Important distinction:

Likely electrolyte-related (supplement and monitor): Occasional skipped beats, brief fluttering, palpitations that come and go and correlate with dehydration/fasting periods.

See your doctor soon: Frequent palpitations (multiple times daily), palpitations that last more than a few seconds, associated lightheadedness or near-fainting.

Go to ER: Sustained rapid heartbeat, chest pain, actual fainting, shortness of breath with palpitations.

If your palpitations resolve with electrolyte supplementation within a week or two, it was very likely an electrolyte issue. If they persist despite adequate supplementation, get an ECG to rule out other causes. Don't mess around with cardiac symptoms.

Adding an exercise perspective — if you're working out on GLP-1 meds, your electrolyte needs are even higher. I run 30-40km per week and I go through 2-3 LMNT packets on running days plus a separate magnesium supplement. Before I figured out the electrolyte thing, I was bonking on every run and thought the medication was killing my fitness.

Nope. I was just chronically under-salted. Bumped up sodium and it was like flipping a switch. Performance came back immediately.

Point being: the general population guidelines for sodium are for people eating 2000+ calories of standard (already salty) food. If you're on GLP-1 eating 1200 calories of whole foods and exercising, you probably need to actively add salt. Counterintuitive but true.

UPDATE: It's been 5 days on the DIY electrolyte drink (morning) + 400mg magnesium glycinate (bedtime). The leg cramps are GONE. Completely. Haven't had a single one since day 3. The palpitations have reduced significantly too — had one brief episode yesterday but nothing like before.

Total cost: about £15 for supplies that will last months. you're a legend. Feeling so much better. This should honestly be standard advice given with every GLP-1 prescription. 🙏