If you’re familiar with the ketogenic diet or if you want to reduce the odds that the fat that you consume is stored as body fat, there’s a good chance you’ve heard about medium-chain triglyceride oils, also known as “MCTs.” They’re called “medium chain” because the tails of the carbon atoms aren’t as long as most fats, which means the fat digests much more quickly and easily than, say, olive oil.
This also means the fat is more readily converted to ketones. This is good news because evidence suggests that MCT oils can help you get into ketosis, the state in which the body burns fat for energy instead of glucose, which can be ideal for people who are looking to lean out. They might also improve digestive health, mental acuity, and athletic performance. With so many potential benefits to MCT oils, it’s no surprise that there are a multitude of options out there today. We did the research to help you find the best MCT oils on the market — these are our favorites.
Best MCT Oils
- Best MCT Oil Overall: BUBS Naturals MCT Oil Powder
- Best MCT Oil for Weight Loss: KOS Organic Coconut Milk Powder
- Best MCT Oil for Keto: Onnit MCT Oil
- Best MCT Oil Powder: BUBS Naturals MCT Oil Stick Packs
- Best Budget MCT Oil: Sports Research MCT Oil
- Best MCT Oil for Energy: Onnit MCT Oil
- Best Organic MCT Oil: KOS Organic Coconut Milk Powder
- Best MCT Oil Capsules: Zeal Naturals Pure MCT Oil Capsules
Editor’s note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. The opinions and articles on this site are not intended to diagnose, prevent, and/or treat health problems. It’s always a good idea to talk to your doctor before beginning a new fitness, nutritional, and/or supplement routine. Individual needs for vitamins and minerals will vary.
Best MCT Oil Overall
Picking the best MCT oil is difficult since there are so many similarities between many brands. This one stood out above the rest for its straightforward approach, great taste, and how easy it is to incorporate into your daily routine.
BUBS Naturals MCT Oil Powder
BUBS Naturals is known for making high-quality, convenient supplements, and its MCT oil powder is right on the money. We like that the ingredients list is only two items long — coconut oil plus starch to prevent clumping. You can easily mix the unflavored powder into your coffee or throw it in your protein shake for a rich texture.
BUBS Naturals MCT Oil uses a mix of coconut oil and tapioca starch to create a powder that is flavorless, mixes easily with hot and cold drinks, and provides 7 grams of fat per serving.
Our tester has been using BUBS Naturals MCT Oil Powder for months as part of their morning coffee routine, and they noted that it mixes seamlessly with zero clumping, and while it’s flavorless, it adds a creamy texture and light sweetness to coffee, eliminating the need for adding cream or sugar. While it’s on the pricier end of the MCT oil spectrum, this keto- and paleo-friendly powder mixes and tastes the best out of the bunch.
Specs
- Calories: 70 calories
- Fat: 7 grams
- MCT Source: Coconut Oil
- Servings Per Container: 30
- Price: $37
Pros
- BUBS Naturals uses 100 percent virgin pressed coconut oil rather than palm oil or another source for the MCTs.
- This powder mixes easily with any beverage, hot or cold.
- This MCT powder has zero aftertaste and doesn’t affect the flavor of anything you mix it into.
Cons
- This only comes in powder form, so if you want capsules or liquid, this isn’t the one for you.
- The price is a little higher than some other MCT oil powders.
This might be a bit more pricey than some other powders, but we like the simple formula and quality of ingredients. Plus, this powder easily mixes with just about any drink, making it easy to stay on track with a daily regimen.
Best MCT Oil for Weight Loss
Many people use MCT oil for weight loss because it helps them feel fuller, can potentially stimulate the release of appetite control hormones, and can help the body achieve and maintain a state of ketosis. (1) KOS’s organic formula is our favorite for weight loss because of its low calorie count.
KOS Organic Coconut Milk Powder
You’ll find that many MCT oils have a ton of calories, which makes sense because they’re essentially pure fat, and fat has nearly double the calories per gram compared to protein and carbs. However, KOS Organic Coconut Milk Powder has only 15 calories per serving, though each scoop only provides just under two grams of MCT. This works well because you may need to take this several times throughout the day to aid in appetite control.
KOS Organic Coconut Milk Powder is derived from organic coconut milk and has only two grams of fat and 15 calories, making it a great choice for calorie counters.
