The global functional drinks market is now worth about £115bn a year and is predicted to double by 2030, but a Guardian taste test found that many of the brightly packaged cans and bottles lean heavily on sweetness, artificial flavouring and marketing claims rather than proven health benefits. The drinks sampled included electrolyte lemonade, probiotic fizzy pop, CBD drinks, protein waters and productivity drinks, with the article asking whether the new generation of functional drinks lives up to the hype.
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. The drinks are marketed 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." Influencers promote them, podcasters are sponsored by them, and Gillian Anderson has a functional drinks brand called G Spot.
What's Actually in These Drinks
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.
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. Last year a complaint against Trip was upheld after its ads suggested the drink could reduce levels of the stress hormone cortisol and promote calm, while last year Myota was censured for illegally suggesting a food product could have medicinal effects when promoting its metabolic booster drink. 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. 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.
The Evidence Gap
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. 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.
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.
Functional drinks aren't 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 about six decades ago before Red Bull took them global about three decades ago. 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.
The CBD Question
The Food Standards Agency on the third anniversary of its previous guidance 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."
Electrolytes and Protein
Electrolyte drinks are huge on social media, blamed on #watertok and heatwaves, and many wellness influencers sell or promote them. 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.
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. 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. 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.
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.
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."
Why This Matters:
The functional drinks market's explosive growth to £115bn globally and £100m in the UK reflects consumer demand for health benefits, but the gap between marketing claims and scientific evidence raises questions about value for money and regulatory oversight. With one in four new food and drink launches now making functional benefit claims, consumers are paying premium prices for products whose active ingredients may be present in doses too small to make a clinical difference—or whose benefits come primarily from caffeine rather than exotic botanicals. The regulatory challenges faced by brands like Trip and Myota last year show that health claims enforcement is struggling to keep pace with innovation. For consumers seeking genuine health improvements, the evidence points to whole foods and balanced diets rather than ultra-processed drinks with artificial sweeteners and unproven adaptogens. The market's success depends on whether brands can substantiate their claims or whether consumer scepticism will eventually curtail growth.",
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