Liquid folate supplement - is it stable, or is it a waste of money?

[parabola]

I'm looking for a methylfolate supplement and this seemed like a good way to control the dose (100 mcg/drop), but I seem to remember something about folate being very photo/thermo-labile? Would it be a waste of money?

http://www.biocare.co.uk/default.as...temGroupGuid=21&LanguageGuid=EN#productAnchor