Electrolytes on GLP-1 Medications: The Complete Guide
How much sodium, potassium, and magnesium you need on Ozempic, Wegovy, Mounjaro, or Zepbound — and how low electrolytes cause fatigue, cramps, headaches, and dizziness.
Key takeaways
- Aim for 2,000–4,000 mg sodium, 2,500–3,500 mg potassium, and 320–420 mg magnesium daily on a GLP-1.
- Low sodium — not dehydration alone — is the most common cause of GLP-1 fatigue and lightheadedness.
- Leg cramps at night almost always mean magnesium and potassium are low.
- Plain water without electrolytes can make symptoms worse by diluting what little sodium you have left.
- One electrolyte serving in the morning and one in the afternoon covers most people.
Most of the fatigue, headaches, dizziness, and leg cramps people blame on their GLP-1 medication are actually electrolyte problems. When you eat 30–50% less food, you also take in dramatically less sodium, potassium, and magnesium — the three minerals that regulate fluid balance, nerve signalling, and muscle contraction.
This guide covers exactly how many milligrams of each electrolyte you need per day on a GLP-1, the symptoms of running low, and how to build a simple daily routine that keeps your energy steady.
Why GLP-1 medications drain electrolytes
GLP-1 receptor agonists reduce appetite and slow gastric emptying. Eating less food means eating less salt, less potassium-rich produce, and fewer magnesium-rich whole grains, nuts, and greens. At the same time, many people deliberately increase water intake — which flushes even more sodium out through the kidneys.
Add in occasional nausea, vomiting, or diarrhea during dose escalation and the deficit compounds quickly. Electrolyte depletion is cumulative: it builds over weeks, which is why so many people feel fine for a month and then hit a wall.
Daily targets for each electrolyte
- Sodium — 2,000–4,000 mg per day; more if you sweat heavily or train
- Potassium — 2,500–3,500 mg per day from food plus supplementation
- Magnesium — 320 mg (women) to 420 mg (men); glycinate for sleep, citrate for constipation
- Chloride — comes along with sodium; no separate target needed
- Calcium — 1,000–1,200 mg per day, especially important during rapid weight loss
Symptoms of low electrolytes on a GLP-1
- Afternoon fatigue that coffee does not fix
- Lightheadedness when standing up quickly
- Headaches, especially in the first 48 hours after an injection
- Night-time leg cramps or eyelid twitching
- Heart palpitations or a racing pulse at rest
- Brain fog and poor exercise tolerance
How to time electrolytes through the day
Split your intake. One serving with breakfast primes fluid balance for the day; a second in the early afternoon prevents the classic 3 pm crash. If you exercise, add a third serving during or right after training.
Magnesium is the exception — take it at night. Magnesium glycinate 200–400 mg roughly an hour before bed supports sleep quality and relaxes muscles; magnesium citrate at the same time also helps with constipation.
Food sources that make it easier
- Sodium — broth, pickles, olives, salted cottage cheese, lightly salted meals
- Potassium — avocado, potato, white beans, salmon, spinach, banana, coconut water
- Magnesium — pumpkin seeds, almonds, dark chocolate, black beans, leafy greens
- Calcium — Greek yogurt, cheese, fortified milk alternatives, sardines
Frequently asked questions
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