Many physique-industry / bodybuilding oriented tanners, use formulations primarily consisting of caramel / Yellow / and or Red. There are multiple reasons this is done, but not without consequence that negatively impact a bodybuilder’s quality of tan.

Caramel can positively impact a tan’s color, hence there’s a slight amount in Mar Tan. But because caramel coloring is so cheap and inherently light in comparison to the deeper browns it’s mimicking, many companies use it to the point of abuse.This results in too light of an excessively sticky tan, that needs to be overly-layered to establish a base.

Yellow / Red are also in Mar Tan. However, many other companies look will depend on these colors, as they have dramatic visual impact, but often aren’t optimal for stage; ‘highlighting’ a competitor. They do this Instead of looking to have the most practical competitive tanner, often create too light / bright  a formula, that draws from presentation of a physique. Often, these generic colors are intended to be light enough for a bikini competitors (that do not require to be nearly as dark,) knowing full well its weakness requires additional layers / formula (so more product sold) when used by bodybuilders.

Alternatively, Mar Tan utilizes a deep / rich brown cosmetic formula, in-combination with other deep tones; whereas most tanning companies choose to primarily focus on the cheaper / lighter alternatives. When properly applied, Mar Tan actually dyes a layer of the skin and establishes a base for any competitor, that is then complimented with your contest coat.
In short, if you are looking for a bodybuilding contest color, designed by bodybuilders, for bodybuilders, withe specific requirements of our sport in mind: