Dried egg on a breakfast plate is mostly protein, and protein is stubborn. Protease is the enzyme in our dishwasher and laundry detergents that takes it apart, breaking egg, milk and blood into small pieces that rinse away.
Bottom line: In HERA's assessment, the protease left on washed fabric is far below the level that showed any effect on skin. The real thing to manage is dust, so pour powder gently.
Quick facts
- What it is: An enzyme, a protein that splits other proteins
- Where it comes from: Microbial fermentation, often with Bacillus bacteria
- EPA Safer Choice: Subtilisin, the most common detergent protease, is listed with a yellow triangle
- EWG grade: B (see the EWG page)
- CAS number: 9014-01-1 for subtilisin
How protease cuts through protein
Proteins are long chains of amino acids. Protease cuts the bonds between them by adding a water molecule across each one, a reaction called hydrolysis. The best part: the enzyme comes out of every cut unchanged and moves on to the next bond, which is what makes it a catalyst. The short fragments dissolve and wash away.
Starch goes to amylase, its partner in our dishwasher tabs, dishwasher powder and Max Strength Laundry Powder. Those three also contain sodium percarbonate, a chlorine-free oxygen bleach, and TAED, its activator.
Does enzyme residue bother skin?
A 2008 research review found that the hazards of raw enzymes did not translate into a risk of skin reactions for people using enzyme laundry products (Basketter et al., 2008). HERA's numbers back that up (HERA, 2007):
- A wash leaves about 0.0035 micrograms of subtilisin per square centimeter of fabric.
- Even if all of it stayed active and moved to your skin, the dose would be several orders of magnitude below the level that showed no effect.
- Wash solutions with up to 2 percent enzyme granulate caused no irritation, even on damaged human skin.
Those figures are for laundry; we found no comparable measurement for dishes.
Handling and safety
Breathing enzyme dust is the main health concern for detergent enzymes (Basketter et al., 2008). HERA says allergic symptoms can be ruled out when consumer exposure stays within about 1 nanogram per cubic meter of air. It puts laundry exposure at no more than 0.16 ng/m3 and its worst dishwasher case, opening the door mid-cycle, under 1.9 ng/m3, and expects no breathing effects in either case (HERA, 2007).
- Pour or scoop powder gently, as the label directs, without shaking it into the air.
- Add detergent right before you run the dishwasher and close the dispenser, so little hands cannot reach it.
- Close the bag or tub after each scoop and store it dry, up high and away from children and pets.
- If powder gets in someone's eyes, rinse gently with plain water for several minutes and follow the first aid directions on the label.
- If a child swallows some, call Poison Help at 1-800-222-1222, free and open 24 hours a day.
How it rates
Subtilisin's yellow triangle means it meets Safer Choice criteria for its job but carries some hazard, which for enzymes is dust. See how we vet ingredients for our full method.
HERA found subtilisins readily and ultimately biodegradable, with more than 99 percent removed in sewage treatment, and concluded that their use in detergents poses no risk to the environment (HERA, 2007). That is the enzyme class, not our formula.
Where you will find it
Laundry
- EWG Verified Max Strength Laundry Powder (fragrance-free)
Dish
- EWG Verified Dishwasher Tabs (fragrance-free)
- EWG Verified Dishwasher Powder (fragrance-free)
Kits and bundles
- Dish Starter Kit (fragrance-free)
- Home Kitchen Kit (fragrance-free)
- Ultimate Home Bulk Bundle (fragrance-free)
- Expert Home Cleaner Kit (mixed: includes scented sprays)
See all our ingredients →
Sources
- America's Poison Centers. (n.d.). Get poison help. https://poisoncenters.org/get-poison-help
- Basketter, D. A., English, J. S., Wakelin, S. H., & White, I. R. (2008). Enzymes, detergents and skin: Facts and fantasies. British Journal of Dermatology, 158(6), 1177-1181. https://doi.org/10.1111/j.1365-2133.2008.08561.x
- Environmental Working Group. (n.d.). Protease. EWG's Guide to Healthy Cleaning. https://www.ewg.org/cleaners/substances/4908-PROTEASE/
- HERA. (2007). Human and environmental risk assessment on ingredients of household cleaning products: Subtilisins (protease) (Updated ed.). https://www.heraproject.com/substance/protease/
- U.S. Environmental Protection Agency. (n.d.). Safer Chemical Ingredients List. Safer Choice. https://www.epa.gov/saferchoice/safer-ingredients
