You finish a long Sunday run, pour yourself a glass of water, and within an hour you’ve got a splitting headache and your legs are cramping. Water alone doesn’t cut it once you’re sweating properly — you need sodium, potassium, and magnesium back in your system. The electrolyte drink market has exploded in the past few years, and now every running shop in the UK has an entire wall of tablets, powders, and ready-to-drink options. Most are fine. Some are overpriced sugar water. A few are exactly what runners actually need.
In This Article
- Why Runners Need Electrolytes
- Best Electrolyte Tablets
- Best Electrolyte Powders
- Best Ready-to-Drink Options
- What to Look for in an Electrolyte Drink
- When to Use Electrolytes: Before, During, and After
- Electrolytes vs Energy Drinks vs Isotonic Sports Drinks
- Budget Picks vs Premium Options
- Frequently Asked Questions
Why Runners Need Electrolytes
When you sweat, you don’t just lose water — you lose dissolved minerals that your muscles and nerves need to function. The average runner loses 1-2 litres of sweat per hour in moderate conditions, and each litre contains roughly 900-1400mg of sodium plus smaller amounts of potassium, magnesium, and calcium.
What Happens When Electrolytes Drop
- Sodium depletion — muscle cramps, nausea, headache, confusion in severe cases
- Potassium loss — muscle weakness, irregular heartbeat, fatigue
- Magnesium deficit — cramping, muscle twitching, poor recovery
- Calcium drop — tingling in extremities, muscle spasms
When Water Alone Isn’t Enough
For runs under 60 minutes in cool weather, plain water is usually fine. But electrolyte replacement becomes important when:
- Running longer than 60-90 minutes
- Running in temperatures above 20°C (see our hot weather running guide for more)
- You’re a heavy sweater (salt stains on your kit are the giveaway)
- Training twice in one day
- Running a race where you need to perform, not just finish
The NHS hydration guidelines confirm that physical activity increases fluid and mineral requirements beyond normal daily needs.
Best Electrolyte Tablets
Tablets are the most popular format for UK runners — portable, lightweight, and easy to dose. Drop one in your bottle, wait for it to dissolve, and you’re set.
SiS GO Hydro (Best Overall Tablet)
About £8 for 20 tablets | 40p per serving
- Sodium: 525mg per tablet
- Potassium: 65mg
- Magnesium: 12mg
- Calories: 8 per tablet (virtually zero-calorie)
- Flavours: lemon, berry, pineapple & mango, cola
- Dissolve time: about 2 minutes in 500ml water
SiS is the dominant brand in UK running for good reason. Their GO Hydro tablets deliver a high sodium dose without any meaningful sugar — ideal if you’re getting calories from gels separately and just want hydration. The flavour is light enough to drink all day without becoming sickly, which matters during long training sessions. Available everywhere from Boots to Decathlon to every running shop in Britain.
Precision Hydration PH 1000 (Best for Heavy Sweaters)
About £9 for 10 tablets | 90p per serving
- Sodium: 1000mg per tablet (the highest on this list)
- Potassium: 100mg
- Magnesium: 25mg
- Calories: 6 per tablet
- Flavours: unflavoured
- Dissolve time: about 90 seconds in 500ml
If you regularly finish runs with white salt lines on your face and kit, Precision Hydration exists for you. Their PH 1000 tablets contain nearly double the sodium of standard electrolyte tablets. They also offer PH 250, 500, and 1500 variants so you can match your intake to your actual sweat rate — something no other brand offers at this granularity.
The unflavoured option means you can add it to whatever you’re already drinking without flavour clashes. More expensive per serving than SiS, but worth it for genuinely heavy sweaters who cramp on standard-strength products.
Nuun Sport (Best Flavour Range)
About £8 for 10 tablets | 80p per serving
- Sodium: 300mg per tablet
- Potassium: 150mg
- Magnesium: 25mg
- Calories: 15 per tablet
- Flavours: 12+ options including watermelon, tropical, strawberry lemonade
- Dissolve time: about 3-4 minutes in 500ml
Nuun is the brand for people who find most electrolyte drinks boring or unpleasant. Their flavour range is vast and most of them taste like an actual drink rather than salty medicine. Lower sodium than SiS or Precision Hydration, but the higher potassium and magnesium balance compensates for moderate sweaters. The tubes are small enough to carry two in a running vest pocket.
Best Electrolyte Powders
Powders give you more control over concentration and usually work out cheaper per serving than tablets. They also dissolve faster and can be mixed stronger for particularly sweaty sessions.
SiS GO Electrolyte Powder (Best All-in-One)
About £25 for 1.6kg (40 servings) | 63p per serving
- Sodium: 340mg per 40g serving
- Potassium: 60mg
- Carbohydrates: 36g (delivers energy alongside electrolytes)
- Flavours: lemon & lime, orange, tropical
- Best for: long runs where you want hydration AND fuel in one drink
This is an isotonic formula — it replaces both electrolytes and energy in one product. At 36g carbs per serving, it’s designed for runs over 90 minutes where you’d otherwise need separate drinks and gels. Mixes cleanly without clumps if you shake properly. The 1.6kg tub is excellent value for regular marathon trainers.
