inositol
Is a cyclic hexavalent alcohol, which therefore only contains OH groups on the C atoms. There are various isomers (meso-, myo-....), of which myo-inositol is the most important free inositol isomer. They all have different functions in the cell, but the following general statements apply to all of them:
Component of every living cell. Involved in cation transport across the cell membrane. Involved in nerve stimulation. Growth factor for many animal cell types.
Normally sufficient self-synthesis.