Can I use a curling iron on both dry and wet hair?

You should not use a curling iron on wet hair. Curling irons are designed to be used on dry hair only. Using a curling iron on wet hair can be extremely damaging to your hair and can cause significant harm.
When you use a curling iron on wet hair, the high heat from the curling iron can cause the water trapped in the hair shaft to turn into steam. This can result in the hair becoming excessively dry and brittle, leading to breakage, split ends, and even hair damage. The rapid expansion of steam within the hair can cause the hair fibers to weaken, and the high heat can also cause the hair's proteins to denature, leading to irreversible damage.
To achieve the best results while using a curling iron and to protect your hair from damage, it's essential to follow these steps:
Start with Dry Hair: Ensure that your hair is completely dry before using a curling iron. You can use a blow dryer to dry your hair thoroughly or let it air dry naturally before styling.
Apply Heat Protectant: Before using any hot styling tool, apply a heat protectant product to your hair to create a barrier between the high heat and your hair strands. This can help minimize the damage caused by the curling iron.
Use the Right Temperature: Adjust the curling iron to the appropriate temperature setting based on your hair type and texture. Fine or damaged hair should be styled at lower heat settings, while coarser hair may require higher heat settings.
Section Your Hair: Divide your hair into manageable sections before curling to ensure even styling and minimize the time you expose your hair to the heat.
Avoid Overheating: Limit the time you keep the curling iron on each section of hair to prevent excessive heat exposure.
Regularly Trim Your Hair: Keeping your hair ends trimmed regularly can help prevent split ends and minimize damage caused by styling tools.
By using a curling iron on dry hair and following proper hair care practices, you can achieve beautiful curls while minimizing the risk of hair damage and maintaining the health of your hair.