The only real difference is enzymes. Biological (bio) detergents contain enzymes that break down protein, starch and grease stains, so they clean well at low temperatures such as 20 to 30°C. Non-biological (non-bio) detergents contain no enzymes and rely on surfactants and heat instead. Bio is better for food stains, sweat and sportswear; non-bio is the usual choice for anyone who prefers it for sensitive skin, though there is no scientific evidence that enzymes make eczema worse. Neither standard type is right for wool or silk.
The bio versus non-bio choice is mostly a UK question; in many other countries nearly every detergent is biological. Knowing what the enzymes actually do makes it easy to pick the right one for each load. For the bigger picture on fresh, clean washing, see our main guide to the best smelling laundry in the UK.
What Makes a Detergent "Bio"?
Enzymes are proteins that speed up a specific chemical reaction. In laundry, each enzyme targets a different type of stain and breaks it into small pieces that wash away.
| Enzyme | Breaks down | Typical stains |
|---|---|---|
| Protease | Proteins | Blood, egg, grass, sweat, baby food |
| Amylase | Starches | Gravy, pasta sauce, porridge, chocolate |
| Lipase | Fats and oils | Butter, make-up, greasy collars and cuffs |
| Cellulase | Tiny cotton fibres on the surface | Keeps cotton smoother and colours brighter by reducing fuzz |
| Mannanase | Gums and thickeners | Ice cream, sauces, some cosmetics |
If the pack says "biological" or the ingredients list names enzymes such as protease or amylase, it is a bio detergent.
Bio vs Non-Bio at a Glance
| Factor | Bio | Non-bio |
|---|---|---|
| Stain removal | Stronger on food, sweat, grass and body oils | Fine for everyday dirt, weaker on protein and food stains |
| Best temperature | 20 to 40°C; very hot washes can deactivate the enzymes | Often needs 40°C or more for tough stains |
| Energy use | Makes cooler, cheaper washes effective | May need warmer washes for the same result |
| Wool and silk | Avoid; protease can damage protein fibres | Safer, but a dedicated wool detergent is best |
| Sensitive skin | No scientific evidence enzymes worsen eczema | Often preferred by people with eczema |
| Fragrance | Usually scented; fragrance-free versions exist | Usually scented; fragrance-free versions exist |
Does Bio Detergent Irritate Skin?
This is the main reason people choose non-bio, so the evidence matters. The National Eczema Society says there is no scientific evidence that the enzymes in biological detergents make eczema worse, but that many people with eczema still find non-bio suits their skin better. It also recommends avoiding perfumed products and fabric conditioner, using less detergent and adding an extra rinse.
In other words, fragrance and leftover residue are more likely culprits than enzymes. If your skin reacts, switch to a fragrance-free product first, and only then try changing from bio to non-bio. Our guide to the healthiest laundry detergent covers the label details to look for.
Which Should You Use?
Everyday Family Wash
Bio at 30°C cleans well and keeps energy use down.
Gym Kit and Sweaty Clothes
Bio. Enzymes break down sweat and body oils that cause lingering smells in synthetic fabrics.
Baby Clothes
Many parents choose fragrance-free non-bio and skip fabric conditioner. Wash new items before the first wear.
Eczema or Sensitive Skin
Start with fragrance-free. If your skin still reacts, try non-bio and an extra rinse.
Wool, Silk and Cashmere
Neither. Use a detergent made for wool on a cool, gentle cycle.
Stained Whites
Bio, with an oxygen-based stain remover for anything stubborn.
Tip: You do not have to choose one for everything. Many households keep a bio detergent for everyday loads and a gentle or wool detergent for delicates.
Our Pick: A Biological Detergent
Signature Detergent No.102 (16 fl oz)
An enzyme-powered detergent that lifts stains without bleach, brightens whites and protects colours. It has a light fragrance, so it suits everyday loads rather than skin that reacts to scent.
View ProductQuick Summary
- Bio contains enzymes; non-bio does not. That is the whole difference.
- Bio is better for food, sweat and grass stains, especially at 20 to 40°C.
- There is no scientific evidence that bio enzymes worsen eczema.
- Fragrance is the more common skin irritant; choose fragrance-free first.
- Use a wool detergent for wool and silk, not bio.
Shop Laundry Care
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Shop Laundry CareFrequently Asked Questions
Is bio or non-bio better?
Bio is better at removing stains, especially at low temperatures. Non-bio is a good choice for people who prefer it for sensitive skin. For most everyday washing, bio gives better results.
How do I know if my detergent is bio?
The pack will usually say "biological", and the ingredients list will name enzymes such as protease, amylase or lipase. Non-bio products say "non-biological".
Does bio washing powder cause eczema?
The National Eczema Society says there is no scientific evidence that enzymes in biological detergents make eczema worse. Fragrance and detergent residue are more common irritants.
Can I use bio detergent on baby clothes?
You can, but many parents prefer fragrance-free non-bio for babies. Whichever you use, wash new clothes before the first wear and rinse thoroughly.
Can you use bio detergent on wool?
It is best not to. Protease enzymes break down proteins, and wool and silk are protein fibres. Use a detergent made for wool instead.
Does bio detergent work in a cold wash?
Yes. Enzymes are one of the main reasons modern detergents clean well at 20 to 30°C, which also saves energy.
Sources: National Eczema Society, FAQs and Household irritants and eczema; Allergy UK, Atopic dermatitis triggers, allergens and irritants.