Here's an excerpt from "The effect of red color on perceived self-attractiveness":
Recent research showed that individuals are perceived as more attractive when presented with the color red.
Elliot and Niesta (2008) found that men consistently rated women as higher in attractiveness when a border of red framed their photographs or when they were presented with a red shirt compared to other colors. This red effect was also found for women perceiving men (Elliot et al., 2010; Roberts, Owen, & Havlicek, 2010).
Red color, for example, represents a sexual signal that might have evolved from our biological heritage. This reasoning is supported by research showing that nonhuman female primates exhibit red coloration for example as indicator of fertility (Elliot & Niesta, 2008). [...] Thus, it is most likely that the meaning of the color red also has a biological background [...] Nonetheless, societal learning seems to have turned the originally pure sexual meaning of red color into a more romantic association: red equals love.
Bearing in mind that people are likely to associate (i.e., learn to associate) wearing red with being attractive, we now propose that the color red can heighten individuals’ self-attractiveness.
Judging oneself as more attractive, when the desire for a sexual intimacy is increased (through the color red), seems to be an efficient strategy to attract potential partners.
In sum, given that the meaning of red has such genuine biological roots and is bolstered through societal learning, we argue that wearing red affects individuals’ self-attractiveness judgments, because the color shapes their look and they are inclined to base inferences on their appearance (Bem, 1967). Accordingly, the color red should be influential when inferring one’s sexual receptivity and self-status. We assume that those two variables mediate the effect of color on self-attractiveness, as was found regarding the perception of others (Elliot & Maier, 2012; 2014).
Thus, based on the results of this study, red increases one's self-attractiveness and attractiveness, but can a red book cover increase sales? Interestingly, red enhances men’s attraction to young, but not menopausal women. And we know a red bearded New York based author who gets complemented consistently on his barbe rouge.