Best Electrolyte Drinks for a Half Marathon

A half marathon sits in that sweet spot. Long enough to expose poor fuelling, short enough to tempt you into taking risks.

At 13.1 miles, most runners will be out on course for 1 hour 20 minutes to 3 hours. That means you are losing fluid and electrolytes through sweat for a sustained period, while asking your muscles to keep producing power. Get hydration wrong and you will feel it quickly. Heavy legs, rising heart rate, cramps, and a fading finish.

Choosing the right electrolyte drink can make the difference between holding pace and hanging on.

Why Electrolytes Matter Over 13.1 Miles

When you sweat, you do not just lose water. You lose sodium, chloride, potassium and small amounts of other minerals. Sodium is the key player for endurance athletes.

Sodium helps:

• Maintain fluid balance
• Support nerve signalling and muscle contraction
• Reduce the risk of cramping linked to sodium depletion
• Encourage fluid absorption in the gut

For most runners, a half marathon will require somewhere between 300mg and 800mg of sodium per hour, depending on sweat rate and conditions. Warmer races and heavier sweaters sit at the top end.

A well-formulated electrolyte drink helps you replace what you are losing, without upsetting your stomach.

What to Look for in a Half Marathon Electrolyte Drink

Before diving into specific products, here is what matters:

1. Sodium content: Look for at least 300mg sodium per serving if you are relying on the drink as your primary hydration source.
2. Carbohydrates or no carbs?: Some drinks are purely electrolyte-based, others combine electrolytes with carbs. If you are taking gels separately, a low-calorie electrolyte drink can work well. If you prefer a simpler set-up, a combined carb and electrolyte drink can streamline your fuelling.
3. Gut comfort: A half marathon is not the place to experiment. Choose a drink you have tested in training.
4. Portability: Tablets for bottles, powders for soft flasks, or pre-mixed options. Think about how you will carry and mix it on race day.

Now, let’s look at some of the best options available at XMiles:

Precision Fuel & Hydration Electrolyte Drink Tablets

Precision Fuel & Hydration is known for its evidence-based approach to sweat testing and sodium replacement. Their electrolyte drink tablets deliver a range of sodium strengths, making them ideal for runners who know they are heavy or salty sweaters.

These tablets dissolve easily in water, creating a light-tasting drink that is easy to sip alongside gels. If you struggle with cramping late in races, increasing sodium intake with a product like this can be a game-changer.

Best for: runners with moderate to high sweat rates who want to dial in sodium intake without adding extra carbs.

Active Root Electrolite Drink Mix

Designed for athletes who want effective hydration with a natural edge. Alongside key electrolytes such as sodium, it includes ginger extract, which many endurance athletes use to support gut comfort during harder efforts.

For a half marathon, this can be particularly useful if you are prone to stomach issues when racing at higher intensity. The mix is light, refreshing, and easy to sip

Best for: runners who want natural ingredients and added gut support alongside reliable electrolyte replacement.

OTE Hydro Tabs

OTE Hydro Tabs are a simple, low-calorie electrolyte solution that slots easily into any race-day set-up. Drop a tablet into your bottle before the start, and you have a light-tasting drink focused purely on hydration.

Each tablet contains a carefully chosen blend of electrolytes including sodium for water and plasma balance, potassium for nerve function, and magnesium to aid energy production.

Best for: runners who want a no-fuss electrolyte option that keeps them properly hydrated.

VOOM Hydrate Smart Electrolyte Drink

Hydrate Smart combines electrolytes with around 18g of carbohydrates per serving in a hypotonic formula designed for quick absorption. It also includes a cognition blend with ingredients such as Alpha GPC and L-Tyrosine to support focus during longer efforts.

This makes it a good option if you want hydration, some carbohydrate intake and mental sharpness in one drink.

Best for: runners who want a combined electrolyte and light carb solution with added focus support.

FAQs

Do I need electrolytes if I am only running for 90 minutes?

Yes, especially if you are racing hard. Higher intensity increases sweat rate and sodium loss, even over shorter durations.

Should I increase sodium in hot weather?

In most cases, yes. Warmer conditions increase sweat rate, so practising a slightly higher sodium intake in training can help.

Can I mix electrolyte tablets stronger for race day?

You can, but test it first. Increasing concentration raises sodium per sip, but it also changes flavour and can affect gut tolerance.

Summary

Electrolyte drinks are not just for hot summer races. Even in cooler UK conditions, you are still losing sodium and fluid over 13.1 miles.

By choosing a product that fits your fuelling strategy and testing it in training, you give yourself the best chance of holding pace, staying comfortable, and finishing strong.