Propel gets its sweetness from two zero-calorie artificial sweeteners: sucralose and acesulfame potassium (often listed as Ace-K). These two ingredients appear in all Propel electrolyte waters and powder packets, regardless of flavor. Neither contains sugar, which is why Propel has zero calories and zero grams of sugar per serving.
Why Propel Uses Two Sweeteners Instead of One
Sucralose is roughly 600 times sweeter than table sugar, so only a tiny amount is needed. Ace-K is also intensely sweet on its own. But the reason Propel combines them comes down to timing: each sweetener hits your taste buds differently. Sucralose has a slow, lingering sweetness, while Ace-K delivers a sharper initial burst that fades faster. When blended together, they create a sweetness curve that more closely mimics how real sugar tastes as you swallow a drink. This is a common strategy in low-calorie beverages, not unique to Propel.
You’ll find the same pairing in many diet sodas, flavored waters, and sugar-free sports drinks. The combination also lets manufacturers use less of each individual sweetener, which can reduce the metallic or bitter aftertaste that some people notice with Ace-K on its own.
How These Sweeteners Differ From Sugar in Your Body
Neither sucralose nor Ace-K provides calories or raises blood sugar directly. Your body doesn’t break them down for energy the way it processes table sugar. According to the Mayo Clinic, artificial sweeteners don’t affect blood sugar levels, which is one reason they’re popular in products marketed toward active, health-conscious consumers.
That said, “zero-calorie” doesn’t automatically mean biologically inert. Research from Cedars-Sinai found that people who regularly consumed non-aspartame artificial sweeteners (a category that includes sucralose and Ace-K) had lower bacterial diversity in their small intestine compared to people who didn’t use these sweeteners. The same study observed altered levels of inflammatory markers in the blood of sweetener consumers. This research is still relatively early, and it doesn’t prove these sweeteners cause harm at the amounts found in a bottle of Propel. But it does suggest that the gut microbiome responds to them in measurable ways.
Are There Propel Products With Natural Sweeteners?
No. Propel confirms that all of its electrolyte bottled waters and powder packets use Ace-K and sucralose. None of the current Propel products use stevia, monk fruit, erythritol, or any other natural or sugar-based sweetener. If you’re specifically looking for an electrolyte drink sweetened with stevia or no sweetener at all, you’ll need to look at other brands.
Safety Limits and Typical Intake
The FDA has set acceptable daily intake limits for both sweeteners. For sucralose, the limit is 5 milligrams per kilogram of body weight per day. For Ace-K, it’s 15 milligrams per kilogram per day. For a 150-pound person, that works out to about 340 mg of sucralose or roughly 1,020 mg of Ace-K daily before reaching the threshold.
A single bottle of Propel contains very small amounts of each sweetener, well below these limits. You would need to drink an impractical number of bottles in a single day to approach the FDA ceiling. For most people drinking one or two bottles, the intake is a small fraction of what regulators consider safe.
Why It Tastes Sweet Without Tasting Like Diet Soda
Propel’s ingredient list also includes citric acid and natural flavors, which play an important supporting role. Citric acid adds tartness that balances and masks any artificial aftertaste, while the natural flavors (fruit-derived compounds) give each variety its specific taste profile. The overall effect is a drink that reads as lightly sweet and fruity rather than syrupy or obviously “diet.” The low concentration of sweeteners helps too. Propel isn’t trying to replicate the intense sweetness of a soda. It’s designed to taste like lightly flavored water, so the sweetener levels are calibrated to be subtle.