Atención y alerta

Brahmi (Water hyssop)

Bacopa monnieri

A 2014 meta-analysis of nine trials (518 people) found faster performance on an attention test (Trail Making B, about 18 ms) and quicker choice reaction time. These are small effects, and the analysis was based on few studies.

Greater galangal

Alpinia galanga

In a single-dose crossover trial of 59 caffeine-habituated young adults, 300 mg of a proprietary extract (E-AG-01) improved an alertness score over placebo at 3 hours, and with caffeine improved sustained attention; one small study.

Guarana

Paullinia cupana

Single doses of a standardised extract (about 11–12% caffeine) in 26–28 student volunteers improved alertness ratings and speed on some attention tasks; a 3-day trial of 1 g seed powder daily found no change in cognition, sleep or anxiety.

Guayusa

Ilex guayusa

A single 650 mg dose of a commercial guayusa extract improved several reaction-time and working-memory scores and self-rated focus over 2 hours in a small randomised crossover trial, though it reduced accuracy on one inhibition task. The effects are consistent with its caffeine.

Lion's mane

Hericium erinaceus

In a small trial in healthy young adults, a single dose sped up performance on one task (Stroop) at 60 minutes, while most other measures did not change.

Roseroot

Rhodiola rosea

A 2011 meta-analysis of 11 placebo-controlled trials suggested possible benefits for physical and mental performance but noted no independent replication; a 2009 critical review found statistical shortcomings in nearly all positive studies.

Toothed clubmoss

Huperzia serrata

A 2019 meta-analysis of nine trials in mild cognitive impairment reported higher memory-quotient and MMSE scores than placebo, while warning that the underlying studies were of low quality.

Vetiver

Chrysopogon zizanioides

In a small experiment, people who breathed low levels of volatiles from cut vetiver roots during a screen task kept faster reaction times; higher levels had no effect.