How much magnesium should I take to help with water retention?

January 6, 2026 •

3 min read

According to the National Institutes of Health, approximately 50% of the U.S. population does not consume enough magnesium in their diet. Magnesium plays a critical role in fluid and electrolyte balance, and a deficiency can sometimes contribute to excess fluid retention or edema. While there's no single ideal amount for everyone, understanding magnesium's function provides useful context.

Quick Summary

This guide covers magnesium's role in reducing water retention, explores different types of supplements and their effectiveness, and identifies magnesium-rich foods to help restore fluid balance.

Key Points

Consider magnesium for PMS-related water retention: Research indicates magnesium supplementation may help with fluid retention associated with premenstrual symptoms.
Choose high-bioavailability forms: Magnesium citrate and glycinate are well-absorbed and may be effective for addressing fluid balance and bloating, while magnesium oxide is less bioavailable.
Boost dietary magnesium first: Focus on increasing intake through foods like spinach, pumpkin seeds, almonds, and legumes, which provide magnesium along with other vital nutrients.
Address underlying causes: Water retention can have various causes; consider reducing sodium, increasing potassium, staying hydrated, and exercising for a comprehensive approach.
Consult a healthcare professional: Before starting any magnesium supplement, speak with a doctor, especially if you have existing health conditions or take other medications.
Listen to your body: If you experience side effects like diarrhea, nausea, or abdominal cramping, consider adjusting your intake or trying a different form.

Understanding Magnesium's Role in Fluid Balance

Magnesium is an essential mineral involved in over 300 biochemical reactions, including the regulation of electrolytes like sodium and potassium. It helps control fluid levels by influencing the sodium-potassium pump, which moves fluids in and out of cells. When magnesium levels are low, this balance can be disrupted, leading to the body holding onto excess water. Correcting a magnesium deficiency can help restore this natural balance, prompting the body to excrete surplus fluid.

Water retention can also be a common symptom of Premenstrual Syndrome (PMS), and several studies have explored magnesium's effectiveness in alleviating this issue. Magnesium acts as a muscle relaxant and can also help with some of the other symptoms associated with hormonal fluctuations.

Magnesium and Water Retention

Research indicates that magnesium supplementation may help reduce water retention, particularly for individuals experiencing PMS-related symptoms. Studies have explored the use of magnesium for this purpose. It is important to note that the Tolerable Upper Intake Level for supplemental magnesium is 350 mg per day for adults, according to health authorities. Exceeding this should only be done under medical supervision. The total magnesium from all sources (diet and supplements) should also be considered against the Recommended Dietary Allowance (RDA), which is 310-320 mg for adult women and 400-420 mg for adult men.

Always consult a healthcare professional before starting any new supplement, particularly if you have a pre-existing medical condition, such as kidney disease, or are taking other medications.

Choosing the Right Magnesium Supplement

Different forms of magnesium have varying levels of bioavailability (how well the body absorbs them) and can have different effects. Choosing a highly bioavailable form is often recommended for better results.

Comparison of Magnesium Supplement Forms for Water Retention


Magnesium Form	Key Features for Water Retention	Bioavailability	Common Uses
Magnesium Citrate	Known for high absorption; also has a mild laxative effect that can relieve constipation-related bloating	High	Constipation, overall magnesium support
Magnesium Glycinate	High absorption; less likely to cause digestive upset; may help with relaxation and PMS symptoms	High	Sleep, anxiety, PMS symptoms
Magnesium Oxide	Lower absorption rate; used in studies for PMS water retention, but higher amounts can cause diarrhea	Low	Antacid, short-term constipation relief
Magnesium Chloride	Good absorption; can be taken orally or topically (e.g., bath flakes, oil)	High	General magnesium support, muscle relaxation

Dietary Sources of Magnesium

Before turning to supplements, boosting your intake through magnesium-rich foods is a safe and effective strategy. Your body can regulate excess magnesium from food, but not always from supplements.

Leafy Greens: Spinach, Swiss chard, and kale are excellent sources.
Nuts and Seeds: Pumpkin seeds, almonds, cashews, and chia seeds pack a significant amount of magnesium.
Legumes: Black beans, lentils, and chickpeas provide a solid dose.
Whole Grains: Quinoa, brown rice, and oatmeal are good options.
Dark Chocolate: A small amount of dark chocolate can be a tasty source.

The Broader Context of Water Retention

Magnesium alone is not a cure-all for water retention. Many factors contribute, including diet, hydration, exercise, and hormonal changes. It's crucial to address these as part of a comprehensive approach.

Stay Hydrated: Counterintuitively, drinking more water can help reduce water retention by signaling to your body that it doesn't need to hold onto fluids.
Reduce Sodium Intake: High sodium levels force the body to retain water. Limiting processed and salty foods can make a big difference.
Increase Potassium: Potassium works with magnesium to manage fluid balance. Foods rich in potassium, like bananas and avocados, can help.
Exercise Regularly: Physical activity helps improve circulation and lymphatic drainage, moving fluid away from tissues.
Elevate Your Legs: For swelling in the feet and ankles, elevating your legs can use gravity to help drain accumulated fluid.

Conclusion

For those interested in using magnesium for water retention, understanding the role of magnesium in fluid balance is important. Research indicates that magnesium supplementation may offer benefits, particularly for PMS-related fluid buildup. Choosing a highly absorbable form like magnesium citrate or glycinate can potentially increase effectiveness. However, the best strategy is a holistic one that combines a nutrient-rich diet—including leafy greens, nuts, seeds, and legumes—with good hydration and regular exercise. Before adding a new supplement to your regimen, it is essential to consult with a healthcare provider to ensure it is the right approach for your specific health needs and to confirm an appropriate amount. Integrating more magnesium into your diet naturally provides numerous health benefits while helping to support a healthy fluid balance.

Frequently Asked Questions

Yes, several studies have shown that magnesium supplementation may reduce fluid retention, bloating, and other symptoms associated with premenstrual syndrome (PMS).

It is generally safer and preferable to obtain magnesium from dietary sources. While supplements can help address a deficiency, food sources like leafy greens and nuts contain a complex of nutrients that work together. Your body also excretes excess magnesium from food more efficiently than from supplements.

The timeframe can vary, but some studies on PMS symptoms have shown noticeable improvements in fluid retention within the second month of consistent magnesium supplementation. Dietary changes may take longer to show effects.

To reduce water retention, focus on foods rich in both magnesium and potassium, which help maintain fluid balance. Excellent choices include leafy greens (spinach), nuts and seeds (pumpkin seeds, almonds), bananas, avocados, and legumes.

Yes, taking excessive amounts of supplemental magnesium can cause side effects like diarrhea, nausea, and abdominal cramping. In very high amounts, it can lead to more serious complications. The safe upper limit for supplements is generally considered to be 350 mg per day for adults.

For bloating caused by constipation, magnesium citrate is often recommended due to its gentle laxative effect. Magnesium glycinate is a good option if you want to avoid digestive upset, while magnesium chloride is also highly bioavailable.

Yes, drinking more water can surprisingly help, as can reducing sodium intake and increasing potassium consumption through diet. Regular exercise and elevating swollen legs and ankles are also effective strategies.