McCoy's 5A (modified) is a general purpose medium that supports the propagation of many types of primary cells, established cell lines, and explants from biopsy tissues. This medium will support the growth of primary mammalian cells derived from normal bone marrow, skin, spleen, kidney, lung, rat embryos, and other tissues.

This McCoy's 5A is modified as follows:
With Without
• High Glucose • Sodium Pyruvate
• L-glutamine
• Bacto-peptone
• Phenol Red
• HEPES
The complete formulation is available.
Dr. Thomas McCoy originally formulated McCoy's 5A medium as a modification of Basal Medium 5A. Unlike other media, McCoy's 5A contains the reducing agent glutathione, bacto-peptone, and a high level of glucose. This product also includes Dr. Hsu's addition of Hanks' salts to enable use outside a CO2 incubator.