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Do Multivitamins Affect Ketosis? (Should You Take Them)

Isaac Robertson
Published by Isaac Robertson | Co-Founder & Chief Editor
Last updated: August 6, 2023
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The ketogenic diet claims that it can help boost athletic performance and help with weight loss.

But, to achieve this, you need to go into a state of ketosis — the body burns fat for fuel, not sugar.

The big question is, how do multivitamins and supplements affect the state of ketosis? I spent hours of research and consulted our resident dietitian on the matter and here's what we found.

Quick Summary

  • Most multivitamins you purchase in pills are pure compounds, and won't affect your keto diet.
  • The best multivitamins for a keto diet are magnesium, omega-3 fatty acids, and vitamin D.
  • Avoid multivitamins that have carbs, dextrin, and maltodextrin as they might affect your ketosis.

Do Multivitamins Affect Ketosis?

pills and capsules in a yellow background

Yes, multivitamins can affect ketosis. But the effect is not as straightforward as it sounds.

To be clear, no, you don’t have to stop taking them. It’s safe to take multivitamins when on a keto diet, and they can even help reduce the effects of the keto flu.

You don’t have to worry about multivitamins having too many net carbs and kicking you out of ketosis.

Most essential vitamins and minerals you purchase in pill form are pure compounds and won’t disrupt ketosis.

“A good multivitamin will make sure you’re covering all of your bases.”

- Whitney English, RD

However, the problem is with supplements that have fillers, such as too many carbs.

Pills can have dextrin and maltodextrin, which are simple sugars. Protein powders, flavored drink supplements, and gummies can have added sugars and carbs as well.

But, even if you have some carb intake through the multivitamin you’re taking, most likely, it won’t be enough to break your fast and impact the ketosis.

This is because most supplements have small amounts of carbs.

How to Choose a Multivitamins for a Keto Diet?

woman raising up a sachet of vitamins thinking, medicine kit

A correct multivitamin will ensure your daily vitamin and mineral needs are covered and boost your health and energy levels.

Some studies show that multivitamins can even protect us from illnesses such as heart disease and different kinds of cancer, and they can lower body fat. (1)

But not all multivitamins are equal.

For example, supplement companies can make multivitamins with nutrients in an ineffective form, such as too little vitamins C, K2, and magnesium. Instead of these, risky ingredients are used, such as iron and folic acid.

These can hamper the metabolism, decrease fat oxidations, and increase hunger. By fixing these issues, you’re more likely to achieve and maintain healthy body weight.

For a healthy keto lifestyle, whole foods and unprocessed foods are the key. They will give you all the vital nutrients and correct fat intake.

But, it’s not always possible to get essential nutrients from food only, so here’s what ingredients your multivitamins should have.


magnesium food sources in an image

Magnesium is a mineral that boosts energy, supports the immune system, and regulates blood sugar levels.

It’s also important for nerve and muscle function.

So, for example, if you have muscle cramps, it may be a sign that you need a magnesium supplement, and you should supplement with magnesium citrate.

It’s estimated that 57% of Americans have a magnesium deficiency. (2)

On a ketogenic diet, it’s even more challenging to meet the magnesium needs. This is because foods rich in magnesium, such as beans and fruits, are also high in carbs.

In addition to boosting energy levels and regulating blood sugar, it also supports the immune system.

On a keto diet, you can have 500 mg of magnesium per day.

You can intake it through low carb vegetables, such as:

  • Leafy green vegetables non-starchy vegetables— such as spinach
  • Pumpkin seeds
  • Avocado
  • Nuts

Omega 3 Fatty Acids

omega 3 food sources in an image

Omega 3 fatty acid is an essential fatty acid most commonly found in cold-water fish, such as salmon, tuna, herring.

It helps regulate inflammation and support cognitive health.

For people on a keto diet, omega 3 vitamins reduce inflammation, insulin levels, and triglycerides.

So, how much omega 3 should you have? It’s recommended to eat fish three times a week.

If you don’t regularly eat fish, you can use a fish oil supplement or flaxseed oil supplement as an Omega 3 substitution.

When choosing a fish oil supplement, selecting a reputable brand that undergoes third-party testing is important to ensure purity and potency.

Additionally, be mindful of any rancid smells, as this may indicate the oil has gone bad. By incorporating fish oil into your diet, you can harness the power of omega 3 fatty acids to support your overall well-being.

Pro tip: Be careful when shopping for fish oils, as FDA doesn’t regulate most. Make sure the brand is trustworthy and that the smell isn’t rancid.

Vitamin D

scattered vitamins and a bottle of vitamins

One study claims that 50% of the world’s population has Vitamin D deficiency. (3) This can lead to:

  • Heart disease
  • Autoimmunity
  • Cancer
  • Diabetes

A ketogenic diet won’t necessarily put you into a Vitamin D deficiency, but because Vitamin D deficiency is so common, chances are you won’t hurt from Vitamin D supplementation.

Take it in the morning, and not evening, so it doesn’t affect your sleep.

Related article10 Foods That Knock You Out of Ketosis

Ketogenic Diet Multivitamins Side Effects

medical person checking a person's blood pressure

It might make sense to cover all your bases with a multivitamin. But, taking a multivitamin supplement means taking synthetic nutrients, which isn’t the same as having a healthy balance you can get from a few nutrients of natural origins.

Thinking about potential side effects before taking a vitamin supplement is important. It's not unusual for some people to experience digestive discomfort or allergic reactions when they take vitamin supplements.

Additionally, taking excessive amounts of certain vitamins can cause toxicity and adverse effects. Therefore, following recommended dosage guidelines and consulting with a healthcare professional before starting any vitamin supplement regimen is crucial.

Dietary supplements can cause issues because:

  • Taking vitamins in the wrong form is ineffective
  • Taking vitamins in the wrong amounts is ineffective and dangerous

For example, taking exogenous ketones is less effective than entering ketosis naturally, especially for fat metabolism.

In addition, taking digestive enzymes can interfere with burning fat, fluid balance and cause high blood pressure.

When it comes to nutrition, your best bet is a balanced diet, which includes healthy fats.

Another thing not to disregard is sodium intake, for steady blood pressure levels, and to avoid keto flu.

What's Your Experience With Taking Multivitamins on a Keto Diet?

Following a ketogenic diet can help you lose weight, have better insulin resistance, and a healthier digestive system. But maintaining a keto diet is a challenging task.

Vitamin and mineral supplements can help you stay in this state and secure the vitamins and minerals you need in your nutrition.

Remember: always check the multivitamin label, and avoid multivitamins that have carbs.

What's your experience with using multivitamins in a keto diet? Let me know if you experienced any benefits or side effects in the comments below.


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