group [5]. NOW Foods' MCT oil label carries a plain caution: MCT oil "may cause GI upset", and taking it with food reduces the effect.
Dose and pace seem to matter. In the Courchesne-Loyer study, a supplement built up gradually from 20 g to 30 g a day, split across four doses, was reported as having no side effects in eight healthy adults [4]. The practical lesson from both studies is to start with a teaspoon, take it with food, and increase slowly if you choose to use it at all.
If you have a digestive condition, are pregnant or breastfeeding, or take regular medication, speak to a qualified medical professional before adding MCT oil to your routine.
Cooking: Why MCT Oil Stays Off the Hob
MCT oil is sold as a supplement oil, and it is not designed for high heat. NOW Foods says its MCT oil is "not recommended for use in frying due to low smoke point", while noting it can stand in for other oils in dressings and sauces. Its neutral taste also adds nothing to a dish.
Extra virgin olive oil is a genuine cooking oil. Its mostly monounsaturated fat is relatively stable when heated, and it copes comfortably with sautéing, roasting and shallow frying at home temperatures. Our article on olive oil at high heat explains why the old warning against cooking with it does not hold up, and our guide to the healthiest cooking oil sets it beside the other common oils.
The two sit comfortably side by side. MCT oil goes into a drink, a shake or a cold dressing; olive oil goes into the pan and onto the plate.
Which to Use, and When
For most kitchens the question is not either-or. The table matches each oil to the job it does well.
| What you want | Better pick | Why |
|---|---|---|
| A quick, measurable rise in blood ketones | MCT oil, especially C8-rich | C8 was the most ketogenic fat tested in human metabolic studies |
| Sautéing, roasting, shallow frying | Extra virgin olive oil | Copes with home cooking heat; MCT oil is not for frying |
| Salad dressings and finishing | Extra virgin olive oil | Brings flavour and polyphenols; MCT oil is tasteless |
| A neutral fat in coffee or a shake | MCT oil | No flavour, mixes in easily; start small |
| A fruity, peppery coffee | Extra virgin olive oil | A flavour choice rather than a ketone one |
| The everyday fat in a Mediterranean-style diet | Extra virgin olive oil | The fat studied in the PREDIMED trial |
If coffee is where the comparison started for you, our guide to olive oil in coffee covers the olive oil version, method and all. For the olive oil itself, the grade matters more than the brand: look for "extra virgin", a named origin, dark glass and a harvest or best-before date. For a fuller walkthrough, see our guide to choosing a quality olive oil.
Three Fair Objections
"MCT oil beat olive oil in the weight trial, so why use olive oil?" Because they do different jobs. The 2008 trial found a modest difference within a supervised weight-loss programme [6]; it did not test cooking, flavour or a long-term diet. Olive oil's own evidence comes from a different question: in the PREDIMED trial (Estruch and colleagues, New England Journal of Medicine, 2018), 7,447 Spanish adults at high cardiovascular risk followed a Mediterranean diet supplemented with extra virgin olive oil or nuts, or a reduced-fat diet [9]. That was a whole dietary pattern, not a single oil, and neither trial makes either oil a medicine.
"MCT oil is a saturated fat — isn't that a problem?" Chain length matters. In the companion analysis of the 2008 trial, MCT oil did not adversely affect metabolic risk factors compared with olive oil [7], and the meta-analysis found no adverse effect on blood lipids [8]. The trials were short, though, so this is reassurance rather than a long-term verdict.
"Do I need ketones at all?" Probably not, unless you are following a ketogenic diet or have a specific reason to. Raising ketones is a measurable effect, not a health outcome in itself. Ketogenic diets used for medical conditions are run under specialist supervision.
Why Sidr & Stone
We should be clear about our position: we grow and sell olive oil, not MCT oil — which is exactly why this article gives MCT oil its due on ketones. Our oil is for the pan, the salad and the bread. Sidr & Stone's Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) is pressed from olives grown on our own family-owned farm on the plains outside Marrakech, Morocco.
- Single-estate — Sidr & Stone's olive oil comes from our own family-owned farm near Marrakech, and we control every step from tree to bottle, with no blending across origins.
- Rain-fed — our trees are not irrigated; they take what the season gives.
- Organically grown — no synthetic fertilisers, pesticides or herbicides are used (not yet certified; certification is in progress).
- Single harvest — a small, limited batch, picked when the fruit is ready; the current batch's harvest details are on the product page.
- Cold-pressed within hours of harvest — mechanical extraction only, with no solvents, refining or deodorising.
- Unfiltered extra virgin — minimally processed, so it may show natural sediment, which is normal.
- 100% natural — a single ingredient, olive oil, with nothing added.
- Dark glass with a gold label — protective packaging against light.
- 10% of profits to charity — a brand-wide Sidr & Stone commitment.
- Fulfilment in the UK, EU, and US.
We will not tell you our oil is better than MCT oil — for raising ketones it is not, and that would be the kind of claim this article warns against. What we will say is that it is single-estate Moroccan, rain-fed, organically grown and cold-pressed within hours of harvest: an unrefined extra virgin oil that tastes of something on the food you cook every day.
Frequently Asked Questions
Is MCT oil better than olive oil?
It depends on the job. MCT oil raises blood ketones quickly and may make a small difference within a weight-loss diet; extra virgin olive oil is the better oil for cooking, dressing and everyday eating, and it is the fat studied in the PREDIMED trial.
Why does MCT oil produce ketones?
Medium-chain fats are absorbed quickly and go mainly to the liver, which breaks them down fast and turns part of them into ketones. C8 is the most ketogenic; C10 and C12 produce smaller rises.
How do I choose a good MCT oil?
