Vitamin D4 is a vitamin produced in fungi from the UV irradiation of 22,23-dihydroergosterol (Provitamin D4).1 It is produced by several mushroom species including A. bisporus, F. velutipes, G. frondose, and C. cibarius and in S. cerevisiae. Vitamin D4 is 60% as active as vitamin D3 at healing rickets in rats.
1.Keegan, R.-J., Lu, Z., Bogusz, J.M., et al.Photobiology of vitamin D in mushrooms and its bioavailability in humansDermatoendocrinol.5(1)165-176(2013)
















