Electrolytes: What They Are, Who Needs Them & Which Powder to Buy
Electrolytes are the salts in your body, mainly sodium and potassium. Food gives most people more sodium than they need. You need an electrolyte drink only in long or hard exercise, heat or heavy sweat.
Start here
Do you need electrolytes?
Here is each common claim, graded by the best human evidence we found.
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Guidelines back itReplacing sodium in long, hot or hard exercise
Sports guidelines back them for long or hard exercise, heavy sweat and heat. Needs vary a lot between people. How much sodium, by the hour
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StudiedSugar helping sodium absorb
Glucose (a sugar) and sodium cross the gut wall together, and water follows (Wright 2011). Rehydration solutions are built on this. Sugar in each formula
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Not shownMore sodium is always better
Unclear. A 2022 review of 28 studies did not test drinks saltier than about 1,150 mg per liter; within that range, more electrolyte helped. What that review found
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Not shownPreventing muscle cramps
Two small studies found no clear link to low salt (Sulzer 2005, Miller 2010). Cramps have many causes. Cramps and sodium
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Not shownEasing “keto flu” on keto or fasting
Some people on low-carb diets add sodium. Low insulin may make the kidneys pass more of it (DeFronzo 1975), but no trial has set a dose. Keto and fasting
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Not neededSipping them every day at rest
At rest there is little sweat loss to replace (next section). The daily limit
How much sodium you need
On a normal day, you need no extra (the daily limit). In exercise, what you lose depends on how much and how salty you sweat, which varies a lot (Baker 2016).
| Your situation | What to drink |
|---|---|
| Under an hour of exercise, or a normal day | Water. |
| Long or hard exercise, heavy sweat, heat | A sodium drink. Start with one serving and adjust. Your hourly loss |
| Keto or fasting | No set amount. Some people report adding sodium, but no trial has set a dose. Ask your doctor first if you take blood pressure or diabetes medicine. Keto and fasting |
| High blood pressure, heart failure, kidney disease, or a low-salt diet | Ask your doctor before a high-sodium drink. Extra sodium can raise blood pressure (FDA). |
| Kidney disease, or you take an ACE inhibitor, an ARB or a potassium-sparing water pill | Ask your doctor before a high-potassium drink. These drinks hold potassium too, and these conditions and medicines can raise blood potassium. |
Check the sodium line: most powders are low
Many powders hold far less sodium than a hard hour of sweat. We read the NIH labels of 184 electrolyte powders from 62 brands. The typical serving had 180 mg of sodium, and 76% had under 300 mg. More than half listed more potassium than sodium, though sodium is the main mineral you sweat out.
| Item | Value |
|---|---|
| A hard hour of sweat, average athlete | 1,000 mg |
| LMNT Recharge, one stick | 1,000 mg |
| Our pick (Redmond), one scoop | 810 mg |
| Typical powder label (median) | 180 mg |
The dosage guide has sodium lost per hour by sweat rate, and how many servings of each product cover it.
Which electrolyte to buy
Buy a drink with enough sodium to matter that is on a public testing list. Our pick is Redmond Re-Lyte Hydration, at the top of the page. No tested electrolyte costs less per 1,000 mg of sodium. 7 of the 11 drinks we score are on a list. LMNT, the best-known brand, has the most sodium in one stick (1,000 mg), and it is on Informed Choice.
- Buy Transparent Labs Hydrate — Tropical Punch (40 servings) on Amazon
- Buy BUBS Naturals Hydrate or Die Electrolytes (20 sticks) on Amazon
- Buy LMNT Recharge Electrolytes — Citrus Salt (30 sticks) on Amazon
- Buy Nuun Sport Electrolyte Tablets — Lemon Lime (40 tablets) on Amazon
- Buy SaltStick FastChews Chewable Electrolytes — Lemon Lime (60 chews / 30 servings) on Amazon
- Buy Liquid I.V. Sugar-Free Hydration Multiplier — Lemon Lime (14 sticks) on Amazon
See all 11 we score, with each score, cost and testing list.
When you don’t need one
- It’s a normal day, or your workout is under an hour. Drink water.
- You want it for cramps. Two small studies found no clear link between cramps and low salt (see above).
- You have high blood pressure, heart failure or other heart disease, or kidney disease, or a doctor told you to limit salt. Ask your doctor first (see the table above). The same goes if you take a water pill, an ACE inhibitor or an ARB: these drinks hold sodium and potassium.
- You plan to drink a lot of water on a long run. Don’t drink so much that you gain weight during the event. Too much water can drive blood sodium down, as it did in some marathon runners (the marathon data).
How fast do they work? Sports-drink studies track blood volume over the first 3 hours of exercise (Rowlands 2022), but none we cite gives a simple “works in X minutes” figure.
Electrolyte guides
Do you need them?
How much
Which formula
Which product
Sports drinks are not oral rehydration solutions. If you are sick with vomiting or diarrhea, ask a doctor or pharmacist what to drink. For a sick child, ask a pediatrician.
Questions
What are electrolytes and what do they do?
Electrolytes are minerals that carry an electric charge in your body, mainly sodium, potassium, chloride and magnesium. They help control how much water your body holds, and they let your nerves and muscles work. Sodium is the main one you lose in sweat (Baker 2016).
Do I actually need an electrolyte supplement?
