From the FDA Drug Label
Directions shake well before using drink a full glass (8 ounces) of liquid with each dose may be taken as a single daily dose or in divided doses adults and children 12 years of age and over - 6.5 to 10 fl oz maximum 10 fl oz in 24 hours children 6 to under 12 years of age - 3 to 7 fl oz maximum 7 fl oz in 24 hours children 2 to under 6 years of age - 2 to 3 fl oz in 24 hours maximum 3 fl oz in 24 hours children under 2 years of age - ask a doctor
The amount of magnesium citrate needed to cause diarrhea is not explicitly stated in the drug label. However, the label provides the maximum daily doses for different age groups:
- Adults and children 12 years of age and over: maximum 10 fl oz in 24 hours
- Children 6 to under 12 years of age: maximum 7 fl oz in 24 hours
- Children 2 to under 6 years of age: maximum 3 fl oz in 24 hours It can be inferred that taking more than the recommended maximum daily dose may increase the risk of diarrhea, but the exact amount required to cause diarrhea is not specified 1.
From the Research
Magnesium citrate typically causes diarrhea at doses of 200-300 mL (10-15 ounces) of the standard oral solution. For most adults, a single 10-ounce bottle of magnesium citrate is sufficient to produce a bowel movement within 30 minutes to 6 hours. The laxative effect occurs because magnesium citrate draws water into the intestines through osmosis, which softens stool and stimulates intestinal contractions. Lower doses of 5-7 ounces may cause looser stools without full diarrhea in some individuals. Sensitivity varies between people based on factors like body weight, gut motility, and individual tolerance. It's essential to stay well-hydrated when taking magnesium citrate to prevent dehydration from the resulting fluid loss. If using for constipation relief or bowel preparation, follow specific instructions from your healthcare provider, as excessive use can lead to electrolyte imbalances and dependence 2, 3.
Some studies have investigated the efficacy of magnesium citrate in various contexts, including colonoscopic preparation and pediatric toxic ingestions 4, 5, 6. However, the primary concern in this context is the dose required to cause diarrhea, and the evidence suggests that 200-300 mL is typically effective.
Key considerations when using magnesium citrate include:
- Staying well-hydrated to prevent dehydration
- Following specific instructions from a healthcare provider to avoid excessive use
- Being aware of individual tolerance and sensitivity to the laxative effect
- Monitoring for potential side effects, such as abdominal pain, nausea, and electrolyte imbalances.
Overall, magnesium citrate is a commonly used and effective laxative, but it's crucial to use it responsibly and under the guidance of a healthcare provider to minimize potential risks and maximize benefits 2.