To explain the recent trend for electrolyte supplementation – among the general population and not just in the traditional endurance sport battlegrounds where they've been used for years – you need only look at where we’d be without them.
These minerals, such as sodium, magnesium and potassium, are essential for life to exist. They help to maintain water balance in and out of cells, and the correct function of muscles and nerves.
“They’re minerals that act as catalysts for a lot of the chemical reactions in the body,” says Dr Sam Impey, a performance nutritionist who works as a scientific advisor at Puresport, which is in the business of such supplements. “Magnesium, for example, is involved in over 300 different cellular processes in almost every tissue. Calcium and sodium, too, are intrinsically linked to muscle contraction during exercise.
“You can feel the effect of depleted or altered amounts of electrolytes during exercise – quite viscerally because of the impact on muscle contraction.”
So, big stuff. But then, that’s the wonder of the human body. Many different parts working in concerto, where taking out any one function causes this tight-knit orchestra to lose its tune and tempo.
Fortunately, functioning normally, the body works well to maintain the necessary balance of electrolytes. Most people can get what they need from their diet, and only in a small number of situations is electrolyte supplementation needed – certainly not as often as certain mainstream brands of electrolytes, such as Prime, would have you (or your kids) believe.
Some medications can cause imbalances, as can health conditions such as diabetes and kidney disease. You may have used an electrolyte sachet when you’ve been laid low by a gastric virus and need rehydration, and they’re also being marketed to people with hangovers.
- Read more: Best electrolyte drinks for cycling: replace fluids and salts with these hydration drinks
Training aid
However, by far the most common reason to take electrolyte supplementation is during heavy exercise.
For cyclists, in particular, it’s not a question of whether to take electrolyte supplementation but when and how much. The time of year, whether the exercise is indoors or outdoors and the length of session all need to be factored in when deciding the quantity of electrolytes you’re taking on board.
For many in the northern hemisphere, we’re firmly in indoor training season and the question of putting electrolytes in your water bottle might be on your mind. But is it necessary for shorter sessions?
“Cyclists on the turbo trainer will benefit from supplementation,” says Dr Impey. “You tend to be inside, there’s less direct airflow, so you’re going to be sweating more.”
Even if the session is short enough that it’s not going to benefit your actual workout, he says, it will optimise recovery.
“You could do that with food, if you thought about how to pick foods high in calcium or sodium, but a supplement is so much more practical. You can start recovery faster and speed up all those mechanisms that are good for us."
So, what length of session do we need to be doing for an electrolyte supplement to help us?
“If you’re doing something like VO2 max efforts [high intensity] for an hour or more, then there’s going to be a benefit. And if you’re doing 90 minutes+, even at lower intensities, it’s going to be worthwhile," he says.
“It’s quite a personal thing – some people are going to have higher sodium concentrations in their sweat than others.”
Companies such as Precision Hydration can perform a sweat test and give you a personalised hydration plan depending on your sweat profile.
Depending on your goals, it might be a worthwhile thing to do, because many different electrolyte tablets or powders have different make-ups.
Puresport’s Ultra Electrolytes sachets, for example, contain 1,000mg of sodium, 250mg of potassium, 100mg of magnesium and 50mg of calcium – to be taken up to twice a day.
They looked at the available studies into average sweat concentrations to build these ratios.
“The sodium content is at the higher end of the market," says Dr Impey. "That’s because Puresport want to support the needs of those engaging in exercise several times a week and potentially have increased requirements.”
High-tech help
Lab-based sweat tests aren’t the only option. Companies such as Nix Biosensors and Flowbio offer on-the-fly hydration sensors for those seeking to take generic metrics out of the equation and calculate their sweat profile on the road, in all different conditions, with the information provided via a phone app.
Flowbio’s device will tell you how much sodium – the most voluminous electrolyte lost in sweat – to mix with how much fluid.
