The quick answer
Soapnut powder is the ground, dried fruit shell of the soapnut or soapberry tree (Sapindus mukorossi), known in India as reetha or ritha. The shell is rich in saponins, natural compounds that foam in water and lift away oil and dirt, so the powder works as a plant-based cleanser. People use it as a traditional hair wash, often mixed with shikakai and amla, and as a gentle laundry and household cleaner. It is for washing only, not for eating.
Keep soapnut powder and soapnut liquid out of your eyes; if it gets in, rinse with plenty of clean water. Do not eat or drink it, keep it away from children, and patch test on a small area of skin before using it on your scalp.
What Is Soapnut Powder?
Soapnuts are the round fruits of Sapindus mukorossi, a deciduous tree also called Chinese soapberry, washnut or reetha. It is native to China and cultivated in India, Japan and Pakistan, where it grows naturally in the sub-Himalayan foothills at about 200 to 1,500 meters (Sochacki and Vogt, Plants, 2022). The fruits are about 2 cm across and turn from yellow-orange to dark brown as they dry, with a hard black seed rattling inside.
The cleaning power is in the dried fruit wall around the seed. Saponins make up about 10 to 11.5% of the fruit, concentrated in that outer shell (Sochacki and Vogt, 2022). Soapnut powder is simply those dried shells ground fine, which makes them easier to measure and mix than whole nuts.
Other Sapindus species are used the same way around the world. In South America, Sapindus saponaria is popularly called "monkey soap" (Adriano et al., Chemistry & Biodiversity, 2026).
How Soapnuts Clean: Saponins
The word saponin comes from the Latin sapo, meaning soap. Each saponin molecule pairs a sugar portion that is drawn to water with a fat-friendly portion that clings to grease, so in water they lower surface tension, form foam and help oil and grime rinse away, much like a conventional surfactant (Sochacki and Vogt, 2022). In one lab test reported in that review, a soapnut solution emulsified kerosene about as well as sodium dodecyl sulfate (SDS), a common synthetic detergent.
One practical note comes out of the research: hard water raises the amount of soapnut saponin needed to start working (Sochacki and Vogt, 2022), so if you have hard water, you may need a little more powder.
Using Soapnut Powder for Hair
In India, soapnut has long been part of herbal hair care. A 2026 article in the Indian Journal of Dermatology lists soapnut, shikakai, coconut oil, hibiscus and henna among the plant-based ingredients many Indian communities use (Palaniappan et al., 2026). The classic combination is reetha with shikakai and amla:
| Herb | Plant and part used | Traditional role in hair care |
|---|---|---|
| Reetha (soapnut) | Sapindus mukorossi, dried fruit shell | The main cleanser and foaming agent |
| Shikakai | Acacia concinna, dried pods | A second saponin-rich cleanser, used to wash hair |
| Amla | Emblica officinalis (Indian gooseberry), dried fruit | Added for conditioning and strengthening hair |
| Neem | Azadirachta indica, leaf | Traditionally used against dandruff and lice |
(Plant roles from a 2023 review of tropical herbs in hair care, Sang et al., Heliyon.) That review notes these plants show promising properties in lab and formulation studies. There is little clinical research testing soapnut hair washes in people, so treat any claims about hair growth or dandruff as unproven.
To use it, people usually mix a spoonful or two of soapnut powder with water into a thin paste, or blend it with shikakai and amla powders, then massage it into wet hair and scalp and rinse well. Start with a small amount: soapnut removes oil, and you can always wash a second time. Read more in our amla guide and neem guide. If you oil your hair before washing, our Jamaican black castor oil guide covers a popular choice.
Using Soapnut Powder for Laundry and Cleaning
The washnut gets its name from its cleaning use: people in its native range have long used it as a natural detergent (Sochacki and Vogt, 2022). Researchers have tested soapnut in textile processing too. In a 2023 study in Heliyon, a small amount of soapnut extract helped clean raw cotton knit fabric alongside an enzyme treatment, as a gentler alternative to harsh chemicals (Raafi et al., 2023).
We found few published tests comparing soapnuts with modern laundry detergent on everyday stains, so expect gentle cleaning rather than heavy-duty stain removal. Soapnut liquid is best for lightly soiled laundry, hand washing and wiping down surfaces. For grease or set-in stains, pretreat or use a conventional product.
How to Make Soapnut Liquid
- Stir a spoonful or two of soapnut powder into a couple of cups of water in a pot.
- Bring it to a simmer and let it bubble gently for several minutes, stirring now and then.
- Let it cool, then strain it through a fine cloth or coffee filter to remove grit.
- Pour it into a labeled bottle and keep it in the refrigerator. It has no preservatives, so make small batches and throw it out if it smells sour or grows mold.
- Use it as a hair wash, add some to a laundry load, or dilute it for wiping counters.
Label the bottle clearly so no one mistakes it for a drink.
Cautions and Safety
- Do not eat it. Soapnuts are not a food. A review of soapnut pharmacology lists emetic (vomit-inducing) effects among those studied (Upadhyay and Singh, Revista do Instituto de Medicina Tropical de São Paulo, 2012).
- Keep it out of your eyes. Like any soap, it stings. Rinse well with clean water if it gets in.
- Patch test first. Purified soapnut saponins caused no skin irritation in animal tests (Sochacki and Vogt, 2022), but a homemade powder or liquid is not the same as a tested extract, and anyone can react to a plant.
- Watch for dryness. Because it removes oil, use less or wash less often if your hair or skin feels dry afterward.
Find It at William's
We don't currently list soapnuts or soapnut powder online; call the store to check what's on the shelf. Amla is a traditional companion to soapnut in Ayurvedic hair washes, and our amla guide explains how it is used.
Frequently Asked Questions
Is soapnut the same as reetha?
Yes. Reetha (also spelled ritha) is the common Indian name for the soapnut, Sapindus mukorossi. You may also see it called soapberry, washnut or Chinese soapberry.
Can I use soapnut powder as shampoo?
Many people do, usually mixed with water or with shikakai and amla. Keep it out of your eyes, patch test first, and use less if your hair feels dry.
Does soapnut powder really clean clothes?
Its saponins act as natural surfactants, and it has a long history as a detergent where the tree grows. Few studies compare it with modern laundry detergent, so it is best for lightly soiled loads and hand washing.
What is the difference between soapnut and shikakai?
Both are saponin-rich plants used to wash hair. Soapnut is the dried fruit shell of Sapindus mukorossi. Shikakai is the dried pod of Acacia concinna, a climbing shrub. They are often used together.
Is soapnut powder safe for skin?
Purified soapnut saponins did not irritate skin in animal tests, but homemade powders vary and anyone can react to a plant. Patch test on a small area first and stop if you notice redness or itching.
Can you eat soapnuts?
No. Soapnuts are a cleaning plant, not a food, and research on the plant lists emetic effects. Store soapnut powder and liquid away from food and out of reach of children.