You should only ever eat fruit skins if the fruit is organic and the skin is clean.
At this point I think its safe to say there are hundreds of scientific studies out there telling you why. This is one example[1].
I quote from their abstract:
Notably, the distribution of pesticides in the apple peel and pulp layers is visualized through Raman imaging, confirming that the pesticides penetrate the peel layer into the pulp layer (∼30 μm depth). Thus, the risk of pesticide ingestion from fruits cannot be avoided by simple washing other than peeling.
You should only ever eat fruit skins if the fruit is organic and the skin is clean.
At this point I think its safe to say there are hundreds of scientific studies out there telling you why. This is one example[1].
I quote from their abstract:
[1] https://doi.org/10.1021/acs.nanolett.4c01513