How the liquids rule works

The TSA’s 3-1-1 rule covers anything liquid, gel, cream, paste or aerosol in a carry-on bag. Each container can hold up to 3.4 ounces (100 ml), and all of them together must fit in one quart-size bag, one bag per traveler. Serums, moisturizers, sunscreen lotions and face mists all count.

Solid items are different. Stick deodorant and solid lip balm aren’t treated as liquids, and solid skincare sticks generally follow the same logic. Officers at the checkpoint always have the final say, so if anything is borderline, put it in your liquids bag.

Why solids travel better

  • Space. Your quart-size bag fills fast. Every solid frees up room for something that has to be liquid.
  • Leaks. Pressure changes in flight push product out of bottles and pumps. Solid sticks have nothing to leak.
  • Hygiene. You apply a stick straight to skin, so there are no fingers in a jar on a plane tray table.
  • Decanting. No transferring serums into tiny bottles before every trip.

The carry-on kit

In your liquids bag: a small moisturizer and sunscreen, if they’re creams or lotions.
Anywhere in your bag: a solid sunscreen stick, lip balm, and a peptide skincare stick.

What cabin air does to skin

Airplane cabins are kept at very low humidity, far drier than most homes, so skin loses water faster on a long flight. Tight, flaky or dull skin after landing is common. The fix is simple: moisturize before you board, keep a balm or stick for dry spots like the cheeks and around the nose, and drink water.

If you have a window seat, wear sunscreen. UV light at altitude still reaches you through the window.

A simple flight routine

  • Before boarding: cleanse, moisturize, sunscreen.
  • In flight: lip balm, and a swipe of your peptide stick on dry or tired-looking areas. No need to touch your face with your hands.
  • After landing: rinse, moisturize, and stick to your usual routine. Travel is when routines fall apart, which is why portable formats help.
The Collagen + Copper Stick on a wooden desk beside a laptop and coffee
From your bag to your desk to your seat: the same stick, no decanting.

Heat: the other travel problem

Many skincare sticks are held together with butters that soften in a hot car or a sunny bag. If you travel somewhere warm, look for sticks built on heat stable bases. Ours is being developed to hold its shape in a warm bag, and heat, cold and shelf stability will be tested before anything ships.

The bottom line

Keep liquids to what has to be liquid, and let solid sticks carry the rest. You’ll fly with more room in your bag, nothing leaking, and a routine you can keep wherever you land. Our guide to layering a skincare stick shows where it fits at home too.