<p>Effects of Skin Lightening Cream Agents – Hydroquinone and Kojic Acid, on the Skin of Adult Female Experimental Rats</p>

Abstract

Introduction: Skin bleaching is the act of using steroid-and chemical-containing products to lighten the skin. Hydroquinone and kojic acid are often used in skin bleaching creams. Hydroquinone was suspected to be harmful. This study investigated the effects of kojic acid and hydroquinone on the skin of adult female Wistar rats and the potential use of aloe vera for amelioration. Materials and Methods: Eighty [n=80] adult female Wistar rats with an average weight of 120 g were randomly divided into eight groups, marked A, B, C, D, E, F, G, and H. Group A animals served as the control group; group B was treated with 2% hydroquinone, group C was treated with 2% kojic acid, group D was treated with 4% hydroquinone, group E was treated with 4% kojic acid, group F was treated with 2% hydroquinone and 2% kojic acid, group G was treated with 4% hydroquinone and 4% kojic acid, and group H was treated with 4% hydroquinone, 4% kojic acid, and aloe vera. The preparations were applied to the tail skin and treatment lasted 28 days. Skin samples were excised and processed using H&E, Masson's trichrome, and p65 immunohistochemical assays on tissue sections. Results: Hydroquinone caused structural disruptions of the stratum corneum of the epidermis and the overlying keratin. p65 was also prominently expressed in the treated groups. Hydroquinone reduced skin thickness and caused epidermis disruption. Discussion: The prominent expression of p65 in the sections indicated deleterious effects of hydroquinone. Kojic acid was not found to have deleterious effects. Aloe vera prevented extensive disruption of stratum corneum by hydroquinone. The use of hydroquinone in skin lightening creams might raise health concerns. Aloe vera could be protective against hydroquinone.

Follicular Granular Parakeratosis: A Case Report, Literature Review, and Proposed Classification

“…Hydrophilic agents such as hydroquinone, arbutin, or vitamin C would first contact with sebum, follicular debris, bacteria, and other exogenous materials coating the skin, then penetrate to the skin via their actual pathway through the hair follicle. A previous study suggested that topical hydroquinone could induce follicular inflammation by demonstrating the prominent expression of p56, a marker of cell proliferation, degeneration, and inflammation, in the hair follicles [13]. Furthermore, a high level of facial sebum contents filled in the follicular space can interfere with the follicular drug delivery, especially hydrophilic substances [14].…”

Skin-Lightening Products: Consumer Preferences and Costs

“…However, vitamin E alone has shown minimal efficacy in the treatment of hyperpigmentation disorders such as melasma [16]. Vitamin C, kojic acid, topical corticosteroids, tretinoin, niacinamide, and salicylic acid are also among the most commonly used topical skin-lightening agents [14,[17][18][19]. The actual efficacy of preparations containing only low percentages of these ingredients has not been fully elucidated [20].…”

“The unfair drive to be fair”: Psychosocial aspects and implications of the use of skin lightening agents

“…11 In a study done on adult female mice, Aloe vera was found to reduce the harmful topical side effects of hydroquinone. 13…”