Muji launches its first clothing item ever registered as a cosmetic, a moisture-retaining innerwear line

Ryohin Keikaku said it will launch a "wearable skincare" innerwear line on 10 August — the first clothing item the Muji operator has ever had registered as a cosmetic in Japan, according to a release distributed via PR TIMES.

The eight-item range uses a rayon fibre carrying 17 amino acids that the company says retain moisture in the skin even after washing, and adds what Ryohin Keikaku calls "M stitch" construction, which flattens seams at points that typically rub against sensitive skin. Womenswear styles include a ballet-neckline camisole and lace trims in off-white, black and muted tones; menswear comes as a crew-neck top in half- and long-sleeve versions, in off-white and black. The line goes on sale at all Muji stores and its online store on 10 August; Ryohin Keikaku did not disclose pricing in the release.

The headline claim is regulatory, not just marketing. Cosmetic registration in Japan covers products that carry an approved cosmetic effect — the same category as lotions, serums and sunscreen — a stricter commitment than the loose "moisture-retaining" or "anti-odour" language most performance apparel uses to imply a skin benefit without answering to a regulator for it. For Muji, a brand built on plain, dependable basics rather than beauty claims, putting an innerwear line through that process is a small but genuine widening of what its "no-brand quality" positioning is willing to promise.

Whether shoppers actually buy skincare framing on a T-shirt, rather than a bottle, is the open question Muji's own sales figures — not yet disclosed — will eventually answer.