People with curly, wavy or frizz-prone hair who regularly blow-dry or flat-iron their hair straight and want it to start out smoother and more manageable. It is a retail shampoo for everyday home use; no salon application or mixing is involved.

Most shampoos for curly hair are made to boost curl definition. Strait-Line works the opposite way: it is made for days when you plan to wear your hair straight, adding weight and slip so waves relax more easily under a blow-dryer or flat iron. The result is a smoother starting point without committing to a chemical relaxer.

Wet hair thoroughly, massage the shampoo through the scalp and lengths, then rinse well. Follow with conditioner, then blow-dry or flat-iron. Use a heat protectant before styling with hot tools.

Pros

• Cleanses while starting to smooth waves and frizz, so heat styling takes less effort
• Dimethicone adds shine and weight that helps hair lie flatter
• Picasso nut oil helps hair retain moisture

Cons

• Contains silicone, so it is not suitable for a silicone-free routine
• The smoothing is temporary and does not replace a salon straightening service
• Strait-Line is an older L'ANZA line, so it may not be easy to find again once current stock is gone