TSA allows medically necessary liquids and injectable medications in carry-on bags, exempt from the 3.4 oz liquid rule. You don't need to declare them, but having them in a clear bag with your syringes and needles in a labeled sharps container makes screening faster. Reconstituted peptides should stay in carry-on (not checked luggage) to avoid temperature extremes in the cargo hold. TSA screeners may inspect but generally don't question medications. There's no requirement to have a prescription label, though having one can avoid questions.