Problem: Your hair feels fried and looks as dull as driftwood.

How It Happens: Chlorine and salt water sap moisture from already dry hair and rough up its cuticles, giving it that lackluster look. Overusing products, which is common in heat and humidity, can also cause dullness. “The more product residue, the less light your hair is going to reflect,” says stylist Keith Harold. Translation: no shine.

To Fix It Now: Use a heated iron on your hair (a flat iron if you wear it straight; a curling iron if you like waves or curls). The heat from these tools seals the cuticles, letting hair lie flat and reflect more light. Just don’t overdo it. Using these tools more than a couple of times a week can make hair even drier.

To Prevent It Next Time: Use a clarifying shampoo to rinse away product buildup and any residue left by chlorine or salt water. (Try Kenra Clarifying Shampoo, $10, www.kenra.com for stores.) These formulations are gentle on dry, color-treated, and damaged hair.

Glaze your hair. Both salon and at-home glazes protect all hair types from sun damage and seal in moisture by combining mild dyes with shine enhancers to leave strands smooth and glossy. (Try John Frieda Luminous Color Glaze Clear Shine, $10 at drugstores.)