Breakage from moisture deficiency occurs when the hair is not receiving enough hydration on a daily or weekly basis.  The hair’s moisture can be affected by heat styling or chemical processes.

Some examples are :

Using a blow dryer

Using a blow dryer on your hair is not a good idea because it pulls out moisture and causes the hair to become dry and break.  Instead set the hair on rollers and use a hooded dryer.  If you insist on blow drying I would recommend that you use a very good heat protector and use a radial brush to gently blow dry each section of hair.

Using a Marcel Flat Irons

Using a Marcel flat irons is damaging to the hair because the tools heated in the oven have uncontrolled heat. You never really know what the temperature is on the tools and the extreme heat will cause damage. Instead use ceramic irons where the heat can be controlled.

Using pressing comb

Just like a using a Marcel flat irons, using tools such as a pressing comb that is heated on the stove top of the oven is damaging. The heat is uncontrolled and this calls for a high change of heat damage to your hair. Instead use ceramic irons where the heat can be controlled.

Water and Protein moisturizers

The cause could simply be a lack of not hydrating the hair enough from within (water intake) and not enough moisturization deep conditioning/daily water based moisturizers.

Protein moisturizers are good as they strengthen the hair by supporting the cuticle by filling up broken spaces along the hair line and adding structure to the entire length of the hair strand.