Quick answer: A well-planned keto diet comes first, but some people benefit from supplements while their body adjusts. Common options include electrolytes and magnesium, omega-3 fatty acids, vitamin D if levels are low, probiotics, zinc, MCT oil, a greens powder and collagen protein. Supplements can interact with medications and conditions, so choose them with your provider.
Key takeaways
Leafy greens, avocado, nuts, seeds, fish and eggs cover many nutrient needs on keto.
Electrolytes and magnesium are the most commonly discussed supplements, since fluid and mineral losses are common early on.
People with kidney disease or on blood pressure medication need guidance, and testing nutrients such as vitamin D helps avoid guesswork.
Food first
Leafy greens, avocado, nuts, seeds, fish and eggs cover many nutrients. See keto micronutrients.
Common supplements
Electrolytes and magnesium
Fluid and mineral losses are common early on keto. See balancing electrolytes. People with kidney disease or on blood pressure medication should ask first.
Omega-3 fatty acids
Found in fatty fish; they support heart and brain health.
Vitamin D
Deficiency is common; test before supplementing.
Probiotics
Diet changes can shift the gut microbiome; fermented foods or probiotics may help digestion.
Zinc
Important for immunity and repair; meat and shellfish are good keto sources.
MCT oil, greens and collagen
MCT oil may support ketosis (start small to avoid digestive upset), greens powders add plant nutrients, and collagen adds protein.
How much?
Follow the label or your provider’s advice.
Healthy aging lens
Nutrient status, especially vitamin D, magnesium and omega-3s, supports healthy aging; testing helps avoid guesswork.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have diabetes or take insulin, sulfonylureas or SGLT2 inhibitors (risk of low blood sugar or ketoacidosis), or if you take blood pressure medication or diuretics. The same is true if you have kidney, liver, gallbladder or pancreas disease, or high cholesterol, if you are pregnant, breastfeeding, or have a history of disordered eating, or if you want a keto plan tailored to your labs and goals.
See a medical provider promptly for nausea and vomiting, abdominal pain, confusion, fruity-smelling breath with rapid breathing, or very high blood sugar or ketone readings, which can signal ketoacidosis.
What the research shows
Most keto supplement advice comes from experience rather than trials. The best description of keto flu is a 2020 study by Bostock and colleagues that reviewed 448 forum posts from 300 people. About a third described symptoms such as headache, fatigue, nausea, dizziness and brain fog, usually in the first one to two weeks, and many mentioned electrolytes as a remedy. Because these were self-reports from the internet, they cannot show how common keto flu is or whether electrolytes are what helped.
For omega-3s, more is not always better. A 2021 meta-analysis by Gencer and colleagues of seven large trials with 81,210 people found a 25% higher risk of atrial fibrillation with marine omega-3 supplements, and a 49% higher risk in trials using more than 1 gram a day. Participants were mostly older adults with heart risk factors, so the finding applies most to that group.
Vitamin D is worth checking on any diet. In national NHANES data analyzed by Forrest and Stuhldreher, 41.6% of 4,495 US adults had 25-hydroxyvitamin D at or below 20 ng/mL. Because that survey was a single snapshot, testing your own level is the best guide to whether you need a supplement.
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Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Which nutrients should we test before I add anything on keto?
Could supplements alongside a ketogenic diet interact with any of my current medications or other supplements?
Would any labs or health history details help us decide whether supplements alongside a ketogenic diet makes sense for me?
How would we tell whether supplements alongside a ketogenic diet is a good fit for me, and when should we check in again?
Frequently asked questions
Do I need supplements on keto?
Not always; food comes first, but electrolytes often help early on.
Which electrolytes matter on keto?
Sodium, potassium and magnesium.
Is MCT oil necessary?
No, but it may make ketosis easier.
Can supplements interact with medications?
Yes. Check with your provider.
Sources
- Bostock ECS, Kirkby KC, Taylor BV, et al. Consumer Reports of "Keto Flu" Associated With the Ketogenic Diet. Front Nutr 2020. PMID: 32232045. https://pubmed.ncbi.nlm.nih.gov/32232045/
- Gencer B, Djousse L, Al-Ramady OT, et al. Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. Circulation 2021. PMID: 34612056. https://pubmed.ncbi.nlm.nih.gov/34612056/
- Forrest KY, Stuhldreher WL. Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res 2011. PMID: 21310306. https://pubmed.ncbi.nlm.nih.gov/21310306/
- Swanson D, Block R, Mousa SA. Omega-3 fatty acids EPA and DHA: health benefits throughout life. Adv Nutr 2012. PMID: 22332096. https://pmc.ncbi.nlm.nih.gov/articles/PMC3262608/
- David LA, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 2014. PMID: 24336217. https://pmc.ncbi.nlm.nih.gov/articles/PMC3957428/
- Prasad AS. Zinc in human health: effect of zinc on immune cells. Mol Med 2008. PMID: 18385818. https://pmc.ncbi.nlm.nih.gov/articles/PMC2277319/
- St-Pierre V, et al. Plasma Ketone and Medium Chain Fatty Acid Response in Humans Consuming Different Medium Chain Triglycerides During a Metabolic Study Day. Front Nutr 2019. PMID: 31058159. https://pmc.ncbi.nlm.nih.gov/articles/PMC6481320/
- NIH ODS: Magnesium
- NIH ODS: Omega-3 Fatty Acids
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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