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Persimmon Soap Not Working? 8 Reasons Why (and What to Try Next)

The "persimmon soap fail" threads come up again and again. Read enough of them and the same handful of causes keeps appearing. Most are fixable.

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You read the glowing posts, ordered the soap, used it for a week and… you can still smell it. Or your partner can. You’re not the only one. “Persimmon soap fail” is a recurring post title in menopause and over-60 communities.

We read through those threads and the replies. The same handful of explanations kept coming up, and one more turns up in the household-odor threads that the soap threads never mention. Work through all eight in order before you decide persimmon soap isn’t for you.

1. The odor isn’t nonenal

This is the big one. Persimmon soap targets a specific smell: the greasy, grassy, “dusty closet” odor linked to 2-nonenal, which researchers have found in people aged 40 and older (what the studies actually show). It is not designed for:

• Sweat-driven armpit odor, which is sharp, sour or oniony and comes from bacteria breaking down sweat.
• Teenage or hormonal body odor. In one thread, a parent asked whether it would help their stinky 23-year-old. Commenters pointed out that persimmon soap targets nonenal, which that kind of odor usually isn’t.
• Groin or skin-fold odor, which often has a bacterial or fungal component. If you are wondering about the fungal half of that, the published evidence is thinner than the internet suggests — we went through it in can a fungal infection cause body odor.
• A sharp, ammonia-like smell, which is a different molecule with a different cause: urea from urine is nearly odourless until urease-positive bacteria break it down into ammonia on whatever surface it landed on, over hours. That is a cleaning-and-timing problem rather than a sebum problem, and we work through it in why urine smells so strong in older adults. If you are washing someone who cannot easily shower, an alkaline true soap is the wrong tool for that smell altogether — see no-rinse body wash for the elderly.

Try next: Where is the smell strongest? If it’s the neck, scalp, pillow and collars, nonenal is a good guess. If it’s mostly the armpits, see #7 and the alternatives below. Not sure you even have it? Read how to check without asking anyone. If you’re in perimenopause you may well have both smells at once, which is why the soap can seem to half-work — we untangle them in perimenopause body odor: nonenal, sweat or something else.

2. You’re washing the wrong places

Most of us lather up our armpits and call it done. Nonenal forms in sebum, the skin’s oil. It concentrates where oil glands are dense: the nape of the neck, behind the ears, the scalp and hairline, the upper back and chest. A 2016 study measuring skin emissions chose the nape of the neck as its sampling site for exactly that reason.

Try next: Make those areas the focus. If your hair is short or thinning, wash your scalp with the bar as well. Our how-to guide has a diagram.

3. It’s rinsed off too fast

A quick swipe and rinse gives the tannin very little contact time. Letting the lather sit for a moment is the most common tip in user threads.

Be clear that this is a user habit, not a tested dose. Nobody has published a contact time for persimmon tannin on skin. What is on record is a Japanese cosmetics patent from 2001 whose formulas were all leave-on — a mist, gel, lotion, aerosol and emulsion — rather than a soap, which is at least consistent with longer contact mattering. It’s company patent data, not peer-reviewed evidence, and it does not tell you that thirty seconds of lather beats five.

Try next: Lather the target areas first, finish the rest of your shower, then rinse. It costs nothing to try, which is the honest argument for it.

One thing worth ruling out here is the water itself. In hard water a true soap partly converts to insoluble calcium and magnesium salts, which neither lather nor rinse, and skin washed in hard water has been measured carrying significantly more cleanser residue afterwards (Danby et al., J Invest Dermatol). If the bar leaves a film that will not shift, read can hard water cause body odor before concluding the bar is at fault — though be warned that whether hardness changes how you smell has never been tested at all.

4. You haven’t given it long enough

Some users notice a change after one shower. Others describe a gradual improvement over a week or two. If you judge on day three, you may be judging too early.

Try next: Use it daily for at least two weeks before deciding.

5. The smell is living in your fabrics

This catches almost everyone. Nonenal transfers to pillowcases, shirt collars, cardigans, sofa cushions and car seats. Your skin can be clean while your pillow still smells, and you’ll blame the soap.

