"most well studied" is a grammatically correct and usable phrase in written English.
Example: The effects of climate change have been the most well studied topic in recent years.
This is one of the most well studied questions on Wikipedia.
The Caucasus, which is Russia's paradigmatic "Orient," is most well studied, but the Russian empire was not just the Caucuses.
The patellamide pathway is the most well studied and characterized example.
The ascomycete Trichoderma reesei is one of the most well studied cellulolytic microorganisms.
Aminoglycosides are the most well studied class of small molecules to target RNA.
Neotropical primates are among the most well studied forest mammals concerning their population densities.
Neurofibromin has multiple domains, with the GAP-related domain (GRD) being the most well-studied.
And yet the basic biology of even that most well-studied form of dementia remains fuzzy.
Indirect inhibition of the FACT histone chaperone is the most well-studied activity of the curaxins27,28,47.
The neurofibromin protein contains at least four major domains, with the GAP-related domain being the most well-studied.
Owing to its economic importance, it is one of the most well-studied geologic regions of the world.
