Why does the formula contain both guarana and L-theanine — don't they contradict each other? — Braintus Focus, 90 capsules – brain and cognitive support complex, OstroVit

This is one of the most studied combinations in nootropic formulas. Guarana contains caffeine, which speeds up getting into tasks and helps maintain alertness for longer. A side effect of caffeine familiar to many is a feeling of anxiety, a "buzzing" head or difficulty switching between tasks at high doses.

L-theanine is an amino acid that affects the character of mental activity: it does not suppress alertness but smooths the "sharp edges" of the caffeine effect. As a result, focus becomes calmer and steadier, without a feeling of being wound up.

That is why these two components are often put into one formula rather than into different products: their actions complement rather than cancel each other. Guarana provides the energy to get started, and L-theanine helps channel it in a productive direction.

If you already know that you tolerate caffeine and L-theanine well separately, this combination is likely to suit you. If your sensitivity to stimulants is increased, it is worth starting by assessing your personal tolerance and not combining it with other sources of caffeine on the same day.