Try next: On day one of your trial, wash all bedding, put on fresh pillowcases and wash the shirts and knits you wear most. A normal cool, quick cycle often won’t shift it, because 2-nonenal is oil-soluble and leaves only when the skin oil does; our guide to getting old person smell out of clothes sets out the soak-and-strip wash that works. Change pillowcases every few days during the trial.

Reaching for a fabric spray instead is the shortcut almost everyone tries, and it is a different operation from washing: masking, trapping and sanitising are three separate jobs and none of them is removal, which we take apart in does Febreze remove body odor.

6. The bar isn’t really a tannin soap

Search results are crowded with “persimmon” bars, and not all of them list persimmon tannin at all (look for kakishibu or Diospyros kaki on the ingredient list). Some listings describe a different soap entirely, and counterfeits of well-known brands circulate on big marketplaces.

There’s a second reason to read the ingredient list rather than the star rating. Persimmon bars are moving through Amazon’s Vine reviewer programme in volume right now: in the last month the Vine and beauty-reviewer subreddits have run threads like “For the most wanted ‘Old Person Smell’” and “For what kind of smell?”, with members picking persimmon bars out of the queue and asking each other what the smell even is. Reviews written by people who were sent a bar, rather than by people who bought one because they had the problem, tell you much less than the rating suggests. We have since pulled that apart properly — Amazon’s own description of the programme, the badge it applies, and what the FTC says about free products — in is persimmon soap legit.

Try next: Read the ingredient list before you buy, and buy from the brand or a reputable importer. Our comparison of five bars lists the key ingredients of each.

7. A scent is masking, or clashing with, what’s left

Many persimmon soaps are scented, with citrus, lemongrass, lavender or mint. Perfume doesn’t remove an odor. It adds a second smell on top. Some users find the soap’s own fragrance unpleasant, and one r/bodyodor commenter said their bar had the same sweet, putrid note they were trying to get rid of.

Try next: Switch to an unscented or fragrance-free bar so you can judge what’s actually happening.

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8. Your rooms are putting it back on you

This is the one that defeats people who have done everything else right. If you wash properly, put on clean clothes, and then sit in the same armchair, sleep in the same unwashed duvet, put on the same coat and drive the same car, you are re-dosing yourself from the reservoirs several times a day. The soap is being judged on a fight it can’t win.

The clue is timing. Skin-source odor builds gradually through the day. Reservoir odor arrives the moment you put something on or walk into somewhere — a coat out of the closet, the car on the way to work, an armchair after twenty minutes. Readers in an r/OverSeventy thread this August described tracking theirs down to stored winter coats and to bedding, not to their skin at all.

Furniture is the worst offender because it does not merely hold the smell, it keeps producing it from the oil already soaked into the padding — the reason a cleaned chair comes back after a couple of good weeks, which we set out in getting old person smell out of furniture.

This is also the one place where there is some measured evidence about the surroundings rather than the body. A 2026 study in Scientific Reports looked at 35 older people’s homes and 75 visitors, and found that ventilation combined with enclosed storage and buffering materials did better than ventilation on its own. Enclosed storage is the unglamorous part people skip.

Try next: for the two weeks of your trial, treat one room and one seat as well as your skin. Strip and wash the bedding, wash or air the coat and the two knits you wear most, ventilate the bedroom daily, and put seldom-worn clothes in closed storage rather than leaving them hanging to absorb the room. Our guide to old person smell in a house separates the three different household smells that get lumped together, because only one of them is the one your soap addresses.

How long is it supposed to keep working?

This one deserves its own answer, because it is the most common objection raised by people who never bought a bar at all — and because getting the model wrong makes a working bar look like a failing one. In a September 2026 r/Menopause thread on 2-nonenal, two different commenters made the same point independently: it is a soap, you rinse it off, so whatever it does must stop at the shower door.

The part of that which is correct: a true soap is built to leave with the water, and nobody has published a measurement of how much persimmon tannin, if any, stays on skin after rinsing. The published record of persimmon tannin meeting living skin is a single animal study about pigmentation, not odor. So if a seller tells you a bar gives you all-day protection, they are going well past the evidence, and we are not going to tell you otherwise about ours.

