Can Magnesium Glycinate Slow Urinary Frequency?
No, magnesium glycinate is not recommended for treating urinary frequency, as there is no guideline support or high-quality evidence demonstrating efficacy for this indication, and the available research shows it does not improve urinary storage symptoms.
Evidence Against Magnesium Glycinate for Urinary Frequency
The only study examining magnesium glycinate's effect on urinary parameters found that it increased urinary magnesium but did not improve urinary frequency or storage symptoms 1. In this 2004 trial of 61 renal stone patients, magnesium glycine supplementation (21 mEq daily for one month) actually caused a significant decrease in urinary pH without any beneficial changes in urinary citrate or calcium, effects that were similar to potassium chloride placebo 1. Importantly, this study was conducted in kidney stone patients, not patients with urinary frequency as a primary complaint 1.
What the Guidelines Actually Recommend for Urinary Frequency
First-Line Treatment
- Behavioral therapies must be offered first as they are equally effective as antimuscarinic medications for reducing symptom levels and carry no risk of adverse effects 2
- These include bladder training, bladder control strategies, pelvic floor muscle training, and fluid management 2
- Behavioral therapies may be combined with pharmacologic management simultaneously only if the patient has moderate to severe symptoms 2
Second-Line Pharmacologic Options
- Mirabegron 25-50 mg once daily is the preferred pharmacologic option, achieving continence more than placebo (NNTB 12) and improving urinary incontinence (NNTB 9) with moderate-quality evidence 2
- Tolterodine 2 mg twice daily or darifenacin should be preferred for patients concerned about side effects, particularly elderly patients, as tolterodine has discontinuation rates due to adverse effects similar to placebo 2
- Solifenacin is associated with the lowest risk for discontinuation due to adverse effects among antimuscarinics (NNTB 9 for achieving continence) 2
Why Magnesium Is Not Indicated
While dietary magnesium may have a role in kidney stone prevention by complexing with oxalate and potentially decreasing calcium oxalate supersaturation 3, this mechanism is entirely unrelated to treating urinary frequency. The evidence for magnesium in stone prevention itself is uncertain, as randomized trials examining magnesium supplementation had high dropout rates and magnesium was given in combination with other compounds 3. Higher dietary magnesium was associated with a 30% lower risk of stone formation in men, but no association has been observed in women 3.
Alternative Amino Acid with Actual Evidence
Interestingly, glycine (not magnesium glycinate) has shown promise for urinary storage symptoms. A 2021 study found that 3 g of glycine twice daily for four weeks decreased the number of nocturnal voids, urgency, and total score for urine storage items, improved sleep latency, and reduced bladder pain 4. However, this was a small study (20 participants) and glycine is not included in current clinical guidelines for urinary frequency management 4.
Critical Safety Considerations for Actual Treatments
- Antimuscarinics should not be used in patients with narrow-angle glaucoma unless approved by an ophthalmologist, and should be used with extreme caution in patients with impaired gastric emptying, history of urinary retention, or patients taking 7 or more concomitant medications 2
- The 2024 guidelines require discussing the potential risk for developing dementia and cognitive impairment with all patients prescribed antimuscarinic medications 2
Common Pitfalls to Avoid
- Do not use unproven supplements like magnesium glycinate when evidence-based treatments (behavioral therapy, mirabegron, antimuscarinics) are available 2
- Do not prescribe antimuscarinics without discussing dementia risk, especially for chronic use 2
- Do not abandon antimuscarinic therapy after one medication fails - patients may respond better to a different agent or dose modification 2