During-effort fuel · electrolyte · reviewed 28 Aug 2026
GU Hydration Drink Tabs 35
320 mg of sodium per tablet is 70 mg more than Precision's PH 500 (250 mg) but less than half of PH 1500's 750 mg, paired with 55 mg of potassium and just 3 g of carbs, built for topping off electrolytes without adding real fuel.
Score breakdown
The overall score is the average of what's below, each measured against every other electrolyte we've reviewed.
35
Mixed
Based on 3 of 5 measures ?A dimension a product doesn't declare is left out of its average rather than counted against it -- so this score reflects fewer measures than a product with a full panel.
Sodium dose ?Sodium per serving, on a scale topping out at 1000 mg — a single dose covering the top of what's typically lost to sweat in an hour.32
Value (cost/1000mg Na) ?What it costs to get 1000 mg of sodium from this product. Not physiological -- a market-based scale from $3.00 (0) to $1.00 (100).45
Potassium ?Potassium per serving, on a scale topping out at 200 mg — roughly the upper end of typical hourly sweat loss.28
Cost per 1000mg sodium
$2.09/1000mg
Sodium per tablet
320mg
Comparison
6 of 11 electrolytes heldPrices per single sachet at the cheapest box size we track. Best in green, worst in red, across the gels shown.
| Measure | GU Energy Labs GU Hydration Drink Tabs | LMNT LMNT Citrus Salt | Nuun Nuun Sport | Precision Fuel & Hydration Precision Fuel & Hydration PH 1000 | Science in Sport SiS GO Hydro | 4Endurance 4Endurance Electrolytes |
|---|---|---|---|---|---|---|
| SodiumThe main electrolyte lost in sweat, and the biggest single driver of cramping and hyponatremia risk. | 320 mg | 1000 mg | 300 mg | 500 mg | 345 mg | 250 mg |
| PotassiumWorks alongside sodium in muscle and nerve function. | 55 mg | 200 mg | 150 mg | 130 mg | 65 mg | 70 mg |
| CalciumInvolved in muscle contraction; lost in far smaller amounts than sodium. | not declared | 0 mg | 13 mg | 20 mg | 102 mg | 10 mg |
| MagnesiumSupports muscle and nerve function; some evidence it blunts cramping. | not declared | 60 mg | 25 mg | 10 mg | 8.1 mg | 50 mg |
| CarbohydrateMinimal by design. This is a hydration product, not a fuel source. | 3 g | 0 g | 4 g | 3 g | 0.9 g | 0 g |
| Price per tabletWhat one tablet costs. | $0.67 | $1.50 | $0.75 | $1.20 | $0.75 | $0.27 |
| Cost per 1000mg sodiumThe only price that compares across different sodium concentrations. | $2.09 | $1.50 | $2.50 | $2.40 | $2.17 | $1.08 |
Verdict
what it does · what it costsWhat it does well
- 320 mg sodium and 55 mg potassium per tablet for just 10 calories and 3 g of carbs
- $0.67 a tablet in a 12-count tube, cheaper per serving than Skratch's $1.20 scoop or Precision's $0.80-$1.20 tablets
- Sweetened with stevia and cane sugar rather than the sucralose used in Precision's PH tablets
What it costs you
- Calcium and magnesium aren't declared on the label; only sodium and potassium are broken out
- 3 g of carbs and 1 g of sugar won't offset a bonk the way a 19 g-carb drink mix like Skratch's will
- GU's own site sells only in boxes of 4 or 8 tubes (48-96 tablets); no single-tube trial size direct from the brand
Where to buy
Prices and links as last checked.
Who this is for
the numbers, appliedThe field tells you what it is. This is who should act on it.
Worth the money if
- You want a low-cost, low-calorie tablet for all-day sipping rather than a carb-carrying sports drink
- You're comparing tablet electrolytes and want a middle dose between Precision's PH 500 and PH 1500
Look elsewhere if
- You need calcium or magnesium numbers for a documented electrolyte plan; GU doesn't disclose them
- You want carbohydrate alongside electrolytes; GU's 3 g per tablet is negligible next to a drink mix