Quick answer: L-theanine is an amino acid found naturally in tea leaves. It's often paired with caffeine, and studies have looked at whether the combination changes how caffeine feels. The evidence is mixed, and there's no authorised UK health claim for L-theanine. Caffeine is the ingredient with the claim: it contributes to increased alertness and improved concentration.
L-theanine at a glance
| L-theanine | |
|---|---|
| What it is | An amino acid, not a stimulant |
| Where it's found | Tea leaves: green, black, oolong and matcha |
| In a cup of tea | Small amounts, varying by tea and brewing |
| In studies | Often 100 to 200mg, alongside caffeine |
| UK health claim | None authorised |
What the research says
- Several small studies have tested L-theanine with caffeine on attention tasks, with mixed results.
- Many people report the pairing feels smoother than caffeine alone, which is partly why tea feels different from coffee.
- The EU food safety authority reviewed L-theanine claims and didn't find enough evidence to approve them, which is why brands can't make health claims for it.
Is L-theanine safe?
It's been part of tea drinking for centuries, and it's widely sold as a food supplement. The caffeine it's usually paired with is what to keep an eye on: stay under 400mg a day and avoid caffeinated drinks if you're under 16, pregnant or breastfeeding.
How to read a label
- "L-theanine" means the pure amino acid, usually with an amount.
- "Green tea extract" contains L-theanine naturally, but the amount varies unless the extract is standardised.
- Caffeine per can is still the number that matters most.
Where PÜRCHARGE fits
PÜRCHARGE gets its L-theanine from green tea extract, so we don't state a fixed amount. Each still 330ml can also has 125mg of caffeine from green coffee, enXtra®, rhodiola, Panax ginseng, electrolytes and nine vitamins, with 3.8g of sugar. Caffeine contributes to increased alertness and improved concentration. Max two cans a day.
Compare it with tea in energy water vs matcha.
FAQs
What does L-theanine do with caffeine?
It's studied for whether it changes how caffeine feels. Results are mixed, and there's no authorised claim for it in the UK.
Is L-theanine natural?
Yes. It occurs naturally in tea leaves. It's also made for supplements.
How much L-theanine is in green tea?
A small amount that varies with the tea and how long you brew it. Supplements and studies use far more than a typical cup.
