Facial skin-lightening benefits of the tetrapeptide Pro-Lys-Glu-Lys on subjects with skin types V–VI living in South Africa


M Farwick, Head of R&D Active Ingredients, Consumer Specialties, Evonik Goldschmidt GmbH, Goldschmidtstraße 100, 45127 Essen, Germany. E-mail: mike.farwick@evonik.com


Background  Irregular skin pigmentation may be a substantial contributor to the signs of aging and to a person’s lack of psychological well-being. Although a large number of skin-lightening agents are available, the opportunity exists to identify more efficacious agents, agents that target alternative biological mechanisms.

Aims  To provide clinical evidence of the skin-lightening effect of the tetrapeptide, Pro-Lys-Glu-Lys (PKEK), on subjects with skin types V–VI living in South Africa.

Methods  Pro-Lys-Glu-Lys was evaluated in a double-blind and vehicle-controlled clinical study using expert grading of digital images by comparing its effects in subjects with skin types V–VI suffering from facial melasma and postinflammatory hyperpigmentation.

Results  This study demonstrated the efficacy of PKEK on subjects with skin types V–VI. On comparing the two treatments, the skin-lightening peptide-containing formulation was significantly superior to the vehicle at 12 weeks on overall appearance (P < 0.05) and evenness of skin tone (P < 0.01).

Conclusions  The tetrapeptide, PKEK, has proven skin-lightening benefits on skin discoloration from melasma and postinflammatory hyperpigmentation. These studies have been conducted on subjects with skin types V–VI living in South Africa, but we believe this technology to be suitable for all racial groups.