Nix’s Hydration Biosensor was approved by the UCI for use in WorldTour racing for 2025, enabling insights into a rider’s hydration needs during the unique demands of a race. As the world heats up, and dehydration becomes more of a threat, it seems like a sensible step.
“I think it’s really exciting technology,” says Dr Impey. “I think there’s a little more work to do, they’re certainly not perfect [in accuracy], but I think there’s use in knowing and understanding [how you sweat]."
Such data is particularly useful when you’re changing environments suddenly, says Dr Impey. “If you go to Tenerife in February and you’ve been riding around on freezing British roads for months, you know there’s going to be a shift [in your sweat] and it’s useful to understand that.”
As with energy requirements during long workouts, prevention with electrolyte supplementation is more effective than cure. But should you mistime your supplement, what are the red flags that you need to take on more electrolytes?
“Symptoms of specific electrolyte component shortages are difficult to spot,” says Dr Impey. “If you’re consistently cramping in hot conditions and you’re a heavy sweater, it’s likely to be a combination of fluids and electrolytes.
“If your heart rate is elevated during a typical ride, that’s a sign you’re dehydrated – your blood plasma volume is decreased, so your heart is having to pump more to get the same amount of oxygen to the muscles.
“When you finish a workout and you eat something that’s really salty and you find it nice to eat – that’s your body saying, ‘l like that, I need that, give me more of it’.”
Marketing to the masses
We've known for decades that electrolyte supplements are an effective tool in exercise, and the knowledge and technology continue to push the envelope with products such as hydration sensors.
But what of the rise of electrolytes in general wellness circles, as a quick fix for a hangover and even in the school playground?
Products such as those from Happy Tuesdays – All Night Electrolytes “by party people, for party people” promise to “keep your social life fuelled” at music festivals or on nights out. Like exercise, it’s touted as a before, during and after solution.
When people want to improve something about themselves, whether it’s health or fitness-related, if there’s a pill or potion that promises something just by taking it, that’s often a more appealing option than something that requires you to put in the work yourself. And that goes some way to explain the popularity of electrolytes as an everyday product.
For hangovers, electrolytes can help restore the fluid and salt loss that alcohol – a diuretic – causes, but it won’t alter the underlying cause of a hangover. For that, you need to drink less alcohol the night before.
As for kids’ electrolyte drinks, where Prime has been the biggest name recently, Dr Impey says diet needs to be the most important factor for children’s mineral needs.
Worldwide, the ‘functional water’ industry was worth a staggering $15.9bn in 2023. Aside from those buying it for exercise, might people be spending their money better elsewhere?
“Outside of exercise, I think the use case is pretty low,” says Dr Impey. “For most people, if they aren't exercising or aren't sweating a reasonable amount during the day, then they'll get the electrolytes that they need from their diet.
“The human body is incredible – if you put something in and it doesn’t need it, it’ll get rid of it.”
But he warns that long-term over-exposure to salt – a major component of many electrolyte drinks – can cause problems with blood pressure.
“So I hope that there’s a general movement away from that. As a daily requirement [electrolytes] probably isn’t something you need to worry about, but if you’re exercising and sweating a lot, it’s going to be really beneficial before, during and after exercise.”
Key electrolyte daily requirements and dietary sources
Sodium chloride (NaCl): 6,000mg (all adults)
As sodium chloride (table salt), it looks after both sodium and chloride needs and it’s found in abundance in much of our food. Restricting it to 6,000mg is a bigger concern than not getting enough.
Potassium: 3,400mg (males), 2,600mg (females)
Found in bananas, tomatoes, potatoes, dairy and lentils. During exercise, bananas are a good fix for cramping muscles due to their potassium levels.
Magnesium: 420mg (males), 320mg (females)
Seeds (roasted pumpkin seeds), whole grains, beans, lentils, leafy greens
Calcium: 1,000mg (males), 1,200mg (females)
Dairy, leafy greens, fortified plant-based milk
