Testosterone Propionate 100mg/ml . 100 Fast-acting testosterone ester. Great for fast strength and mass. Like all forms of testosterone, Propionate is highly anabolic and androgenic. By its very nature it dramatically increases nitrogen retention in the muscle allowing protein to be stored in the muscle to a larger degree; as protein is the building block of muscle and increased lean tissue improves our metabolic rate, on this basis alone we have a highly desirable hormone.