Glamour Magazine: L-theanine is a popular supplement for people who are struggling with insomnia and anxiety, but how effective is it?

“It is one of the more popular amino acids at the moment, getting its ’15 minutes of fame,'” says Dr Ahmed El Muntasar, aesthetics doctor and GP.

While helping with sleep is one of its most commonly discussed benefits (more on that later), Dr Muntasar explains that L-theanine also may have the capacity to help with things like anxiety. 

“There were studies from the late 90s that looked at EEGs which is basically monitoring of brain frequency and they found that actually L-theanine at high dosages of up to 20mg (which is quite high) could potentially reduce frequencies in the brain which is linked to reduced anxiety and reduced stress,” he explains. 

While this sounds great, this doesn’t sound super achievable considering the high levels of the stuff that would be needed. 

But fear not; Muntasar refers to another study from 2008, which “demonstrated it does not need to be in such high doses at a dietary level; you can still get a very similar effect of increased mental sharpness [with a lower dose], which would reduce stress and anxiety and improve sleep.”

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