Sleep is one of the most common complaints we hear — and one of the most undertreated. Patients with anxiety, depression, ADHD, and PTSD almost universally report sleep problems. And even patients without a primary psychiatric diagnosis often come in struggling with chronic insomnia that's making everything else worse.
Before diving into the supplements: CBT-I (Cognitive Behavioral Therapy for Insomnia) is the gold-standard first-line treatment for chronic insomnia, with more durable results than either medication or supplements. If you have access to a CBT-I trained therapist, that's worth pursuing. These supplements work best alongside good sleep hygiene and behavioral approaches — not instead of them.
That said, these three are the best-evidenced supplements for sleep, and ones we discuss regularly with patients.
1. Magnesium Glycinate — The Foundation of a Good Sleep Stack
Magnesium is one of the most important minerals for sleep regulation, and deficiency is surprisingly common — particularly in people under chronic stress.
An 8-week double-blind RCT found magnesium supplementation at 500 mg/day significantly increased total sleep time, sleep efficiency, and serum melatonin, while reducing Insomnia Severity Index scores, sleep onset latency, and cortisol levels versus placebo. The mechanism is elegant: magnesium activates GABA-A receptors (promoting sleep-onset relaxation) and suppresses cortisol (reducing the hyperarousal that keeps anxious patients awake at night). It also upregulates endogenous melatonin production — meaning it supports your body's own sleep signaling rather than just replacing it.
If you're only going to add one supplement for sleep, this is the one. It addresses the physiology of stress-driven wakefulness directly, and the safety profile is excellent.
Dose: 300–400 mg elemental magnesium glycinate, 30–60 minutes before bed.
Caution: Reduce dose in kidney disease.
2. Ashwagandha KSM-66 — For When Stress and Anxiety Are Running Your Sleep
If your insomnia is driven by anxiety, rumination, and a mind that won't slow down at bedtime — ashwagandha addresses the root cause in a way that pure sleep supplements don't.
A 2021 systematic review and meta-analysis of 5 RCTs (n=372) found ashwagandha produced significant improvements across every major sleep parameter: sleep quality (SMD −1.16), sleep onset latency (SMD −0.53), total sleep time (SMD −0.45), wake after sleep onset (SMD −0.39), and sleep efficiency (SMD −0.68). Effects were most pronounced in participants with diagnosed insomnia and at doses ≥600 mg for ≥8 weeks.
The NIH Office of Dietary Supplements confirmed these findings, noting particular benefit in the insomnia subgroup including improvements in mental alertness on rising — meaning the quality of sleep improves, not just the quantity.
If you're already taking ashwagandha for anxiety, your sleep should improve as a secondary benefit. If insomnia is your primary complaint and anxiety is a significant driver, ashwagandha is the supplement most likely to help.
Dose: 600 mg/day (can be taken as a single evening dose or split). Minimum 8-week trial for full effect.
3. Melatonin — You're Probably Taking Too Much
Melatonin is the most widely used sleep supplement in the country — and most people are taking 5 to 20 times the evidence-supported dose.
Here's the problem with the 5 mg and 10 mg doses that dominate drugstore shelves: those are pharmacological doses, 10–50 times above physiological levels. Chronic use at high doses can cause receptor downregulation — your brain reduces its sensitivity to melatonin over time, making the supplement progressively less effective and potentially interfering with your body's own melatonin production.
The evidence supports 0.5–1 mg for sleep onset and 1–3 mg for sleep maintenance. At these doses, melatonin signals your circadian rhythm that it's time to sleep without the receptor downregulation that can develop with chronic high-dose use.
A 2025 scoping review of 51 RCTs on over-the-counter sleep products concluded that melatonin has among the most substantial evidence for effectiveness and safety in insomnia — particularly for sleep onset latency, circadian-related insomnia, jet lag, and older adults (whose natural melatonin production declines with age).
The melatonin available in our dispensary is Pure Encapsulations 0.5 mg for most patients — the evidence-aligned dose, pharmaceutical grade, no adulterants. For patients with sleep maintenance insomnia or older adults, Thorne Melaton-3 at 3 mg is appropriate.
Dose: 0.5–1 mg for sleep onset. 1–3 mg for sleep maintenance. Take 30–60 minutes before intended sleep time.
A Note on Combining These Three
These three complement each other well and address different mechanisms. Magnesium handles cortisol-driven hyperarousal and supports GABA signaling. Ashwagandha addresses the HPA axis and longer-term stress resilience. Melatonin handles circadian timing and sleep onset signaling. Together they cover the three most common physiological drivers of insomnia in anxious, stressed adults.
One practical note: if you're already on our anxiety protocol (ashwagandha + magnesium glycinate + L-theanine), you already have two of the three insomnia supplements covered. Adding low-dose melatonin completes an effective sleep stack with no redundancy.
Struggling with sleep? Florida Behavioral Health Associates evaluates and treats insomnia — including its psychiatric contributors — via telehealth throughout Florida. New patient appointments within 1–2 days. Book an appointment →
