Why do I get muscle cramps on Ozempic?

Muscle cramps on a GLP-1 medication are most likely caused by electrolyte depletion — particularly magnesium. Eating significantly less means taking in less magnesium, potassium, and sodium from food. Magnesium is directly involved in muscle contraction and relaxation, and low levels are a well-documented cause of cramping.

Does magnesium help with GLP-1 muscle cramps?

Magnesium is directly involved in muscle contraction and relaxation, and deficiency is a well-documented cause of muscle cramps. Supplementing magnesium when dietary intake is reduced from eating less has a plausible mechanistic basis. Talk to your clinician about the right dose and form for you.

What electrolytes should I take on a GLP-1?

Magnesium, potassium, and sodium are the three electrolytes most likely to be depleted when eating significantly less. Magnesium and potassium come predominantly from plant foods; sodium comes from salt and processed foods. Eating more leafy greens, nuts, seeds, and staying adequately hydrated helps. An electrolyte supplement can fill gaps that food alone cannot bridge on a low-appetite day.

Are muscle cramps a serious side effect of GLP-1 medications?

Muscle cramps are typically not serious, but they indicate an electrolyte or dehydration issue worth addressing. If cramps are severe, frequent, or accompanied by other symptoms, contact your clinician. They can arrange blood tests to check electrolyte levels if needed.

GLP-1 articles · GLP-1 & weight-loss medications

GLP-1 and Muscle Cramps: The Magnesium and Electrolyte Angle

Muscle cramps on a GLP-1 medication are usually a sign that electrolyte levels — particularly magnesium — have dropped. When you eat significantly less, you take in less magnesium, sodium, and potassium from food. Replacing them is usually straightforward once you know what's missing.

Jonathan Meagher · 28 June 2026 · 5 min read

Educational information only. This article does not diagnose, treat, cure or prevent any condition and is not medical advice. Whether a weight-loss medication is right for you, and decisions about starting, stopping or adjusting it, are a matter for you and your qualified healthcare professional.

Why do GLP-1 medications cause muscle cramps?

GLP-1 medications don't directly cause muscle cramps. What they do cause is significant appetite suppression — and eating much less is the proximate cause of the cramping most people experience.

When food intake drops substantially, several things happen: total calorie intake falls, and with it, the dietary intake of nearly every micronutrient and electrolyte. Magnesium, potassium, and sodium — the three electrolytes most important for muscle function — all come predominantly from food. Less food means less of all three.

What role does magnesium play?

Magnesium is directly involved in muscle contraction and relaxation. At the cellular level, muscle fibres require adequate magnesium to properly relax after contracting. When magnesium levels are low, muscles are more prone to remaining contracted — which is what produces cramps.

Magnesium deficiency (or insufficiency — being in the lower range of normal) is one of the most well-documented causes of muscle cramps in the clinical literature. And dietary magnesium comes mostly from plant foods: leafy greens, nuts, seeds, whole grains, and legumes. These are foods many people eat less of when appetite is suppressed.

Which other electrolytes matter?

Potassium — works with magnesium in regulating muscle function and nerve signalling. Found in high amounts in bananas, potatoes, leafy greens, and legumes — all foods that may drop off when eating less overall.
Sodium — regulates fluid balance and nerve function. While most Western diets have adequate sodium, eating very little processed or salted food may reduce intake. Dehydration compounds sodium imbalance.
Hydration — dehydration worsens cramping independently of electrolyte levels and also reduces the body's ability to use the electrolytes it does have effectively.

What practical steps help muscle cramps?

Prioritise magnesium-rich foods: leafy greens (spinach, kale), nuts (almonds, cashews), seeds (pumpkin seeds, sunflower seeds), legumes
Consider a magnesium supplement — glycinate and malate forms are generally well-tolerated; talk to your clinician about dose
Use an electrolyte supplement that includes magnesium, potassium, and sodium on low-appetite days when food intake is particularly restricted
Stay well-hydrated — actively drink water throughout the day rather than relying on thirst signals, which may be dampened when eating less
Include a banana or potato at some point daily — useful, accessible sources of potassium

When should I speak to my clinician?

Most GLP-1-related muscle cramps respond well to the above. Contact your clinician if:

Cramps are severe or happening very frequently
They're accompanied by weakness, fatigue, or other symptoms
They don't improve after addressing electrolytes and hydration

Your clinician can arrange blood tests to check electrolyte levels directly if there's concern about deficiency. Don't self-diagnose or self-treat significant symptoms without professional assessment.