1. Sodium Lauryl & Sodium Laureth Sulfate (SLS) (a.k.a. sulfates)
Sodium Lauryl and Sodium Laureth Sulfate (SLS) are found in many mass-market shampoos. These chemicals are potent detergents used to remove oil and dirt from the hair, and provide richer foam. They give that refreshing, rich lather in the shower, but what you could lose in this instance outweighs the temporary satisfaction you could gain when rinsing.
"Unfortunately, sulfates strip off the natural protective layer of the scalp and hair, causing dryness and irritation," Harth notes. Sulfates, he explains, have been shown to "damage the protein in the hair strands causing more breakage and split ends," which of course won't help with hair loss and can exacerbate it.
2. Sodium Chloride (AKA salt)
Sodium chloride is another common ingredient of mass-market shampoos. Commonly used to thicken shampoos and conditioners, it can "dry the scalp, causing redness and itching," Harth says, and this scalp irritation can "damage hair follicles and cause more hair loss."
3. Triethanolamine (TEA) and Diethanolamine (DEA)
Triethanolamine (TEA) and Diethanolamine (DEA) are used in shampoo and conditioners as foaming agents and emulsifiers. "DEA and TEA are believed to damage the keratin in the hair and irritate, contributing to more hair loss," Harth adds.
4. Parabens
Many shampoos and conditioners use propylparaben and methylparaben as preservatives. These parabens were shown to irritate the scalp and cause allergic contact dermatitis. "There is also evidence that suggests the parabens can affect hormonal balance in women, affecting menstrual cycle and pregnancy," Harth says, as another reason why they should be avoided.
What To Look For Instead: Vitamin B-5
So, if you should avoid all of these hair care ingredients if you want to prevent hair loss, what ingredients should you look for instead? Celebrity Hair Stylist Michael Canale says there's one shampoo ingredient to keep an eye out for to promote thicker hair: Vitamin B-5.
Also known as pantothenic acid, this B vitamin is a great option for anyone who wants thicker, stronger locks, which is why it's one of the most common ingredients in hair-thickening shampoos. It's known to strengthen hair follicles. Canale explains that Vitamin B-5 "swells the hair shaft, plumping each strand of hair to give it a thicker and more voluminous appearance." Nice!
Ultimately, it's important to be aware of what you're putting in your hair and see if stopping the usage of products with these ingredients causes a change in your locks. "Using the wrong hair products can over-irritate the scalp, damage the hair strands, and indirectly cause more hair loss," Harth concludes, so it's important to visit your doctor for more information and to find products that work for your hair and not against it!
Additionally, it's always important to ensure you're taking in the right amount of nutrients to promote healthier locks. The products you apply to your hair can only do so much; what you put into your body is just as important, if not more crucial. As Canale says, "You can also train your hair thickness by taking in the right proteins and nutrients." Noted!