Probably not, if you eat a normal diet and exercise for less than an hour. Food gives most people more sodium than they need: Americans eat about 3,400 mg a day, over the 2,300 mg limit (FDA). Sports guidelines back sodium drinks for long or hard exercise, heavy sweat and heat (ACSM 2007). How much you need
What should I look for in an electrolyte powder?
Check the sodium first. The typical powder label we read had 180 mg a serving, and 76% had under 300 mg. In sweat, an average athlete loses about 1,000 mg in a hard hour (Baker 2016). Then check the sugar (useful fuel in long exercise, not needed otherwise), the cost per 1,000 mg of sodium, and whether it is on a public testing list. Our pick, Redmond Re-Lyte Hydration, has 810 mg of sodium and no sugar, and is on Informed Choice. See Redmond Re-Lyte Hydration on Amazon
Does the sugar in some electrolyte formulas actually help, or is it marketing?
It helps, for one job. Glucose (a sugar) and sodium cross the gut wall together, and water follows (Wright 2011). In hard exercise over an hour, sugar is also fuel (ACSM 1996). For everyday sipping or keto, you don’t need it.
What's the bigger real-world risk — not getting enough electrolytes, or something else?
In long endurance events, drinking too much water is a known risk. It can drive blood sodium dangerously low, called hyponatremia. In the 2002 Boston Marathon, 13% of runners tested had low blood sodium. Weight gain during the race was the strongest factor linked to it, along with racing over 4 hours and very low or high body weight (Almond 2005). A 2015 expert consensus advises drinking to thirst (Hew-Butler 2015). Don’t overdrink
Do electrolytes help with keto specifically?
Some people on low-carb diets add sodium. Insulin makes the kidneys hold on to sodium (DeFronzo 1975), so lower insulin on keto may make them pass more. Tiredness and headache in the first days, called keto flu, come from people’s own reports (Bostock 2020). No trial has set a sodium dose. Ask your doctor first if you have high blood pressure, heart or kidney disease, or take blood pressure or diabetes medicine. Keto and fasting
How long does it take for electrolytes to work?
No study we cite gives a simple “works in X minutes” figure. Sports-drink studies track blood volume over the first 3 hours of exercise (Rowlands 2022). So drink during long exercise, rather than waiting to feel a change.
Does the sugar in some electrolyte drinks make them work faster?
Sugar helps the gut take up sodium and water (Wright 2011), but no study we cite times it in minutes. More sugar is not always better: in a 2022 review, lower-strength drinks kept blood volume up best (Rowlands 2022). What that review found
How long can you go before over-hydrating becomes a risk?
It depends on how much you drink, not on the time. The warning sign is gaining weight during an event, which means you drank more than you sweated out. In the Boston Marathon study, weight gain and finishing in over 4 hours were both linked to low blood sodium (Almond 2005).
If there's no onset-time data, how do I know when to use electrolytes?
Use them for long or hard exercise, heavy sweat or heat. In sweat, an average athlete loses about 1,000 mg of sodium an hour, but it varies a lot (Baker 2016). That is a loss, not a target: you do not have to replace all of it. Start with one serving, drink to thirst, and adjust. On a normal day, or for a workout under an hour, water is enough. Your hourly loss
How we checked this
Scores. Every electrolyte we score gets the same five marks: sodium per serving, testing you can look up, cost per 1,000 mg of sodium, a label that states the amounts, and no recall. Scores checked October 27, 2026. Full method.
Testing lists. We searched five public testing lists for each of the 12 electrolyte products we checked. 8 are on at least one list. One of those is listed but not scored, because we could not price it: Klean Athlete Klean Hydration, Natural Orange (NSF Certified for Sport). NSF lists one Liquid I.V. flavor, Sugar Free Raspberry Lemonade, and other DripDrop sticks (21 g, 17 g and 9 g); none is the product we price.
The shelf. The label figures above come from 184 electrolyte powder labels from 62 brands in NIH’s Dietary Supplement Label Database, read September 18, 2026. We report only figures that held in both halves of a random split of the labels.
Sources
- Sawka MN, et al. ACSM position stand: exercise and fluid replacement. 2007. PubMed 17277604 (sodium drinks in long, hard or hot exercise). Convertino VA, et al. ACSM position stand: exercise and fluid replacement. 1996. PubMed 9303999 (under an hour, little difference between a sports drink and water).
- Baker LB, et al. Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. J Sports Sci. 2016. PubMed 26070030. From Gatorade’s research institute (details).
- Wright EM, et al. 2011. PubMed 21527736
- Rowlands DS, et al. Sports Med. 2022. PubMed 34716905. No outside funding; its lead author was previously paid by Lucozade-Ribena-Suntory and Frucor, two sports-drink makers, to report on weaker drinks. Sulzer NU, et al. 2005. PubMed 16015122. Miller KC, et al. 2010. PubMed 19997012
- DeFronzo RA, et al. 1975. PubMed 1120786. Almond CS, et al. N Engl J Med. 2005. PubMed 15829535. Hew-Butler T, et al. Exercise-associated hyponatremia consensus. Clin J Sport Med. 2015. PubMed 26102445. Bostock ECS, et al. Front Nutr. 2020. PubMed 32232045
- FDA, sodium in your diet (2,300 mg limit; about 3,400 mg average intake; high sodium raises blood pressure). Label census: NIH Dietary Supplement Label Database, read September 18, 2026.