Vitamin B12 is considered a growth factor.
According to the reference provided, a growth factor is defined as:
a substance (as a vitamin B12 or an interleukin) that promotes growth and especially cellular growth.
Therefore, based on this definition, vitamin B12 fits the description of a growth factor. It should be noted that while vitamin B12 is mentioned explicitly, other substances like interleukins are also growth factors, and the reference does not say it is the only vitamin called a growth factor.
