Skratch Labs delivers 380 mg sodium per 16 oz serving with 80 calories from real cane sugar, positioning it as a combined fuel-and-hydration solution for endurance athletes. Nuun Sport provides 300 mg sodium with zero calories and stevia sweetening, making it a hydration-only tablet ideal for shorter efforts or athletes who fuel separately. The core trade-off: Skratch uses a 4% carbohydrate solution (research-backed for gastric emptying and carb oxidation during 90+ minute sessions), while Nuun eliminates carbs entirely to keep calorie count at zero.
What are the key ingredient differences between Nuun and Skratch Labs?
The fundamental split comes down to carbohydrates and electrolyte ratios. Skratch Labs uses non-GMO cane sugar to create an 80-calorie, 20-gram carbohydrate drink designed to fuel and hydrate simultaneously. The 4% carbohydrate concentration sits in the research-validated 4–8% range for fastest gastric emptying—meaning it absorbs quickly without causing GI distress during hard efforts. Nuun tablets dissolve into a zero-calorie drink sweetened with stevia leaf extract, delivering electrolytes without any carbohydrate fuel.
Sodium levels differ by 80 mg per serving: Skratch provides 380 mg, Nuun gives 300 mg. That gap matters when you’re sweating out 500–1,000 mg sodium per hour in hot conditions or high-intensity work. Potassium flips the script—Nuun contains 150 mg versus Skratch’s 39 mg. Nuun also edges ahead on magnesium: 25 mg compared to Skratch’s 10 mg. These secondary electrolytes support muscle function, but sodium remains the rate-limiting factor for most athletes.
Flavor sources separate the two as well. Skratch uses real fruit powder (strawberry, lemon, orange depending on flavor variant) with no artificial colors or flavors. Nuun relies on natural flavors, citric acid for tartness, and stevia for sweetness. Both are non-GMO, gluten-free, dairy-free, and vegan.
Which approach fits your training? Use Skratch for sessions longer than 90 minutes where you need carbs and electrolytes in one bottle—think marathon training runs, century rides, or Olympic-distance triathlons. Choose Nuun for recovery hydration, gym sessions under 60 minutes, or when you prefer to control your carb intake through gels and solids rather than your drink. For a detailed comparison of hydration strategies across sports, see our best sports drinks for performance and recovery guide.
How does sodium content compare—and why does it matter for athletes?
Skratch Labs packs 380 mg sodium into each 16 oz serving, while Nuun Sport delivers 300 mg per tablet mixed in the same volume. To put those numbers in context: the average endurance athlete loses roughly 950 mg sodium per liter of sweat. If you’re drinking 500–600 ml (16–20 oz) per hour during a long run or ride, Skratch’s 380 mg gets you closer to replacing actual sweat losses than Nuun’s 300 mg does.
Research consistently shows sodium is the critical electrolyte for maintaining plasma volume, delaying fatigue, and preventing hyponatremia during prolonged exercise. Potassium and magnesium matter—they support muscle contraction and nerve signaling—but you lose far more sodium through sweat than any other electrolyte. The 2026 consensus among exercise physiologists is clear: prioritize sodium replacement first, especially in sessions exceeding 75–90 minutes or in heat above 75°F.
Here’s where each product lands in real-world sweat scenarios:
- Marathon or ultra runners: Skratch’s 380 mg per bottle means you’ll consume roughly 760 mg sodium across two bottles in a three-hour race—still below total sweat loss, so many athletes add salt tabs or pickles at aid stations.
- HIIT or CrossFit (45–60 min): Nuun’s 300 mg covers moderate sweat losses without overloading sodium when you’re not depleting multiple liters.
- Cramp-prone or heavy sweaters: Neither Skratch nor Nuun alone will fully replace sodium if you’re losing 1+ liter per hour. Upgrade to Fast Pickle athlete-grade electrolyte shots, which deliver 1,100 mg sodium in a single 3.4 oz serving—the highest single-dose option for cramp prevention and rapid sodium replenishment.
Verdict: Skratch edges Nuun for longer, hotter, sweat-heavy efforts. Nuun works fine for moderate sessions or when you’re stacking multiple hydration sources throughout the day.
Does the carbohydrate difference affect performance?
Skratch Labs provides 80 calories from cane sugar per 16 oz serving, translating to roughly 20 grams of carbohydrates in a 4% solution. That concentration is no accident—studies on gastric emptying and carbohydrate oxidation during exercise consistently show that 4–8% carbohydrate solutions absorb fastest and fuel working muscles most efficiently. Drinking Skratch during a two-hour bike ride or long run delivers a steady carb trickle that delays glycogen depletion.
