How hot you’ll want your Hot Brush will depend entirely on your hair type. If you have thin or fine hair that doesn’t need much effort to straighten, you’ll need it to be a lower temperature. If you use very high temperatures on that fine hair, you will undoubtedly damage it.
For thin hair that doesn’t need a lot of straightening, but rather de-wave or smoothing, you’ll want to avoid temperatures above 160 degrees Celsius. You’ll probably still need at least 140 degrees to achieve the styling ability you want, but make sure to stay in your safe window. Hotter temperatures will straighten faster, but straight hair does you no good if that hair is falling out.
For super thick, extra curly hair, you will probably want at least 200 degrees Celsius. Your Hot Brush will go all the way up to 230 degrees, but that is the absolute max, and you will need that kind of heat on your hair only if it's super thick, curly, and stubborn.
We’d advise sticking between 210-230 degrees for your thick, very curly hair. If you have neither extreme (fine or thick), you will want to stick right around 160-180 degrees.