Straight hair can never be made totally curly just by using a special shampoo, but the best shampoos can go a long way in assisting your straight hair to curl and respond to curling agents like irons and curling products. Learn what to look for and how to apply a shampoo in order to get the most curl out of your hair.
When selecting a curling shampoo, you are looking for a product that is moisturising and renewing without adding weight to your hair. Avoid products that focus too much on moisture, since they tend to be thicker and will weigh down your hair and make curls a challenge. Look for catchphrases like "anti-frizz" or "lightweight" when selecting a product.
Find the key ingredient on the label. Search the products for polymers by the name(s) of Acrylates C10-30 and Alkyl Acrylate Crosspolymer. These types of ingredients have the potential to help curl hair, but you should remember that you are washing out this product in your shampoo, so don't be too hopeful of dramatic results. Products that come out and tell you they promote curls are usually a good place to start, but don't expect miracles; rather, expect the shampoo will not hinder your attempts to curl like a regular shampoo might.
Be prepared to follow with a curling conditioner, with the same description as above, and curling products and tools. A good shampoo and conditioner is a great first step to curling your straight hair, but it is not the only step you'll have to take. After your shower, allow your hair to naturally dry until it is no longer dripping. Apply a curling mouse or gel, and use a scrunching movement to work it into your hair. Do not comb or pull, but hand brush. Curl your dry hair further with an iron, curlers or by braiding and hair spraying, before releasing the braid.