When I fly to America, I have to take insulin for four months.

Everything needs to be checked, and attention should be paid to low temperature protection during the check-in process (the warehouse temperature is below MINUS 30 degrees)

Yes, as long as there is English on the medicine package. You don't need to prove anything to get through customs. Just tell them that these are insulin for their daily treatment, not for sale. Don't worry, many people wear it like this.