Hi Mira💖
With your hair type and length, I would prefer the 45 mm size. It works better for long and thick hair because a bigger brush can handle the hair more effectively and create a beautiful, airy result 🥰 The result is more of a soft, blow-dried volume and movement rather than tight curls ✨
38 mm is better suited for shorter hair or if you want clearly tighter curls. Since you mentioned your hair is heavy and curls don’t always hold, too small curls can actually fall flat faster. A bigger, softer shape often lasts better and looks more natural in longer hair ❤️
Since your curls hold well with heat, this brush works really nicely for you – and you get a slightly different result than with a straightener, more of a salon-style blowout look 😊