Electrolyte Supplements Compared: Sodium Content Is the Key
Quick Verdict
Most products marketed as “electrolyte drinks” contain trivial amounts of sodium and are primarily sugar water. LMNT leads with 1000mg sodium per sachet — roughly 3-5x more than competitors. If you sweat heavily during training, fast intermittently, or follow a low-carb diet, sodium is the electrolyte you are most likely deficient in. Check the sodium content, not the marketing.
Product Overview
| Factor | LMNT | SiS GO Hydro | Bulk Electrolytes | High5 Zero | Myprotein Electrolyte Plus |
|---|---|---|---|---|---|
| Format | Powder sachet | Effervescent tab | Capsule | Effervescent tab | Powder sachet |
| Price | ~£35 / 30 sachets | ~£8 / 20 tabs | ~£10 / 90 caps | ~£7 / 20 tabs | ~£12 / 30 sachets |
| Cost per serving | ~£1.17 | ~£0.40 | ~£0.11 | ~£0.35 | ~£0.40 |
| Servings | 30 | 20 | 90 (3 caps = 1 serving) | 20 | 30 |
Electrolyte Content Comparison
| Per Serving | LMNT | SiS GO Hydro | Bulk Electrolytes | High5 Zero | Myprotein Electrolyte Plus |
|---|---|---|---|---|---|
| Sodium | 1000mg | 250mg | 200mg | 250mg | 300mg |
| Potassium | 200mg | 60mg | 100mg | 65mg | 150mg |
| Magnesium | 60mg | 0mg | 50mg | 5mg | 50mg |
| Calcium | 0mg | 0mg | 0mg | 0mg | 0mg |
| Calories | 0 | 10 | 0 | 8 | 15 |
| Sugar | 0g | 1.5g | 0g | 1g | 3g |
| Caffeine | 0mg | 0mg | 0mg | 0mg | 0mg |
The difference is stark. LMNT delivers 4x the sodium of most competitors. Everything else clusters around 200-300mg — barely meaningful during a hard training session where you can lose 500-1500mg of sodium per hour through sweat.
Why Sodium Matters Most
When you sweat, you lose primarily sodium — roughly 900-1400mg per litre of sweat depending on individual variation. A 90-minute training session can easily produce 1-2 litres of sweat, meaning you lose 900-2800mg of sodium.
A SiS GO Hydro tab replaces 250mg. That is 10-28% of what you lost.
Symptoms of sodium depletion during training include muscle cramps, headaches, fatigue, dizziness, and reduced performance. These are often attributed to dehydration when the real issue is electrolyte depletion — drinking more water without sodium actually makes it worse by diluting your remaining electrolytes.
When You Actually Need Electrolytes
Not every gym session requires supplemental electrolytes. They matter most when:
- Training over 60 minutes — particularly in warm environments
- Heavy sweaters — if your skin feels gritty or your clothes show white salt marks
- Fasting — insulin drops during fasting cause the kidneys to excrete more sodium
- Low-carb or keto diets — same mechanism as fasting; lower insulin means less sodium retention
- Rucking or outdoor cardio — prolonged effort in sun and wind increases sweat losses
- Morning training — you have not consumed electrolytes for 8+ hours
For a 45-minute weights session in an air-conditioned gym, water alone is usually fine.
The Sugar Problem
Many “sports drinks” and electrolyte products include sugar under the guise of energy delivery. For endurance events over 90 minutes, carbohydrates during exercise have evidence behind them. For general gym training and hydration, the sugar adds calories you probably don’t want.
High5 Zero and SiS GO Hydro keep sugar minimal. Myprotein Electrolyte Plus includes 3g per serving — small but unnecessary for non-endurance use.
The DIY Option
You can make an effective electrolyte drink for pennies:
- 1/2 teaspoon salt (~1150mg sodium)
- Juice of half a lemon
- 500ml water
- Optional: pinch of potassium salt (Lo-Salt) for ~300mg potassium
This replicates LMNT’s sodium content for roughly £0.02 per serving. It tastes less refined but the electrolytes are identical. If budget matters more than convenience, DIY is unbeatable.
Who Each Product Suits
LMNT — best for heavy sweaters, fasters, and keto/low-carb athletes who need serious sodium replacement. The price is high but the sodium content is unmatched in a convenient format.
Bulk Electrolyte Capsules — cheapest per serving and useful for topping up throughout the day. Low sodium per serving means you may need multiple doses.
SiS GO Hydro — convenient tabs, decent taste, but modest sodium. Better suited for light to moderate training.
High5 Zero — similar to SiS. Popular with runners. Low calorie but low sodium too.
Myprotein Electrolyte Plus — reasonable middle ground on sodium content with good potassium. The added sugar is unnecessary.
DIY salt water — the most cost-effective option by orders of magnitude. Genuinely effective.
Where to Buy
For more on electrolyte needs during training, see our electrolytes guide.
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