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Soap nuts for laundry are dried fruit shells used as a plant-based wash. They contain saponins, compounds that can help loosen soil in water. Research shows that soap nuts can clean some types of stains, but results vary. They may not match a formulated detergent on every load.

What are soap nuts?

Soap nuts, also called soapberries, come from trees in the Sapindus genus. The dried shells contain saponins, which can reduce water’s surface tension and help disperse oils and dirt.

Despite the name, soap nuts are not true nuts. They are fruit shells. Some people place them in a reusable cloth bag in the washing machine. Others make a liquid by simmering the shells in water. Follow the directions supplied with the product you buy.

Soapberry use in the United States

Soapberry use also has a U.S. connection. The University of Florida’s IFAS Extension soapberry guide describes Florida soapberry and western soapberry, both North American native trees. It also gives instructions for making liquid soap from their fruit husks and says you can use it for laundry. The guide warns that the seeds are poisonous, so use the husks and keep the seeds away from children and pets.

These native species are different from Sapindus mukorossi, the species used in the laundry study below. The U.S. example documents a way to make and use soapberry liquid. It does not show how common this practice is or measure how well the homemade liquid cleans.

Do soap nuts clean clothes?

They can remove some types of soil, but performance depends on the stain and washing conditions. In a 2023 study of soapnut extract for laundry washing, the extract performed comparably to commercial detergent on some test stains. However, it performed poorly on protein-based stains, and the commercial detergent had the best overall results in the tests. The researchers tested a specific extract under set conditions, so the findings do not predict how every soapnut product will work at home.

An earlier study tested soapnut shells on naturally soiled cotton at 60°C and 90°C. The researchers reported good washing performance, especially at 90°C. Since the study tested particular fabrics and wash settings, it cannot predict results in every household machine. Read the study on soapnut shell washing performance.

Where soap nuts may fall short

Laundry detergents often combine surfactants with other ingredients that target different soils. For example, enzymes can help break down some protein-based stains. Soapnut shells do not provide the same mix of ingredients, so heavily soiled clothes and some food, body, or grease stains may need another treatment.

Also, cleaning visible dirt does not prove that a wash has killed germs. In the 2023 study, soapnut extract alone reduced microorganisms less effectively than the tested soapnut extract combined with carvacrol. Do not treat soap nuts as a disinfectant.

Are soap nuts better for the environment?

“Plant-based” does not automatically mean “environmentally harmless.” A product’s impact can depend on how it is grown, processed, transported, used, and discarded.

One laboratory study compared wastewater from soapnuts, other plant-based surfactants, and commercial detergents. Read the study comparing laundry products and wastewater toxicity.

How to try soap nuts

If you are looking for Natural Laundry & Cleaning options, you may want to test soap nuts, start with a small load of lightly soiled clothes. Follow the package directions and check the results before using them for work clothes, towels, or heavily stained items. Treat stains before washing. If clothes still look or smell unclean after the cycle, try a detergent suited to the fabric and soil.

Frequently asked questions

Do soap nuts work in cold water?

Results can vary by product and washer. Check the package instructions. The studies cited above tested specific preparations and wash conditions.

Do soap nuts make a lot of suds?

Not necessarily. Foam alone does not show how well a laundry product cleans. Check the clothes after washing.

Can soap nuts replace regular detergent?

They may work for some lightly soiled loads, but they may not suit every stain or laundry need. Test them on a small load before using them as your only laundry product.