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Sallowness was assessed using a digital image analysis technique able to quantify yellow color.
Cincinnati - Results of a recently published clinical trial demonstrate that reduction of skin yellowing (sallowness) can be added to the list of anti-aging skin benefits of topical niacinamide.
The study, sponsored by Procter & Gamble, used a double-blind, placebo-controlled, split-face, randomized design. It enrolled 50 Caucasian females ages 40 to 60 years old with evidence of facial fine lines/wrinkles, textural changes and hyperpigmentation who applied an oil-in-water moisturizer containing 5 percent niacinamide to one side of the face and matching vehicle (control) contralaterally twice a day for 12 weeks.
Sallowness was assessed using a digital image analysis technique able to quantify yellow color. The results showed significant increases in baseline on the vehicle-treated sides that were prevented with the use of the niacinamide-containing preparation.
"Skin yellowing is a particular concern among women in certain Asian populations. The results of this study show that topical niacinamide improves skin texture as well as tone through effects on redness, hyperpigmentation and yellowing. Overall, because of its chemical stability and compatibility, tolerability and broad spectrum of efficacy, niacinamide seems to be a very useful addition to facial skincare products," Dr. Bissett says.
The women enrolled in the clinical study focusing on the anti-yellowing effect of niacinamide had signs of facial aging graded at baseline using a scale of 0 to 5 (where 0 = normal skin). To be eligible for participation, they were required to have scores of 2 in assessments of facial fine lines/wrinkles, cheek skin texture and facial hyperpigmented spots.
The subjects underwent a two-week washout period from their existing skincare products prior to baseline evaluations, and, during the study, they all used the same commercially available cleanser with the test moisturizers, but no other skincare products. Forty-nine of the 50 women completed the entire study, and their compliance with moisturizer application was excellent.
Capture of the digital images was performed under rigorously controlled, standardized conditions. In addition to being used for assessment of skin yellowing, the images were analyzed for changes in area of both linear depressions in the crow's feet region and hyperpigmented spots. Red blotchiness in color images was evaluated by expert graders blinded to treatment assignment.
Plausible mechanism The idea that topical niacinamide might prevent or reduce skin yellowing stems from knowledge that glycation protein production is the underlying cause of the dyschromia. Dr. Bissett explains that glycation proteins are generated in a spontaneous oxidative reaction involving protein (collagen in the skin) and sugar as substrates. The glycation proteins have a characteristic yellow-brown color and accumulate in the skin during adulthood due to the slow turnover of collagen.
"Since niacinamide is a precursor for the synthesis of the endogenous antioxidants NADH and NADPH, increasing its availability via topical application might be expected to inhibit the oxidative reaction and reduce production of the glycation proteins. In fact, results from previous laboratory studies of collagen cultured (in a ribose-containing medium) showed a benefit for niacinamide in preventing glycation," he says.
The mechanisms whereby niacinamide seems to improve the other signs of facial aging remain to be fully elucidated.