While a balanced diet is important and calories aren’t the end-all to weight management, it’s easier to balance your intake when each serving is only 15 calories compared to 70 or 100. We should mention that there are no additives in this MCT oil, which means you may experience some powder clumping in the package, so make sure you store it properly.
Specs
- Calories: 15 calories
- Fat: 2 grams
- MCT Source: Organic Coconut Milk
- Servings: 179
- Price: $22.97
Pros
- The only ingredient in this powder is organic coconut milk, without any additives or preservatives.
- This is vegan, keto, and paleo-friendly.
- There are 179 servings per container, making this option very cost-effective.
Cons
- People have commented that the formula clumps because there are no preservatives or anti-coagulants in the formula, so be sure to store it in a cool, dry place.
- It only has 2 grams of fat, which may not be as effective in decreasing appetite as brands with higher amounts.
KOS’s low-calorie formula makes it easy to take multiple servings of MCT oils per day to potentially help curb appetite when dieting. (1) Just be sure to invest in a frother since this powder may not mix very well. Luckily, that should be no problem with the money you’ll save from this low-cost formula.
[Related: The Best Types Of Supplements For Performance, Weight Loss, And Health]
Best MCT Oil for Keto
Keto diets have been medically advised for years to help people with epilepsy, diabetes, and even acne. (2) But many people also follow a keto diet to aid in weight loss as well. No matter the reason, Onnit MCT Oil provides a high dose of MCTs and is keto-friendly, so it won’t throw your diet off track.
Onnit MCT Oil
Each serving of this 100 percent pure coconut oil provides 12.7 grams of MCTs, which may more readily convert into ketones than other types of fats. (3) Some studies have even shown that you can remain in ketosis when taking larger doses of MCT oils with carbs, which is why we like this for keto diets since the MCT content is higher than many other options on the market.
With 14 grams of fat, Onnit's MCT Oil provides a higher dose than many other brands. Plus, a third of that is caprylic acid, which breaks down faster than other types of MCTs.
This oil also includes caprylic acid, an MCT oil which breaks down even faster than other types of MCT), which may help the body achieve ketosis more quickly. (3) Our testers noted that the taste might not be the best, but we recommend diluting this in a drink to tamp down the bitterness. But the high MCT oil content per serving and its ability to break down quickly makes it a solid option for those on a keto diet.
Specs
- Calories: 130 calories
- Fat: 14 grams
- MCT Source: 100-percent pure coconut oil
- Servings: 47
- Price: $24.95
Pros
- This has a very high MCT (12.7g) and caprylic acid (5.2g) content, which might help you stay in ketosis or get there quicker.
- With 47 servings per container, this is a fairly cost-effective MCT oil.
- Its liquid form makes it easy to use this instead of olive oil or other cooking oils to increase your MCT intake.
Cons
- Since this is an oil, it may not mix as well as powders, specifically with cold beverages.
- It has a noticeable bitter taste, which may be too much for some people.
MCT oils are synonymous with keto diets because of how much more readily they convert to ketones than other fats (3). Onnit brings the noise with a big dose of highly ketogenic MCTs, which may help you maintain or more quickly reach ketosis.
[Related: Intermittent Fasting 101: A Guide to Benefits, Muscle Gain, And More]
Best MCT Oil Powder
MCT oil powders are a great addition to coffee to make your morning Joe more decadent and rich. Adding an MCT powder to your supplement lineup makes it easy to toss into just about anything you’re drinking, and BUBS Naturals MCT Oil Stick Packs are our favorite because of their convenience and easy mixability.
BUBS Naturals MCT Oil Stick Packs
Thanks to the added starch to prevent clumping, this MCT oil powder is easy to use in most liquids, even cold beverages, which are notoriously difficult to mix MCT powder into. We like to use a frother, which BUBS Naturals also has on their website, for an even creamier texture when mixing it with coffee. This powder also comes in individual servings, which makes it convenient to take on the go.
BUBS Naturals MCT Oil uses a mix of coconut oil and tapioca starch to create a powder that is flavorless, mixes easily with hot and cold drinks, and provides 7 grams of fat per serving.