Nuun contains zero carbohydrates and zero calories. It hydrates but does not fuel. For efforts longer than 60–75 minutes, your body needs 30–60 grams of carbohydrates per hour to sustain performance. A single Skratch bottle gives you 20 grams, meaning you still need gels, chews, or other solids to hit the upper end of that range. Nuun gives you none—you’ll rely entirely on separate fuel sources.
Practical implications by sport:
- Triathletes and marathoners: Skratch simplifies nutrition by combining hydration and carbs in one bottle. You’ll still carry gels for the full 30–60 g/hr target, but Skratch reduces how many you need.
- Cyclists on 3+ hour rides: Skratch works as your baseline fluid + carb source; add bars or rice cakes for additional fuel.
- CrossFit, pickleball, or gym athletes: Nuun is sufficient. You’re not depleting glycogen in 45-minute sessions, so zero-calorie hydration keeps you topped off without unnecessary sugar.
- Low-carb or keto athletes: Nuun is the obvious pick. Skratch’s 20 grams of sugar per bottle will kick you out of ketosis.
Some athletes prefer Nuun even for long efforts because they want precise control over sweetness and fuel timing—they’ll drink Nuun for hydration and consume gels or homemade fuel at specific intervals rather than mixing carbs into every sip. That’s a valid approach if GI comfort or taste preference drives your strategy.
Bottom line: sessions over 60 minutes benefit from carbohydrates. Skratch delivers them; Nuun doesn’t. Choose accordingly or plan to fuel separately.
Are there artificial ingredients or allergens in Nuun or Skratch?
Neither Nuun nor Skratch Labs contains artificial sweeteners, colors, or flavors—a deliberate break from mainstream sports drinks like Gatorade Frost or Powerade, which rely on synthetic dyes and high-fructose corn syrup. Both brands target athletes who scrutinize ingredient labels and prefer minimally processed formulas.
Skratch Labs ingredients: Non-GMO cane sugar, citric acid, sodium citrate, real fruit powder (varies by flavor—strawberry, lemon, orange, etc.), calcium citrate, magnesium citrate, potassium citrate. The only “processed” ingredient is the sugar itself. No gluten, dairy, soy, or animal products—vegan and safe for most dietary restrictions. The real fruit powder provides color and flavor naturally, so a lemon-lime Skratch looks pale yellow rather than electric green.
Nuun Sport ingredients: Citric acid, sodium bicarbonate, sodium citrate, potassium bicarbonate, magnesium oxide, natural flavors, stevia leaf extract, avocado oil (to bind the tablet), riboflavin (for color in some flavors). Stevia is a zero-calorie plant extract—natural but polarizing. Some athletes report a subtle aftertaste or mild GI sensitivity when consuming multiple Nuun tablets in a day. The citric acid can also irritate sensitive stomachs if you’re sipping frequently on an empty stomach.
Allergen considerations: Both are gluten-free, dairy-free, and vegan. Neither contains common allergens like nuts, eggs, or shellfish. If you’re highly sensitive to stevia or prefer to avoid all sweeteners (even natural ones), look at unsweetened electrolyte powders like LMNT Raw or DIY mixes of sodium citrate and potassium chloride.
Takeaway: Skratch’s ingredient list is shorter and simpler—sugar, citrate salts, fruit powder. Nuun adds stevia and natural flavors, which some athletes tolerate perfectly and others avoid. Both are leagues cleaner than conventional sports drinks that use Red 40, Blue 1, or sucralose.
Which electrolyte drink should you choose based on your sport?
The right choice hinges on session duration, sweat rate, and whether you need mid-effort fuel. Here’s the sport-by-sport breakdown based on what the research actually says about hydration and carbohydrate demands:
Marathon and ultra runners, triathletes, road cyclists (2+ hours): Skratch Labs. You’re burning through glycogen and losing significant sodium via sweat. Skratch’s 380 mg sodium + 20 g carbs per bottle means fewer items to juggle—one bottle handles baseline hydration and partial fueling. You’ll still need gels or solids to hit 30–60 g carbs per hour, but Skratch reduces the number you carry. On century rides or Ironman-distance races, plan for two Skratch bottles per hour plus supplemental gels.
CrossFit, HIIT, or metcon sessions (<60 minutes): Nuun. You’re not on your feet long enough to deplete glycogen, and your sweat losses stay moderate unless you’re training in extreme heat. Nuun’s 300 mg sodium rehydrates without adding unnecessary calories. If you’re doing multiple sessions per day (morning strength, evening conditioning), Nuun between workouts keeps you topped off without interfering with meal timing.
