Reading MUJI's "Fermented Plant Extract Head Scrub" Through Its Ingredients: Salt Is the Main Ingredient, and the Cleansing Agents Are Mild

He started with a press release issued by Ryohin Keikaku on February 26, 2026. According to the release, the product is a new item in a hair care series built on a skincare-inspired approach and committed to "100% naturally derived ingredients." It is a scrub-type product used before shampooing, once or twice a week depending on the condition of the scalp, and the release says its naturally derived scrub removes old dead skin cells from the scalp as well as the sebum buildup that causes odor.

Kazunosuke rates MUJI's Fermented Plant Extract hair care series highly. He says it ranks quite high in quality among drugstore products, at a level that, a dozen or so years ago, wouldn't have been out of place as a salon-exclusive product. The price isn't under 1,000 yen, but he says the quality is not to be underestimated.

At the same time, he calls the phrase "100% naturally derived ingredients" "wordplay." Writing "natural ingredients" gives the impression that nothing is chemically synthesized, but "naturally derived ingredients" only requires that the origin be natural. Petroleum, for example, is a natural resource, so even ingredients chemically synthesized from petroleum can be called naturally derived. The release's own footnote states that it "contains ingredients made by chemically reacting natural ingredients." For that reason, the speaker's view is that "100% naturally derived ingredients" on a hair care product doesn't mean much. He says he'd rather they didn't use the expression because it sounds dubious, but that even setting it aside, the series is of high quality.

For moisturizing ingredients, it contains three fermented plant extracts: the company's own rice bran ferment, plus Job's tears seed ferment and barley seed ferment.

It comes in three scents—lavender, grapefruit, and mint—all with the same ingredient formula. There is also information that a head scrub will be added to the new "Relaxing" series, and the speaker said there will likely effectively be four versions by the time the video is published. However, since the ingredients of the Relaxing version aren't known yet, he says he'd like to cover whether it's the same formula separately.

As for how it became popular, he introduced a Yahoo! News article from October 2. The article was about caring for scalp odor with a 1,490-yen head scrub, and reported that it was a popular product with more than 490 reviews on the official online store. According to Kazunosuke, the reviews are split by scent, with 432, 507, and 354 reviews, for a total of over 1,200. Despite having been on sale only a short time, it is on its way to becoming a hugely popular product, he says.

Reviews quoted in the article included comments such as:

• After using it, I noticed I didn't smell even in the afternoon
• I have my sixth-grade son, whose head odor bothers me, use it too
• The shampoo afterward lathers better, and my hair lifts up fluffily from the roots
• My hair is silky and fluffy after blow-drying

Some posts also reported noticing a change in hair texture, not just the scalp.

From here he moves into the ingredients. He says head scrubs are a category he has rarely seen in his whole history of analyzing shampoos. Its biggest distinguishing feature is that sodium chloride—that is, salt—is listed before water in the full ingredient list. The gritty particles are this salt.

While saying he doesn't know the exact concentration, the speaker offers the following estimate. A typical shampoo contains around 10–15% cleansing agents. By comparison, he thinks the salt probably makes up several tens of percent, likely around 30–40%.

There are many kinds of scrubbing agents, such as sugar in sugar scrubs and polyethylene beads in facial cleansers. Kazunosuke praises the choice of salt among these from a safety standpoint, for three reasons: it dissolves easily in water, it poses no risk of accumulating in the environment when washed away, and it causes almost no irritation when it gets on the skin.

He also mentioned, while noting that he doesn't know whether there is sufficient evidence, that there has long been a "grandma's wisdom"-type care method of massaging the scalp with highly concentrated salt to remove odor. He thinks that containing a high concentration of salt may give it some effect on the scalp.

Next he evaluated the combination of cleansing agents. He says the formula is mild while still delivering a reasonable amount of cleansing power.

• Sodium Methyl Cocoyl Taurate: A taurate-based cleansing agent. Its cleansing power is relatively high, but it is a highly versatile ingredient that can be used mildly, and one Kazunosuke has long recommended. He says MUJI's previous series also used it in products with higher cleansing power.
• Sodium Cocoyl Glycinate: An amino acid-based cleansing agent. Its cleansing power is relatively high among amino acid-based agents.
• PEG-150 Distearate: A nonionic surfactant. It has slight cleansing power but works mainly as a thickener.
• PEG-120 Methyl Glucose Triisostearate: Also nonionic, used as an almost water-soluble thickening ingredient.

What the speaker focused on is that there are two nonionic ingredients. Nonionic ingredients make it easier to emulsify oily substances such as waxes. He therefore sees a good chance that these are behind the reviews saying shampoo lathers better after use.

He says the fragrance gives the impression of a natural scent, with little artificiality, and is pleasant to use. However, he felt the lavender and grapefruit scents were fairly strong, so he says that personally, mint seems the easiest to use. It also contains menthol, so it is presumably a slightly cooling formula.

