Sleep & Anxiety Supplements
The short version: magnesium glycinate and L-theanine have the most defensible evidence and excellent safety, low-dose melatonin earns a narrow circadian role (but new data warns against taking it nightly for years), and most other "natural" sleep aids are oversold.
This is the supplement-pillar quick reference. For the full evidence base, mechanisms, dose recommendations, and the addiction question for each of magnesium (glycinate and L-threonate), L-theanine, melatonin, apigenin, ashwagandha, glycine, phosphatidylserine, taurine, valerian, and CBD — see the dedicated Sleep supplements page in the Sleep section.
Quick summary
| Supplement | Evidence | Safety | Addiction risk | Verdict |
|---|---|---|---|---|
| Magnesium glycinate (200–400 mg) | Moderate | Excellent | None | Worth trying |
| L-theanine (200–450 mg) | Weak–Moderate | Excellent | None | Worth trying |
| Magnesium L-threonate (cognition) | Moderate | Good | None | Worth trying (cognition focus) |
| Melatonin (0.3–1 mg) | Moderate (narrow) | Good short-term | None | Case-specific, not nightly forever |
| Ashwagandha (300–600 mg, root) | Moderate | Moderate (rare hepatotoxicity, interactions) | None | Selective use |
| Apigenin (~50 mg) | Weak/preliminary | Good | None | Optional |
| Glycine (3 g) | Weak | Excellent | None | Optional |
| Phosphatidylserine (100–400 mg) | Weak/preliminary | Good | None | Optional |
| Valerian | Weak/mixed | Good | Low | Skip |
| Taurine | Not a sleep aid | Good | None | Not for sleep |
| GABA (oral) | Weak/negative | Good | None | Skip |
| CBD | Preliminary | Variable (drug interactions) | Low | Skip absent indication |
On the addiction question, specifically
None of the supplements above produces clinically significant addiction, tolerance, or withdrawal in the doses studied. This is a key advantage over prescription sleep medications:
- Benzodiazepines, Z-drugs, OTC antihistamines — all carry meaningful tolerance, dependence, and withdrawal risks, plus a falls-and-dementia signal above age 50.
- Dual orexin-receptor antagonists (suvorexant, lemborexant, daridorexant) — newer prescription class without dependence/tolerance/rebound, similar to natural supplements in this respect.
That said:
- "No addiction" doesn't mean "use forever without thinking." A psychological dependence ("I can't sleep without it") can develop with any sleep aid. The strongest sustainable approach is foundational sleep hygiene plus CBT-I if needed, with supplements as occasional adjuncts.
- Long-term safety data (>1–2 years continuous daily use) is limited for most of these. Magnesium has the longest clean track record; melatonin's long-term picture now carries a cardiovascular caveat (see below).
The melatonin caveat worth knowing
A 2025 observational cohort presented at the American Heart Association linked a year or more of melatonin use to higher rates of heart failure and death. It is observational and confounded — heavy long-term users tend to have worse insomnia and more co-morbidity — so it cannot prove cause. But it is enough to favour using melatonin strategically (circadian resets, lowest effective dose of 0.3–1 mg) rather than as an open-ended nightly habit. Higher doses (3–10 mg) are no more effective and more likely to cause grogginess. Full detail in Sleep supplements.
What to combine, what to avoid
Reasonable combinations
- Magnesium glycinate + L-theanine (evening, 1–2 h before bed) — common stack, both safe, complementary mechanisms (magnesium modulates NMDA/GABA, L-theanine raises alpha waves).
- Magnesium glycinate + low-dose melatonin for travel or shift transition — fine, short-term.
Be cautious with
- CBD + benzodiazepines / Z-drugs / SSRIs / statins / warfarin — CBD inhibits CYP3A4 and CYP2C9.
- Ashwagandha + thyroid medications, immunosuppressants, sedatives — can amplify effects; it also modulates CYP3A4.
- Multiple sedatives layered — even "natural" sedatives can have additive effects with each other and with alcohol.
Avoid layering with prescription sleep aids
If you're on a prescription sleep medication, talk with your prescriber before adding any of these supplements. Most are safe, but the conservative approach is to use one strategy at a time.
When supplements aren't enough
Persistent sleep problems (insomnia ≥3 nights/week for ≥3 months) call for:
- CBT-I as first-line — it produces large, durable effects that no supplement matches. See Insomnia treatment.
- Screening for OSA if any risk factor — see Sleep breathing.
- Evaluation for underlying mood, pain, or medical conditions.
Supplements are adjuncts, not solutions, for chronic insomnia. The same is true of anxiety: ashwagandha has the cleanest short-term anxiety signal in the supplement space, but the autonomic-retraining levers (slow breathing, mindfulness, exercise, social connection) are far higher-leverage long-term. See Stress.