First, let’s unpack the difference between hair straighteners and flat irons. While a flat iron is a hair straightener, a hair straightener isn’t necessarily a flat iron.

Straighteners include many different types of styling tools, including irons, round brushes, hot brushes, and dryers. Any potential damage to the hair shaft comes from the heat itself, and temperature and distribution play big parts in achieving the look you want while keeping hair soft and healthy. “Straighteners vary greatly by material and the ability to reheat, meaning the amount of time it takes for the unit to heat back to the temperature you set,” says Jessica Irvin, stylist and owner of Infinity Salon in Portland, Oregon.

That’s why you hear a lot about ionic straighteners. The addition of negative ions during styling results in frizz-free and smoother hair. Ceramic irons naturally create negative ions, and tourmaline and titanium flat irons add even more. Heat distribution and recovery are also important when shopping for a hair straightener. “Irons transfer that heat to the hair, compacting the hair cuticle, making the hair straight and shiny,” says Irvin. “Then it must reheat to be able to do that again on the next pass. Good straighteners are able to do this in seconds so that every section is given the same or consistent heat.”

For best results, start with clean and well-conditioned hair (though an occasional day 2 or day 3 refresh is fine). Use a heat protectant every time and select the proper heat setting for your hair type. For those with fine or damaged hair, use a volumizing shampoo first and be sure hair is completely dry before you begin styling. Depending on your hair type, the best temperature to use will also vary. For brittle hair, you’ll want to use the lowest setting possible to avoid damage, and for fine hair, you avoid going above 350 to 375 degrees Fahrenheit. If you straighten your hair more than you don’t, give your locks some regular TLC with a good-quality leave-in conditioner or hair mask.