What is the rating of SiS gel?

December 27, 2025 •

3 min read

Customer reviews of SiS gels, particularly the GO Isotonic Energy Gel, often show an average rating of 4 to 5 stars on major retailer sites. This article gives a comprehensive overview of the rating of SiS gel, considering expert opinions and user feedback across different products.

Quick Summary

SiS gels generally receive positive ratings from both users and experts, known for their isotonic formula, taste, and ability to provide quick energy. Popular options such as the GO Isotonic and Beta Fuel lines are reviewed, with key differences highlighted for specific athletic needs.

Key Points

Isotonic Formula: SiS GO gels are isotonic, so they can be taken without water, which is convenient for athletes and reduces stomach issues.
High User Ratings: The GO Isotonic gels consistently receive high ratings (4 to 5 stars) from consumers on sites like Amazon and The Feed.
Beta Fuel for Endurance: For longer events, the high-carb Beta Fuel line offers 40g of carbohydrates per gel, praised by ultra-runners for its performance and dual-source absorption.
Positive Flavor Feedback: Many athletes find the flavors across the SiS range palatable and not overly sweet, a common complaint with other gel brands.
Informed Sport Certified: SiS gels are Informed Sport tested, offering assurance to athletes that the products are free of banned substances.
Variety of Options: SiS offers gels with added caffeine or electrolytes, catering to different athletic needs and environmental conditions.
Generally Easy to Digest: A main advantage highlighted by users is the easy digestibility of SiS gels, with low incidence of gastrointestinal distress.

Understanding the Rating of SiS Gel

The positive rating of SiS gel stems from several factors, which differ based on the product line. SiS (Science in Sport) offers energy gels, with the most notable being the GO Isotonic and the high-carb Beta Fuel series. User reviews frequently mention easy digestion and good flavors as major benefits, while some athletes note potential issues with packaging.

The GO Isotonic Gel: A Consistent Performer

The SiS GO Isotonic Energy Gel is often cited as a standard in the energy gel market. The isotonic formulation is a key selling point, enabling athletes to use the gel without needing more water, which can prevent stomach upset during exercise. User reviews on platforms such as Amazon and Running Warehouse show high ratings, in the 4- to 5-star range, with thousands of reviews supporting its performance and taste.

Key features of the GO Isotonic:

Isotonic Formula: This feature ensures quick absorption and reduces gastrointestinal distress, especially for new gel users or those with sensitive stomachs.
Flavor Variety: The GO Isotonic line offers many flavors, with many reviewers praising the light, non-cloying taste compared to other brands.
Moderate Carbohydrate Content: Each sachet provides 22 grams of carbohydrates, suitable for endurance activities or shorter, higher-intensity sessions.

The Beta Fuel Gel: High-Carb Performance

For athletes in ultra-endurance events, the SiS Beta Fuel line offers a much higher carbohydrate load per gel, with 40 grams per serving. This reduces the number of gels an athlete needs to take, simplifying fueling strategy. Reviews from ultra-runners and cyclists praise its effectiveness in providing sustained energy and reducing stomach issues, despite the higher carb concentration. The Beta Fuel series uses a 1:0.8 ratio of maltodextrin to fructose to enhance absorption.

Comparison of SiS Gels: GO Isotonic vs. Beta Fuel


Feature	SiS GO Isotonic Energy Gel	SiS Beta Fuel Gel
Carbohydrate Content	22g per gel	40g per gel
Absorption Rate	Fast; no extra water needed	Fast; optimized 1:0.8 carb ratio
Best For	Shorter events, new users, sensitive stomachs	Long endurance events (2+ hours)
Taste Profile	Milder, lighter flavors	Can be stronger, sweeter due to higher carb load
Gut Comfort	High; isotonic formula minimizes distress	High, but requires a trained gut to avoid issues
Packaging Size	Larger volume (60ml) relative to carbs	Standard gel sachet size for high carb density

Additional SiS Gel Options: Caffeine and Electrolytes

Besides the main lines, SiS offers variants with added benefits. The GO Energy + Caffeine gel includes either 75mg or 150mg of caffeine to boost alertness, while the GO Energy + Electrolyte gel is designed for long, warm sessions to replace electrolytes lost through sweat. Reviews for these specialized gels are generally positive, though individual tolerance for caffeine should be considered.

Conclusion on the Rating of SiS Gel

The overall rating of SiS gel is very positive, driven by its reputation for effective, fast-acting energy and excellent taste. The GO Isotonic gel is highly rated for easy digestion and convenience, making it a favorite among many athletes, both beginners and experienced. The Beta Fuel series provides a high-carb alternative for longer efforts, also receiving strong marks for performance. While some minor criticisms exist regarding packaging or specific flavor intensity, the brand's commitment to Informed Sport testing and a variety of options for different needs contribute to its high standing in the sports nutrition market. As with any sports fuel, individual testing during training is crucial to ensure optimal performance and gut tolerance.

Positive Reviews: High ratings are consistently given for the GO Isotonic and Beta Fuel gels, particularly on their taste and gentle effect on the stomach.
User Preference: The choice between GO Isotonic and Beta Fuel depends heavily on the athlete's specific needs, such as duration and intensity of exercise, but both lines are well-regarded.
Performance: Expert and user reviews confirm the effectiveness of SiS gels in providing sustained energy and supporting endurance goals without causing GI distress.
Minor Drawbacks: Some users report larger packaging for the GO Isotonic gel and a potential stickiness, though these are often outweighed by the benefits.

Ultimately, for athletes seeking a reliable, effective, and stomach-friendly energy gel, the SiS range is a highly-rated and recommended option.

Frequently Asked Questions

An isotonic gel, like the SiS GO Isotonic, has a similar concentration of fluids and salts to the body's cells. This allows for fast and easy absorption without needing extra water, reducing the risk of stomach upset during exercise.

Yes, many athletes with sensitive stomachs find SiS gels, particularly the GO Isotonic line, highly tolerable. The isotonic formula's quick absorption helps minimize the gastrointestinal issues that thicker, higher-sugar gels can cause.

For long endurance events lasting over two hours, the SiS Beta Fuel gel is often recommended. It provides 40g of carbohydrates per gel, nearly double the amount of the GO Isotonic, which reduces the number of gels you need to consume to meet your fueling targets.

You do not need to drink water with SiS GO Isotonic gels, as their formula allows for quick absorption. However, for the higher-carb Beta Fuel gels, or if you prefer to rinse your mouth, having some water on hand is often recommended.

The main difference is the isotonic formulation of many SiS gels, which gives them a more fluid, watery consistency and allows for consumption without extra water. Traditional gels are often thicker, more concentrated, and require water for proper digestion and absorption.

SiS offers specific gel variants that contain caffeine, such as the GO Energy + Caffeine and Beta Fuel Nootropics gels, with different levels of caffeine to suit varying needs. Standard GO Isotonic gels do not contain caffeine.

User ratings can be found on major retail websites like Amazon, specialized sports nutrition sites like The Feed, and running or cycling review sites. Average ratings often land between 4 and 5 stars, with individual experiences varying slightly by flavor and product line.