背景:谷胱甘肽在发现其抗黑色素生成特性后已成为潜在的皮肤美白成分。已经考虑了各种作用机制来解释这种性质,其中之一是黑色素合成途径向产生较亮的菲莫莫拉宁而不是较暗的真莫拉宁的倾斜,从而产生减轻的效果。
目的:评估与安慰剂和基准相比,口服补充L-谷胱甘肽相关的L-半胱氨酸的皮肤美白和抗黑斑作用。
方法:在一个为期12周的随机研究中,研究了这种L-半胱氨酸-L-谷胱甘肽口服组合的效果。双盲,平行组,纳入124名亚洲女性受试者的基准和安慰剂对照试验。妇女被随机分为4个相等的组(500mgL-半胱氨酸和250mgL-谷胱甘肽,250毫克还原L-谷胱甘肽,500毫克L-胱氨酸,或者安慰剂,daily).在基线测量皮肤颜色,6周和12周后通过分光光度法。从数码照片确定面部黑点的大小和颜色。
结果:口服补充与L-谷胱甘肽相关的L-半胱氨酸12周后,观察到明显的皮肤增白。该组合还在6周和12周后诱导面部黑斑尺寸的显著减小。值得注意的是,观察到的效果不仅明显优于安慰剂,也可以单独使用L-半胱氨酸或单独使用L-谷胱甘肽。
结论:在12周内每天口服500mgL-半胱氨酸和250mgL-谷胱甘肽是一种安全的治疗方法,可以有效减轻亚洲女性的皮肤并减少面部黑斑的大小。
BACKGROUND: Glutathione has become a potential skin-lightening ingredient after the discovery of its anti-melanogenic properties. Various mechanisms of action have been considered to explain this property, one of them being the skewing of the melanin synthesis pathway toward the production of lighter
pheomelanin instead of darker eumelanin, consequently producing a lightening effect.
OBJECTIVE: To evaluate the skin lightening and anti-dark spot effects of oral supplementation with L-Cystine associated with L-Glutathione as compared to placebo and benchmark.
METHODS: Effects of this L-Cystine-L-Glutathione oral combination were investigated in a 12-week randomized, double-blind, parallel-group, benchmark- and placebo-controlled
trial involving 124 Asian female subjects. Women were randomly allocated into 4 equal groups (500 mg L-Cystine and 250 mg L-Glutathione, 250 mg reduced L-Glutathione, 500 mg L-Cystine, or a placebo, daily). Skin color was measured at baseline, after 6 and 12 weeks by spectrophotometry. Size and color of facial dark spots were determined from digital photographs.
RESULTS: A significant skin lightening was observed after 12 weeks of oral supplementation with L-Cystine associated with L-Glutathione. This combination also induced a significant reduction in the size of facial dark spots after 6 and 12 weeks. It is noteworthy that the observed effects were not only significantly better than those obtained with placebo, but also with L-Cystine alone or L-Glutathione alone.
CONCLUSIONS: The daily oral administration of 500 mg L-Cystine and 250 mg L-Glutathione during 12 weeks was a safe treatment to effectively lighten the skin and reduce the size of facial dark spots of Asian women.