I desire to learn whether levomenthol is superior to Menthol as a pain killer in humans.
I didn't find a wiki article about levomenthol and the article Menthol doesn't mention this molecule.
The chemical formulas are the same but I understand that the only difference is the spatial position of chemical bonds between the atoms, as can be learnt in pubchem:
- https://pubchem.ncbi.nlm.nih.gov/compound/Menthol
- https://pubchem.ncbi.nlm.nih.gov/compound/l-Menthol
My problem
I don't know what are the main ways for chemists to decide which one should work better in humans but hope for a simple explanation for non chemists.
I thought about this after reading that Strepsils, the famous British sore throat lozenges, contain levomenthol.
I think about this because I know some other medicines are "levo" versions of others (for example, cetrizine and levocetrizine).
My question
Is levomenthol superior to Menthol as pain killer in humans and what are the ways to determine this?