The ketogenic diet is a popular diet for weight loss and general health. Some supplements can improve the effectiveness of the diet, while others prevent nutrient deficiencies or ease the side effects.

The ketogenic diet, which people commonly call the keto diet, focuses on high fat foods and includes few to no carbohydrates. This approach may have several health benefits. Some evidence suggests that for some people, it may be a more effective weight loss plan in the long term than a low fat diet.

If a person eats a variety of healthful whole foods on the keto diet, they may find that they have very few, if any, nutritional deficiencies.

However, some supplements can help with the discomfort that can occur as a person’s body adjusts to a keto diet. They can also help a person get the right amount of fats in their diet.

In this article, we look at seven supplements that may be useful for people on the keto diet.

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A person on a keto diet can use supplements to fill in any nutritional gaps.

Some supplements, such as medium chain triglyceride (MCT) oil and omega-3 fatty acids, can increase the effectiveness of the keto diet and help people achieve the intended ratio of fat in their diet.

As the keto diet limits or eliminates many different foods, people who follow this diet can also use supplements to fill in any nutritional gaps. Magnesium, electrolytes, and fiber may be especially important.

Adjusting to extreme carbohydrate restriction can cause uncomfortable side effects because the body takes time to get used to making ketones and using this new source of energy.

The body usually burns carbohydrates for energy, but when a person eats few to no carbs on the keto diet, the body must get its energy from other sources. So, the body burns fat and turns it into ketones, which it can then use for energy. This process is called ketosis.

People often refer to the side effects of the diet as the “keto flu.” Those beginning this diet may experience:

Certain supplements, such as electrolytes, digestive enzymes, and L-theanine, may help minimize these symptoms.

The following supplements may be helpful for people on a keto diet:

Medium chain triglyceride oil, or MCT oil, is a type of fatty acid that occurs in coconut oil. The liver metabolizes these fats, transforming them into a source of fuel.

A 2018 study found a “clear ketogenic effect” when people took supplemental MCTs. MCTs may also help a person lose more weight, according to some research.

MCTs are not in many other foods, so taking a supplement can allow a person to get the potential benefits of these fats.

MCT oil is liquid at room temperature. People can mix it into foods or smoothies, or they can take it alone. A standard dose is 1 teaspoon. People should try this to start because a higher initial dose, such as 1 tablespoon or more, may induce diarrhea.

Magnesium is a mineral and electrolyte that is abundant in the body. The body needs magnesium for many different processes, including food metabolism, transmission of nerve signals, balance of fluids, maintenance of bone and muscle health, and more.

Although a few keto friendly foods, such as nuts and spinach, are high in magnesium, the diet is low in other magnesium rich foods, including whole grains, fruit, beans, and dairy products.

If a person is not getting adequate magnesium from foods while following the keto diet, they may need a supplement. A supplement may also be beneficial for those experiencing constipation.

Some evidence suggests that many people are at a high risk of magnesium deficiency due to chronic diseases, medications, and decreases in food crop magnesium levels.

Magnesium supplements are available in different forms. The Office of Dietary Supplements (ODS) state that the body may absorb some types — including magnesium aspartate, citrate, lactate, glycinate, and chloride forms — more readily than others. However, a doctor may recommend a specific form of magnesium to meet a person’s needs.

High doses of magnesium can cause diarrhea. Therefore, a person should start with the lowest dose on the package, which may be 100–200 milligrams (mg) per day.

If no diarrhea occurs, a person may gradually increase the dose, although they should not take more than 400 mg per day unless a doctor advises a higher dose.

As the body adjusts to a keto diet, the kidneys may excrete more water. This increased excretion can cause the body to lose vital electrolytes, which include not only magnesium but also potassium, chloride, phosphorus, and sodium.

Taking an electrolyte supplement can help rebalance the levels of these minerals. Electrolyte supplements vary in their mineral content, so it is important for a person to read labels to be sure that they are not getting too much of these minerals. Most contain a combination of calcium, potassium, and magnesium.

A keto friendly supplement should contain no sugar or sweeteners.

