Optical Brighteners: why to avoid them and what to use instead
They don't clean anything — they deposit fluorescent dye on fabric to trick the eye — and they are poorly biodegradable and toxic to aquatic organisms.
The short answer
Pure cosmetic additive with an environmental cost and no cleaning benefit. Easy to eliminate: Ecolabel-certified detergents don't contain them, and oxygen bleach whitens for real.
- Where it hides
- Laundry detergents, fabric softeners, white paper and card
- Cleaner swap
- Enzyme-based detergents, oxygen bleach (sodium percarbonate) for genuine whitening, and line drying in sunlight.
- Also listed as
- Fluorescent whitening agents, FWA, Stilbene derivatives, Distyrylbiphenyl
The label names to scan for
- Optical brighteners
- Fluorescent whitening agents (FWA)
- Distyrylbiphenyl disulfonate
- Disodium distyrylbiphenyl disulfonate
- Stilbene disulfonic acid derivatives
What regulators have actually done
Permitted in most markets, but EU Ecolabel, Nordic Swan and most organic textile standards exclude them. Not typically named on detergent labels — the term 'optical brightener' may appear only in the ingredient annex.
How they fake whiteness
Optical brighteners absorb ultraviolet light and re-emit it as visible blue, which cancels the yellow cast of aged fabric. The garment is not cleaner — it is fluorescing. That's also why 'whites' look startling under nightclub UV lighting.
The residue stays on your skin
The compounds are designed to bind to fabric and survive rinsing, so they remain in contact with skin all day. They are a documented, if uncommon, contact sensitiser, which is why they're excluded from most baby and sensitive-skin ranges.
Optical Brighteners: frequently asked questions
How do I know if my detergent has them?+
Most don't declare it plainly. A UV torch on a washed white shirt will show a bright blue glow if brighteners are present.
What whitens laundry without them?+
Sodium percarbonate (oxygen bleach) plus a warm wash, and sun-drying, which bleaches naturally.