Kao unveils humidity-responsive UV sunscreen technology amid changing climates

Kao Corporation has launched its latest addition to its Bioré UV lineup: Bioré UV Aqua Rich Airy Hold Cream. The sunscreen uses the Japan-based company’s recently developed humidity-responsive technology to adapt to moisture levels, helping prevent stickiness in humid conditions and dryness in air-conditioned environments.

The new formulation comes amid rising temperatures and humidity levels in Japan, which Kao says have increased consumer complaints about sunscreen stickiness. Kao’s 2019 survey of over 1,200 women revealed that more than 90% of sunscreen users experienced sunburn despite using sunscreen.

Further research in 2024 showed that 65% of women relied on parasols and other physical barriers to avoid sun exposure. Based on this feedback, Kao researchers hypothesized that consumers need a more comfortable sunscreen formulation that would inspire them to apply and reapply in adequate amounts.

The sunscreen offers SPF50+/PA++++ protection and contains moisturizing ingredients like hyaluronic acid and a vitamin C derivative.

Kao’s Bioré UV has also partnered with K-pop group Stray Kids for the campaign “Sunlight is your spotlight.” The campaign aims to inspire people to enjoy the outdoors with proper UV protection and help expand Bioré UV’s global footprint.

It will launch in April 2025 in over 15 countries, including Japan, the US, and the UK. It will feature short films and visual content on social media and select retailers. The company hopes to draw on Stray Kids’ global influence to convey the importance of responsible sun awareness.

The Bioré UV Aqua Rich Airy Hold Cream will be available in March at select stores in Japan, online, and later in 2025 in Thailand, Hong Kong, and Taiwan. Although the cream is not sold in the US and UK — the markets where the campaign featuring Stray Kids is running — the initiative hopes to boost overall brand awareness and sun care education while laying the groundwork for potential product launches in these regions.

Kao’s research showed that 65% of women relied on parasols and other physical barriers to avoid sun exposure.UV protection technology

Kao’s Bioré UV Aqua Rich Airy Hold Cream features the company’s latest humidity-responsive sunscreen technology. The technology responds to changes in humidity by integrating agar hydrogel capsules containing UV absorbers and a water-retaining polymer in a water-based (oil-in-water) formulation.

This formulation forms a protective film on the skin that changes moisture content depending on environmental humidity.

Using agar hydrogel capsules, Kao could encapsulate a large amount of UV absorbers, which are not traditionally soluble in water, and disperse them in the sunscreen’s aqueous phase.

The aqueous phase refers to the water-based part of the sunscreen formula, versus the oil-based part.

Kao says that the capsules’ ability to disintegrate and spread during application creates a semi-solid, light texture that liquefies under pressure. Combined with a water-retaining polymer capable of holding several hundred times its weight in moisture, Kao claims the formulation provides a smooth, breathable film.

Environmental adaptabilityThe sunscreen’s film absorbed over twice the amount of moisture compared to traditional formulations.

The formulators tested the sunscreen under varying humidity levels and found it adaptable. The new formulation and a conventional sunscreen were applied to glass plates and monitored for changes after drying at low humidity, spraying with water, and redrying. 

While the conventional sunscreen’s thickness remained unchanged, Kao’s formulation expanded and contracted with changes in moisture. Conventional formulations stayed the same thickness after being applied, dried, sprayed with water, and redried. The Bioré UV Aqua Rich Airy Hold Cream formulation’s thickness increased to approximately 175% of its original thickness when sprayed with water before returning to its 100% thickness state.

The research demonstrated its ability to absorb sweat or humidity and then release the moisture to prevent stickiness and discomfort.

Kao also tested how the sunscreen responded to fluctuating humidity levels ranging from 21% to 88%. At higher humidity levels, the film absorbed over twice the amount of moisture compared to traditional formulations, which confirmed its effectiveness in hot, sticky environments to the researchers.

In user trials of Bioré UV Aqua Rich Airy Hold Cream, conducted from May to June last year, over 70% of the participants reported feeling comfortable throughout the day in hot, humid weather.