Sodium versus salt: labels, sweat losses and intake

Sodium is an essential electrolyte, but most UK adults do not need a routine extra salt habit. Sports replacement questions depend on actual losses. Salt and sodium are not the ...

Evidence reviewed: 25 September 2026. Research doses describe study methods; they are not personalised dosing instructions.

The short answer

Sodium is an essential electrolyte, but most UK adults do not need a routine extra salt habit. Sports replacement questions depend on actual losses. Salt and sodium are not the same weight: label conversions are essential when comparing food, electrolyte powders and bicarbonate.

What it is

Sodium is a mineral ion. Table salt is sodium chloride and contains about 40% sodium by weight. Sodium can also be present in other salts, including bicarbonate or citrate. A product's sodium total therefore cannot be inferred only from whether the ingredient list says table salt.

How it works: mechanism versus outcome

Sodium contributes to extracellular fluid balance and nerve and muscle function. The body regulates its concentration through water balance and kidney handling. Low blood sodium does not always mean too little dietary salt; excess water can be a major cause in endurance exercise.[2]

Benefits: what the evidence can support

UK public-health guidance advises adults to consume no more than 6 g salt daily, equivalent to about 2.4 g sodium. That is a maximum guideline, not a target to reach. Sports guidance separately considers substantial sweat losses and individual conditions; it does not justify blanket salt loading.[1] [3]

Where evidence is mixed or weak

Visible sweat or a salty shirt does not precisely quantify sodium loss. A cramp is not a reliable diagnostic test for sodium depletion. Research on prolonged exercise cannot establish that extra sodium improves ordinary daily energy or concentration, and a sodium-containing blend is not inherently superior.

Dosage and forms used in research

To estimate salt equivalent, multiply sodium by 2.5. For example, 500 mg sodium corresponds to 1.25 g salt. Keep milligrams and grams consistent. For sports planning, sodium concentration per litre and total fluid intake are both relevant; a fixed per-hour prescription cannot suit every athlete.

Timing and duration

Ordinary dietary intake does not need a special supplement window. Event-specific plans should reflect conditions, duration and tolerability rather than a routine pre-workout salt shot. Count sodium from food, drinks, bicarbonate and other supplements together.

Side effects and safety

High habitual salt intake is relevant to blood pressure. People with kidney or heart disease, hypertension or prescribed sodium restrictions should not copy athlete replacement protocols. Confusion, vomiting or collapse during exercise requires assessment because both heat illness and fluid/electrolyte disorders can be serious.[1] [2]

Medicines and other supplements

Diuretics, medicines affecting kidney function and other treatments can alter fluid and sodium handling. Some effervescent medicines also contribute sodium. A pharmacist can review the full intake in the context of your condition; do not adjust prescribed medicines or fluid restrictions to accommodate a supplement.

Common myths

Salt and sodium can be compared gram for gram

Salt contains sodium plus chloride, so their numerical amounts differ.

Low blood sodium always means I need more salt

Water balance and medical causes can be central. It requires context and sometimes urgent assessment.

Frequently asked questions

How much salt is 500 mg sodium?

Approximately 1.25 g salt equivalent, using the standard factor of 2.5.

Should I add salt before every workout?

A universal benefit is not established. Sweat losses and the session conditions matter.

Why is sodium bicarbonate covered separately?

It has a distinct buffering research question and can deliver a large sodium load. It is not just another ordinary hydration serving.

Find the relevant ALL TOLD product information

Use the final product label for ingredients, allergens and serving directions. A study of an ingredient is not a trial of an ALL TOLD product or combination. Product links identify the relevant catalogue entries; they do not establish equivalence to a research preparation.