Alcohol
You should watch out for shampoos with alcohol in them.
According to the Chicago Tribune, "Alcohol is a common shampoo ingredient, but not all alcohols are friendly to the health of your hair. Some strip moisture and healthy oil from the scalp and hair shaft, leaving behind brittle hair that lacks shine and flexibility."
If your hair becomes brittle and damaged, it is more likely to break and fall out.
But not alcohol has the same effect on your hair, so before throwing out your favorite shampoo, check specifically for short-chain alcohols.
The Chicago Tribune explains, "Isopropyl alcohol, ethanol, propanol, SD alcohol, propyl alcohol, SD alcohol 40, and alcohol denat are the short-chain alcohols you’re definitely going to want to watch out for."
These types of alcohol can have a harmful impact on your hair. The article continues, "These alcohols evaporate quickly, but they take necessary moisture and oil along with them. These are the alcohols that leave your hair dry, brittle, and frizzy."
With that in mind, if you are struggling with thinning hair (or if you want to prevent that challenge in the future), consider eliminating these short-chain alcohols from your haircare products.