Zymosterol is an intermediate in cholesterol biosynthesis. Disregarding some intermediate compounds (e.g. 4-4-dimethylzymosterol), lanosterol can be considered a precursor of zymosterol in the cholesterol synthesis pathway.
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.