Skratch Labs Hydration Mix (Best Natural Formula)
About £22 for 20 servings | £1.10 per serving
- Sodium: 380mg per serving
- Potassium: 39mg
- Magnesium: 39mg
- Calories: 80 per serving
- Flavours: lemon & lime, raspberry, strawberry, matcha green tea
- Best for: runners who react badly to artificial sweeteners or flavourings
Skratch uses real fruit for flavour rather than artificial sweeteners — a genuine differentiator for runners whose stomachs rebel during exercise. The ingredient list is short and recognisable: cane sugar, dextrose, sodium citrate, fruit powder. If other electrolyte products give you GI issues during long runs, try Skratch. Available from Sigma Sports and most specialist running retailers in the UK.
High5 Zero (Best Budget Powder)
About £6 for 20 tablets | 30p per serving
- Sodium: 250mg per tablet
- Potassium: 65mg
- Magnesium: 50mg (highest magnesium here)
- Calories: 5 per tablet
- Flavours: citrus, berry, tropical, blackcurrant
- Best for: daily training hydration without breaking the bank
High5 Zero is technically a tablet but functions like an instant powder — it fizzes up rapidly and dissolves faster than the competition. At 30p per serving, it’s by far the cheapest option that still delivers meaningful electrolytes. The high magnesium content is notable — useful for runners who cramp despite adequate sodium intake, as magnesium deficiency is often the hidden culprit.
Best Ready-to-Drink Options
Sometimes you don’t want to measure, mix, or wait. Ready-to-drink electrolyte beverages cost more but deliver convenience.
Lucozade Sport Low Cal (Best Supermarket Option)
About £1.50 per 500ml bottle
- Sodium: 200mg per bottle
- Potassium: trace
- Calories: 50 per bottle
- Available: every Tesco, Sainsbury’s, Co-op, and petrol station in the UK
The realistic option for most runners. Lucozade Sport Low Cal delivers basic electrolyte replacement with minimal sugar, and you can buy it at literally any shop on your run route. Is it optimal? No — the sodium is lower than tablets. Is it convenient and good enough for a midweek training run? Without question.
Tribe Hydrate (Best Clean Ingredients)
About £2.50 per 500ml carton
- Sodium: 300mg
- Potassium: 200mg (highest potassium of any option here)
- Calories: 40 per carton
- Ingredients: coconut water, fruit juice, Himalayan salt
- Available: Holland & Barrett, Whole Foods, online
Tribe uses coconut water as the base — naturally rich in potassium — and adds Himalayan salt for sodium. No artificial anything. The taste is light and slightly tropical. Premium priced but popular with ultrarunners and natural-food-focused athletes. The cartons fit in most running vest pockets though they’re slightly bulky compared to soft flasks.
ORS Hydration Tablets (Best Medical-Grade)
About £4 for 12 tablets | 33p per serving
- Sodium: 470mg per tablet
- Potassium: 300mg
- Glucose: 3.5g (small amount aids absorption)
- Available: Boots, pharmacies, Amazon
- Based on: WHO oral rehydration formula
Originally designed for treating dehydration from illness, ORS tablets follow the World Health Organisation’s proven oral rehydration formula — the same science used in developing countries to treat cholera dehydration. For runners, this means maximum absorption efficiency. The taste is functional rather than pleasant (salty-sweet), but if you want the most scientifically proven formula for actual rehydration, nothing beats it.
What to Look for in an Electrolyte Drink
Sodium Content (Most Important)
Sodium is what you lose most of through sweat. Look for at least 300mg per serving for moderate sweaters, 500mg+ for heavy sweaters. Products with under 200mg sodium are glorified flavoured water.
Low or Zero Sugar
Unless you specifically want energy (long runs, races), choose low-calorie electrolyte products. Sugar aids absorption slightly but most runners get enough carbs from food and gels separately. Mixing high-sugar electrolyte drinks with gels risks GI distress.
Stomach Tolerance
The best electrolyte drink is one you can actually stomach while running. Test any new product on training runs before race day. Common issues: artificial sweetener sensitivity (try Skratch), excessive sweetness (try Precision Hydration unflavoured), carbonation causing bloating (avoid tablets that fizz too much in the bottle).
Practical Considerations
- Dissolve time — waiting 5 minutes for a tablet to dissolve at a race start is stressful. SiS and Precision dissolve fastest.
- Flavour fatigue — can you drink this for 4 hours during a marathon? Subtle flavours beat strong ones over time.
- Temperature stability — powders and tablets travel better than liquids in heat. A warm pre-mixed bottle grows bacteria faster.
