J. Cosmet. Sci., 64, 45–58 (January/February 2013) 45 A new strategy to modulate alopecia using a combination of two specifi c and unique ingredients ESTELLE LOING, ROGER LACHANCE, VIRGINIE OLLIER, and MICHEL HOCQUAUX, R&D Department, Lucas Meyer Cosmetics, place de la cité-Tour de la cité 2600, boulevard Laurier, #900 Québec (QC) G1V 4W2, Canada (E.L., R.L.) and R&D Department, Lucas Meyer Cosmetics, 18 avenue de l’Europe, 31520 Ramonville Saint Agne, France (V.O., M.H.). Accepted for publication June 6, 2012. Synopsis Male pattern hair loss is a major cosmetic concern affecting both genders with a preference for men. Major causes of hair loss in genetically predisposed individuals include hormonal dysfunction, loss of extracellular matrix (ECM) proteins in the follicular bed, and localized microinfl ammation. Few options are yet available to correct the problem. For this purpose, a cosmetic active ingredient was developed by combining a Trifolium pratense fl ower extract and a biomimetic peptide and tested clinically for the prevention of hair loss. Thirty volunteers with recessing hair were recruited for this randomized, placebo-controlled study. Clinical effi cacy, following daily topical application of the mixture to the scalp, was checked using TrichoScan™ for the mea- surement of human hair. Within 4 months of application, anagen hair increased at an average by +13%, telogen hair density decreased by −29%, and the anagen/telogen (A/T) ratio increased by +46% over baseline in the treated group. Results strongly differed from those of the placebo group (anagen, −2% telogen, +23% A/T ratio, −33%). Investigation of the potential mechanisms involved in the positive effects of the test product on hair growth pointed at inhibition of 5-α-reductase activity, reduction of infl ammatory reactions, and stimulation of ECM protein synthesis in the vicinity of the hair follicle. INTRODUCTION The presence of hair is a characteristic of mammals. Other species may have some kind of fi lamentous outgrowth but that certainly do not qualify as hair. Hair is a unique fi lamen- tous structure that extends from the dermis to the outside of the body, normally covering some areas entirely, such as the scalp, while sparing other zones, such as the palms and the soles. Human hair naturally comes in a variety of shapes, sizes, lengths, and colors, depending mainly on the specifi c genetic makeup of each individual. In mammals in general, hair serves diverse functions, such as providing protection, thermal regulation, camoufl age, warning and mating signals, and a sense of touch (1). But for humans, it is Address all correspondence to E. Loing at estelle.loing@lucasmeyercosmetics.com

JOURNAL OF COSMETIC SCIENCE 46 even more than that. Hair is linked to our personality, appearance, sex, and social status plays a role in seduction and is instrumental to nonverbal communication. For all these reasons, the absence of hair, especially on the scalp, has a huge impact on one’s life. Each hair is composed of two distinct structures: the dynamic hair follicle located in the dermis and the hair shaft, a hard keratinized part that extends above the skin sur- face. The hair follicle is made of dermal and epidermal compartments closely interact- ing in the regulation of hair growth. The central structure of the hair follicle is the dermal papilla rich in mesenchymal cells (2). The papilla is connected to the capillary bed in the dermis and is embedded in a hair matrix consisting of epidermal cells capable of dividing rapidly to give rise to hair. The hair shaft comprises three layers: a cuticle, a medulla, and a cortex. Thickness of the shaft totally depends on the size of the papilla the bigger the papilla, the stronger the shaft (3). Hair grows in cycles delimitated by three distinct phases: anagen, catagen, and telogen (Figure 1). Anagen is the growth phase during which new materials are deposited in the hair shaft by rapidly dividing follicular cells. Anagen scalp hair grows by 1 cm per month for a period of 2–6 years. The duration of the anagen period dictates the maximal length of hair and is genetically determined. Catagen is a transition phase, lasting for about 2–3 weeks, marked by a stop of hair growth. During this phase, the hair follicle involutes, becomes attached to the hair shaft and keratinizes forming a club hair that is pushed upward toward the scalp, as the dermal papilla breaks away. Telogen is the resting phase. The hair follicle regresses, becomes fully keratinized, and can easily be pulled out. The telogen phase lasts around 3 months for scalp hair. Following shedding, the next hair can start growing as the papilla and the follicle join again. An adult healthy scalp normally bears 70–85% hair in the anagen phase and 10–15% in the telogen phase, the rest being in the catagen phase (4). Male pattern alopecia is generally associated with a shortening of the anagen phase and premature entry into the catagen phase (5). Figure 1. Normal hair physiology: hair cycles through anagen (growth phase), catagen (transition phase), and telogen (resting and falling phase) before reentering early anagen to initiate the growth of a new hair.