Should I use Perpetuem or Sustained Energy?

Hammer Nutrition offers two superb long distance fuels in powder form – Sustained Energy and Perpetuem. Sustained Energy (“SE” as it’s commonly referred to) was introduced in 1992 and its formula has remained unchanged ever since. Perpetuem first became available in early 2003. Both of these fuels are intended to be used as your primary or sole fuel when exercise goes beyond two hours.

Deciding whether to use Sustained Energy or Perpetuem (or both) will undoubtedly be influenced by personal preference; however, there are a few differences between these two time-proven fuels that can assist you in the selection process.

CALORIES: Each scoop of Perpetuem contains 135 calories. Sustained Energy contains approximately 107 calories per scoop.

PRIMARY INGREDIENTS: Sustained Energy contains a 7:1 ratio of complex carbohydrates to soy protein, and is virtually fat free. Perpetuem’s carbohydrate-to-protein ratio is approximately 8:1, with 1.25 grams of de-oiled soy lecithin fat (lysolecithin) added to each scoop of the formula.

Three reasons for the inclusion of this specific fat in Perpetuem are:

1) To act as a preservative, increasing the “shelf life” of the carbohydrate and protein components
2) To assist the body in more liberally releasing its fatty acids stores, which account for up to two–thirds of one's energy requirements in long bouts of exercise
3) To slightly slow the rate of digestion and thus decrease hunger pangs

AUXILIARY NUTRITIENTS: Perpetuem contains Trisodium Phosphate (aka Sodium Tribasic Phosphate). This nutrient was not added to the Sustained Energy formula. Primary among its benefits, Trisodium Phosphate is a powerful acid-buffering nutrient, reducing the burning sensation effects of lactic acid buildup.

FLAVORS: Sustained Energy has always come in a neutral (“plain”) flavor. Perpetuem comes in four flavor options—orange-vanilla, strawberry-vanilla, chocolate, and caffe latte (includes 12.5 mg of caffeine per scoop).


We have noted that Sustained Energy may be the ideal fuel choice when endurance exercise intensity is at a higher level (approximately 70–85% MHR), whereas Perpetuem may be a more attractive choice the longer the athlete goes and when exercise intensity is at a more aerobic pace (under 70% MHR). Additionally, over the course of many years we have noted that Sustained Energy may be the best option for very lean athletes (the “high metabolizer/hyper–metabolic” types), while Perpetuem—with its added healthy fat component—may be more appropriate for athletes with a naturally higher body fat percentage. The rationale for this suggestion is that athletes with a higher body fat percentage have a greater volume of calories available from body fat stores, which the lysolecithin component of Perpetuem may effectively assist in accessing for use as energy.

Bottom line: With Sustained Energy and Perpetuem, you have two great long distance fuel choices. When exercise goes beyond about two hours, you can use either product as your sole fuel, in tandem with each other, or as your primary fuel along with any of the other Hammer Nutrition fuels. Taking into account the earlier-listed differences between the products, as well as testing each product under a variety of conditions in your long–duration workouts, will allow you to determine which fuel works best for you.