If you’ve noticed more hair in your brush or irritation on your scalp, your shampoo could be to blame. According to professional hairstylists and experts, certain widely used shampoo ingredients may actually be doing more harm than good—causing excessive shedding, dryness, and even scalp inflammation. From harsh sulfates to hidden allergens, the ingredients in some formulas can disrupt your scalp’s natural balance and contribute to thinning hair over time.
Here’s what to watch out for, according to the pros.
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1. Formaldehyde
"The first type of shampoo and ingredient that can lead to hair loss and shedding is any shampoo containing formaldehyde," says celebrity hairstylist and creative education director for Scruples, William Whatley.
This ingredient is often found in certain treatments and shampoos. Exposure to formaldehyde can lead to inflammation, allergic reactions, and damage to the hair shaft.
"There are several lawsuits against different brands that use formaldehyde as an ingredient in hair [products]. While it serves as a stabilizing agent, its side effects can be highly irritating to the scalp, causing skin damage and irritation, which may lead to hair loss and shedding," he adds.
"Formaldehyde-releasing ingredients, while intended to preserve shampoo formulas, often irritate sensitive scalps, prompting patients to complain of itching, redness, and increased hair shedding due to chronic inflammation," Dr. Ross Kopelman, hair transplant surgeon at Kopelman Hair Restoration. Yikes!
2. High sulfate content shampoo
The second ingredient to watch out for is high sulfate content shampoo. Whatley says this "is a cleansing ingredient that’s found in some detergents. A high sulfate ingredient, like sodium lauryl sulfate, can also lead to skin irritation and skin reaction, and that can cause damage that can lead to hair loss and shedding."
Valerie Aparovich, biochemist and certified cosmetologist-aesthetician at OnSkin, elaborates further and highlights how this can strip your hair of essential natural oils. "Sulfates are salts of sulfuric acid that create abundant foam when coming into contact with water, performing more efficient yet harsh cleansing," she notes. Aparovich adds that the most common forms in shampoo formulations "are sodium laureth sulfate (SLES), sodium lauryl sulfate (SLS), and ammonium lauryl sulfate (ALS). Sulfates are high in pH and can strip the scalp of beneficial oils, disrupting its hydrolipid barrier, provoking irritation, and compromising hair growth potential."
If used regularly, it can "lead to hair strands getting weaker, drier, more fragile, and prone to shedding," she adds.
Dr. Kristina Collins, a board-certified dermatologist, says to avoid these "aggressive surfactants that strip away natural oils from the scalp and hair. While they create a rich lather, they can be overly drying."