The other ingredients are as follows:

• Propanediol, glycerin, pentylene glycol: moisturizing
• Citric acid: pH adjustment
• Caprylhydroxamic acid: a preservative/preservative-boosting ingredient that also acts as a chelating agent
• Rice bran ferment, Job's tears seed ferment, barley seed ferment: MUJI's proprietary fermented ingredients. However, unlike MUJI skincare, where some products contain more of them than water, they don't seem to be at such high concentrations in this hair care product
• Hydrolyzed soy protein: damage repair
• Rice germ oil, argan kernel oil, grape seed oil, meadowfoam seed oil: oily ingredients that moisturize the scalp and give hair a moist feel
• Ceramide NP (human-identical ceramide)
• Five amino acids: alanine, arginine, sodium glutamate, serine, and proline
• (Dihydroxymethylsilylpropoxy) hydroxypropyl hydrolyzed soy protein: a heat-activated ingredient that reacts to blow-dryer heat to protect hair and repair damage. It is also included in the Fermented Plant Extract hair care series
• Polyquaternium-51: a moisturizing ingredient known as Lipidure

Looking at the full ingredient list again, Kazunosuke noticed that caprylhydroxamic acid is about the only ingredient that looks like a preservative. With sodium chloride at such a high concentration, bacteria can't grow. By the same logic as soy sauce not containing preservatives, the product is designed with almost no preservatives. He says this is also one of its appeals.

The "free-from" claims are no synthetic fragrance, colorants, mineral oil, parabens, or alcohol, and it has been allergy tested (with the note that this doesn't mean no one will have an allergic reaction). Since it uses no synthetic fragrance, all the fragrance appears to come from natural essential oils and the like. The base ingredients are also carefully put together, and the speaker thinks people with a wide range of skin types can use it. It may be tough for people who dislike scents, but even then, he suggests mint might be relatively easy to use.

All versions are 1,490 yen including tax for 200g. That's a bit expensive for an ordinary hair care product, but Kazunosuke said that since you only need to use it once or twice a week—and the manufacturer's guideline is up to twice a week—it lasts quite a long time.

Since it is essentially a scalp care product, he would have liked to try it on a scalp, but this time he tested it on his usual 100% human-hair extension. So he can't tell its effect on the scalp, but he says he can convey an impression of the product. He used the mint scent.

As for how to use it, he recommends thoroughly pre-rinsing first and washing the scalp well. When he squeezed out the product, it was packed with grains and grit, and he felt it might be about half salt.

His impression was that it didn't lather very well. Shampoos with a high salt content tend to lather weakly. The speaker explains that adding some sodium chloride improves lather, but beyond a certain amount it actually makes lathering harder, so this can't be helped. Instead of cleansing with foam, the product is positioned as one that cleanses physically with a salt scrub. He says it can remove sebum left on the scalp and the substances that cause odor.

He speaks cautiously about any antibacterial effect. A high concentration of salt creates an environment where bacteria can't grow, but personally he doesn't think it can do anything like sterilize the scalp. Still, since people say odor is considerably reduced, it may have some effect. Judging from the ingredients, there are no other antibacterial or odor-absorbing ingredients, so the speaker's guess is that any effect would come from the high concentration of sodium chloride.

As for the finish, even on the damaged extension sample, there wasn't much squeakiness. Some overseas scrub shampoos tend to leave hair squeaky, but by comparison this gave a soft finish, he says. However, some reviewers with heavily damaged hair reported squeakiness. So he advises that people concerned about damage can simply massage the scalp without washing all the way to the ends. His assessment is that if hair is only somewhat damaged, washing normally probably won't accelerate the damage.

After blow-drying, the hair didn't become rough. The hair felt somewhat firm when running fingers through it, but compared with products that leave coating ingredients like silicone behind and feel sticky, it had a natural texture, and it came together light and fluffy—enough that some people might say "this alone is enough." He notes that since this product is meant to be followed by shampoo and treatment, in most cases the finish will be even better.

Kazunosuke broke down the reasons for the effects described in reviews into several possibilities.

1. The action of the high concentration of sodium chloride on the scalp, and reduced odor.
2. The fragrance is clean and feels refreshing.
3. The possibility that the nonionic surfactants make accumulated silicones and the like easier to remove.
4. A simple pre-rinse effect. If you remove some sebum before shampooing, lather naturally improves. For people who don't normally pre-shampoo, he says simply shampooing after the head scrub can be expected to increase lather.

Even so, what the speaker considers best about this product is that the base ingredient formula is well put together. He says there aren't many head scrubs among Japanese hair care products, and his impression is that most are from overseas brands. Those products are likely to have high cleansing power, and many may be hard to use for people with sensitive skin or a weakened scalp. This product is made with mild ingredients, so a wide range of people can easily try it.

Taurate-based cleansing agents are also used in high-end salon-exclusive products, and the speaker thinks even people with some damage can use it. However, scrubbing hair that has accumulated damage could increase that damage. He says the basic, best way to use it is to just spread the lather over the hair and massage the scrub into the scalp. He also cited, as a personal recommendation, the simple packaging that doesn't look out of place in the bathroom.

Finally, Kazunosuke touched on a hair care problem he has talked about before. Lately, he says, shampoos have become too mild in cleansing power, leading to "buildup," in which coating ingredients from treatments and the like accumulate, and more people are seeing their hair texture decline. The speaker thinks that for such hair too, removing accumulated coating ingredients with this head scrub may help improve its condition.

Kazunosuke's verdict is that, as a pre-shampoo-type product used before shampooing, it is a "two birds with one stone" item that cares for the scalp and hair at the same time. He called it one of MUJI's most highly recommended hair products, and closed by saying he'd like people who are bothered by scalp odor or hair that feels flat and heavy to try it. As for the new head scrub in the Relaxing series, he says he'd like to go over its ingredients separately if he gets the chance.