My sister-in-law is a beautician and said that certain shampoos do cause hair loss. I was curious about this myself, as my hair is thin. I don't want to lose any extra because of bad shampoo choices. It seems that there are a couple of ingredients to stay clear from. These additives are said to cause irritation and hair loss. To avoid the shampoos and/or other haircare products that cause hair loss, stay clear of the ones that contain these ingredients: Sulfates - These are contain in many shampoos because it is what makes the shampoo foam. These will usually be stated as Sodium lauryl sulfate (SLS) and ammonium lauryl sulfate (ALS) on the bottle's list of ingredients. Sodium Chloride/salt - This ingredient is placed into shampoos to thicken the formula. It can cause irritation and hair loss. Formaldehyde - Is a cheap preservative that should be avoided. It can cause other problems other than just hair loss. It's a chemical that can actually damage DNA.