Guide

What do caffeine and L-theanine do together for focus?

The caffeine–theanine pairing is marketed as “focus without the jitters”. Here we separate what is formally authorised from what remains at the level of research.

Short answer: The only authorised cause-and-effect relationship for attention belongs to caffeine. When EFSA assessed an application on black tea and attention, it attributed the effect to caffeine, not to L-theanine. There is no authorised health claim for L-theanine. Studies on the caffeine–theanine combination exist, but they are study findings, not authorised claims.

What EFSA concluded

In a 2018 opinion, EFSA’s NDA Panel reviewed an application on black tea and attention. The Panel accepted that a cause-and-effect relationship had been established — but attributed the effect to the caffeine content. The applicant had argued that the two substances worked together; the Panel did not accept this.

The proposed wording was that black tea improves attention owing to its caffeine content.
The condition: at least 75 mg of caffeine from 2–3 servings within 90 minutes.
Three human intervention studies supported the opinion.

Earlier, in 2009, claims linking black tea consumption to improved mental focus were turned down; the dossier was found not to have demonstrated causality.

Where L-theanine stands

EFSA addressed L-theanine from tea separately, in relation to cognitive function, alleviation of psychological stress, maintenance of normal sleep and reduction of menstrual discomfort. The Panel considered that while tea itself was not sufficiently characterised for the claimed effects, L-theanine from tea was sufficiently characterised as a substance.

The outcome: there is no authorised health claim for L-theanine in the EU register. That does not mean the ingredient does nothing; it means the evidence submitted did not reach the threshold for authorisation. More on the ingredient in What is L-theanine?.

Combination studies

The literature does contain studies in which caffeine and L-theanine were given together. In one, a combination of 97 mg L-theanine with 40 mg caffeine was associated with improvements in attention measures. It is worth repeating that this is a study finding and not an EFSA decision. No claim has been authorised or rejected for the combination as such.

Practical notes on caffeine

Caffeine is a stimulant and individual responses vary considerably.
Caffeine taken late in the day can make it harder to fall asleep. For focus, the hour you take it may matter more than the dose.
Count caffeine-containing supplements together with coffee, tea and energy drinks — total intake is what matters.
Caffeine intake is restricted during pregnancy and breastfeeding — covered in Pregnancy and breastfeeding.

Magnesium and cognition

Magnesium L-threonate is marketed in connection with cognitive function, on the basis of animal data suggesting it can raise magnesium levels in brain tissue. The honest assessment: the evidence in humans remains limited and early-stage. The differences between forms are set out in Magnesium forms compared.

Frequently asked

The questions most often searched on this topic, answered as they are.

What happens when caffeine and L-theanine are taken together?

There are studies in which the two were given together; in one, 97 mg L-theanine with 40 mg caffeine was associated with improvements in attention measures. That is a study finding. No claim has been authorised or rejected for the combination as such.

Does the attention claim belong to L-theanine?

No. EFSA accepted a cause-and-effect relationship for black tea and attention but attributed it to the caffeine content, with a condition of at least 75 mg of caffeine from 2–3 servings within 90 minutes. There is no authorised claim for L-theanine.

Is L-theanine habit-forming?

There is no finding that it is; long-term safety studies are also limited. One review notes that the safety profile appears favourable in studies lasting up to 12 weeks. Data on long-term use is insufficient.

How much L-theanine is used per day?

Trials span 50–900 mg/day; a systematic review reports 200–450 mg/day as well tolerated in adults. That is the range used in the literature, not a dose recommendation.

Is caffeine in the evening a problem?

It can be. Caffeine late in the day can make it harder to fall asleep, and for focus the timing may matter more than the dose. In Magvela, caffeine is only in the RISE capsule taken in the morning.

Should I count supplement caffeine alongside my coffee?

Yes. Total intake is what matters: coffee, tea, cola, energy drinks and caffeine-containing supplements all count together. Caffeine intake is restricted in pregnancy and breastfeeding — see Pregnancy and breastfeeding.