Functional drinks are being sold with promises of focus, calm, energy, hydration, gut health and even beauty, but a Guardian taste test found that many of the brightly packaged cans and bottles lean heavily on sweetness, artificial flavouring and marketing claims. The pitch is simple. Buy the drink, buy the feeling. The reality, according to the article, is a market built on slogans, additives and a lot of expensive wishful thinking.
The market is booming. Globally, functional drinks are now worth about £115bn a year and are predicted to be worth twice that by 2030. In the UK, the market is generating £100m a year in sales, with a quarter of consumers now saying they want functional benefits from the drinks they buy, up from 13% in 2024. Mintel says one out of every four new food and drink launches now makes a functional benefit claim. That’s not a niche. That’s an industrial sales machine, with branding polished enough to make ordinary soft drinks look like self-improvement in a can.
Marketing the Mood
The drinks are sold with slogans such as “Show yourself some love. Fuel your focus. Life’s too good for bad energy. Find your calm in the everyday chaos. Live fit.” The article says these are not new-age slogans but marketing taglines on cans of functional soft drinks. It says influencers love them, podcasters are sponsored by them, and Gillian Anderson has a functional drinks brand called G Spot. The whole thing reads like wellness language pressed into service for retail margins.
The piece says functional drinks can contain added vitamins such as A, B12 or D, minerals such as magnesium, chromium or molybdenum, botanical ingredients such as ashwagandha, ginseng, reishi, chaga and lion’s mane mushrooms, and ingredients including green tea, yerba mate, matcha, L-theanine, caffeine or CBD. Some are enriched with collagen, protein, fibre or probiotics. Consultant dietitian Sophie Medlin, who works at City Dietitians, said: “They do offer more than other regular soft drinks do. But would I encourage people to start drinking them? No. When I’m working with patients, sometimes functional drinks can help get them off less healthy things they already drink, like colas.” She said three groups of people consume them: people who drink a lot of soft drinks and want to swap to something less unhealthy; people looking for something to drink instead of alcohol; and people who previously didn’t buy soft drinks but think functional drinks are a worthwhile addition to their diets.
The Label Does the Heavy Lifting
Health claims on foods, drinks and supplements are tightly controlled in the UK, and some brands have already been in trouble with the Advertising Standards Authority. A 2025 complaint against Trip was upheld after its ads suggested the drink could reduce levels of the stress hormone cortisol and promote calm, while in 2025 Myota was censured for illegally suggesting a food product could have medicinal effects when promoting its metabolic booster drink. The article says producers can only legally make health and nutrition claims about certain ingredients, so vitamins C, D or B12 often do a lot of heavy lifting on labels. It says that as long as a product contains 15% of an adult’s recommended daily allowance of B12 per 100ml, a brand can say its drink reduces tiredness and fatigue, supports neurological functioning and helps the immune system, regardless of whether it contains lion’s mane, ginseng or ashwagandha.
Gopi Chandratheva, a registered nutritionist who works in the NHS and privately, said some functional drinks add a long list of vitamins and minerals in small amounts to create a health perception even when those nutrients make little difference to overall intake. The article says Huel’s Daily Greens drink is marketed as containing 41 vitamins, minerals and superfoods and has high levels of vitamins D and B9, but each serving provides less than 20% of daily phosphorus, iron, zinc, molybdenum and chromium requirements. Celsius contains nearly 300% of the RDA for vitamin B7 and well over 100% of the adult RDA for B2, B3, B5, B6 and B12. Plenty of label noise. Not much clarity.
Chandratheva said products often group together ingredients with very different mechanisms of action and levels of evidence. Medlin said there’s nowhere near enough research on clinically significant doses of adaptogens and other natural products, and there are no long-term studies about people taking these products every day yet. She said the problem with adaptogens and other natural products is that ingredients such as mushrooms can vary depending on where or how they’re grown, making it difficult to know what would cause a meaningful effect. Chandratheva said mixing multiple adaptogens or nootropics with vitamins, minerals and stimulants such as caffeine, or relaxants such as CBD, might not be wise. “These drinks should be taken with caution, as they contain bioactive compounds and may interact with other medications,” she said. “Often other ingredients are added to these drinks which can outweigh the benefits.” Medlin said if people feel a benefit, it’s likely to be from ingredients like caffeine rather than from the ingredients they’re paying a lot of money for.
Old Tricks, New Packaging
The article says functional drinks are not exactly new. Teas, coffee and alcohol are described as the original functional drinks, while probiotic fermented drinks such as kefir also have a long history. Coca Cola was marketed in the late 19th century as a medicinal temperance drink to rival alcoholic tonic wines and was supposed to cure everything from addiction to indigestion. Energy drinks containing taurine and caffeine emerged in the 1960s before Red Bull took them global in the 1990s. Sports drinks such as Lucozade and Gatorade are also functional drinks. The new breed of mushroom-laden, herb-infused self-optimisation-obsessed functional drink really took off during the pandemic.
