Functional Beer / Ingredients

L‑theanine, ashwagandha, magnesium: what is in a functional beer?

Functional beers add ingredients meant to help you relax. What each one is, and what the evidence behind the leading brand says.

Updated 8 November 2026By the Functional Beer team

A functional beer is an alcohol-free beer with added ingredients meant to do something: help you relax, focus or recover. The category is growing fast. Worldpanel puts UK functional drinks at around £178 million, up 24.5%, with almost 30% of households buying them.

The common ingredients

L‑theanine is an amino acid found in tea leaves. Ashwagandha is a root used for centuries in Ayurvedic medicine. Magnesium is a mineral involved in hundreds of processes in the body. Some drinks used CBD, but the Food Standards Agency now advises no more than 10mg a day.

Doses vary a lot between brands, and some do not list them. Our functional beer ranking shows the dose wherever the label gives one.

Why people buy them

IWSR found people try functional drinks out of curiosity or for alcohol-like effects, while 37% of no-alcohol beer buyers cite a healthy lifestyle. A functional beer tries to do both: something that tastes like beer and still helps you switch off.

Our pick

IMPOSSIBREW Enhanced Lager

IMPOSSIBREW is the best-known example. Its Social Blend of L‑theanine, ashwagandha and magnesium was developed with Dr Paul Chazot, Chair of Pharmacology at Durham University. In their study of 700+ people, 84% felt more relaxed. It is also the #1 alcohol-free beer on Trustpilot.

Shop LagerSee our full ranking

Sources

• Retail Gazette: CBD, functional drinks and Trip
• IWSR: no-alcohol and functional drinks both booming
• Food Standards Agency: food fact check, CBD safety and health claims

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