L-Theanine and Caffeine: Why People Take Them Together
L-theanine and caffeine are often sold side by side, and many people ask whether they can be taken together. The pairing is not new: both occur naturally in the tea leaf, so every cup of tea already contains some of each. This guide explains what the two ingredients are, how much of each you will find in drinks and capsules, and how to keep track of your daily caffeine.
What is L-theanine?
L-theanine is an amino acid found naturally in the leaves of the tea plant (Camellia sinensis) and, in small amounts, in some mushrooms. It is one of the compounds behind the savoury, rounded taste of green tea. Chemically it is L-glutamic acid gamma-monoamide. Unlike the amino acids in protein foods, it is not used to build proteins in the body.
No health claims are authorised for L-theanine in Great Britain.
What is caffeine?
Caffeine is a natural compound found in coffee beans, tea leaves, cocoa beans, guarana and kola nuts. In supplements it is usually caffeine anhydrous, a dried, concentrated form. It can be made from natural sources such as coffee beans, or synthetically.
No health claims are authorised for caffeine in Great Britain.
Why are they paired?
Because tea contains both. A cup of tea typically contains some L-theanine alongside caffeine, although the amounts vary a great deal with the type of tea, how it is grown and how long it is brewed. Taking the two as separate capsules simply lets people choose their own amounts of each, rather than relying on the variable content of a brew.
How much caffeine is in everyday drinks?
The NHS gives these approximate amounts:
| Drink or food | Approximate caffeine |
|---|---|
| Mug of tea | 75 mg |
| Mug of instant coffee | 100 mg |
| Mug of filter coffee | 140 mg |
| Can of cola | up to 40 mg |
| 250 ml can of energy drink | up to 80 mg |
| 50 g bar of plain chocolate | up to 25 mg |
How much caffeine is too much?
For healthy adults, the European Food Safety Authority considers up to 400 mg of caffeine a day, and single doses of up to 200 mg, to be of no safety concern. If you are pregnant or breastfeeding, the NHS advises no more than 200 mg a day from all sources, and supplements containing caffeine are not recommended. Caffeine supplements are not suitable for children or anyone under 18.
One 200 mg caffeine capsule is roughly the same as two mugs of instant coffee. Two capsules provide 400 mg, which is the whole of the EFSA daily figure on its own, so count every coffee, tea, cola, energy drink and pre-workout product on top.
Our L-Theanine and Caffeine capsules
| Product | Per capsule | Suggested use |
|---|---|---|
| L-Theanine 400mg Vegan Capsules | 400 mg pure L-theanine, single ingredient | 1 to 2 capsules daily with a large glass of water |
| Caffeine 200mg Vegan Capsules | 200 mg natural caffeine anhydrous from coffee beans | 1 to 2 capsules daily with a large glass of water |
Both are in vegan HPMC capsules with no fillers or binders and are made in the UK. The caffeine label carries the warning: high caffeine content, not recommended for children or pregnant or breast-feeding women.
How people take them
- Follow each label and do not exceed the recommended daily dose of either product.
- If you take them together, many people start with one capsule of each, rather than the maximum.
- Take caffeine earlier in the day. The NHS suggests cutting down on caffeine in the afternoon and evening as part of good sleep habits.
- Count caffeine from all sources, including drinks, chocolate and other supplements.
If you are interested in L-theanine as part of an evening routine without caffeine, see Magnesium, Valerian and L-Theanine: An Evening Routine Guide.
Who should not take caffeine, or check first
- Pregnancy and breastfeeding. Caffeine supplements are not recommended. Speak to your midwife or doctor before taking L-theanine.
- Under 18. Neither product is intended for anyone under 18.
- Heart and blood pressure. Speak to your doctor first if you have a heart condition or high blood pressure, or take medicine for either.
- Sensitivity to caffeine. If caffeine makes you feel jittery, anxious or affects your sleep, avoid caffeine supplements.
- Medication. Some medicines interact with caffeine, and L-theanine may interact with medicines for blood pressure or with stimulants. Ask your pharmacist if you take any prescription medicine.
Frequently asked questions
Does L-theanine contain caffeine?
No. Our L-Theanine contains pure L-theanine only, with no caffeine.
Can I take L-theanine with my morning coffee?
Many people do. Follow the L-theanine label and remember that your coffee counts towards your daily caffeine.
Is caffeine from coffee beans different from synthetic caffeine?
The caffeine molecule is the same. The difference is the source it is made from. Ours is derived from coffee beans.
How much caffeine is in one of your capsules?
200 mg per capsule, about the same as two mugs of instant coffee.
This article is general information and is not medical advice. Food supplements should not replace a varied, balanced diet and a healthy lifestyle.
Leave a comment