Electrolytes on Keto: Sodium, Potassium and Magnesium Explained
Electrolytes matter more on keto because lower insulin makes your kidneys excrete more sodium, and potassium and magnesium follow. Replacing the three key electrolytes — sodium, potassium and magnesium — is the single most effective way to prevent keto flu, cramps, fatigue and headaches. Most people need more salt than they expect, plenty of potassium-rich whole foods, and often a magnesium supplement.
Why keto depletes electrolytes
On a higher-carb diet, elevated insulin signals the kidneys to retain sodium. When you cut carbs, insulin falls and the kidneys release more sodium and water — which is why the scale drops quickly in the first week, but also why you can feel rough.
As sodium leaves, the body shifts potassium and magnesium balance too. The shortfall in all three is what drives the classic early symptoms: headaches, muscle cramps, light-headedness and low energy.
How much of each you need
Sodium: many keto-adapted people aim for around 3,000–5,000mg of sodium a day — noticeably more than standard advice — by salting food generously and sipping salted water. Adjust down if you have high blood pressure or take medication, and check with your doctor.
Potassium: roughly 3,000–4,000mg a day from food. Avocado, spinach, salmon, mushrooms and courgette are excellent keto sources. Be cautious with potassium supplements, which can be risky in large doses.
Magnesium: many people fall short even off keto. Aim for around 300–400mg a day from leafy greens, nuts and seeds, and consider a supplement such as magnesium glycinate or citrate, taken in the evening to aid sleep and reduce cramps.
How to get them in
Lead with food: a daily avocado, a big serving of leafy greens, oily fish, nuts and seeds covers a lot of ground for potassium and magnesium. Then add salt deliberately to meals and water for sodium.
A simple electrolyte drink — water with a quarter-teaspoon of salt, a squeeze of lemon and a magnesium supplement — works well during the first week and around training. Choose unsweetened or stevia-sweetened mixes rather than sugary sports drinks.
Keto Club reminds you to keep sodium, potassium and magnesium up — especially in the adaptation window and around COREFit sessions — so the most common cause of feeling flat on keto is handled before it starts.
Frequently asked
Why am I so tired on keto?
Fatigue early on keto is most often an electrolyte shortfall, especially sodium. Salt your food, drink salted water, and eat potassium- and magnesium-rich foods like avocado and leafy greens. Energy usually returns within a few days.
Do I need electrolyte supplements on keto?
You can get most electrolytes from food, but many people benefit from added salt for sodium and a magnesium supplement, since magnesium is hard to get enough of from diet alone. Be cautious with potassium supplements and prefer food sources.
Can too much salt be a problem on keto?
For most healthy people the higher salt intake on keto is well tolerated because so much is being excreted. If you have high blood pressure, kidney issues or take related medication, talk to your doctor before increasing sodium.