The scalp produces natural oils to keep hair healthy and shiny. These oils also give weight to dry hair which causes it to be less curly. However, washing the hair with shampoo gets rid of these natural oils. Using oils to smooth and weigh down thick, curly hair is a common straightening and detangling technique. Many hair straightening products and chemicals use natural oils as a base ingredient.

Olive oil is a natural oil made from olives that can be found in any grocery store. It's primarily used as an ingredient for cooking foods, but it can also be used to straighten curly or frizzy hair. You can use it as a conditioner by heating it and leaving it on your hair for thirty minutes under a shower cap and then washing it out with shampoo. Olive oil is good for hair because it is moisturizing and contains many vitamins and minerals that your hair can absorb easily.

Mineral oil is also used in many haircare and beauty products. It is an effective lubricant and can be combed through hair to remove tangles and smooth away frizz. It has many emollient properties and can help prevent breakage. Mineral is hydrophobic, which means it repels water molecules, so it needs to be washed from the hair thoroughly after use.