What is the average muscle mass of a bodybuilder with respect to their body mass?

The average muscle mass of a bodybuilder with respect to their weight can differ considerably depending on various aspects, such as:

• Genetics
• Training intensity
• Diet
• The use of PEDs.

Bodybuilders generally have a higher percentage of muscle mass compared to the average population due to their harsh training and strict diet plans.
While bodybuilders can have a high percentage of muscle mass, exceeding 50% pure muscle mass is highly unlikely, if not impossible. In a healthy individual, muscle tissue typically accounts for about 40–50% of total body weight.
The human body has other tissues and organs, including bones, organs, connective tissues, and fat, which all contribute to overall body weight.
Bodybuilder's goal is to reduce their body fat percentage to showcase their muscle definition, which can create the impression of having a higher proportion of muscle mass.
However, even in professional bodybuilders, pure muscle mass hardly exceeds 40–45% of total body weight.
Noteworthy is the fact that the quest for abnormally large muscle mass can occasionally be linked to the use of PEDs, including anabolic steroids, which can profoundly influence muscle growth in ways that go beyond what is possible by natural means.