Fair Shelf

Value math

Cost Per Dose: The Number That Matters

Bottle price hides the truth. Cost-per-dose reveals it.

Short answer

Cost-per-dose is the monthly cost divided by the number of servings. It removes bottle-size and serving-size tricks and lets you compare two products in seconds.

Key comparison points

  1. 01Why bottle price is misleading
  2. 02How to calculate cost-per-dose
  3. 03Serving size traps
  4. 04Subscription pricing gotchas
  5. 05How much variation is normal
  6. 06A reasonable cost-per-dose for magnesium

Same dose, different value

Bottle priceServingsCost / dose
£1230£0.40
£1830£0.60
£3430£1.13

What Fair Shelf compares

  • Cost-per-dose, not cost-per-bottle
  • Subscription vs one-off pricing
  • Servings per container

Stop reading. Start comparing.

Run a like-for-like magnesium comparison or join early access for category reports.

Related magnesium guides

Value pickBest Value Magnesium Glycinate in the UKForm explainerMagnesium Glycinate vs BisglycinatePricingWhy is Magnesium So Expensive?

Informational only — not medical advice. Fair Shelf does not tell you to start, stop or switch supplements. Always check the label and speak to a qualified professional if unsure.