When to Use Electrolytes: Before, During, and After
Pre-Run (Preloading)
Drink 500ml of electrolyte solution 60-90 minutes before a long run or race. This tops up your stores and ensures you start properly hydrated. Don’t guzzle it immediately before starting — you’ll just need the loo at kilometre two.
During Runs
- Under 60 minutes: water only (unless it’s hot)
- 60-90 minutes: sip electrolyte drink every 15-20 minutes
- Over 90 minutes: drink 400-800ml per hour of electrolyte solution, adjusting for heat and sweat rate
- Races: have a plan — don’t rely on whatever the race provides if it’s a brand you’ve never tried
Post-Run (Recovery)
Replace 150% of fluid lost within 2-3 hours after finishing. Weigh yourself before and after a long run — every kilogram lost represents roughly a litre of fluid needed. An electrolyte drink in this window speeds recovery faster than plain water because sodium helps your body retain fluid rather than just flushing it through.
Electrolytes vs Energy Drinks vs Isotonic Sports Drinks
These three categories get confused constantly. They serve different purposes:
Electrolyte drinks (what this article covers):
- Primary purpose: replace minerals lost through sweat
- Low or zero calories
- Examples: SiS GO Hydro, Nuun, Precision Hydration
Energy drinks (Red Bull, Monster, etc.):
- Primary purpose: caffeine and sugar boost
- Very high calories and stimulants
- NOT designed for exercise hydration — the caffeine is diuretic and the sugar concentration slows absorption
Isotonic sports drinks (Lucozade Sport, SiS GO Electrolyte):
- Primary purpose: replace electrolytes AND provide energy simultaneously
- Moderate calories (typically 150-250 per 500ml)
- Best for runs over 90 minutes where you want everything in one drink
For training runs under 90 minutes, pure electrolyte drinks (zero/low calorie) are usually the right choice. For longer efforts and races, isotonic options that combine electrolytes with carbohydrate fuel make sense.
For advice on pre and post-run nutrition, see our running nutrition guide which covers the food side of race preparation.
Budget Picks vs Premium Options
Best Value Overall
High5 Zero at 30p per serving delivers solid electrolytes for daily training without overthinking it. For most runners doing 3-5 runs per week under 90 minutes, this is all you need.
Best for Race Day
Precision Hydration PH 1000 justifies the 90p premium when performance matters. Their sweat testing service (available at some UK running shops) tells you exactly which strength to use — removing the guesswork entirely.
Best for Sensitive Stomachs
Skratch Labs at £1.10 per serving is expensive for daily use but worth trying if other products cause GI issues. Use it for races and long runs only, and use something cheaper for standard training.
Monthly Cost for Regular Runners
Running 5 times per week, using electrolytes for sessions over 60 minutes (roughly 3 per week):
- High5 Zero: about £4/month
- SiS GO Hydro: about £5/month
- Nuun Sport: about £10/month
- Precision Hydration: about £12/month
- Skratch Labs: about £14/month
Even the most expensive option costs less than a single takeaway coffee per week. Electrolyte supplementation is one of the cheapest meaningful performance improvements available to runners.
According to British Athletics, proper hydration strategy is one of the most overlooked aspects of training for distance runners at all levels — from parkrun regulars to marathon competitors.
Frequently Asked Questions
Can I make my own electrolyte drink at home? Yes. A basic recipe: 500ml water, a pinch of table salt (about 1/4 teaspoon for 500mg sodium), a squeeze of lemon juice, and a teaspoon of honey if you want some carbohydrate. It won’t taste as refined as commercial products, but it replaces the same minerals at a fraction of the cost. Good for training runs, less ideal for races where you want reliable flavour and concentration.
Do I need electrolytes for a parkrun? Probably not, unless it’s properly hot (above 25°C) or you haven’t eaten or drunk anything beforehand. A 5K takes 20-30 minutes for most runners — not long enough to deplete electrolytes meaningfully. Save them for your longer sessions and don’t overcomplicate a parkrun.
Are electrolyte tablets or powders better? Neither is objectively better — they deliver the same minerals. Tablets are more convenient (individually dosed, portable, no measuring). Powders are cheaper per serving and let you adjust concentration. Most runners keep tablets in their kit bag for convenience and use powder at home for long run preparation.
Can you have too many electrolytes? Yes, though it’s difficult to overdo with standard products used as directed. Excess sodium can cause bloating, puffiness, and elevated blood pressure. Stick to manufacturer dosing recommendations. If you’re drinking electrolytes all day on rest days, you’re probably overdoing it — save them for training days and use plain water otherwise.
Why do some electrolyte drinks taste so salty? Because sodium is inherently salty and high-sodium products (500mg+) can’t fully mask it. Products like Precision Hydration embrace the salt taste rather than trying to cover it with sweetness. If saltiness bothers you, choose lower-sodium options (300mg range) like Nuun, or use strongly flavoured variants that mask the mineral taste better.