Dose dependent sun protective effect of topical melatonin: A randomized, placebo-controlled, double-blind study

Area of Science:

• Dermatology
• Photobiology
• Endocrinology

Background:

• Ultraviolet radiation (UVR) exposure from sunlight contributes to various skin conditions.
• Previous research suggests topical melatonin may offer photoprotection, but studies in natural sunlight and optimal dosing are lacking.

Purpose of the Study:

• To evaluate the sun protective efficacy of three different topical melatonin concentrations (0.5%, 2.5%, 12.5%) against natural sunlight-induced erythema.
• To determine the optimal dosage of topical melatonin for photoprotection.

Main Methods:

• A randomized, placebo-controlled, double-blind study was conducted on 23 healthy volunteers.
• Participants' backs were exposed to natural sunlight (UV-index 9) after application of melatonin creams (0.5%, 2.5%, 12.5%) or placebo.
• Erythema was assessed using chromatography and visual scoring at multiple time points post-exposure.

Main Results:

• The 12.5% melatonin cream significantly reduced erythema formation compared to placebo and no treatment (p=0.001).
• No significant differences in erythema were observed between placebo and the 0.5% or 2.5% melatonin concentrations.

Conclusions:

• Topical application of 12.5% melatonin cream provides significant protection against erythema induced by natural sunlight.
• Higher concentrations of melatonin are necessary for effective photoprotection against UVR.