Pickleball, tennis, recreational lifting: Either works—choose by taste preference and whether you want a few calories intra-workout. Nuun gives you hydration only; Skratch adds a light carb boost that some recreational athletes find helpful during back-to-back matches or two-hour gym sessions. Neither is wrong here.
Cramp-prone athletes or heavy sweaters: Upgrade sodium beyond what either drink offers. If you’re losing 1+ liter of sweat per hour (common in heat, humidity, or high-intensity efforts), Skratch’s 380 mg won’t fully cover losses. Add a second Skratch serving, salt tabs, or switch to Fast Pickle for a concentrated 1,100 mg sodium shot mid-effort. Fast Pickle is the go-to for athletes who cramp despite using standard electrolyte drinks—its high sodium content and natural pickle brine formulation delivers rapid replenishment when you need it most.
Low-carb or keto athletes: Nuun or zero-carb alternatives like LMNT. Skratch’s 20 grams of sugar per bottle will disrupt ketosis. Nuun’s stevia-sweetened, carb-free formula keeps you hydrated without kicking you out of fat-burning mode.
Final note: If you’re sweating heavily in heat above 80°F for 90+ minutes, prioritize sodium content above all else. Choose Skratch over Nuun, or upgrade to Fast Pickle if cramping is a recurring issue. Sodium is the rate-limiting electrolyte—potassium, magnesium, and even carbs matter less if you can’t maintain plasma volume. For more sport-specific hydration protocols, check out our expert sports drink reviews.
Frequently Asked Questions
Which has more sodium, Nuun or Skratch Labs?
Skratch Labs delivers 380 mg sodium per 16 oz serving, while Nuun Sport provides 300 mg. For endurance athletes sweating heavily (losing 500–1,000 mg sodium per hour), Skratch’s higher sodium content makes it the better match. Athletes in shorter, lower-sweat sessions will find Nuun’s 300 mg adequate. Fast Pickle offers the highest single-dose sodium at 1,100 mg per 3.4 oz shot for cramp prevention.
Does Nuun or Skratch Labs contain artificial sweeteners?
Neither uses artificial sweeteners. Skratch Labs uses real cane sugar (80 calories per serving) for both flavor and carbohydrate fuel. Nuun uses stevia leaf extract, a natural zero-calorie sweetener, making it carb-free. Both brands avoid artificial colors and flavors, relying instead on real fruit powder (Skratch) or natural flavors (Nuun). If you’re sensitive to stevia, Skratch is the cleaner choice.
Can I use Nuun for long endurance workouts instead of Skratch?
Nuun lacks carbohydrates, so it won’t fuel efforts longer than 60–75 minutes. Skratch Labs provides 80 calories (20 g carbs) per bottle, supporting glycogen during 90+ minute sessions. If you choose Nuun for hydration, you’ll need to add separate fuel—gels, chews, or solids—to hit the 30–60 g/hr carb target for endurance performance. For marathons, triathlons, or century rides, Skratch is the simpler all-in-one option.
Is Skratch Labs better than Nuun for CrossFit and HIIT?
For most CrossFit or HIIT sessions under 60 minutes, Nuun’s zero-calorie hydration is sufficient—you’re not depleting glycogen enough to need mid-workout carbs. Skratch’s 80 calories won’t hurt, but they’re unnecessary for short, intense efforts. Choose Nuun if you prefer lighter hydration; choose Skratch if you’re doing back-to-back sessions or training in extreme heat where combined sodium + fuel aids recovery between rounds.
Do Nuun and Skratch Labs have the same potassium and magnesium?
No. Nuun Sport contains 150 mg potassium and 25 mg magnesium per serving, while Skratch Labs has 39 mg potassium and 10 mg magnesium. Nuun’s higher potassium/magnesium levels may benefit athletes prone to muscle cramps or those on low-carb diets. However, sodium remains the rate-limiting electrolyte for most athletes—Skratch’s 380 mg sodium typically outweighs Nuun’s extra potassium in real-world sweat-loss scenarios.
Which tastes better, Nuun or Skratch Labs?
Taste is subjective, but patterns emerge. Skratch Labs uses real cane sugar and fruit powder, yielding a lightly sweet, natural flavor profile—most athletes describe it as ‘clean’ and not overly sugary. Nuun’s stevia sweetening tastes slightly tart with a subtle aftertaste some users notice. If you dislike stevia, Skratch is the safer bet. Both are far less sweet than Gatorade or Powerade, appealing to athletes who want function over candy-like flavor.