Improved Sleep Quality
Enhances overall sleep architecture including deeper, more restorative sleep stages. Supports sleep continuity and reduces nighttime awakenings.
TL;DR
Sleep quality is about continuity and depth, not just hours in bed. CBT-I is the first-line treatment and outperforms every supplement; melatonin is a circadian timing signal rather than a sedative, and magnesium and glycine offer modest help at the margins.
Why It Matters
Cognitive behavioural therapy for insomnia is recommended ahead of medication by the AASM and NICE, with durable effects that outlast drug therapy. Melatonin's evidence is strongest for circadian problems — jet lag, shift work, delayed sleep phase — where low doses (0.5-1 mg) taken hours before target sleep time shift the clock; high doses taken at bedtime mostly act as a weak hypnotic. Magnesium and glycine show small improvements in sleep-onset latency and subjective quality. Untreated obstructive sleep apnoea is the most commonly missed cause of unrefreshing sleep.
How to Measure
Two weeks of a sleep diary recording bed time, estimated sleep onset, awakenings, wake time and out-of-bed time; from that compute sleep efficiency. Score the Insomnia Severity Index and the Epworth Sleepiness Scale. Screen for apnoea with STOP-BANG and arrange a sleep study if positive. Wearables are useful for trends in timing and consistency, unreliable for sleep staging. Bloods worth checking: ferritin (restless legs), TSH, and 25-OH vitamin D.
Biomarkers
Target Ranges
Sleep efficiency
>85%
Sleep onset latency
<30 minutes
Wake after sleep onset
<30 minutes
Insomnia Severity Index
<8
Ferritin (if restless legs)
>75 ng/mL
Optimization Protocol
Start with CBT-I, either with a therapist or a validated digital programme — stimulus control and sleep restriction do the heavy lifting. Fix the basics: fixed wake time every day, morning daylight, caffeine cut-off 8-10 hours before bed, no alcohol within 3 hours of sleep, cool dark room. Supplement layer if still needed: magnesium glycinate 200-400 mg elemental 1-2 hours before bed; glycine 3 g at bedtime; melatonin 0.5-1 mg taken 2-4 hours before target sleep time for delayed phase, or on arrival-time schedule for jet lag. Refer for a sleep study if there is snoring, witnessed apnoeas, or persistent daytime sleepiness despite adequate time in bed.
Lifestyle Levers
- •Fixed wake time seven days a week
- •Morning daylight within an hour of waking
- •Caffeine cut-off 8-10 hours before bed
- •No alcohol within 3 hours of sleep
- •Cool, dark, quiet bedroom
- •Bed reserved for sleep only
- •Wind-down routine without bright screens
- •Regular daytime exercise, not late evening
Supporting Supplements
Black Cohosh
Sleep improvements appear secondary to fewer night-time hot flushes rather than a direct hypnotic effect.
Magnesium
A first-line sleep supplement with good evidence, a strong safety profile and high deficiency prevalence.
Glycine
Glycine 3 g before bed improves subjective sleep quality and reduces next-day fatigue in small but consistent crossover trials.
Valerian Root
Valerian improves subjectively rated sleep quality in pooled analyses, but objective measures and trial quality are both weak.
Apigenin
Isolated apigenin has not been tested for sleep in humans; the reputation rests on chamomile.
Passionflower
Small trials suggest passionflower mildly improves sleep quality, with effects short of pharmaceutical hypnotics.
5-HTP
5-HTP is widely sold as a sleep aid but human trial evidence is thin and mostly from small studies combining it with GABA.
Melatonin
First-line for circadian issues, jet lag and delayed sleep phase; less effective for staying asleep.
Reishi
Reishi's sleep reputation rests mainly on rodent sleep-architecture work and traditional use; human trials report improved wellbeing but rarely measure sleep directly.
Ashwagandha
Worth trying if stress or a racing mind is what keeps you up — effects build over 2-8 weeks.
L-Theanine
A gentle, non-sedating option best suited to stress-related sleep problems.
Supporting Research
Frequently Asked Questions
Typical Timeframe
CBT-I produces meaningful change in 4-6 weeks. Melatonin for circadian shifting works within 2-7 days. Magnesium and glycine effects, if present, show within 1-2 weeks. Fixed wake time takes about 2 weeks to stabilise the rhythm.
Research Summary
My Notes
Sign in to add personal notes
This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.