The part of it which is the wrong model is the more useful half. The objection assumes the smell arrives from outside and has to be blocked, like rain. It doesn’t. Ishino and colleagues (2010), in the Journal of Biological Chemistry, showed that trans-2-nonenal is generated endogenously during the peroxidation of polyunsaturated fatty acids, and that it reacts preferentially with lysine residues on protein to form a specific adduct, which they detected in living tissue. The compound is made in your own skin oil, where the oil already is, and some of it ends up chemically bound rather than loosely sitting on the surface.

That changes what a wash can even be. There is no incoming smell for a residual coating to intercept, so the only thing a soap can plausibly do is a removal event: take the oil, and whatever has formed in it, down the drain. On that model, “it had worn off by lunchtime” is not a product failure. It is what you would expect, and the real question is a different one — how fast the supply rebuilds.

How fast it rebuilds is the question nobody has answered, and the mechanism says it never stops. Haze and colleagues (2001) found 2-nonenal is generated by the oxidative degradation of ω7 unsaturated fatty acids with lipid peroxides as the initiator — a process with no bacterial step in it at all. Your skin keeps making sebum and oxidation keeps happening, so the clock restarts after every shower. This is the same reason an armchair that smelled fine for a fortnight starts up again, which we go through in getting it out of furniture: cleaning the surface does not empty the reservoir underneath it.

There is a counterintuitive detail here that is worth knowing, because it kills the obvious fix. You might assume the answer is to wash more often, on the theory that older skin is producing more of the raw material. It isn’t. Piérard-Franchimont and Piérard (2002), in Dermatology, measured sebum excretion in 100 postmenopausal women, half on hormone therapy and half not, and found a significant decline in sebum output over the first decade after menopause — and that HRT did not significantly control seborrhoea either. Output falls while the stale smell rises, which only makes sense if the problem is what happens to the oil rather than how much of it there is. More washing does not address oxidation, and it does cost you something.

So how should you judge it? Compare like with like. Check at the same point in the day, in the same conditions, rather than comparing a post-shower sniff on Tuesday to a six-o’clock one on Friday — and run the fabric side of the trial at the same time, or you are measuring your pillowcase. Whether the bar does anything at all is a separate question from how long it lasts, and we lay out what is and isn’t known about that in does persimmon soap actually work.

And the other meaning of the question: how long does the bar itself last? TanniBar’s own page says about a month of daily showers, which is the brand’s figure rather than a measured one. What reliably shortens it is leaving the bar standing in water, as above — a soft bar disappears fast and you end up using several times as much per wash.

Still smelling it? Alternatives users report

If you’ve worked through all eight and nothing has changed, people in r/Menopause and r/Perimenopause most often mention:

• Glycolic acid toner swiped on dry underarms after showering, then deodorant once it dries. It does lower skin pH, which is measured, though whether that reduces smell has never been tested — we go through the whole chain in glycolic acid for body odor. Don’t use it on broken skin or genitals.
• Mandelic acid washes and leave-on deodorants, the active in some “whole-body” deodorant brands. These are aimed at bacterial odor rather than at oxidized skin oil, which is why they and persimmon soap are not substitutes for one another — we compare the two categories in persimmon soap vs Lume.
• Benzoyl peroxide or chlorhexidine washes for bacteria-driven odor. They can bleach fabric or irritate skin, so follow the label, and don’t pile them onto skin that’s already sore (see persimmon soap side effects).
• Hypochlorous acid sprays, which come up constantly in the cleaning and skincare threads. They are a disinfectant, so they belong to the bacterial smell rather than to this one, and there is a specific reason they don’t address oxidised skin oil — we go through the chemistry here.
• Hormone therapy. Some perimenopausal users say their odor changed once they started HRT — in both directions, which makes more sense once you know that estrogens and androgens move skin oil output opposite ways. The measured part and the unmeasured part are laid out in does HRT cause body odor. Either way it’s a conversation for your doctor.

The bottom line

When persimmon soap “doesn’t work,” the most common reason is that the odor isn’t nonenal. The next most common are washing the wrong spots, and leaving the smell sitting in the laundry, the chair and the closet while you judge the soap on your skin. Fix those, give it two weeks with an unscented bar, and you’ll know whether it’s right for you.

Frequently asked questions

Sources