Alternatively, a person may wish to try adopting the following practices to get the three main electrolytes:

  • taking a magnesium supplement daily
  • adding some extra salt to the diet or consuming beef or chicken broth daily
  • eating potassium rich, keto friendly foods, such as avocado or cooked spinach, every day
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Fiber supplements may help with constipation during a keto diet.

Fiber is the indigestible part of plant foods, and it is important for keeping the digestive system healthy.

Without enough fiber, a person may become constipated. People should get 25–31 grams of fiber per day, depending on their age and sex.

Many keto friendly foods, including nuts, seeds, avocado, and leafy greens, contain fiber. However, if a person focuses on meat, seafood, eggs, and dairy, they may not get enough fiber on the keto diet.

Fiber supplements can be helpful if people find that they become constipated while following the keto diet. They should look for a keto friendly formula that does not contain sugar.

It is also important to drink plenty of water, which helps keep digestion running smoothly. Taking fiber supplements without adequate water intake could make constipation worse.

Omega-3 fats are a type of polyunsaturated fatty acid (PUFA). Omega-3s are present in high amounts in some fatty fish and eggs, and they also occur in plant form in some nuts and seeds.

Studies show that consuming enough omega-3s can have health benefits, including helping prevent weight gain. The ODS state that many people could benefit from a higher intake of omega-3s.

The other type of PUFA, omega-6, occurs in many conventionally raised, grain-fed meats. Omega-6s are also in some vegetable oils, including corn and cottonseed oil.

One study found that among people following a ketogenic Mediterranean diet, those who ate more omega-3s experienced positive effects on their insulin, triglyceride, and inflammation levels.

Omega-3 levels may be higher in meats that come from grass-fed or pasture raised animals, as well as in eggs from pasture raised or vegetarian-fed hens. If a person on the keto diet does not eat grass-fed meats or seafood, they may want to consider an omega-3 supplement.

Omega-3 supplements vary in their dosage and origin. Some come from fish oil, krill oil, algae, flaxseed, or other natural omega-3 sources. A person should follow the dosage directions on the product.

People who take medications that affect blood clotting, such as blood thinners, should ask a doctor before using omega-3 supplements. People who are allergic to fish or shellfish should avoid supplements that contain fish oil, krill oil, or other fish based ingredients.

The gut uses enzymes to break down different parts of foods during digestion. If a person who is switching to a keto diet ate a large number of carbs previously, they might find that they have trouble with the change.

Symptoms such as bloating, nausea, fatigue, and constipation are common because of the high amount of fats that a keto diet requires.

Digestive enzymes could help alleviate some of these symptoms. Many of these supplements contain several different types of enzyme, but it is important to choose one that contains lipase, which is the enzyme that breaks down fat.

Supplements that contain proteases and peptidases are also a good choice, as these break down protein.

In most cases, a person will take their digestive enzymes with a high fat meal or a few minutes before eating. They should always follow the dosage directions on the product and look for those that are keto friendly.

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L-theanine supplements may help improve sleep quality.

L-theanine is an amino acid that is difficult to obtain from foods. The only known good source of l-theanine is green or black tea, but the amounts may vary depending on the type of tea and how a person brews it.

Studies show that taking this supplement may help improve sleep quality, decrease anxiety, and improve mental cognition. As a result, it could be an excellent option if a person experiences mental fog or trouble concentrating as they transition to the keto diet.

L-theanine supplements are available in pill or powder form. There is no recommended dosage, but many products suggest 100–400 mg daily. Alternatively, people may choose to drink unsweetened tea, particularly green tea, which contains natural L-theanine.

A range of supplements can help people on a keto diet by improving the effects of the diet, preventing nutrient deficiencies, and easing some of the side effects of cutting out carbohydrates.

The keto diet has health benefits for many people, but it may not be safe or sustainable for everyone. People who have diabetes or other health conditions should ask a doctor before making any dietary changes.


People can buy most of the supplements listed above from a drugstore or a grocery store. Otherwise, they can choose from a range of brands online: