During-effort fuel · drink mix · reviewed 26 Aug 2026
SiS Beta Fuel 80 Drink Mix 66
The same 1:0.8 ratio as SiS's gel, in an 80 g-per-bottle liquid format, but with just 4 mg of sodium — effectively none, despite being marketed as a complete fuel.
Score breakdown
The overall score is the average of what's below, each measured against every other drink mix we've reviewed.
66
Strong
Absorption rate ?How much carbohydrate an hour the glucose-to-fructose blend can move. Scored from the stated or derived ratio (1:0.8 tops out this scale); an Estimated ratio counts the same as a Stated one here.95
Carb density ?How much fuel one scoop or sachet carries. 90 g is the ceiling here, matching the top of the range cited for multi-transportable-carb intake.89
Sodium ?Sodium carried by the mix itself, on a scale topping out at 1000 mg — the upper end of what's typically lost to sweat in an hour.0
Value (cost/gram) ?Price of one gram of carbohydrate. Not physiological -- a market-based scale from $0.15/g (0) to $0.02/g (100).78
Cost per gram of carbohydrate
$0.048/g
Glucose : fructose
1:0.8
Comparison
5 of 14 drink mixes heldPrices per single sachet at the cheapest box size we track. Best in green, worst in red, across the gels shown.
| Measure | Science in Sport SiS Beta Fuel 80 Drink Mix | Tailwind Nutrition Tailwind Endurance Fuel | Skratch Labs Skratch Labs Super High-Carb Sport Drink Mix | Maurten Maurten Drink Mix 320 | Precision Fuel & Hydration Precision Fuel & Hydration Carb & Electrolyte Drink Mix |
|
|---|---|---|---|---|---|---|
| CarbohydrateHow much fuel one sachet carries. | 80 g | 25 g | 50 g | 80 g | 30 g | |
| Glucose : fructoseGoverns how fast you absorb it. More fructose, higher ceiling. | 1 : 0.8 | n/d | n/d | n/d | 1 : 0.5 | |
| SodiumAgainst 400 to 1000 mg an hour typically lost in sweat. | 4 mg | 310 mg | 200 mg | 245 mg | 500 mg | |
| ProvenanceWhether that ratio is read off the panel, computed from it, or inferred. | Stated | Not disclosed | Not disclosed | Not disclosed | Stated | |
| Price per sachetWhat one costs. Not comparable across sachet sizes. | $3.87 | $1.03 | $2.62 | $3.64 | $2.13 | |
| Cost per gramThe only price that compares across sachet sizes. | $0.048 | $0.041 | $0.052 | $0.045 | $0.071 | |
| Sachets for 90 g/hrHow many you open an hour to hold a 90 g/hr target. | 1.1 | 3.6 | 1.8 | 1.1 | 3.0 |
Verdict
what it does · what it costsWhat it does well
- 1:0.8 maltodextrin-to-fructose, matching the field-leading ratio, stated on the label.
- 80 g of carbohydrate in one bottle, tied with Maurten for the most concentrated drink here.
- Two-ingredient carbohydrate blend, nothing else in the formula beyond flavouring.
What it costs you
- 4 mg of sodium on the current official label is effectively zero; you will need a separate sodium source regardless of how much of this you drink.
- $0.048 a gram, more than Tailwind or 4Endurance's drink for the same carbohydrate.
- Not confidently available as a single sachet at US retail; box-only pricing here.
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 the field-leading absorption ratio in a drink rather than a gel.
- You already carry sodium separately and just need the carbohydrate.
Look elsewhere if
- You want the drink itself to carry meaningful sodium.
- You want the lowest cost per gram of carbohydrate.