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Updated: Jun 6, 2026
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Published on: August 19, 2025
Effects of sunscreen on human skin's ultraviolet radiation tolerance
Chao Yuan1, Xue-min Wang, Yi-mei Tan
1Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, China.
Purpose:
To observe the alteration ultraviolet radiation (UVR) of skin's tolerance after its exposure to the small dose of UVR under the protection of sunscreen.
Methods:
Eleven subjects who applied sunscreen were exposed to 0.75 dose minimal persistent pigment darkening (MPPD) and minimal erythema dose (MED) by the Phototherapy Unit for 4 weeks. Each week their MPPDs and MEDs were measured by solar simulator. Meanwhile, SPECTCOLOMETER® and VISIOSCAN VC98® were used to detect the test areas and control areas.
Results:
The values of MPPD and MED increased significantly after the exposure to UVR. But there were no visible changes on the surface of skin's texture.
Conclusion:
With the protection of sunscreen, the UVR tolerance of skin was greatly increased after the skin's exposure to the small dose UV.
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