Electrolyte Caplets vs Powder vs Drinks for Running

Electrolyte caplets, powders and ready-made drinks can all deliver the same sodium; the real difference is whether that sodium is tied to the fluid you drink. Drinks and powders are the simplest choice when you can mix or pick up the same drink all race, while caplets suit races where you refill with plain water and want to count sodium separately.

None of them is worth carrying for a run under an hour, where water is enough. Between 60 and 90 minutes, consider one only if it’s hot, you sweat heavily or salty (white marks on your cap or shirt), or you’re training twice that day. Past 90 minutes in Malaysian heat, plan some sodium, sized to the fluid you actually drink, with roughly 200 to 550 mg an hour as a starting range. Our guide to how much sodium runners need per hour explains where that range comes from. This piece is about the format.

What matters more than the format?

The ratio of sodium to water. The American College of Sports Medicine’s fluid position stand suggests drinks with about 20 to 30 mmol of sodium per litre, roughly 460 to 690 mg (Sawka et al., 2007). For ultra-marathons, the International Society of Sports Nutrition goes further and says concentrations above 575 mg per litre, more than most commercial drinks provide, may be needed to reduce the risk of low blood sodium (Tiller et al., 2019).

Whatever format you choose, it’s doing one job: putting a known amount of sodium next to a known amount of water. The danger isn’t picking the wrong format. It’s drinking far more than you sweat, whatever is in the bottle. In a study of 161 km ultra finishers, those who developed low blood sodium had taken sodium supplements at the same rate as everyone else; overdrinking set them apart (Hoffman and Stuempfle, 2015). We explain the warning signs in dehydration vs hyponatremia in ultras.

How do the three formats compare?

Two things in that table catch people. Sports drinks vary a lot in sodium, so read the sodium line on the label and multiply by what you’ll drink rather than assuming “isotonic” means enough. And a caplet without water is sodium without the fluid it was meant to go with; take each one with a proper drink, not a sip.

Which format for which Malaysian session?

Road half or full marathon with drink stations. If the race serves an isotonic drink at most stations and you’re happy drinking it, that’s usually enough sodium for a recreational marathon. Check the label of the race’s drink sponsor in advance. If the stations near the end only have water, or you dislike the drink, a caplet or two in your pocket fills the gap. At the Borneo International Marathon in Kota Kinabalu, or any hot coastal course, the back half is where this matters most.

Long road ride. Powder wins. You carry two bottles, you can mix one strong and one plain, and petrol stations sell plain water. We set out a five-hour plan in cycling hydration in Malaysian heat.

Trail ultra with water-only refills. This is where caplets earn their place. When the aid station fills your flask with plain water and the next one is two hours up a ridge, separating sodium from fluid is the easiest way to keep the numbers right. Some races offer an electrolyte drink at every station; check the race guide for the Taman Negara Ultra or whatever you’ve entered, rather than assuming.

Weekend hike or training run up Bukit Kutu. For most people, water plus a normal salty breakfast and snack is fine. If you’re out four hours in the midday heat and finish with white crust on your cap, take a powder sachet or a caplet next time.

Gym, 5K, 10K, an hour of football. Water. Skip the electrolytes and eat a normal meal afterwards.

A worked example: one runner, three formats

Take a runner who has measured their sweat rate at about 1 litre an hour and plans to drink 600 ml an hour during a five-hour marathon. They want around 300 to 400 mg of sodium an hour.

• Drink only: a sports drink at 20 mmol per litre gives 460 mg per litre, so 600 ml provides about 275 mg an hour. At 30 mmol per litre, about 415 mg. Which end you’re at depends entirely on the brand.
• Powder: mixed to 700 mg per litre, 600 ml gives 420 mg. Mixed half strength because it tasted salty in training, 210 mg. The scoop decides.
• Caplets with plain water: at 220 mg each, taking one with every 500 ml gives about 265 mg an hour. Add a salty snack at halfway and the total sits comfortably in range.

Any of the three works. What fails is the runner who drinks 1.2 litres an hour of plain water “to be safe” and then takes caplets on top to compensate. The fix there is to drink less, not to add salt. Use our sweat rate calculator to find your own number before choosing anything.

Does extra sodium make you faster?

The evidence says no, at least in the short term. In a double-blind crossover trial, 11 endurance athletes exercised for two hours with either 1,800 mg of sodium or a placebo. Sweat rate, heart rate drift, skin temperature, perceived effort and the time-to-exhaustion test that followed were the same in both trials (Earhart et al., 2015). At the 2001 Cape Town Ironman, 413 triathletes were randomised to salt tablets, placebo tablets or nothing. Athletes taking salt swallowed an extra 3.6 g of sodium on average, and their blood sodium at the finish was no different from the other groups (Hew-Butler et al., 2006).

So treat electrolytes as a way to keep sodium in step with what you drink over a long, hot day, not as a performance aid. If someone sells you a format by saying it makes you faster, ask for the study.

Choosing a caplet: what to check on the label

• Sodium per caplet, in milligrams. Not “electrolytes” and not “salt”. Table salt is about 39% sodium by weight.
• Directions that link to fluid. A dose per 500 ml of water is easier to follow honestly than a dose per hour.
• A daily maximum. Useful as a ceiling on race day.
• Other minerals. Fine to have, but sodium is the one sweat loses in quantity.

Our own caplet, Elec Stamina, lists 220 mg of sodium, 90 mg of potassium, 50 mg of calcium and 15 mg of magnesium per caplet. The pack directions are one caplet for every 500 ml of water you drink during exercise, up to ten a day. It’s built for long, hot sessions where you refill with plain water. If your runs are under an hour, you don’t need it, and if a sports drink already covers your race, you may not either. If a doctor has told you to limit salt, ask them before using any electrolyte product.

For the bigger picture on fluid, heat and sodium, start from our running hydration and electrolytes guide for Malaysia.

References

1. Sawka MN, Burke LM, Eichner ER, et al. (2007). American College of Sports Medicine position stand: exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377-390. doi:10.1249/mss.0b013e31802ca597
2. Tiller NB, Roberts JD, Beasley L, et al. (2019). International Society of Sports Nutrition position stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 16(1), 50. doi:10.1186/s12970-019-0312-9
3. Hoffman MD, Stuempfle KJ (2015). Sodium supplementation and exercise-associated hyponatremia during prolonged exercise. Medicine & Science in Sports & Exercise, 47(9), 1781-1787. doi:10.1249/MSS.0000000000000599
4. Earhart EL, Weiss EP, Rahman R, Kelly PV (2015). Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes. Journal of Sports Science & Medicine, 14(1), 172-178. PMC4306770
5. Hew-Butler TD, Sharwood K, Collins M, Speedy D, Noakes T (2006). Sodium supplementation is not required to maintain serum sodium concentrations during an Ironman triathlon. British Journal of Sports Medicine, 40(3), 255-259. doi:10.1136/bjsm.2005.022418