Most athletes pick an energy gel based on flavor, brand, or habit. Very few check the glucose-to-fructose ratio. That single number has more impact on your race-day fueling strategy than almost any other variable on the label.
The carbohydrate composition of an energy gel determines how much fuel your body can actually absorb and use per hour. The ratio between glucose and fructose shapes how that absorption works and understanding the underlying physiology is worth the two minutes it takes to read.
Why Does Glucose-to-Fructose Ratio Matter in Energy Gels?
Your gut absorbs glucose and fructose through completely separate intestinal transporters, and that distinction is physiologically significant. Glucose travels via the SGLT1 transporter, which research indicates saturates at roughly 60g per hour. When glucose intake exceeds that threshold, unabsorbed carbohydrate remains in the intestinal tract, where it draws in water through osmosis - a mechanism associated in the scientific literature with gastrointestinal discomfort during exercise.
Fructose uses a separate transporter, GLUT5, which operates independently of SGLT1. Research on multiple transportable carbohydrates (MTC), developed primarily through the independent work of sports scientist Asker Jeukendrup in the early 2000s, demonstrated that combining glucose with fructose in specific ratios may increase total carbohydrate throughput by engaging both transporters simultaneously. This research is independent and does not involve SUPPLME products.
What Is the Optimal Glucose-to-Fructose Ratio for Endurance Performance?
A 2:1 glucose-to-fructose ratio is the most researched formulation for endurance athletes targeting higher carbohydrate intake per hour. Independent studies by Jeukendrup and colleagues - research conducted without involvement of SUPPLME - have investigated how this ratio, compared to glucose-only formulations at equivalent doses, affects carbohydrate oxidation rates and gastrointestinal tolerance during prolonged exercise. Separately, independent research has explored associations between carbohydrate availability and time trial performance in endurance contexts.
A ratio closer to 1:0.8 also appears in the sports science literature and is considered a workable formulation. The 2:1 formulation has the broadest evidence base among those studied. What matters most when evaluating any product is that the ratio is deliberate and declared on the label. A product listing both glucose and fructose without specifying the ratio gives you no useful information. You need the actual numbers to assess whether the formulation aligns with the research.
How Much Carbohydrate Per Hour Should Endurance Athletes Be Taking?
For efforts lasting longer than 90 minutes at high intensity, independent sports science research - including work by Jeukendrup (2010) - suggests carbohydrate intake in the range of 60g to 90g per hour as a general physiological reference point for endurance fueling. The 60g ceiling applies specifically to glucose-only products, based on the known saturation capacity of the SGLT1 transporter. Research on MTC formulations has examined whether dual-transporter strategies can support higher intake volumes without equivalent increases in gastrointestinal load. These findings reflect independent scientific investigation and do not constitute a claim about any specific product.
In practical terms, a gel providing 32g of carbohydrates per serving means you need roughly two to three servings per hour to approach the upper range cited in that research. That makes serving size a relevant variable to assess. Many commercial gels contain only 20g to 22g per packet, which means the arithmetic rarely works in your favour during a long race unless you are consuming gels at a rate most athletes find difficult to sustain.
Frequently Asked Questions
Does the glucose-to-fructose ratio in a gel affect GI problems during running?
Research on intestinal carbohydrate transport indicates that when glucose intake exceeds the absorption capacity of the SGLT1 transporter, unabsorbed carbohydrate can exert osmotic pressure in the gut. Independent sports science research has examined how dual-transporter carbohydrate formulations affect gastrointestinal tolerance during prolonged exercise. That body of research is independent and does not involve SUPPLME products.
Can you take too much fructose in an energy gel?
Yes. Fructose in excess of what the GLUT5 transporter can handle is also associated with gastrointestinal discomfort in the research literature. The 2:1 ratio is studied precisely because it is designed to approximate the relative capacities of both transporters. Products that invert the ratio or push fructose disproportionately high create a different absorption problem, not a solution.
Is maltodextrin the same as glucose in an energy gel?
For practical purposes, yes. Maltodextrin is a rapidly digestible glucose polymer that enters the same SGLT1 absorption pathway as glucose. It counts toward the glucose side of the ratio and is commonly used in gels because it has lower osmolality than pure glucose, which means it requires less water to process per gram.
Does liposomal delivery change how carbohydrates are absorbed in an energy gel?
Liposomal delivery is a general scientific concept in which phospholipid spheres are used to encapsulate compounds for transport. In nutritional contexts, this approach has been studied primarily in relation to micronutrient bioavailability. Its application to energy gel formats is an area of ongoing scientific interest. Any specific claims about product outcomes would require independent clinical validation.
What Should You Actually Do With This Information?
Check the label of every gel you currently use. If it does not specify a glucose-to-fructose ratio, contact the brand and ask. If it uses vague language like dual-source carbohydrates without declaring the ratio, treat that as a red flag. Then calculate whether the carbohydrate dose per serving actually allows you to approach the hourly intake ranges discussed in the independent research at a manageable consumption rate. Most athletes find this simple exercise reveals a significant gap between what they think they are fueling with and what the numbers actually support.
Science over hype. Every time.
That gap between delivery intention and delivery reality is the design problem that informed the formulation of SUPPLME Energy Gel. As a supplement formulated at a 2:1 glucose-to-fructose ratio with 32g of carbohydrates per 40ml serving, it is built to align with the carbohydrate transporter research outlined above. It also incorporates a liposomal delivery format - a scientific approach described in more detail in the FAQ above - as part of its overall design. The formulation reflects a deliberate effort to apply established sports science principles rather than follow category convention.
References
Jeukendrup, A.E., Moseley, L., Mainwaring, G.I., Samuels, S., Perry, S., Mann, C.H. (2006). Exogenous carbohydrate oxidation during ultraendurance exercise. Journal of Applied Physiology, 100(4), 1134–1141. Independent research. Not conducted in association with SUPPLME.
Jeukendrup, A.E. (2010). Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition and Metabolic Care, 13(4), 452–457. Independent research. Not conducted in association with SUPPLME.