During testing, BUBS MCT oil added richness and creaminess to our hot beverages and smoothies with zero bitter taste, which made it a pleasure to take instead of a chore. The only downside is that the price per serving for the individual packets is higher than other powder options. But if you tend to take your MCT oil on the go, it’s worth the added cost.
Specs
- Calories: 70 calories
- Fat: 5 grams
- MCT Source: Virgin Coconut Oil
- Servings: 14
- Price: $36
Pros
- The individual packets are convenient to take with you since you can slide them into a bag or your pocket.
- BUBS Naturals only includes tapioca starch in addition to the coconut oil to prevent clumping, so there aren’t any preservatives or anything else in your powder.
- You don’t have to dig around for a scoop or measure out anything since each packet is one serving.
Cons
- You can’t cook with this powder like you would an oil.
- It’s more expensive to purchase individual packets like this than to buy a tub.
- You’re stuck with one serving size unless you add two packets, which can add up quickly.
This MCT oil powder requires no measuring, is easy to take with you on the go, and mixes well. If you don’t mind paying a little extra for the convenience of packets, this is a great option.
[Related: Best Macros Calculator For Tracking Muscle Gain And Fat Loss]
Best Budget MCT Oil
Though MCT oils aren’t usually the most expensive supplements when compared to protein powders and fat burners, there’s no reason to spend more than you have to. Sports Research Keto MCT Oil is a solid product and still cost-effective.
Sports Research Keto MCT Oil
Each serving of this 100-percent pure organic MCT oil is only about 46 cents and still packs in 14 grams of MCTs. We like that there are no additional ingredients or preservatives — the ingredients list contains organic MCT oil and nothing else. The serving size of one tablespoon is easy to portion out, though the nozzle may drip a bit, so keep a towel handy if you don’t want to get oil all over your counter.
This 100 percent organic MCT oil is loaded with 14 grams of MCTs per serving. It comes in liquid form, which makes it easy to use as cooking oil or mix into baked goods. Plus, at about $0.46 per serving, it's a great option for people working with a tight budget.
The higher amount of fat per serving also means it’s got a higher calorie count than a lot of MCT oils on this list, so if you’re trying to lose weight or you’re tracking your macros, this may not be the best option. But if you’re looking for the most MCT oil for your buck, this is a great choice.
Specs
- Calories: 130 calories
- Fat: 14 grams
- MCT Source: Organic coconut oil
- Servings: 63
- Price: $28.95
Pros
- This pure organic coconut oil-derived MCT supplement is high in caprylic acid, which absorbs faster than other MCTs.
- The large bottle has about two months’ worth of servings if you take one per day, so you don’t need to remember to order it as often.
- Since this is an oil, you can use it in cooking and baking as well as mixing it into a drink.
Cons
- The nozzle has a tendency to drip, which can get irritating.
- Since this comes in a larger bottle, it’s not convenient to take on the go or travel with.
- It’s got a higher calorie count than many MCT oils, which may not be ideal for people trying to lose weight.
Every penny counts when you’re purchasing supplements, especially ones that you may take multiple times per day, like MCT oil. This oil is cost-effective and has a high MCT oil count, which makes it a great choice for athletes working with a tight budget.
[Related: Nutrition For Bulking: 10 Tips For Intelligent Muscle Gain]
Best MCT Oil for Energy
Fats are usually known for slowing down digestion and making our digestive tract work harder to cleave the triglyceride chains. This MCT oil includes caprylic acid, which digests quickly and can be converted into energy faster than other MCT oils. (4)
Onnit MCT Oil
MCT oils have shorter molecule chains than other types of fat, which helps them digest and convert to energy more quickly. But this MCT oil is digested even more quickly since one of the MCT oils included is caprylic acid, which breaks down quicker than most MCT oils. Plus, this has 14 grams of fat, which is a higher amount than other options on this list, so you can expect a more sustained feeling of energy.
With 14 grams of fat, Onnit's MCT Oil provides a higher dose than many other brands. Plus, a third of that is caprylic acid, which breaks down faster than other types of MCTs.
If you start adding in other ingredients (like some other MCT oils do) then that may slow down digestion and provide less potent energy, so if quick energy is your primary objective, you may want to take it by the spoonful. Our testers have noted a bitter taste with this oil, so if you’re willing to wait a bit, it may be worthwhile to mix it with a beverage to cover the taste.
