MASHIRO
MASHIRO Medicated Whitening Powder, 30g (Herb Mint)
MASHIRO Medicated Whitening Powder, 30g (Herb Mint)
@cosme rating: 4.4/7.0
A Japanese quasi-drug whitening tooth powder that lifts coffee, tea, and wine stains from daily use — without the enamel damage that comes with most whitening toothpastes.
✓ 100% authentic
✓ Ships from Japan in 3-5 days
✓ Duties prepaid for US orders
✓ Tracked delivery via Japan Post
Couldn't load pickup availability
What it is
MASHIRO flips the script on what a whitening toothpaste can look like. The compact, design-award-winning jar contains a green powder — not paste — which turns out to be the whole point. Powder can hold nearly double the cleaning agents of paste without getting too dense to use, so each brush genuinely does more. The micro-silica particles are sized at 10 microns or less, fine enough to lift staining without scratching the enamel underneath. It foams lightly, rinses clean, and does not leave that artificial mint-coated feeling that makes your post-brush coffee taste wrong. One jar lasts about 100 uses — two to three months of daily brushing — at a price that makes professional whitening sessions feel hard to justify.
Ingredients
(1) Micro-Silica (無水ケイ酸): ultra-fine cleaning particles that polish away stains safely
(2) Calcium Pyrophosphate (ピロリン酸Ca): high-whitening-power agent targeting yellowing
(3) Dipotassium Glycyrrhizate (グリチルリチン酸2K): licorice-derived active that reduces gum inflammation
(4) Tocopherol Acetate (酢酸トコフェロール): Vitamin E that supports gum circulation
(5) Sodium Copper Chlorophyllin (銅クロロフィリンNa): chlorophyll that gives the powder its green color and helps neutralize bad breath
Cleaning agent: Silica, calcium pyrophosphate Solvent: Water, PEG-8, BG, ethanol Wetting agent: Concentrated glycerin, sodium hyaluronate-2 Foaming agent: Sodium lauryl sulfate Binder: Crystalline cellulose pH adjuster: Sodium polyphosphate, sodium carbonate Flavoring agent: Fragrance (herbal mint type) Sweetener: Stevia extract, xylitol Dipotassium glycyrrhizinate, tocopherol acetate Adsorbent: β-cyclodextrin Refreshing agent: Menthol, clove oil Colorant: Copper chlorophyllin sodium Preservative: Paraben, phenoxyethanol
How to use
Close the lid, flip the jar, and shake two to three times until powder collects in the inner lid. Press a dry toothbrush into the lid. Brush as normal, focusing on stained areas. Rinse thoroughly. Use once daily for maintenance, or twice daily when targeting heavier staining.
We ship internationally from Japan!
Frequently Asked Questions
Is this authentic?
Yes. We only buy from official retailers and directly from the brands here in Japan. Never resellers, never grey market stock.
We are beauty lovers too, so we know the worry, especially with something you are putting on your face. Authenticity is 100% guaranteed by us.
What are your shipping rates?
On orders under US$75, shipping is a flat US$20 to the United States and US$10 to all other countries.
Orders of US$75 or more ship free, applied automatically at checkout. Your exact shipping cost is shown before you pay.
How long does delivery take?
These estimates are for International Airmail (Tracked) and include 3 to 5 business days of processing in Japan.
- United States: 12 to 15 business days
- Canada, United Kingdom, France, Germany: 9 to 12 business days
- Australia, New Zealand, Denmark, Finland, India, Indonesia, Italy, Netherlands, Spain, Sweden, Switzerland: 10 to 13 business days
- China, Hong Kong, Malaysia, Singapore, South Korea, Taiwan, Thailand, Vietnam: 8 to 10 business days
- Rest of the world: 11 to 18 business days
Actual delivery can be affected by customs clearance, seasonal congestion, or carrier delays in the destination country, all of which are outside our control.
Do you offer express shipping?
Yes. As of 22 July 2026, we offer International Express Mail through Japan Post. The cost is based on order weight and is calculated automatically at checkout.
Will I pay customs or import fees?
US orders: No. As of July 1, 2026, all US orders ship DDP (duties delivered prepaid), meaning we prepay all import duties on our end. Nothing is due at your door.
Orders outside the US: Possibly. Duties and import taxes are set by your local customs authority and are not collected at checkout, so any charges on delivery are your responsibility.
We're working on rolling out prepaid duties for more countries soon.
I was surprised. I've tried several toothpastes that claim to whiten, but I didn't really see any results. However, just one use of this one made a huge difference. I was concerned about the pigmentation at the joints between my post-treatment teeth and my original teeth, but this one whitened my teeth overall, and the joints that bothered me faded after just one use. If it's so effective after just one use, it seems like it would be better value for money to use this one regularly than to buy other toothpastes, even if they're more expensive. The flavor is not much different from regular mint, so it's easy to use.
I tried MASHIRO Herb Mint 30g (1,800 yen) toothpaste with whitening properties that I bought at Loft. It doesn't foam much, so you can take your time brushing, and it leaves your teeth feeling smooth and comfortable! It's also made in Japan, so you can rest assured. The container is stylish, so maybe I'll buy the pink pomegranate mint next?
I used it as a test, and my teeth are so much smoother! It also seems to have a whitening effect, so I'll continue to use it.
I received MASHIRO Tooth Powder Herb Mint Flavor from Sumoka Toothpaste Co., Ltd. (@mashiro_tp). Unlike previous whitening products, MASHIRO is a toothpaste designed to both whiten and maintain healthy teeth. Its ultra-fine micro-silica particles remove stains while being gentle on teeth. It contains calcium pyrophosphate, which has excellent whitening properties. It effectively removes stubborn stains and yellowing from coffee and tea. Chlorophyll suppresses bad breath, while vitamin E and GA2 prevent periodontal disease for a dual effect. Daily brushing also effectively combats cavities. One 30g bottle contains enough for approximately 100 uses. The stylishly designed packaging makes it perfect for the bathroom. The mild mint flavor is ideal for those who don't like harsh toothpastes. I noticed a stevia-like aftertaste after brushing, perhaps due to the herb in the herb. It doesn't immediately alter the taste of drinks or food even after brushing. The large capacity means it's quite useful. I'd like to know the correct way to apply it to a toothbrush.
It never runs out. It's a powder toothpaste that lasts for a long time, even if you use it over and over again. It's a little more time-consuming than a tube, so it seems unsanitary to scoop it up with a wet toothbrush. However, when I use a dry toothbrush, a green powder falls onto the sink. What should I do about this? I always wonder. My teeth become incredibly smooth.