Background
Facial redness is multifactorial in nature and may be a sign of many different conditions, including rosacea, photo damage and flushing. Herbal medicines have been used for thousands of years to treat a variety of dermatological conditions. Turmeric (Curcuma longa) and its constituents have been shown to mediate dilation and constriction of peripheral arterioles and have demonstrated anti-oxidant, anti-inflammatory and wound-healing properties.
Objective
To investigate the effects of turmeric and turmeric-containing polyherbal combination tablets versus placebo on facial redness.
Design, setting, participants, and interventions
This was a prospective, double-blind, randomized pilot study. Thirty-three healthy participants were recruited from the dermatology clinic at the University of California, Davis and nearby community from 2016 to 2017. Thirty participants were enrolled, and 28 participants completed the study. The enrolled participants were randomized to receive one of three interventions (placebo, turmeric or polyherbal combination tablets) and were told to take the intervention tablets by mouth twice daily for 4?weeks. Facial redness was assessed at baseline and 4?weeks after intervention by clinical grading and by image-based analysis.
Main outcome measures
The primary outcome measure was image-based facial quantification of redness using a research camera and software analysis system. The investigators performed an intention-to-treat analysis by including all subjects who were enrolled in the trial and received any study intervention. Differences were considered statistically significant after accounting for multiple comparisons. Effect sizes for clinical grading were calculated with a Hedges’ g where indicated.
Results
Twenty-eight participants completed the study and there were no reported adverse events. Based on clinical grading, facial redness intensity and distribution down trended in the polyherbal combination group after 4?weeks (P?=?0.1). Under photographic image analysis, the polyherbal combination group had a significant decrease in redness of 40% compared to baseline (P?=?0.03). The placebo and turmeric groups had no statistically significant changes in image analysis-based facial redness.
Conclusion
Polyherbal combination tablet supplementation improved facial redness compared to the turmeric or placebo. Overall, our findings suggested further investigations into the effects of turmeric and polyherbal formulations in skin conditions associated with facial redness would be warranted.
Trial registration
ClinicalTrials.gov identifier: NCT03065504.

Key words: Turmeric, Curcuma longa, Ayurveda, Redness, Erythema