Written by Rachel Eagleton, Running Science’s Nutritionist.  Find out more about Rachel here:

I’ve been using nuun electrolyte tablets for about 7 years now.  I first discovered them as a newish runner when I lived in Singapore when a 40 minute run would give me a pounding headache.  I could counteract the headache by taking in a sports drink but knew that wouldn’t be doing my teeth or waistline any favours.  Your body has enough glycogen stored to fuel you for exercise sessions of up to 75 minutes or so without sports drinks or gels. 

A friend put me onto nuun tablets which are an electrolyte replacement with just 1g of sugar (dextrose) per serve.  Nuun tablets are added to water and replenish the electrolytes that are lost in sweat during exercise.  Nuun contains the four main electrolytes that are vital in hydration and exercise performance:

  • Sodium – helps you absorb and maintain fluid balance
  • Potassium – also helps maintain fluid balance and assists in muscle contraction
  • Magnesium – helps with normal muscle contraction, and
  • Calcium for normal muscle function

It’s great to see nuun becoming much more readily available in Australia – and this year nuun is the official hydration partner of the City2Surf – so if you are joining 85,000 friends to run from the city to Bondi on August 13 you’ll have a chance to give nuun a try!  Can’t wait?  – order some here.

When would you use nuun?

I pop a tablet into my 500mL water bottle to drink on my way to and from parkrun or any other longer event, and I always have a nuun after a long run.  In summer I pop a nuun tablet into my water bottles to carry on a long run –  I do add in a carbohydrate source such as a gel during my run if I’m running for 90 minutes or so (I’d take a gel with water not nuun as the combination could upset your tummy). I give nuun to my teenagers during their weekend sports matches rather than a sugary sports drink which isn’t needed for matches of less than 90 minutes.  I also think the sweet taste of nuun (sweetened with stevia and a small amount of dextrose) helps them to drink more than if they just had plain water in their drink bottle.

Each nuun tablet contains:

42 kj (10 cals) and

  • sodium: 360 mg
  • potassium: 100 mg
  • magnesium: 25 mg
  • calcium: 13 mg
  • vitamin c: 38 mg
  • 1 g of sugar

Need a boost?

Nuun also comes in a caffeinated form – “nuun boost” which contains 40mg of caffeine per tablet, derived from green tea.  Caffeine reduces perceived effort and is recognized as a Grade A supplement by the AIS meaning it is supported for use and backed by evidence. Recommended caffeine is 1-3mg of caffeine per kg of body weight – so 70mg-210mg of caffeine for a 70kg athlete.   Of course, if caffeine disagrees with you stick to normal nuun.


When it comes to hydration, the amount and timing of beverages will depend on your individual sweat rate and exercise conditions.  In general:

  • Begin exercise well hydrated
  • Follow a hydration plan based on your individual needs while exercising
  • Rehydrate after you finish exercising as you are unlikely (and it’s not necessary) to replace 100% of fluid losses during exercise

It is important not to drink beyond your needs while exercising, as this can result in a dangerous condition known as hyponatremia.  In general aim for pale yellow urine and realise that more is not better.


If you’re confused about how best to fuel for an upcoming event or you’d like to establish healthy eating habits find out more about my 8 week endurance nutrition program.



Whitney 2014 Understanding Nutrition

L Burke 2014 Clinical Sports Nutrition