If you sell supplements, place a label on each bottle that says, “Please refrigerate.” Tests show that people are less likely to refund on the supplements if you add this label.
Why? Your guess is as good as mine. Maybe they feel these supplements must be fresher, and thus of a higher quality. Maybe because the supplements are in the fridge, (as opposed to say, on their table or desk) they forget to send them back. Maybe people are just weird.
Bottom line: Don’t be afraid to test strange and bizarre things, because you never know what is going to improve response or reduce refunds.