Maxifuel Viper Boost energy bar review

Energy product with caffeine and guarana

Our rating 
3.0 out of 5 star rating 3.0
GBP £1.99 RRP | USD $3.15
Maxifuel Viper Boost energy bar

Our review

Highly charged bars with a real buzz but expensive and need careful use
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Maxifuel’s Viper Boost puts a varied mix of sucrose, rice flour, ground almonds, starches, fructose and glucose syrups under a relatively thick (14 percent) dark chocolate skin. 


A relatively low sugar percentage with a high protein and fat content makes it a steady energy delivery bar. Its infamous reputation comes from the caffeine and guarana buzz ingredients for kick-starting workouts or restoring flagging focus in the last gasp of a race. 

Like most stimulant-enriched products, tolerance before queasiness kicks in varies between athletes. Add a crash as noticeable as the boost and you need to check how these bars work for you before racing with them. Very pricey, too.


This article was originally published in Triathlon Plus magazine, available on Zinio.

Product Specifications


Name Viper Boost energy bar (13)
Brand Maxifuel

Weight (g) 45
Sugars 30.4
Vitamin C 343
Calories 425
Total Carbohydrate 68.5
Protein 7.5
Saturated Fat 3.9