Laura Willoughby, alcohol-free drinks expert and founder of the Club Soda mindful drinking movement, said the number of people who don’t drink at all has plateaued in recent years, but the number of people who want to drink less is still rising. She sees functional drinks as a great stand-in for alcohol, and so does Sian Fellowes, who works in hospitality and said: “I haven’t drunk alcohol for six months and I lean very heavily on functional drinks as replacements.” Not everyone who is sober agrees. Tom said: “I gave up drink and drugs because I didn’t want to take anything mind-altering any more. Functional drinks have zero appeal to me.”
The Food Standards Agency in 2023 lowered its recommended daily intake limit for CBD to 10mg from 70mg after new evidence emerged that long-term use might be connected to liver damage and thyroid disease. Chandratheva said CBD has specific medical uses and there is some evidence for anxiety reduction, but most consumer drinks contain relatively small doses and the evidence for meaningful effects from low doses remains limited. Most human trials looking at CBD for anxiety have used doses from 150mg to 600mg. A single can of a Goodrays CBD drink contains 10mg, as do Trip’s CBD drinks. Medahuman’s CBD drinks contain 20mg and a can of Hip Pop’s CBD kombucha has 15mg.
Ceri Jones, a chef and food educator, said: “I’ve tried a CBD drink a few times and always feel incredibly weird for an hour afterwards. A kind of calm-but-spaced-out confusion. I had one on a train a few weeks back, then couldn’t find my way out of the station. So they definitely do something!” Dan Farr, a copywriter, said: “I use CBD drinks, often in the evening because they calm my brain. They work particularly well at the end of the week, or if I’ve been drinking the night before, and help my nervous system settle back into a ‘normal’ rhythm and calm my anxiety.”
Electrolyte drinks are huge on social media, blamed on #watertok and heatwaves, and many wellness influencers sell or promote them. Historically, people probably only drank electrolytes if they’d had a stomach upset, and most electrolyte drinks contain sodium, potassium, calcium and magnesium, and perhaps sugar. Modern electrolyte drinks are marketed on the basis that water alone isn’t fully hydrating. Medlin said that isn’t true: “If you’re drinking enough water and you’re eating a normal diet, you don’t need electrolytes.” She said the popularity of electrolyte drinks and powders may mean many people are suddenly consuming too much salt. The UK guidance says adults should have no more than 6g of salt per day, while the WHO says 5g. Cadence contains 1.25g of salt per 330ml can, as does Na11.
Medlin said magnesium waters are not particularly helpful either. She said if people have symptoms of magnesium deficiency, such as muscle cramps, or are struggling with sleep or mental energy levels or brain fog, it’s worth experimenting with a magnesium capsule. OHMG’s blackcurrant sparkling water contains 100mg of magnesium per can, about a quarter of a UK adult’s NRV, while BetterYou’s citrus and botanical magnesium water contains about half the NRV per can.
On protein or collagen water, Medlin said many people may benefit from more protein in their diet, but if they feel they need more protein, they should eat more protein rather than having a drink with lots of additives. She said these drinks are ultra-processed foods and should be seen in that light rather than as something beneficial. The article says there is still a large gap between what collagen products claim and what the research says, with little high-quality, large-scale research to suggest extra collagen positively affects joints, skin, hair or nails. It says bovine collagen is industrially extracted from the skin, connective tissue and bones left over after cows are slaughtered for meat, while marine collagen is made from fish bones and viscera. Vegan collagen is described as a selection of plant-based peptides mimicking those found in animal-based collagen.
Few functional drinks contain sugar; most use artificial sweeteners, usually steviol glycosides or sucralose, acesulfame potassium or erythritol. Steviol glycosides are 200-400 times sweeter than sugar and sucralose is about 600 times sweeter. Medlin said most sweeteners are ultra-sweet and can make people more likely to look for sugary and sweet things elsewhere, training palates to want sweet flavours. She said that as a gut-health dietitian, she is careful with sweeteners because they’re detrimental to gut bacteria.
Caffeine also needs a health warning. A cup of tea contains 30-50mg of caffeine and a cup of coffee 60-100mg, depending on size and strength, but some energy drinks contain 200mg per can. Chandratheva said too much caffeine can affect health negatively, cause anxiety and poor sleep, and in rare cases fatal heart arrhythmia can result from drinking well above the NRV of 400mg a day or a large amount very quickly. The American Academy of Pediatrics advises that children under 12 do not drink caffeine, and children aged 12-18 should have no more than 100mg a day. In the UK, the NHS says babies and young children should not drink it, and the government is consulting on whether to ban the sale of caffeinated drinks to under-16s in England.
The article says functional drinks with added fibre or live probiotics are perhaps the least problematic and in some cases the least processed. Medlin said adding fibre or probiotics to diets is not unreasonable, but she worries about people with irritable bowel syndrome because most added-fibre drinks contain inulin, usually from chicory root, and that can trigger IBS symptoms. Dr Daniel Lamport, a psychologist at the University of Reading who studies the impact of nutrition on cognition and mental health, said: “There is a place for functional foods, but I’m not convinced there is currently a robust evidence base for many of the claims being made for wellbeing and cognition.” He added: “Ultimately, there is no substitute for a fibre-rich, fruit-and-vegetable-rich, whole-foods diet; on that front, the evidence is clear and compelling on the benefits for cognitive health.”