Read the label for the C8 and C10 percentages and the source oil. Products differ: some are a C8–C10 blend, some are pure C8. Start with a teaspoon taken with food.
Can I cook with MCT oil?
Not at high heat. At least one major manufacturer, NOW Foods, says its MCT oil is not recommended for frying because of its low smoke point. Use it in drinks, shakes or cold dressings, and cook with olive oil.
How does Sidr & Stone's olive oil compare with MCT oil?
They do different jobs. Ours is a single-estate, unfiltered extra virgin olive oil for cooking and eating; it will not raise blood ketones the way MCT oil does, and it is not sold for that purpose.
Is coconut oil the same as MCT oil?
No. In a 2017 study, the coconut oil tested contained only 3% C8 and 5% C10, while the classic MCT oil was 55% C8 and 35% C10. Most coconut oil is lauric acid (C12), which raises ketones far less.
Where can I buy single-estate extra virgin olive oil?
Look for a producer that names one farm and one origin and bottles in dark glass. Ours is available to pre-order from our limited single-harvest batch, with fulfilment in the UK, EU, and US.
Is olive oil a medicine?
No. Olive oil is a food, not a medicine. It has a long traditional history — including being honoured in the Prophetic Sunnah — and a substantial body of modern research, particularly around polyphenols, cardiovascular health, and the Mediterranean diet pattern. It can be a worthwhile part of a healthy routine, but it does not cure diseases and is not a substitute for medical care. Be cautious of any olive oil marketed with specific disease-cure claims.
Final Thoughts
MCT oil and olive oil are both fats, but they answer different questions. MCT oil is a refined supplement oil that does one thing well: it raises blood ketones quickly, with C8 doing most of the work. Its weight-loss evidence is modest, and its common side effect is a sore stomach if you rush the dose.
Extra virgin olive oil is food. It cooks, it dresses, it tastes of the fruit it came from, and it is the fat at the centre of the Mediterranean diet research. If ketones matter to you, MCT oil has a place; for everything you cook, olive oil is the oil to reach for.
Our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) — rain-fed, organically grown and unfiltered — is available to pre-order now from our limited single-harvest batch, with fulfilment in the UK, EU, and US.
Our extra virgin olive oil is grown organically on our own single-estate farm on the plains outside Marrakech: we control every step from tree to bottle, and no synthetic pesticides, herbicides or fertilisers are used. It is not yet certified organic — certification is in progress, and we will publish it as soon as it comes through.
References
- Heidt C, Oertling H, Abramowicz M, Otsubo Y, Tokunaga S, Tsujino S. Medium-Chain Triglycerides: Scientific and Regulatory Perspectives from Germany and Japan with a US Context-A Concise Review. Nutrients. 2026;18(7):1027. doi:10.3390/nu18071027. PMID 41978079
- Vandenberghe C, St-Pierre V, Pierotti T, Fortier M, Castellano CA, Cunnane SC. Tricaprylin Alone Increases Plasma Ketone Response More Than Coconut Oil or Other Medium-Chain Triglycerides: An Acute Crossover Study in Healthy Adults. Curr Dev Nutr. 2017;1(4):e000257. doi:10.3945/cdn.116.000257. PMID 29955698
- St-Pierre V, Vandenberghe C, Lowry CM, Fortier M, Castellano CA, Wagner R, Cunnane SC. Plasma Ketone and Medium Chain Fatty Acid Response in Humans Consuming Different Medium Chain Triglycerides During a Metabolic Study Day. Front Nutr. 2019;6:46. doi:10.3389/fnut.2019.00046. PMID 31058159
- Courchesne-Loyer A, Fortier M, Tremblay-Mercier J, Chouinard-Watkins R, Roy M, Nugent S, Castellano CA, Cunnane SC. Stimulation of mild, sustained ketonemia by medium-chain triacylglycerols in healthy humans: estimated potential contribution to brain energy metabolism. Nutrition. 2013;29(4):635-640. doi:10.1016/j.nut.2012.09.009. PMID 23274095
- Harvey CJDC, Schofield GM, Williden M, McQuillan JA. The Effect of Medium Chain Triglycerides on Time to Nutritional Ketosis and Symptoms of Keto-Induction in Healthy Adults: A Randomised Controlled Clinical Trial. J Nutr Metab. 2018;2018:2630565. doi:10.1155/2018/2630565. PMID 29951312
- St-Onge MP, Bosarge A. Weight-loss diet that includes consumption of medium-chain triacylglycerol oil leads to a greater rate of weight and fat mass loss than does olive oil. Am J Clin Nutr. 2008;87(3):621-626. doi:10.1093/ajcn/87.3.621. PMID 18326600
- St-Onge MP, Bosarge A, Goree LL, Darnell B. Medium chain triglyceride oil consumption as part of a weight loss diet does not lead to an adverse metabolic profile when compared to olive oil. J Am Coll Nutr. 2008;27(5):547-552. doi:10.1080/07315724.2008.10719737. PMID 18845704
- Mumme K, Stonehouse W. Effects of medium-chain triglycerides on weight loss and body composition: a meta-analysis of randomized controlled trials. J Acad Nutr Diet. 2015;115(2):249-263. doi:10.1016/j.jand.2014.10.022. PMID 25636220
- Estruch R, Ros E, Salas-Salvadó J, et al.; PREDIMED Study Investigators. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med. 2018;378(25):e34. doi:10.1056/NEJMoa1800389. PMID 29897866
Disclaimer: This article compares MCT oil and olive oil using published research, manufacturer guidance and the International Olive Council's trade standard available at the time of writing; research findings and product formulations may change, and readers should check current sources. References to NOW Foods describe its published product guidance and are not affiliated with or endorsed by NOW Foods. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.