Specs
- Calories: 130 calories
- Fat: 14 grams
- MCT Source: 100-percent pure coconut oil
- Servings: 47
- Price: $24.95
Pros
- The 14 grams of fat in this MCT oil is a higher dose than you’ll find in many other options.
- Each serving costs around 53 cents, which makes this a fairly budget-friendly oil.
- Onnit goes a step further to refine its coconut oil so it has a higher yield of caprylic acid, which may help provide more energy in the form of ketones.
Cons
- At 130 calories per serving, this may not be the best for people who want to lose weight.
- Powdered MCT oil is usually more convenient to take with you or mix into drinks.
- This oil has a bitter taste, which may deter some people.
If you’re looking for a quick hit of energy, MCT oil is a good choice since your body can digest and convert it to energy quickly. Onnit’s MCT oil may be the fastest to digest because it includes caprylic acid, which breaks down more easily than other MCT oils, making it a great choice for those looking for a quick pick-me-up.
Best Organic MCT Oil
If you keep to a strictly organic diet, your supplements should reflect that. Many MCT oils are organic, but we like this one the best because KOS is known for using high-quality and all-natural organic ingredients.
KOS Organic Coconut Milk Powder
KOS uses only USDA Organic coconut milk to make this MCT oil powder without any other ingredients or additives, so you don’t need to worry about anything else being non-organic. This product is also produced in a Good Manufacturing Practices (GMP) certified facility, so you can be confident in the quality of the formula.
KOS Organic Coconut Milk Powder is derived from organic coconut milk and has only two grams of fat and 15 calories, making it a great choice for calorie counters.
Each serving only provides two grams of MCTs, which keeps the calorie count low — a perk for those who want to lose weight. And at about 13 cents per serving, this is a wallet-friendly option as well.
Specs
- Calories: 15 calories
- Fat: 2 grams
- MCT Source: Organic Coconut Milk
- Servings: 179
- Price: $22.97
Pros
- This MCT oil is USDA-certified organic, so you know what you’re getting is truly organic.
- There aren’t any additional ingredients aside from the MCT-rich organic coconut milk.
- This is a cost-effective product, even if you’re taking multiple servings at a time.
Cons
- This powder can clump up, so you’ll want to ensure it’s stored in a cool, dry place to minimize clumps.
- There are only two grams of fat per serving, so it may not satiate your appetite as well as MCT oils with higher fat content.
KOS produces top-quality products, and this is no exception. It’s made in a GMP-certified facility and is USDA-certified organic, so you can be confident that it only includes what is included on the label.
Best MCT Oil Capsules
If you don’t like the taste or texture of MCT oils, a capsule is a good option. It’s also generally more convenient to pop a couple of capsules instead of mixing a powder or taking a spoonful of oil, especially if you take your MCTs at the gym or office. Our favorite capsules are these pure MCT oil capsules from Zeal Naturals.
Zeal Naturals Pure MCT Oil Capsules
These soft gels deliver 3,000mg of MCTs derived from virgin coconut oil and only have 25 calories per three-capsule serving. What makes these capsules really stand out, though, is their versatility. Obviously, you can take them in capsule form if you’re on the go or in a hurry, but since the capsules dissolve quickly, it’s just as easy to drop them into a cup of coffee or tea to add some richness to your drink.
These soft gels deliver 3,000mg of MCTs and only have 25 calories per three-capsule serving. Plus, they're extremely versatile — you can take them in capsule form if you’re on the go or in a hurry, or you can easily dissolve them into hot drinks.
Since this MCT oil has a low calorie per serving, these capsules can be ideal for people trying to keep their calorie count low, and the fact that these are made in a GMP-certified facility with third-party testing means you know that the label is accurate.
Specs
- Calories: 25 calories
- Fat: 3 grams
- MCT Source: Unrefined coconut oil
- Servings: 120
- Price: $42.99
Pros
- You can take this as a capsule or dissolve the capsules in hot drinks.
- Capsules are more convenient to take with you than a big tub of powder or bottle of oil.
- The certifications and third-party testing give confidence that this has only what’s on the label in it.
Cons
- The capsules are made with gelatin, so this isn’t vegan or vegetarian-friendly.
- These are pretty big, so if you have trouble swallowing pills, they may be difficult to take.
