Supplements
What the evidence actually says about melatonin, magnesium, and other sleep supplements
The sleep supplement market exceeds $1 billion annually, but most products have weak or no evidence supporting their use. Here's what the research shows — and what's mostly marketing.
⚕️ Medical Disclaimer: This information is educational and not a substitute for medical advice. Dosages shown are population averages from research studies — individual needs vary significantly. Consult a healthcare provider before starting any supplement, especially if you take medications, have health conditions, or are pregnant or nursing.
Important context: Supplements are not regulated like drugs. Quality varies wildly between brands, and many products contain different amounts than labeled. If you use supplements, choose brands with third-party testing (USP, NSF, ConsumerLab).
Melatonin
Melatonin
A timing signal, not a sleeping pill. Useful for circadian disorders and jet lag, less effective for general insomnia.
What It Does
- Signals to the brain that it's nighttime
- Shifts circadian rhythm timing
- Reduces time to fall asleep by ~7 minutes on average
- Does NOT increase sleep drive or knock you out
Best For
- Jet lag (strong evidence)
- Delayed sleep phase syndrome
- Shift work sleep disorder
- Older adults with low natural melatonin
Typical dose: 0.5-3mg, 30-60 minutes before desired sleep time. More is not better — higher doses may be less effective and cause morning grogginess. Start with 0.5-1mg.
The dosing problem: Most commercial melatonin is dramatically overdosed. Studies show 0.3-0.5mg is often optimal, but products commonly contain 5-10mg. Higher doses can cause morning drowsiness and may actually disrupt sleep architecture.
Magnesium
Magnesium
May help if you're deficient (common). Activates GABA pathways and promotes relaxation. Form matters significantly.
What It Does
- Activates parasympathetic nervous system
- Regulates GABA receptors (calming)
- Helps regulate melatonin production
- Relaxes muscles
Best Forms for Sleep
- Glycinate: Best absorbed, calming, less GI upset
- Threonate: Crosses blood-brain barrier
- Citrate: Good absorption, may cause loose stools
- Oxide: Poorly absorbed, avoid for sleep
Typical dose: 200-400mg magnesium (elemental) before bed. Magnesium glycinate or threonate preferred for sleep. Effects are subtle and may take 1-2 weeks to notice.
Other Supplements
L-Theanine
Amino acid from tea that promotes relaxation without sedation. May help anxious people wind down.
Mechanism
- Increases alpha brain waves (relaxed alertness)
- Boosts GABA, serotonin, dopamine
- Reduces anxiety without causing drowsiness
Dosing
- 100-200mg before bed
- Safe, well-tolerated
- Can combine with magnesium
Valerian Root
Traditional herbal remedy with inconsistent research results. May have mild effects for some.
The Evidence
- Meta-analyses show inconsistent results
- Subjective improvement often doesn't match objective measures
- Quality varies dramatically between products
If You Try It
- 300-600mg standardized extract
- Take 30-60 min before bed
- May take 2-4 weeks for effect
Glycine
Amino acid that may lower core body temperature, potentially helping sleep initiation.
Mechanism
- May lower core body temperature
- Inhibitory neurotransmitter effects
- Some evidence for subjective sleep quality
Dosing
- 3g before bed (typical study dose)
- Generally well-tolerated
- Limited but promising research
CBD
Heavily marketed for sleep, but evidence is limited and inconsistent. May help anxiety-related sleep issues.
What We Know
- May reduce anxiety (which could help sleep)
- Direct sleep effects unclear
- Quality control is a major issue
- Drug interactions possible
Cautions
- Unregulated market, quality varies
- Can interact with medications
- Long-term effects unknown
- Evidence doesn't match marketing
Quick Comparison
Sleep Supplements: Evidence Summary
| Supplement | Evidence | Best Use Case | Typical Dose | Notes |
|---|---|---|---|---|
| Melatonin | Moderate | Jet lag, circadian issues | 0.5-3mg | Timing signal, not sedative |
| Magnesium glycinate | Moderate | General relaxation, deficiency | 200-400mg | Form matters significantly |
| L-Theanine | Moderate | Anxiety-related sleep issues | 100-200mg | Promotes calm without sedation |
| Glycine | Limited | Sleep quality | 3g | Promising but needs more research |
| Valerian | Weak | Mild insomnia | 300-600mg | Inconsistent results |
| CBD | Weak | Anxiety-related | Varies | Quality control issues |
| Ashwagandha | Limited | Stress-related insomnia | 300-600mg | Adaptogen, indirect effects |
| GABA | Weak | Relaxation | 100-200mg | Poor blood-brain barrier crossing |
⚠️ Special Populations — Consult a Clinician First:
Pregnancy/nursing: Most supplements lack safety data for fetal development.
Children: Dosing, safety, and appropriateness differ significantly from adults.
Depression/anxiety: Some supplements interact with SSRIs, SNRIs, and other psychiatric medications.
Blood thinners: Melatonin and some herbs may affect coagulation.
Autoimmune conditions: Immunomodulating supplements may be contraindicated.
Scheduled surgery: Many supplements should be stopped 1-2 weeks before procedures.
Pregnancy/nursing: Most supplements lack safety data for fetal development.
Children: Dosing, safety, and appropriateness differ significantly from adults.
Depression/anxiety: Some supplements interact with SSRIs, SNRIs, and other psychiatric medications.
Blood thinners: Melatonin and some herbs may affect coagulation.
Autoimmune conditions: Immunomodulating supplements may be contraindicated.
Scheduled surgery: Many supplements should be stopped 1-2 weeks before procedures.
✓ Key Takeaways
✓ Most sleep supplements have weak evidence — behavioral changes work better
✓ Melatonin is a timing signal, not a sedative — useful for jet lag
✓ Magnesium may help if deficient — form matters (glycinate or threonate)
✓ Lower melatonin doses (0.5-1mg) often work better than high doses
✓ Quality varies — choose third-party tested brands
✓ Supplements don't fix underlying sleep disorders