Supplements for sleep
Magnesium glycinate, glycine, L-theanine and ashwagandha: what the trials say, who each suits, and what to skip. UK made, practitioner grade.
How to choose a sleep supplement
Sleep supplements are one of the few areas with real trial evidence, and it points at a short list rather than a blend.
Why these
Magnesium Bisglycinate Capsules: The best-evidenced starting point, with no effect on the bowel, for evening use; magnesium contributes to normal psychological function.
Glycine Capsules: 3 g about an hour before bed in the two human trials, which measured single nights.
L-Theanine Capsules: The amino acid from green tea, for people who want something for the evening wind-down.
Ashwagandha: Root extract; weeks, not days, in the trials.
Unplug: One capsule for people who want a single evening formula, with what it contains stated.
What to skip
Twelve-ingredient sleep blends, which make it impossible to know what helped, and anything sold as a sleep aid. Melatonin is prescription-only in the UK.
Read the evidence
Magnesium for sleep: week by week · How long does glycine take to work? · How long does ashwagandha take to work?
If you take prescribed medicines, are pregnant or breastfeeding, or have a diagnosed condition, talk to your GP or pharmacist first. Not sure which fits? Ask Nutri365, the Nutri Tailor AI health expert, which checks for interactions and contraindications.
Written by Nutri Tailor from the Health Reference Library. Last checked 6 September 2026. General information, not personal advice.
Common questions
How long does magnesium take to work for sleep?
Gradually. Possible early effects in the first week, most measurable change by weeks two to four, and a fair verdict at four to eight weeks. The pooled trials are in older adults with insomnia, so the effect in younger people is less certain.
Can I take magnesium and glycine together?
Yes. They work in different ways and the trials used them separately, so there is no interaction to plan around; many people take both in the evening.
Is melatonin sold as a supplement in the UK?
No. Melatonin is prescription-only in the UK, so it is not sold here and does not appear on this page.
Written by Nutri Tailor from the Health Reference Library. Last checked 6 September 2026. General information, not personal advice.