Basically, 10 different colors of M.U.S.C.L.E. were manufactured for the American toy line, with one of those colors only being produced for five figures included with the board game. The entire toy line was originally pink/flesh colored. Later on to keep interest in the toy line, eight additional colors were added.
The M.P.S. 1997 M.U.S.C.L.E. color tree
Be aware that sometimes you will have slight color variations of a half shade lighter or so. This tends to happen when M.U.S.C.L.E. has been exposed to elements for a long period of time like weather, water, dirt, or chemicals. The color names listed above are what collectors of the 80s and 90s widely referred to them as. Over the years as the hobby evolved, so did the names of said colors. Below is an updated M.U.S.C.L.E. color wheel with current color naming, not to mention much better color quality..
2021 M.U.S.C.L.E. Color Wheel
created by M.P.S. Alumni Brian Bonanno
M.U.S.C.L.E. Mega-Match Board Game, bringing the color wheel total to ten colors