What is the Difference Between Magnesium Citrate and Potassium Citrate?

January 1, 2026 •

4 min read

According to the National Institutes of Health, magnesium is involved in over 300 enzymatic reactions in the body, while potassium is a vital electrolyte. While both magnesium citrate and potassium citrate are essential mineral salts, they serve distinctly different primary purposes in health, from digestive relief to urinary health.

Quick Summary

These mineral citrate salts have different primary functions: magnesium citrate is primarily a laxative and general supplement, while potassium citrate is a urinary alkalinizer used for kidney stones. They affect electrolyte balance and urine composition differently.

Key Points

Primary Function: Magnesium citrate is mainly a laxative for constipation; potassium citrate is a urinary alkalinizer for kidney stones.
Mechanism of Action: Magnesium citrate works by drawing water into the intestines, while potassium citrate works by raising urine pH.
Specific Uses: Magnesium citrate is used for constipation and magnesium deficiency, while potassium citrate is for kidney stone prevention and metabolic acidosis.
Side Effects and Risks: Common side effects for both include diarrhea. However, potassium citrate has a higher risk of hyperkalemia (high potassium) in individuals with impaired kidney function.
Combined Benefits: A combination of potassium and magnesium citrate can be more effective for kidney stone prevention than either alone by increasing urinary citrate and pH.
Bioavailability: Both are highly bioavailable forms of their respective minerals, making them well-absorbed by the body.

Understanding the Core Components

Both magnesium citrate and potassium citrate are mineral salts where the mineral (magnesium or potassium) is bonded to citric acid. The citrate form offers high bioavailability, meaning it is easily absorbed by the body. However, the differing primary mineral is what defines their main clinical applications and effects on the body.

What is Magnesium Citrate?

Magnesium citrate is a form of magnesium supplement with a powerful laxative effect due to its action as an osmotic laxative. It draws water into the intestines, softening stool and stimulating bowel movements. While its primary use is for treating occasional constipation or as a bowel prep for medical procedures, it also provides the general health benefits associated with magnesium.

Uses and Benefits of Magnesium Citrate:

Constipation Relief: Its most common use is as an effective saline laxative for short-term treatment of occasional constipation.
Bowel Cleansing: Often used to prepare the bowel before a colonoscopy or other medical procedures.
Magnesium Deficiency: Corrects low magnesium levels in the body, which can support over 300 enzymatic reactions.
Bone Health: Plays a crucial role in bone density by activating Vitamin D and regulating calcium.
Sleep and Relaxation: Helps to activate neurotransmitters that promote calmness and can aid in better sleep quality.
Heart Health: Contributes to maintaining a healthy heart rhythm and regulating blood pressure.

Common Side Effects of Magnesium Citrate:

Diarrhea
Nausea and stomach cramps
Bloating and gas

What is Potassium Citrate?

Potassium citrate is a urinary alkalinizer, meaning it reduces the amount of acid in the urine. This is its key function for medicinal purposes, primarily to treat and prevent the formation of certain kidney stones. The potassium content also provides the general benefits of this essential electrolyte.

Uses and Benefits of Potassium Citrate:

Kidney Stone Prevention: It's a common treatment for preventing the recurrence of kidney stones, particularly those made of calcium oxalate and uric acid.
Urinary Alkalinization: Raises the urinary pH to make urine less acidic, which helps dissolve existing stones and inhibit new ones.
Metabolic Acidosis: Used to correct certain metabolic imbalances caused by kidney disorders.
Gout: Can prevent kidney stones that occur with gout by neutralizing uric acid.
Bone Health: May help preserve bone mineral density by reducing urinary calcium excretion.
Cardiovascular Support: As a potassium source, it is vital for maintaining normal blood pressure.

Common Side Effects of Potassium Citrate:

Upset stomach, nausea, and vomiting
Diarrhea
Potentially serious side effects like hyperkalemia (high potassium levels) and intestinal issues can occur with improper use, especially in those with kidney problems.

Comparison Table: Magnesium Citrate vs. Potassium Citrate


Feature	Magnesium Citrate	Potassium Citrate
Primary Use	Saline laxative for constipation and general magnesium supplement.	Urinary alkalinizer for kidney stone prevention and treatment.
Mechanism	Osmotic laxative; draws water into the intestines to soften stool.	Urinary alkalinizer; makes urine less acidic to prevent crystallization.
Effect on Urine	Primarily increases urinary magnesium, but less effective at increasing urinary citrate and pH than potassium citrate.	Significantly increases urinary pH and citrate levels.
Main Risks	Dehydration and electrolyte imbalance (including potential potassium loss) with overuse.	Hyperkalemia (high potassium) in individuals with kidney issues or those on certain medications.
Drug Interactions	Can interact with antibiotics, bisphosphonates, and diuretics.	Can interact with potassium-sparing diuretics and other medications.

Can You Take Them Together?

Yes, magnesium citrate and potassium citrate can be taken together, and a combination supplement is sometimes prescribed. This combination can be particularly effective for preventing kidney stones, with studies showing a significantly higher success rate than either supplement alone. When taken together, they increase urinary citrate and magnesium, while also elevating urine pH, which helps inhibit stone formation. However, this should always be done under the supervision of a healthcare provider, especially for individuals with kidney or heart conditions, to avoid risks such as hyperkalemia. For general health purposes, it is more common to take them separately based on specific needs. For example, one might take magnesium citrate for occasional constipation, and a different form of magnesium for long-term supplementation without the laxative effect.

The Role of Citrate

The citrate component in both supplements serves as an important buffer in the body, converting to hydrogen carbonate that can neutralize metabolic acids. This alkalinizing effect is particularly valuable in the kidneys, where it reduces the acidity of urine. While both supplements contribute citrate, the primary effect is determined by the mineral it is bound to. Potassium citrate, for instance, has a more pronounced effect on urinary pH and citrate excretion compared to magnesium citrate.

Conclusion

While both magnesium citrate and potassium citrate are citrate salts that aid in general mineral balance, their distinct functions mean they are not interchangeable. Magnesium citrate is best known and most effective as a fast-acting laxative, drawing water into the bowels. Potassium citrate is a powerful urinary alkalinizer, primarily prescribed to prevent and treat certain types of kidney stones. Their side effects and contraindications also differ, emphasizing the need for a healthcare provider's guidance. In some cases, a combined therapy may be prescribed for maximum benefit, particularly for recurrent kidney stones. Understanding the specific function of each allows for the correct and safe application of these vital mineral supplements.

For more information on the efficacy of potassium-magnesium citrate combinations for kidney stones, you can review research published by the National Institutes of Health.

Frequently Asked Questions

Yes, it is possible to take them together, and sometimes a combined supplement is recommended, particularly for kidney stone prevention. However, you should consult a healthcare provider to ensure it's appropriate for your health status, especially regarding kidney function and potential electrolyte imbalances.

Magnesium citrate is the appropriate choice for constipation. It is an osmotic laxative that works by drawing water into the bowels to soften stool and promote a bowel movement. Potassium citrate does not have a laxative effect.

For kidney stone prevention, potassium citrate is specifically prescribed because it makes the urine less acidic, which is crucial for preventing certain types of stones. While magnesium citrate offers minor benefits, potassium citrate or a combination product is more effective.

The primary function of magnesium citrate is to act as an osmotic saline laxative for the short-term relief of occasional constipation. It can also be taken as a supplement for magnesium deficiency.

The primary function of potassium citrate is to serve as a urinary alkalinizer. It makes urine less acidic to prevent the formation and growth of kidney stones, and to treat certain metabolic conditions.

Yes, both affect electrolytes. Magnesium citrate can cause electrolyte imbalances, including low potassium, with overuse due to its laxative effects. Potassium citrate can cause hyperkalemia (high potassium) if not used properly, especially in those with kidney impairment.

For magnesium citrate, the most common side effects are diarrhea, cramping, and bloating. For potassium citrate, common side effects include stomach discomfort, but the most serious risk is high blood potassium, or hyperkalemia.