In the Mount Nyuto forest in Japan’s Akita prefecture, a certain smell pervades the air. It’s an enigmatic concoction of earthen minerals, fresh water, and steam that rises from the area’s hot springs, or onsen, and that can induce an almost instant mental calm. The natural phenomena, found in locales with geothermal energy beneath their terrains, are also known for their skin-enhancing effects: Silica and the mineral content of sulfur provide a soothing sensation and can even be used to treat topical conditions such as psoriasis, acne, and eczema. These myriad benefits prompted some companies to create bath accessories that use the hot springs not only as olfactory inspiration, but sometimes as the direct source material for the products themselves.

The Yunohana Onsen Powder, for example, made by the Japanese company Okuhida Onsen, is extracted directly from a mineral deposit on Mount Yakedake in the northern Japanese Alps, which has 159 onsen in its vicinity. Because the mountain is an active volcano, it continues to produce highly concentrated mineral hot springs that, over time, have seeped into and hardened within the underlying soil. The minerals are extracted, then refined to produce a fine powder. To use, spoon two tablespoons of the particles into a full tub to create a translucent, mineral-rich bathwater that mimics the experience of sitting in an onsen, including the relief it provides from body fatigue, tension, and stress.

For a more fragrant dip, try the Nyuto Onsen Bath Soak from the Tokyo brand Bathclin. It comes in the form of salt-like crystals that, when added to the tub, create a milky white pool that gives off a homey, calming scent meant to recall that of Mount Nyuto’s forest. Those wanting to celebrate the recent arrival of winter might prefer to use the Daily Transformation Soaking Salts—part of a new collection called The Snow Onsen—which are made in Japan by the brand Aymayori and intended to evoke the experience of bathing en plein air during a snowfall. Notes of Siberian fir, white pine, and hinoki cypress oil mingle with wild orange, tangerine, yuzu, and geranium to create a refreshing, woody redolence. We recommend using the salts with the line’s Hikaru Multi-Use Oil, an antioxidant-rich treatment made for use directly after bathing. Massage it into skin to prolong the soothing onsen scent, or run it through the ends of your hair to add moisture and shine.