Magnesium vs Glycine
Which sleep supplement should you try first?
The Verdict
The short answer: Start with magnesium (most people are deficient), add glycine if needed.
Choose magnesium if: You have signs of deficiency (cramps, restlessness), want general relaxation, or haven't tried either.
Choose glycine if: You run hot at night, wake up feeling unrested despite adequate sleep time, or magnesium alone isn't enough.
The science says: Magnesium deficiency is common and affects sleep. Glycine specifically improves sleep quality through temperature regulation. Both are safe to combine.
Head-to-Head Comparison
| Metric | Magnesium | Glycine |
|---|---|---|
| Evidence Rating | A Better | B+ |
| Sleep Onset | Moderate improvement Better | Mild improvement |
| Sleep Quality | Moderate | High Better |
| Morning Alertness | Moderate | High Better |
| Temperature Regulation | Minimal | High Better |
| Muscle Relaxation | High Better | Moderate |
| Addresses Deficiency | Yes (common) Better | False |
| Side Effects | GI issues possible | Very rare Better |
| Cost | Low | Very Low Better |
| Taste | Neutral (capsules) | Slightly sweet |
Choose Magnesium if you...
- Haven't supplemented magnesium before
- Experience muscle cramps or restless legs
- Feel generally stressed or anxious
- Want broader health benefits beyond sleep
- Have signs of magnesium deficiency
- Trouble falling asleep (not staying asleep)
Choose Glycine if you...
- Already taking magnesium without full results
- Run hot at night or kick off blankets
- Sleep enough hours but wake unrested
- Want to improve sleep quality specifically
- Looking for morning alertness boost
- Sensitive to supplements (glycine very gentle)
Combined Protocol (Recommended)
Magnesium and glycine work through different mechanisms and stack well:
Evening stack:
- Magnesium glycinate: 300-400mg (elemental) - 1 hour before bed
- Glycine: 3g - 30-60 minutes before bed
The combination addresses both deficiency and sleep quality optimization. Magnesium glycinate provides both compounds in one.
Sample Weekly Schedule
The Science
Magnesium
Mechanisms
- Activates parasympathetic nervous system
- Regulates GABA receptors
- Reduces cortisol
- Relaxes smooth muscle
- Supports melatonin production
Key Research
- Magnesium supplementation improves sleep quality in elderly
- Low magnesium associated with poor sleep
- Magnesium glycinate best absorbed with calming effects
Glycine
Mechanisms
- Lowers core body temperature
- Acts as inhibitory neurotransmitter
- Improves blood flow to extremities
- Enhances slow-wave sleep
- Reduces time to sleep onset
Key Research
- 3g glycine before bed improves subjective sleep quality
- Glycine reduces core body temperature facilitating sleep
- Improves next-day cognitive performance after poor sleep
Frequently Asked Questions
Which form of magnesium is best for sleep?
Magnesium glycinate or threonate. Avoid oxide (poor absorption) and citrate (can cause loose stools). Glycinate provides both magnesium and glycine.
Can I take too much glycine?
Glycine is very safe even at high doses (studies use 3-9g). Start with 3g. No serious side effects reported in research.
When should I take these?
Magnesium 1-2 hours before bed, glycine 30-60 minutes before bed. Both can be taken together if convenient.
Will these make me groggy in the morning?
No - unlike sleep drugs, neither causes morning grogginess. Glycine actually improves morning alertness.
Can I take these with melatonin?
Yes, all three can be combined safely. Try magnesium and glycine first; add low-dose melatonin (0.3-0.5mg) only if needed.