Persimmon Soap: What It Is, Benefits, and Whether It Works for Aging Odor

Short answer: Persimmon soap is a cleansing bar made with persimmon tannin (kakishibu), an extract of unripe persimmon fruit that has been used in Japan for centuries. Today it is best known as a soap for aging odor, the change in body odor linked to a skin compound called 2-nonenal that appears from around age 40.

Written by the NENALI team. We make a persimmon soap, so we have a stake in this topic: every scientific claim below names its source so you can check it yourself. Last reviewed: October 2026.

What is persimmon soap?

Persimmon soap is a soap or glycerin bar with one defining ingredient: persimmon tannin. The tannin comes from unripe, astringent persimmons, the same compounds that make an unripe persimmon dry out your mouth. In Japan the fermented juice is called kakishibu and has a long history of household use. It is now a common ingredient in Japanese soaps made for kareishu, the Japanese word for age-related body odor.

Persimmon soap benefits: what does it do?

Persimmon tannin is a polyphenol. Polyphenols of this family are understood to bind odor compounds rather than cover them with fragrance, which is why persimmon soap is used as a deodorizing cleanser. People choose it for three reasons:

• Aging odor. It is the best-known soap ingredient aimed at 2-nonenal, the compound behind the greasy, grassy note that body odor can take on after 40.
• Odor that comes back after a shower. This odor comes from skin oils reacting with oxygen, not from dirt, so it returns between washes. A soap made for it is used daily on the areas where skin oils concentrate.
• Low fragrance. A real persimmon soap does not need a heavy perfume to do its job.

Does persimmon soap work for aging odor?

There is real research behind the idea, and it is worth being exact about what it shows.

• The compound is real. In 2001, researchers analyzed the body odor of people aged 26 to 75 and detected 2-nonenal only in those aged 40 and over. They described its smell as unpleasant, greasy and grassy, and linked it to the oxidation of omega-7 fatty acids on the skin (Haze et al., Journal of Investigative Dermatology, 2001).
• A polyphenol soap reduced it in one study. In 2012, a four-week study gave 20 men aged 43 to 75 a soap containing a polyphenol blend extracted from astringent persimmon, green tea, oolong tea and tiencha. With daily use, the amount of 2-nonenal measured from the body fell significantly, and odor ratings improved (Tatsuguchi et al., Journal of Japan Association on Odor Environment, 2012).
• The limits. That study was small, it was run by a company research institute, and it tested a blend of polyphenols rather than persimmon alone. No study proves that every persimmon soap works for every person, and no brand's bar, ours included, should be treated as a medical treatment.

So the honest answer is this: the mechanism is plausible, the early evidence is encouraging, and results vary with skin chemistry. That is why the NENALI persimmon soap comes with a 60-day money-back guarantee: you test it on your own skin.

Persimmon soap for "old person smell"

"Old person smell" is the blunt phrase people type into a search box when they mean aging odor. It is not a hygiene problem and it has nothing to do with being unclean: it is a normal change in skin chemistry. In one study, volunteers actually rated the body odor of older adults as less intense and less unpleasant than the body odor of young and middle-aged adults (Mitro et al., PLoS ONE, 2012). Persimmon soap became popular because it is aimed at the specific compound involved rather than at sweat.

Persimmon soap side effects

Persimmon soap is a cosmetic cleanser and is used like any other soap. We are not aware of side effects specific to persimmon tannin in a rinse-off soap. The possible ones are those of any soap: dryness or tightness, and occasionally irritation or an allergic reaction to an ingredient. Tannins are astringent, so a bar without a moisturizing base can feel drying on mature skin. If you are prone to reactions, patch test on the inner arm first and stop if irritation appears.

A sudden or strong change in body odor is a different matter. Mention it to a doctor, because soap is not a treatment for a medical cause.

How to use persimmon soap

1. Lather on wet skin and take it first to the neck, chest, back, under-bust and underarms, where skin oils concentrate.
2. Leave it on for twenty to thirty seconds before rinsing. Contact time does more than scrubbing.
3. Use it every day. The skin keeps producing the compound, so consistency matters more than washing harder.

Fabric matters too. Pillowcases and shirt collars hold the odor and hand it back, so wash them regularly.

How to choose a real persimmon soap

• Persimmon tannin or extract on the ingredient list, not just "persimmon fragrance". On a label it usually appears as Diospyros kaki (persimmon) fruit extract or persimmon tannin.
• A moisturizing base, such as glycerin, because skin gets drier with age.
• Low fragrance. Heavy perfume covers odor. It does not remove it.
• A guarantee. Results vary from person to person, so a money-back period is worth more than a bold claim.

Persimmon soap vs. regular soap

Antibacterial soap is a third thing again: it targets the bacteria that turn sweat into odor, which is a different problem from aging odor.

Persimmon soap or persimmon body wash?

Same base, same job. A bar gives more contact time and lasts longer: roughly four weeks of daily use for a 100 g bar. A persimmon body wash is easier if you find a bar awkward, and it travels better. Plenty of people alternate.

Where to buy NENALI persimmon soap

NENALI is sold in one place: nenali.com. It is not on Amazon, eBay or Walmart, it is not in stores, and we have no resellers. A similarly named bar found elsewhere is not ours and is not covered by our 60-day guarantee.

Frequently asked questions

Is persimmon soap the same as nonenal soap?

Mostly, yes. "Nonenal soap" is a nickname for any soap made for 2-nonenal, the compound behind aging odor, and persimmon tannin is the ingredient most of those soaps are built on.

Is persimmon soap a deodorant?

No. A deodorant works on the bacteria that feed on sweat. Persimmon soap is a cleanser aimed at 2-nonenal, which forms when skin oils meet oxygen. Many people use both.

How long does persimmon soap take to work?

Some people notice a difference from the first washes. Because you stop registering your own scent, the clearest sign is usually fabric: a pillowcase or collar that smells different after a week or two.

Is persimmon soap safe for sensitive skin?

It is used like any other soap. If you are prone to reactions, patch test on the inner arm first and stop if irritation appears. Choose a bar with a moisturizing base, because tannins are astringent.

Can I use persimmon soap every day?

Yes. It is meant for daily use, because the skin keeps producing 2-nonenal and the odor returns between washes.

Related guides

• Aging odor (nonenal): is it real, causes and what helps
• Aging odor soap: how to choose one that works

Sources

1. Haze S, Gozu Y, Nakamura S, Kohno Y, Sawano K, Ohta H, Yamazaki K. 2-Nonenal newly found in human body odor tends to increase with aging. Journal of Investigative Dermatology. 2001;116(4):520–524. doi:10.1046/j.0022-202x.2001.01287.x
2. Tatsuguchi I, Matsuoka T, Izumi R, Ijichi S, Shibata H. Preventive effect against the aged men's body odor by the soap containing polyphenol. Journal of Japan Association on Odor Environment. 2012;43(5):362–366. doi:10.2171/jao.43.362
3. Mitro S, Gordon AR, Olsson MJ, Lundström JN. The smell of age: perception and discrimination of body odors of different ages. PLoS ONE. 2012;7(5):e38110. doi:10.1371/journal.pone.0038110

NENALI products are cosmetics. They are not intended to diagnose, treat, cure or prevent any disease.