How to Decode E-Numbers

E-numbers look like code, but the ranges follow a simple logic. Learn what each block means so you can spot the colours and preservatives that matter to your skin at a glance.

E-numbers are not random

An E-number is simply an approved additive that has passed EU safety assessment, given a code. The codes are grouped into ranges, so once you know the blocks, a label stops looking like gibberish and you can find what matters to your skin fast.

Step 1: Learn the number ranges

• E100 to E199, colours (this is the block most relevant to skin reactions)
• E200 to E299, preservatives (benzoates and sulphites live here)
• E300 to E399, antioxidants and acidity regulators (includes vitamin C and the BHA/BHT preservatives)
• E400 to E499, thickeners, stabilisers and emulsifiers
• E500 and up, acidity regulators, anti-caking agents and others

Step 2: Zero in on your trigger ranges

For most skin reactions the action is in the E100s (colours) and E200s (preservatives). If those are your issue, you can largely skip the rest and scan those two blocks.

Step 3: Match names to numbers

Each number is a code for a named additive: tartrazine is E102, sodium benzoate E211, sulphur dioxide E220. You do not need them all, just learn the handful that are your triggers, in both forms, so neither the name nor the number slips past.

Step 4: Look up anything unfamiliar

If you see an unfamiliar E-number sitting in a range you react to, look it up before trusting the product. A quick check now saves a flare later.

A few extra tips

An E-number is not automatically “bad”, many are harmless or even beneficial (vitamin C is E300). The point is not to fear them all, but to know your own few. And remember additives appear in medicines and supplements with the same codes.

Check it against your own list

A free database like Open Food Facts lets you look up what an E-number is on a given product, and Fig is genuinely good for managing a defined eating pattern. These give broad information rather than a check against your own skin. To skip the decoding entirely, a personal-list app like ClearaScan lets you save your trigger E-numbers once and scan any product, food, medication or cosmetic, against your ingredient guard list, flagging only yours. Its Reaction Journal lets you tie a flare back to the product that caused it, a shared Care Circle lets family scan for you, and a Trusted Products list keeps what you have cleared. It is currently in early access. (Disclosure: our editor co-founded ClearaScan, and we are not paid to mention the others.)

Written and reviewed by the Sensitive Skin Lab editorial team.