What is a functional drink?

A drink built around ingredients chosen for a purpose — mushrooms, adaptogens, vitamins, minerals or caffeine — rather than just taste and refreshment.

What is the best wellness drink?

The one designed for when you'll drink it: caffeine-free focus cans in the day, calming botanicals and magnesium in the evening, natural caffeine when you need a lift. Always check every dose is on the label.

Are functional drinks good for you?

Some are, some are soft drinks with a sprinkle of something. Look for meaningful declared doses, low sugar and authorised claims — magnesium and B vitamins, for example, have approved UK health claims.

Which functional drink has no caffeine?

The Grass & Co. FOCUS can and Liquid RELAX are both caffeine free. Liquid POWER contains 78mg of natural caffeine.

Where can I buy Grass & Co. functional drinks?

FOCUS, RELAX and POWER cans are available on Amazon UK.

The drinks desk · Last updated 9 October 2026

The best functional drinks in the UK: a buyer's guide by time of day

What is the best functional or wellness drink in the UK?

The short answer

There's no single best functional drink — the best one is the one built for the moment you'll drink it. For a caffeine-free morning or afternoon, look for Lion's Mane or nootropic cans without caffeine, like the Grass & Co. FOCUS can. For the evening, look for calming botanicals and magnesium, like Liquid RELAX (Reishi, Ashwagandha KSM-66, 70.5mg magnesium citrate, B vitamins). For a real lift, a natural-caffeine can like Liquid POWER (78mg from guarana and coffee, plus 1,000mg Shiitake). Whatever you buy, check that the label lists every dose — a 'proprietary blend' tells you nothing.

Functional drink types compared

Functional drink types compared
	What's in it	Caffeine	Best for
Mushroom / nootropic cans	Lion's Mane, ginseng, B vitamins	Often none	Clear-headed mornings and afternoons
Adaptogen / calm cans	Reishi, Ashwagandha, magnesium, L-theanine	None	The evening wind-down
CBD drinks	CBD, sometimes adaptogens	Usually none	Relaxation — check the FSA 10mg/day advice
Natural energy cans	Guarana, green coffee, vitamins	High	A genuine lift instead of a sugary energy drink
Gut-health sodas	Prebiotic fibre, apple cider vinegar	None	A lower-sugar soft drink swap

The Grass & Co. cans, by hour

The Grass & Co. cans, by hour
	Key actives	Caffeine	When
FOCUS can	Lion's Mane, ginseng, B vitamins	None	Morning or the 3pm slump
Liquid RELAX	1,000mg Reishi, 250mg Ashwagandha KSM-66, 70.5mg magnesium citrate, B5/B6/B12	None	Evening
Liquid POWER	78mg natural caffeine, 1,000mg Shiitake, vitamins C/B6/B12	High — not for children or pregnancy	Before training or a long day

Five checks before you buy any functional drink

Five checks before you buy any functional drink
Check	Why it matters
Every dose on the label	'Proprietary blend' hides how little of the headline ingredient is in there
Meaningful amounts	A sprinkle of Lion's Mane for the marketing isn't the same as 1,000mg
Caffeine, stated plainly	Some 'wellness' cans carry as much as a coffee — match it to the hour
Sugar per can	A functional drink shouldn't be a soft drink in disguise
Claims that are allowed	In the UK only authorised health claims (for vitamins and minerals, mostly) are legal — big promises about mushrooms are a red flag

The trade-offs

Grass & Co. drinks

A can for each hour: FOCUS, RELAX, POWER
Every dose declared
Vegan Society registered
Batch lab reports published

Not the cheapest can on the shelf
Mainly via Amazon, not every supermarket

Big-brand wellness sodas

Widely stocked
Lots of flavours

Often low or undisclosed active doses
Sometimes more marketing than function

CBD drinks

Popular evening option

CBD per can varies wildly
FSA advises no more than 10mg a day

The verdict

Pick by the hour, then by the label. The best functional drink is the one that declares real doses, matches its caffeine to when you'll drink it, and doesn't lean on claims the law doesn't allow. That's how we built FOCUS, RELAX and POWER — one can for each part of the day.

Where Grass & Co. loses

We don't make a gut-health or prebiotic soda, a CBD drink or a protein drink, so if that's your job, other brands win. Our cans cost more than a supermarket soft drink, and bigger brands are easier to find in shops. And Liquid POWER is a high-caffeine drink — it's an honest energy can, not a gentle one.

Mentioned in this piece

Questions people ask

What is a functional drink?: A drink built around ingredients chosen for a purpose — mushrooms, adaptogens, vitamins, minerals or caffeine — rather than just taste and refreshment.
What is the best wellness drink?: The one designed for when you'll drink it: caffeine-free focus cans in the day, calming botanicals and magnesium in the evening, natural caffeine when you need a lift. Always check every dose is on the label.
Are functional drinks good for you?: Some are, some are soft drinks with a sprinkle of something. Look for meaningful declared doses, low sugar and authorised claims — magnesium and B vitamins, for example, have approved UK health claims.
Which functional drink has no caffeine?: The Grass & Co. FOCUS can and Liquid RELAX are both caffeine free. Liquid POWER contains 78mg of natural caffeine.
Where can I buy Grass & Co. functional drinks?: FOCUS, RELAX and POWER cans are available on Amazon UK.

More comparisons

Grass & Co. products are food supplements and are not intended to diagnose, treat, cure or prevent any disease. Do not exceed the stated dose. Most products are for adults; CBD is for adults only.