[switchbak]

Cotton kills, definitely avoid that.

Modern merino wool is a super material, I've moved away from synthetic jerseys entirely. Substantially less stinky, works well in all temps, and not created from plastics.

Eventually we'll understand how to synthesize something as good or better than wool, but for now merino is where it's at.

[driverdan]

Merino wool has downsides too. It stains more easily, is more expensive, is less durable, and gets eaten by bugs. IMO it's less comfortable too.