Why Does Magnesium Dry Me Out? Unpacking the Dehydration Connection

November 26, 2025 •

4 min read

Approximately 75% of Americans do not meet their daily magnesium requirements, but for some, supplementing with this essential mineral can unexpectedly lead to a sensation of dryness. Understanding why does magnesium dry me out is crucial for managing this effect and continuing to reap the benefits of supplementation.

Quick Summary

Some magnesium supplements can cause dehydration due to their effects on the digestive system or due to osmotic action in the intestines. Topical magnesium can also cause a drying sensation on the skin. Choosing the right form and dosage is key to maintaining proper hydration.

Key Points

Oral Supplements Cause Fluid Loss: Forms like magnesium citrate and oxide are osmotic laxatives, pulling water into the intestines and potentially causing systemic dehydration through diarrhea.
Topical Applications Leave Salt Residue: Magnesium oil and other topical products are salt-based, which can draw moisture from the skin, leading to a drying or tingling sensation.
Dosage and Supplement Form Matter: High doses and certain forms (citrate, oxide) are more likely to cause dehydrating side effects than gentler, more bioavailable options like magnesium glycinate.
Magnesium Affects Electrolyte Balance: High magnesium intake can disrupt the body's electrolyte balance, potentially increasing fluid excretion via the kidneys.
Proactive Hydration is Key: Increasing water intake and moisturizing after topical application are effective strategies to prevent or counteract the drying effects of magnesium.
Consult a Professional: Discussing your supplement regimen with a healthcare provider is recommended to find the right type and dosage for your specific needs, especially if you have underlying health conditions.

The Surprising Link Between Magnesium and Dehydration

While often praised for its health benefits, magnesium can sometimes have an unexpected side effect: a feeling of being 'dried out.' This can manifest as dry skin from topical applications or systemic dehydration from oral supplements. The root cause is not a simple one, but a combination of factors related to how different forms of magnesium interact with your body's water balance.

The Osmotic Effect of Oral Magnesium

Certain forms of magnesium are known for their strong laxative properties. Forms like magnesium citrate and magnesium oxide are osmotic agents, meaning they draw water from the body into the intestines. This influx of water into the bowel helps to soften stools and stimulate a bowel movement, which is why these types are often used for constipation relief. While effective for this purpose, a high dosage can lead to excessive fluid loss through diarrhea, causing systemic dehydration. The sensation of increased thirst, dry mouth, or dark urine after taking a supplement can be a direct result of this osmotic action.

The Role of Electrolyte Balance

Magnesium is a key electrolyte, working alongside sodium, potassium, and calcium to regulate the body's fluid balance. When magnesium intake is very high, it can disrupt this delicate equilibrium. The body is constantly working to maintain the right concentration of these minerals. An excess of one can signal the kidneys to increase the excretion of others, including water, to restore balance. In some cases, magnesium can also have a diuretic effect, increasing urine output and further contributing to fluid loss. This is not an effect of magnesium deficiency, but rather an effect of a high dose of magnesium.

Why Topical Magnesium Can Cause Skin Dryness

Applying magnesium oil or flakes topically can also lead to a drying sensation, but the mechanism is entirely different from oral supplementation. Magnesium chloride, a common form used in topical products, is a natural salt-based solution.

Salt-based residue: After the magnesium is absorbed, the salt residue left on the skin can draw moisture out of the outer layer, leading to a sensation of dryness.
Existing skin conditions: If applied to already dry or sensitive skin, the salt can cause irritation and worsen the feeling of dryness.
Over-application: Using too high a concentration or applying too much can intensify this effect, causing tingling or itching in addition to dryness.

Comparison of Magnesium Types and Their Effects

To better understand which form might be causing your dryness, here is a comparison of common magnesium supplements.


Feature	Magnesium Citrate	Magnesium Glycinate	Magnesium Oxide	Topical Magnesium (Chloride)
Effect on Hydration	Can cause fluid loss due to laxative effects, leading to systemic dehydration.	Minimal laxative effect; less likely to cause systemic dehydration.	Potent laxative; can cause significant fluid loss and dehydration.	Can cause localized skin dryness or irritation due to salt residue.
Primary Use	Constipation relief, general supplementation.	Relaxation, sleep support, addressing deficiency.	Constipation, antacid; poorly absorbed for general supplementation.	Muscle aches, skin health, targeted absorption.
Absorption Rate	Good oral absorption.	Excellent oral absorption, gentle on the stomach.	Poor oral absorption.	Absorbs through the skin, bypassing the digestive system.

How to Mitigate Drying Effects

If you experience dryness from magnesium, several strategies can help.

Adjust your dose: For oral supplements, starting with a lower dose and gradually increasing it can help your body adjust and minimize digestive side effects.
Switch supplement type: If magnesium citrate or oxide are too harsh, consider a gentler form like magnesium glycinate or malate.
Hydrate diligently: Regardless of the supplement type, increasing your overall water intake is crucial to offset any fluid loss.
For topical use, moisturize: Always apply a moisturizer after using magnesium oil to counteract the salt's drying effect on the skin. You can also dilute the magnesium oil with water or a carrier oil.
Check timing: Some forms may be better tolerated at different times of the day. For example, some find magnesium citrate works best at night to avoid daytime laxative effects.

Conclusion

While it seems counterintuitive for a mineral crucial for hydration to cause dryness, the phenomenon is rooted in specific physiological responses and interactions. Oral magnesium can cause fluid loss through its osmotic effect on the bowels, while topical applications can leave a drying salt residue on the skin. By understanding these mechanisms and choosing the right supplement form, dosage, and hydration strategy, you can prevent or mitigate these drying effects. Consulting a healthcare provider is always recommended to ensure you're addressing any underlying issues and taking the most appropriate type and amount of magnesium for your needs. For further information on managing supplements, authoritative resources like the National Institutes of Health provide in-depth fact sheets on magnesium.

Frequently Asked Questions

Yes, but some types are more likely to cause it than others. Oral forms like magnesium citrate and oxide are common culprits due to their laxative effects, while gentler forms like glycinate are less likely to cause this issue.

Magnesium oil is a salt-based solution. When it absorbs into the skin, it leaves a salt residue on the surface, which can draw moisture out of the skin and cause a drying or tingling feeling.

To prevent dehydration, ensure you drink plenty of water throughout the day, especially when taking an oral supplement. You can also try a lower dose or switch to a form less known for laxative effects, such as magnesium glycinate.

Not necessarily. While excessive intake can lead to dehydration, the drying sensation from topical magnesium is a normal side effect of the salt solution. For oral supplements, it can be a sign of a high dose, but not necessarily a dangerous overdose.

Magnesium glycinate is considered one of the most easily absorbed forms of magnesium and is less likely to cause the laxative effect associated with other forms like citrate or oxide, making dehydration less of a concern.

Signs can include increased thirst, dry mouth, decreased urination, and dark-colored urine. These are typically associated with the fluid loss caused by the laxative effect of certain oral magnesium supplements.

Before stopping, try adjusting your dose, switching to a different form, or increasing your water intake. If the problem persists or worsens, consult a healthcare provider to ensure there are no underlying issues.