Menopause + Keto: The Electrolyte Math No One Explains

Perimenopause changes how your kidneys handle sodium. Keto changes it again. Stack the two, and the standard "just add a pinch of salt" advice isn't remotely enough. Here's the actual math, with sources — and the numbers most women over 40 need to hit to stop 3am wakeups.

What estrogen does to sodium

Estrogen boosts sodium retention through its effect on the renin-angiotensin-aldosterone system. When estrogen drops in perimenopause and menopause, your kidneys retain less sodium at the same intake. In practice, women over 40 on keto need roughly 20–40% more sodium than a 25-year-old on the same diet to end up with the same blood level.

What keto does on top of that

On a low-carb diet, insulin runs lower. Low insulin tells your kidneys to dump sodium. Studies of ketogenic diets show sodium excretion rising by around 3–5x compared to standard diets in the first weeks, and remaining elevated long-term.

Multiply the two effects together and you get the group that fills this site's inbox: menopausal women on keto who are chronically under-mineralized and don't know it.

The daily numbers

For a menopausal or perimenopausal woman on keto or carnivore, the target daily intake most readers land on:

• Sodium: 4,000–6,000 mg (roughly 1.75–2.5 teaspoons of salt, spread across the day). Yes, that's 2–3x the standard recommendation. That recommendation was written for a different population on a different diet.
• Potassium: 3,500–4,700 mg total, of which 1,000–2,000 mg from added potassium chloride (No Salt or Nu-Salt from the grocery store). The rest comes from food.
• Magnesium: 300–400 mg of magnesium glycinate, taken 30–45 minutes before bed. Glycinate absorbs and doesn't send you to the bathroom.

Why timing matters more than dose

The 3am cortisol pulse is the trigger. What determines whether it wakes you up is your electrolyte level at 3am, not your 24-hour average. That means the biggest dose of sodium and all of the magnesium should land in the second half of the day — with dinner and pre-bed. Front-loading sodium at breakfast fixes almost nothing.

Common failure modes

• You're taking magnesium citrate or oxide. Both are poorly absorbed and mostly work as laxatives. Switch to glycinate.
• You're relying on LMNT alone. One stick has 1,000mg sodium and no magnesium. Fine as part of the plan, not the whole plan. See the LMNT comparison.
• You're afraid of the sodium number. The "salt is bad" advice assumes standard carb intake and normal insulin. It does not apply here. Blood pressure typically improves on this protocol, not worsens.
• You skipped potassium. Leg cramps that persist after magnesium are almost always potassium.

The 4-night test

Run these numbers for four consecutive nights. If your 3am wakeups don't improve, it's not electrolytes and you should look elsewhere (thyroid, late alcohol, sleep apnea). If they do improve — which is the outcome for the large majority of readers — you have your baseline. Full walkthrough here: The 4-Night 3AM Fix.

The bottom line

The generic keto electrolyte advice is written for 30-year-old men. Menopausal women need roughly double the sodium, real magnesium glycinate, and added potassium — with timing weighted toward the evening. The numbers above are what actually works, in the order they actually matter.