1. Piling on products. Product Build-Up is the accumulation of products in your hair. This can happen if you use a product that is not water soluble, meaning just water alone cannot break up the product in your hair. Commonly, products containing silicone or products that are oil-based are the biggest culprits.
As product accumulation increases, hair is less likely to absorb moisture because it's surface is blocked by product. Due to lack of moisture penetrating the hair shaft. As the hair dries out due to loss of moisture the hair shaft is weakened and can start to break.
2. Avoiding water. Drink 8-9 glasses of water a day. When you're dehydrated, your body knows that water may be in short supply. This triggers it to divert resources to vital processes, leaving your hair on its own. Your hair may stop growing completely, and the remaining strands may become brittle and prone to breakage. When your hair is breaking and not growing back, you'll start to notice thinning.
Keeping your scalp hydrated can also relieve the itching that comes with dandruff and, potentially, dandruff itself. If your dandruff is caused by a dry scalp, drinking more water may help.
If you want to fight hair loss and help your hair grow, make sure you're drinking enough fluids every day.
3. Skipping wash day. Your scalp needs to breathe. You can co wash mid wash but you should be clarifying weekly especially if you are using oils and butters.
Going a long time without washing your hair can cause a buildup of a yeast-like fungus called Malassezia on your scalp.
Over time, this leads to a layer of dead skin cells that shed from your head in the form of oily, yellow-ish dandruff flakes. Dandruff can also make your scalp red, scaly, and itchy.