Capsules are a more convenient way for you to take your MCT oil with you on the go. Zeal’s capsules stand out, however, because they can either be taken as capsules or dissolved in a hot drink like coffee or tea.
How We Tested and Chose the Best MCT Oil
Besides the various potential health benefits of taking MCT oils, they may be beneficial for athletes as a source of quick energy, fat loss and increased endurance. Because of its popularity (particularly in the fitness world), there are various options on the market, so we had to narrow down the field a bit. We chose the products on this list based on many factors, but the most important factors were taste, mixability, and ingredient quality.
Taste
While almost all MCT oil supplements are listed as unflavored, many still have a bitter aftertaste. We tried to select ones that either had zero taste or even enhanced a drink’s flavor by adding a dose of creaminess. Any product we included that did have any negative taste had to have some outstanding quality that made up for it, like a higher dose of MCT oil than usual.
Mixability
Unless you’re the type of person who slugs down a teaspoon of MCT oil to start your day (hats off to you), the ability to seamlessly mix your MCT oil into a drink is key.
With liquids and capsules, this isn’t an issue, but when considering powders, we leaned towards ones that mixed easily into beverages like coffee, smoothies, and tea with little to no clumping or grittiness.
Price
As a whole, supplements aren’t cheap. And if you, like most of us, are buying a stack of different supplements, every penny you can save is key. We favored MCT oils that were either easy on the wallet or, if they were on the pricier side, justified the expense with other benefits like excellent ingredients, great solubility, or a high MCT oil dosage.
[Related: The Lifter’s Guide To Magnesium: What This Nutrient Does For Strength]
How Much Does MCT Oil Cost?
The price of MCT oil is generally on the lower end of the price spectrum for supplements, but prices can vary depending on the brand. You can pick up all types — liquid, pow, and capsules — for around 50 cents per serving, with some of the higher-end brands going for over a dollar a serving.
Different Types of MCT Oil
As with most supplements, you’ll find an array of forms available. No form is better than the other, but your personal goals may affect which one you choose. For example, if you’re constantly on the go, being able to throw a bottle of MCT oil capsules in your bag may be your best option. But more on that below.
Capsules
Capsules are usually the most convenient option since they’re easy to cart around with you, and you don’t have to mix them with anything. If you’re averse to taking pills, however, these aren’t a great option. Plus, if you’re taking multiple supplements, adding another pill to your day may not be appealing to you.
Liquid
Using an MCT oil in liquid form gives you more options to seamlessly mix it into your day. You can use it as a cooking oil or blend it into hot drinks.
They do have trouble blending with cold drinks and water (you know, oil and water don’t mix), so be sure to keep those beverages hot.
Powder
An MCT oil powder may be the most versatile option. Powder generally mixes well with hot and cold drinks, it can add a creamy texture to smoothies, and you can even use it to make baked goods, pancakes, and waffles.
Benefits of MCT Oil
Whether or not you follow a keto or paleo diet, there are many potential benefits to taking MCT oil. Some possible benefits include improving exercise performance, helping you maintain gut health, and aiding in mental health.
Gut Health
Maintaining a healthy ecosystem in your gut — which houses trillions of bacteria that help you absorb nutrients, fight inflammation, and perform other roles — is important for your health. A 2016 study on obese people published in Nutrients, for example, found that MCTs improved metabolic health and energy expenditure due to their ability to “improve both intestinal ecosystem and permeability.” (5)
Mental Health
Many consider MCTs as “brain fuel,” but most of the evidence is in brains that are impaired in some way. Among the memory-impaired or people with Alzheimer’s, it’s possible that the brain processes ketones more easily than glucose, so MCTs may be useful here.
Anecdotally, a lot of people report increased mental clarity when taking ketones because ketones easily pass the blood-brain barrier. More clinical research is needed at this point.
Exercise Performance
Can they help you work out? Well, they do digest more quickly than other types of fat, so they’re more readily available as a source of fuel and less likely to be stored as fat. But some evidence also suggests that it might help to prevent a buildup of lactic acid, meaning that it may help to improve endurance in workouts.
What to Consider Before Buying MCT Oil
Because they digest quickly and readily convert into ketones, MCTs appear to reduce the symptoms of fatigue that a lot of people experience when they’re switching to a ketogenic state. (1) There’s also some evidence that adding more of them to your diet could improve gut health and athletic performance, especially if your workouts are endurance-focused. (6). So what factors are important when choosing your MCTs?
