Is levomenthol superior to Menthol as a pain killer in humans and what are the ways to determine this?

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](https://en.wikipedia.org/w/index.php?title=Menthol&oldid=936768369) 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
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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
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Is levomenthol superior to Menthol as pain killer in humans and what are the ways to determine this?


