Functional beverages, decoded: which ones do anything and which are sugar-water with a halo

Walk down the drinks aisle and almost everything now promises to do something: heal your gut, calm your mind, sharpen your focus, power your workout. Functional beverages, drinks sold on a health claim rather than just taste, are one of the fastest-growing corners of food, and the money is real. PepsiCo paid about 1.95 billion dollars for the prebiotic soda Poppi in 2025, and its rival Olipop hit a 1.85 billion dollar valuation on more than 400 million dollars in sales. What is less clear is whether the drinks do what the cans say. The honest test, almost every time, is dose.

Prebiotic sodas: one earns it, one settled a lawsuit

The hottest sub-category is gut-health soda, and it is also the clearest case study in dose. A can of Poppi contains only about 2 grams of prebiotic fibre. The research on inulin, the fibre involved, suggests you need roughly 5 grams a day to shift gut bacteria, so you would have to drink several cans, at which point the sugar works against you. Poppi settled a class action over its gut-health marketing for 8.9 million dollars in 2025, a private lawsuit rather than a regulator's action, and denied wrongdoing. Olipop, by contrast, packs around 9 grams of fibre a can, which sits inside the studied effective range. That difference is the whole story: same category, same promise, very different odds of delivering.

Electrolyte drinks: match them to your sweat

Electrolyte sticks are marketed as everyday hydration, but they were built for people losing a lot of salt. A single LMNT stick carries 1,000 milligrams of sodium, above the American Heart Association's ideal daily limit of 1,500 milligrams. For an endurance athlete, a heavy sweater or someone working in the heat, that is the point and it is useful. For a sedentary person sipping one at a desk instead of water, it is unnecessary, and for anyone with high blood pressure or kidney issues it is a genuine caution. This is a drink whose value depends entirely on the person drinking it.

Adaptogens, nootropics and mushroom coffee: mostly underdosed

Here the halo does most of the work. Ashwagandha, the marquee adaptogen, showed effects on stress and sleep in trials that used 600 milligrams a day or more, and even that evidence is rated low certainty. Most adaptogen drinks contain a fraction of that. Mushroom coffee is the same shape of problem: studies of lion's mane or cordyceps used 750 to 3,000 milligrams of a single extract, while a typical mushroom-coffee serving delivers perhaps 100 to 250 milligrams of a blend, and no trial has tested the blended product itself. Nootropic focus drinks mostly work because of caffeine, which is real, with the novel actives along for the ride.

Kombucha and sleep drinks: it depends

Kombucha is a pleasant, lower-sugar fermented drink, but the human evidence for its health claims is sparse and mixed, and the live bacteria are not standardised between brands. Sleep and calm drinks are ingredient-dependent: melatonin has solid evidence at 0.5 to 5 milligrams and is the one to look for, while magnesium, GABA and L-theanine are weaker as sleep aids. In every case the label, not the name, tells you whether there is a real dose inside.

Our take

Functional beverages are not a scam, but they are not medicine either. A prebiotic soda with 5 grams of fibre or more is a legitimately better choice than a sugary cola, an electrolyte mix earns its place around hard exercise, and a properly dosed melatonin drink can help sleep. Most of the rest is a trace of a trendy ingredient floated in a nicely branded can. Turn the can around, find the milligrams, and if the dose is hidden in a proprietary blend, assume it is below what the studies used. Then remember that whole foods do the real work for less money.

This is general information, not medical or dietary advice. If you have high blood pressure, kidney disease or take regular medication, check with a clinician before adding high-sodium or high-dose functional drinks.