Key Takeaways
- Magnesium L-threonate is best known for its brain-boosting benefits, including improved memory, focus, and sleep.
- Magnesium citrate is often used to relieve constipation and support bone health.
- Choosing the best magnesium supplement depends on your health goals.
Magnesium is an essential mineral that supports many body functions, including nerve and muscle health, energy production, blood sugar and blood pressure regulation, and bone health. Magnesium L-threonate and magnesium citrate are popular options for boosting magnesium levels.
Their unique properties and uses may make one more suitable than the other for your specific health needs and goals.
Magnesium L-threonate: Supports Brain Health
Magnesium L-threonate contains magnesium and L-threonic acid, a compound derived from vitamin C. It is unique because it can penetrate the blood-brain barrier (the semipermeable membrane separating the blood from brain tissue), potentially helping boost cognitive health and support sleep, stress, and anxiety.
- Improves cognitive function: Research suggests magnesium L-threonate may help form new brain connections essential for learning and may boost short and long-term memory, particularly in older adults.
- Supports sleep quality: Some research shows that regularly taking magnesium L-threonate improves sleep quality, mood, energy levels, alertness, and daytime productivity.
- Reduces anxiety and depression: Low magnesium levels can increase anxiety. Research shows magnesium L-threonate reduces stress and anxiety better than a placebo (an inactive substance). Some studies also suggest magnesium might help ease depression.
- Reduces ADHD symptoms: Attention-deficit hyperactivity disorder (ADHD) causes difficulty with focus, impulsivity, and mood regulation. In a small trial, magnesium L-threonate supplementation helped reduce ADHD symptoms in over half of the study participants.
Magnesium Citrate: Good for Digestive and Bone Health
Magnesium citrate combines magnesium with citric acid, which gives it a gentle laxative effect. Beyond its impact on your digestive health, magnesium citrate is also suitable for:
- Constipation relief: Magnesium citrate draws water into the intestines, helping soften stool and stimulate bowel movements. It works within 30 minutes to 6 hours, making it an effective treatment for occasional constipation.
- Bone health: Magnesium citrate helps activate vitamin D, which improves calcium absorption for stronger bones. It also supports the activity of bone-building cells and may contribute to better bone mineral density and strength.
- Heart health: Magnesium helps keep your heart rhythm steady, and some evidence suggests that magnesium citrate may help regulate blood pressure and lower the risk of heart disease and stroke.
- Migraine prevention: Research suggests that higher doses of magnesium citrate—600 milligrams (mg) daily—may help prevent migraines and reduce the severity of migraine symptoms in some people.
Potential Side Effects
Magnesium citrate and magnesium L-threonate are generally safe for most people when taken as directed but may cause side effects such as:
Substantial doses of magnesium (more than 5,000 mg per day) can cause magnesium toxicity and cause serious side effects, such as:
- Abdominal bloating or constipation
- Depression
- Flushed face
- Hypotension (low blood pressure)
- Lethargy
- Nausea and vomiting
- Trouble urinating
How to Take Them
Both magnesium L-threonate and magnesium citrate are oral supplements (taken by mouth) and are widely available over the counter in capsule, tablet, or powder forms. You can also find magnesium citrate in liquid formulas.
Magnesium L-threonate
- Divide doses throughout the day for better absorption (though consistency matters more than timing, as its effects build over time).
- Take it before bedtime for better sleep, or twice daily, splitting the dose by taking one in the morning and one in the evening, for cognitive benefits.
- There is no standard dose of magnesium L-threonate; most supplements contain 2,000 mg, which provides about 144 mg of elemental magnesium daily
Magnesium Citrate
- Magnesium citrate is generally taken once daily or as needed, at any time.
- It tends to work within a few hours, so taking it early in the day can help prevent sleep disruptions if you’re using it for constipation.
- Dosage varies by product, but generally ranges from 250 to 600 mg.
Who Should Avoid Magnesium Supplements?
Magnesium supplements are generally safe for most people, but certain groups should avoid them or talk to a healthcare provider before use:
- People who are pregnant or breastfeeding
- People with heart disease
- People with kidney disease
Magnesium supplements can interact with some medications, including diuretics (water pills), antibiotics, proton pump inhibitors (acid reflux medicines), and bisphosphonates (osteoporosis drugs).
Avoid taking magnesium L-threonate and magnesium citrate together. The combination can increase magnesium blood levels, and people with reduced kidney function are at a higher risk of this complication.
Talk to a healthcare provider before taking magnesium supplements to ensure you can safely do so.
Third-Party Testing
Always read the label and choose a product that has undergone third-party testing to ensure it is safe and contains the ingredients listed on the label and the amounts listed. Look for supplements that have been vetted by reputable third-party agencies, such as those labeled with the USP Verified Mark from U.S. Pharmacopeia (USP) or the CL Certification Seal from ConsumerLab.com.