Hand warmer patches are adhesive patches that provide warmth and relief from cold hands. They work through a chemical reaction that generates heat when the patch is exposed to air. The main components of a hand warmer patch are iron powder, water, salt, activated carbon, and wood powder.

When the package is opened, oxygen in the air reacts with the iron powder to produce an exothermic oxidation reaction. This reaction gives off heat that can keep your hands nice and toasty even in frigid temperatures. The heat output can reach up to 131°F and last for several hours depending on the brand.

Hand warmer patches are very thin and lightweight, making them easy to take with you anywhere. They conveniently stick to the insides of gloves, pockets, or directly onto skin. The adhesive usually contains a small amount of warming ingredients as well so you start feeling warmth immediately after applying.

These single-use Warmers are ideal for numerous cold-weather activities like skiing, ice fishing, or even just walking the dog on a wintry day. They can be hugely helpful for people who struggle with Raynaud’s phenomenon or have poor circulation. The boosted blood flow to the hands can reduce pain and stiffness.

While quite safe when used as directed, you do need to take some precautions with hand warmer patches. Don’t apply them directly to bare skin for more than 20 minutes at a time to prevent irritations or burns. It’s also important to properly dispose of used patches since they can still contain hot remnants of the chemical reaction.