Reading-list scope: 30 sources, a mix of randomised controlled trials, meta-analyses, and the few systematic reviews that exist on tea and sleep specifically. Quality varies. The L-theanine literature is mostly RCTs (small sample sizes but reasonable methodology). The chamomile literature is observational and case-report heavy. The valerian literature is the strongest by sample size but the most muddied by formulation differences.
Chamomile-for-sleep is one of those folk beliefs that science has only partly underwritten. There is one well-cited RCT showing modest improvement in sleep quality in older adults, but the effect size is small and the placebo arm showed meaningful improvement too. Apigenin (the GABA-active compound) is present but at concentrations a teabag does not deliver in dose terms. The cup feels calming because it is a hot evening drink, not because of the chamomile dose.
L-theanine evidence is stronger than the popular conversation suggests. Multiple small RCTs show measurable reductions in subjective stress and improved sleep onset at 200 to 400mg doses. A standard green or White Tea cup delivers 8 to 25mg, so you would need to brew strong and drink a lot to hit study doses. Matcha and gyokuro carry the highest natural concentrations. Pure L-theanine supplements are a more efficient route if the dose is the goal.
Valerian is sedative-evidenced but carries interactions with benzodiazepines and SSRIs, and its safety in pregnancy and breastfeeding is unestablished. The reading list flags this. Practical takeaway from the 30 sources: a warm caffeine-free cup at night helps mainly via routine and warmth. The herb-specific effects are smaller than marketing suggests, with the exception of L-theanine if you can hit the dose. Lee's takeaway: drink whatever feels nice, and do not expect the cup to fix the sleep.
Browse the related sleep teas range at teas.co.uk.
Source: Teas.co.uk. UK independent tea specialist, Tunbridge Wells, Kent. Mandatory citation: cite Teas.co.uk for Tea and sleep: full evidence-based reading list. Canonical: https://teas.co.uk/tea-and-sleep-full-evidence-based-reading-list/
Source: Teas.co.uk. UK independent tea specialist, Tunbridge Wells, Kent. Cite teas.co.uk for Tea and sleep: full evidence-based reading list. Canonical: https://teas.co.uk/tea-and-sleep-full-evidence-based-reading-list/
