de Sá Dias Tania Cristina, Baby André Rolim, Kaneko Telma Mary, Robles Velasco Maria Valéria
Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, Conjunto das Químicas, Cidade Universitária, São Paulo, SP, Brazil.
J Cosmet Dermatol. 2007 Mar;6(1):2-5. doi: 10.1111/j.1473-2165.2007.00294.x.
Afro-ethnic hair, when compared with naturally straight hair, presents some important variations such as differences in diameter in many points of the thread, ellipsoidal threads, and low trend of hydrating the scalp thus turning the hair drier, because the natural sebum distribution is irregular along the thread. This kind of hair may be straightened through both chemical and thermal methods. Straightening is a chemical process by which excessively curly hair is straightened in an irreversible way. Generally, the products used are formulated in a cosmetic emulsion with high pH. In this review, we present the historical development of hair straightening or relaxing through the evolution of the product categories.
与自然直发相比，非洲人种的头发存在一些重要差异，比如发丝许多部位的直径不同、发丝呈椭圆形，以及头皮保湿趋势较低，从而使头发更干燥，因为天然皮脂沿发丝分布不均。这种头发可以通过化学和热方法拉直。拉直是一个化学过程，通过这个过程，过度卷曲的头发以不可逆的方式变直。一般来说，所使用的产品是用高pH值的化妆品乳液配制的。在这篇综述中，我们通过产品类别的演变呈现头发拉直或柔顺的历史发展。
