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PF90 vs. SiS Beta Fuel. Energy gel review summary: Regarding ingredients, nutritional profile, flavor, and the body’s response, they are neck and neck. PF90 breaks the tie with its resealable package, which allows runners to take smaller sips frequently for more stable energy delivery, potentially preventing blood sugar spikes and stomach stresses.

Runivore energy gel comparison. PF90 vs. SiS Beta Fuel.

Precision Fuel (PF) 90 versus Science in Sport (SiS) Beta is a battle between two energy gels designed to provide a boatload of carbohydrates and little else – no electrolytes, no amino acids, nada.

With new studies suggesting that the human body can absorb up to 90-120 g of carbohydrates per hour, we see sports nutrition makers raising the carbohydrate content in their energy gels.

We have tested two such products recently: Precision Fuel & Hydration’s PF90, which the company dubbed the “Jumbo Gel,” and SiS Beta Fuel Gel, which I described as a Super Gel in a recent product review.

Jumbo Gel against Super Gel. Get ready to rumble.

PF90 vs. SiS Beta Fuel – nutrition and ingredients

Both PF90 and SiS Beta Fuel deliver generous servings of carbohydrates at 90 g per sachet and 40 g per sachet, respectively.

PF90 is a much larger energy gel with 360 calories per pack compared to SiS Beta Fuel’s 158 calories. For reference, a GU energy gel typically contains 100 calories and 20-25 g of carbohydrates per pack.

Both use maltodextrin as the primary source of sugar. The SiS gel has a 1:0.8 glucose-to-fructose ratio, which the company claims can increase total exogenous carbohydrate oxidization with less stomach stress. PF90’s glucose-to-fructose ratio is the more common 2:1.

Besides carbohydrates, the two energy gels offer little else. Both brands have the philosophy of keeping energy replenishment and hydration separate for fueling precision. So make plans to reload electrolytes and various micro-nutrients with other race supplements.

PF90 ingredients and nutritional facts

  • Maltodextrin
  • Water
  • Fructose
  • Pectin
  • Acidity regulator (citric acid)
  • Preservatives (potassium sorbate, calcium lactate)



SiS Beta Fuel ingredients and nutritional facts

  • Water
  • Maltodextrin (from maize)
  • Fructose
  • Flavorings
  • Acidity regulators (citric acid, sodium citrate)
  • Gelling agents (gellan gum, xanthan gum)
  • Preservatives (sodium benzoate, potassium sorbate)
  • Sodium Chloride



It’s a tie for this category. Although PF90 delivers significantly more energy, it comes in a much heftier package.

PF90 vs. SiS Beta Fuel – taste and consistency

PF90 comes in only one flavor, an indistinctive yet pleasant fruity taste, but it has a mild aftertaste. Not the horrible kind that requires a chaser, but it lingers noticeably.

The SiS Beta Fuel series offers Orange and Strawberry & Lime flavors. They taste very similar, but Strawberry & Lime provides a tartness kick.

The two gels are similar in texture, leaning slightly to the syrupy side of the spectrum. PF90 gets the slight edge. But it’s due mainly to its packaging, which I will elaborate on below.

PF90 vs. SiS Beta Fuel – packaging designs

PF90 is oversized at 16 cm in length. It’s called the Jumbo Gel for a reason. The sachet is resealable via a twist cap, allowing a stomach-friendly way to take in more carbohydrates by “micro-dosing.” Take sips frequently and twist it shut instead of having to eat a full gel once you’ve torn one open.

Energy gels are essentially thick sugary water. It doesn’t matter how the manufacturers tweak the flavor; it will never be something you would consider delicious. Therefore, any option that lets you consume a smaller amount at a time without making a mess and sacrificing convenience is a plus.

SiS Beta Fuel is 16 cm long as well but not nearly as wide and bulky. The packaging is identical to its original SiS Go Isotonic energy gels, so there are no surprises.


As mentioned in the previous segment, SiS Beta Fuel is a 60 ml gel with 158 calories and 40 g of carbohydrates. It’s a lot to gulp down all at once. Unfortunately, its sachet isn’t resealable, so I recommend taking your time with it. For example, eat one-third, run with it in your hands, take another third, run some more, and finish the rest. Your hands might get a bit sticky, though.

(On a side note, good job by SiS on the package’s graphic design. It’s stylish and feels very premium.)

Since both sachets are large, be sure they fit in your running belts, shorts pockets, and hydration vest compartments.

PF90 gets the win here.


PF90 vs. SiS Beta Fuel – performance

We have tested both options extensively for different running distances and weather conditions. Here are the pros and cons when we took them into the field.

PF90 pros and cons


  • I was able to consume 90 g of carbohydrates in an hour by taking smaller sips frequently. When using traditional gels in the past, I maxed out at 60-70 g of carbohydrates per hour.
  • Smaller sips also help you prevent big blood sugar spikes and troughs.
    It’s a more consistent and stable way of getting in your carbohydrates.
  • However, I’ve also taken larger gulps to get that “surge” feeling ahead of a major climb or during low moments in ultramarathons. Not necessarily a good thing since it’s probably due to a spike in blood sugar (what goes up must come down, after all), but when you push yourself in these long ordeals, everything goes.
  • Simply put, resealable packaging enables fueling flexibility depending on different physical conditions and mental needs during a race.


  • No electrolytes. So for more prolonged efforts, please remember to consider hydration and electrolytes.
  • The first time I used this energy gel, I accidentally dropped the cap when I tried to screw it back on. I had to stop and turn around to pick it up. Not ideal for race. The company sells a Bite Valve if you want to avoid this issue.
  • The packaging is big. It doesn’t fit in my running shorts pocket or the smaller compartments in the front of my hydration vest. When I fuel with PF90, I must use my compressing running belt.
  • It’s too much carbohydrate and too big for shorter workouts and races.


SiS Beta Fuel pros and cons


  • Great mouth-to-muscle response. I felt surges within five minutes after consumption. A significant blood sugar spike is not unexpected when you inject 40 g of carbohydrates. So perhaps not 100% a pro.
  • The tartness of Strawberry & Lime isn’t bad.
  • The more carbohydrates in a gel, the fewer sachets I have to bring and tear open.



  • I found it impossible to eat it all at once. I had to consume a quarter or a third of it and hold it while running before finishing the rest. Not a big deal, but when you’re running hard, little inconveniences could become more annoying than they should.
  • Just like PF90, no electrolytes.
  • 40 g of carbohydrates are a lot to eat in one go. Be sure your stomach is trained for it.
  • It doesn’t fit in some of my fuel-carrying gears.

PF90 versus SiS Beta Fuel – the verdict

PF90 leans and breaks the tape.

In all honesty, it’s a highly subjective call. Regarding ingredients, nutritional profile, flavor, and my body’s response, they are neck and neck.

Due to my new-found preference for micro-dosing energy gels, PF90’s packaging design gets top grades from this reviewer.

Some final words. It’s great that research has shown that we can take in 90-120 g of carbohydrates per hour, and sports nutrition brands have responded with “Jumbo Gels” and “Super Gels” that are more energy-packed than ever. In reality, consuming significantly more calories and carbohydrates than before requires “practice.” You have to train your digestive system and let it adapt to more fuel injection.

Both PF90 and SiS Beta Fuel are great products. Just make sure your stomach is ready.