Composition of Fats
Medium-chain triglycerides are defined as having aliphatic tails of six to 12 carbon atoms — most fats are “long chain,” and the “medium chain” makes them digest more quickly. Usually, you’ll see MCTs split up on the label into capric acid (six atoms), caprylic acid (eight atoms), and lauric acid (12 atoms).
All of these count as MCTs, although since a lot of lauric acid digests more like a long-chain fatty acid, some people prefer MCTs that minimize that one.
Price
The typical price of a quality MCT oil is around $0.50 per serving. There are pricier options that have perks like seamless mixing and zero taste, and individual serving packets, but if you’re on a budget, it’s not hard to find a good MCT oil in your price range. The picks on this list range in price from a few cents per serving to over a dollar, so you should be able to find one that suits you.
Third-party Certifications
To give peace of mind to consumers, a lot of organizations get another company to test their product to ensure everything is accurately stated on the label — this way, you know for sure that you’re getting what you’re paying for.
Certifications
Who says this product is organic? Is it tested and verified as gluten-free? We checked and double-checked to make sure an independent organization has declared the product as non-GMO, organic, sustainable, or whatever else is on the label.
Final Word
You do want to make sure you get plenty of fats from fish, nuts, and other whole food sources, but there are a lot of benefits to getting more MCTs in your diet. If you’re really focused on increasing ketones, improving focus, and boosting your energy level, then one of these supplements should help you get there.
MCT oil comes in various forms, and different brands have different amounts per serving. So when you’re deciding which MCT oil is right for you, consider why you’re using it, how you want to take it, and how much you’re willing and able to spend on it. When you have those nailed down, then you can use this list to choose the best one for you.
FAQs
What makes MCT oil different from other oils?
Medium-chain triglyceride (MCT) oils are different from other oils because they digest faster than long-chain triglycerides (LCTs). This means that MCT oil is absorbed more quickly into the body to be turned into ketones, which provide energy for the brain, muscles, and organs.
What is the best MCT oil?
There are tons of options when you’re selecting which MCT oil to use. We’re big fans of BUBS Naturals MCT Oil because it blends seamlessly with hot and cold drinks and doesn’t change the taste of anything we add it to.
How much does MCT oil usually cost?
MCT oil is generally pretty cheap, costing somewhere between $0.30 and $0.50 per serving. However, some higher-quality MCT oils can cost over a dollar per serving, while you can find some budget options for as little as $0.10 per serving. The price tends to vary depending on the form the MCT oil comes in, the quality or certification of ingredients, and the amount of MCT oil contained in each serving.
References
- St-Onge, M. P., & Bosarge, A. (2008). 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. The American journal of clinical nutrition, 87(3), 621-626.
- Paoli, A., Rubini, A., Volek, J. S., & Grimaldi, K. A. (2013). Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European journal of clinical nutrition, 67(8), 789-796.
- Norgren, J., Sindi, S., Sandebring-Matton, A., Kåreholt, I., Daniilidou, M., Akenine, U., Nordin, K., Rosenborg, S., Ngandu, T., & Kivipelto, M. (2020). Ketosis After Intake of Coconut Oil and Caprylic Acid-With and Without Glucose: A Cross-Over Study in Healthy Older Adults. Frontiers in nutrition, 7, 40. https://doi.org/10.3389/fnut.2020.00040
- Nimbkar, S., Leena, M. M., Moses, J. A., & Anandharamakrishnan, C. (2022). Medium chain triglycerides (MCT): State-of-the-art on chemistry, synthesis, health benefits and applications in food industry. Comprehensive reviews in food science and food safety, 21(2), 843–867. https://doi.org/10.1111/1541-4337.12926
- Rial SA, et al. Gut Microbiota and Metabolic Health: The Potential Beneficial Effects of a Medium Chain Triglyceride Diet in Obese Individuals. Nutrients. 2016 May 12;8(5).
- Nosaka N, et al. Effect of ingestion of medium-chain triacylglycerols on moderate- and high-intensity exercise in recreational athletes. J Nutr Sci Vitaminol (Tokyo). 2009 Apr;55(2):120-5.