The World’s First Isotonic Gel – Does it Matter?

Why Isotonic Energy Gels should matter to you.

Isotonic is a description of the concentration of dissolved particles in a solution, this could be a drink or gel. To be isotonic a solution must have the same concentration of dissolved particles as the fluid in the cells within the body, typically this means having a tonicity between 290-310 mmol/kg.

This concentration affects water and carbohydrate transportation across cell membranes, most importantly the movement from the gut into the bloodstream. Ultimately this will effect how quickly the gel can be used as an energy source.

If a solution is hypertonic, it has a higher concentration than the fluid in the body. This means that water particles will have to be pulled from the cells into the gut to help it absorb and balance up this concentration. This slows down the availability of the energy from the gel and in some instances can bloat your stomach and be very uncomfortable when used during training and racing. A hypertonic solution is better suited to use in the days prior to a major event or following completion – to replace lost glycogen stores.


If a solution is hypotonic, it will have a lower concentration than the fluid in the body. This means that it will empty quickly from the stomach, but it will not contain much energy. Hypotonic solutions are more commonly used when rapid rehydration is required.

The carbohydrate source in SiS GO Isotonic Energy gels is maltodextrin which SiS specially select. They use one with a particular size of molecule, known as its’ molecular weight. This allows SiS to balance the amount of energy delivered versus how quickly it empties from the stomach. This means that you will feel the performance benefits of taking on a SiS GO Isotonic Energy gel far more quickly than when a non-isotonic gel is consumed. The risk of upsetting your stomach is also much less.

SiS Go Isotonic Gel

  • The world’s first isotonic gel
  • Provides a quicker supply of energy to the working muscles than a thicker, more concentrated gel
  • Clean taste and designed to be absorbed without needing additional water
  • Easily digestible and light on the stomach

Learn more about SiS GO Isotonic Energy Gels in the video below featuring Team Sky’s Head of Nutrition – Dr James Morton.