7 Ingredients You Should Avoid if You Have Curly Hair

Sulfates

Sulfates often get a bad reputation when it comes to curly hair. Usually found in shampoo, sulfates provide the rich lather we expect when washing our hair. They act as surfactants, which break down the oils and impurities on the scalp and hair for a squeaky-clean feeling.

However, Zeichner warns that surfactants used in shampoos to give a deep cleanse tend to be drying to the hair and scalp. "Curly hair tends to be more coarse and dry than other hair types, so it is important to choose the right shampoo," explains Zeichner. He adds that sulfates can potentially make coarse hair even drier, and studies indicate that repeated rough washing can damage the cuticle.

Williams, however, counters that they are not harmful when used appropriately. She says that using the more gentle forms of sulfates in the right measure can benefit all hair types by removing dirt and oil. She also adds that most companies have removed the strongest sulfates from their products, such as ALS (Ammonium Lauryl Sulfate) and SLS (Sodium Lauryl Sulfate).

Parabens

Parabens are used in many cosmetic products, as they provide preservative and fungicidal properties. While the function parabens provide is essential, there are studies that have proven their potential for irritation. "Parabens are effective at preventing microbial contamination in cosmetics but can lead to allergic contact dermatitis, so they are increasingly being avoided in skincare and haircare product formulas," shares Zeichner.

The potential for irritation caused by parabens is a concern for curly-haired people. Curly hair tends to be more fragile and hair loss can be a concern as well. The threat of allergic contact dermatitis is the inflammation and irritation it causes to the scalp, both of which have been linked to hair loss. Williams adds that because parabens mimic estrogen, there are concerns about parabens interrupting hormonal functions in women which could increase the risk of breast cancer and other reproductive issues.

Formaldehyde

The word formaldehyde likely invokes images of science class and critters preserved in glass jars. The preservative powers of formaldehyde are coincidentally what made it popular for use in beauty products, where shelf life is essential to profit. It's no wonder that seeing it listed as an ingredient on haircare products would give you pause, but do the facts support this fear? Both experts gave a resounding "yes."

Zeichner explains that formaldehyde is a common cause of skin allergies, especially for those with sensitive skin. Like with parabens, this irritation could lead to even worse problems for the scalp and hair, including hair loss. Williams agrees and adds that it is a potential carcinogen as well. Even if it is not listed as an ingredient, there are other chemical compounds that break down into formaldehyde when exposed to high heat, such as methylene glycol and glyoxylic acid.

Finally, it's important to mention that formaldehyde has most commonly been used in haircare as an ingredient in most chemical straighteners. Beyond damaging the curl pattern during the chemical straightening process, formaldehyde does long-term damage to the hair by making the curl shaft fragile and susceptible to fracture from minor trauma like hair clips and ties. Curly hair is already drier and more susceptible to damage than straight hair, so the effects of formaldehyde on curly hair are particularly detrimental.

Silicones

Silicones are often found in conditioners for their ability to smooth and soften the hair. They form a thin coating around the hair, which can prevent water from entering or exiting the hair shaft. Williams describes silicones as "synthetic oils that behave like natural oils." Silicones can provide some benefit to curls by locking in moisture and preventing frizz.

However, there are diminishing returns when it comes to silicones, as the more of them that you use, the heavier the coating on the hair becomes. "Silicones may initially leave the hair silky and smooth, but with continued use will build up on the hair, weighing it down. So while it may be tempting to use them, I generally recommend avoiding silicone-containing shampoos," explains Zeichner. Curlies may want to consider using only one silicone-containing product as a part of their routine and occasionally clarifying the hair to remove the silicone buildup.

Alcohols

Before discussing alcohols in hair products, it's important to distinguish that there are fatty alcohols and drying alcohols. Williams says that most products contain fatty alcohols like cetyl and cetearyl alcohols, which are good for the hair and keep strands soft and moisturized. However, there are other alcohols that have the potential to irritate the scalp and impact curly hair.

Drying alcohols, like propanol, can make already dry curly hair even more brittle and susceptible to damage. Additionally, some alcohols have the potential to irritate the scalp. Benzyl alcohol is often used as a preservative in products with fragrance. It has the potential to cause contact dermatitis and as such can be damaging to the skin and scalp.

Salicylic Acid

Seeing salicylic acid as an ingredient for hair care might be surprising to you if you have only ever used it to treat acne and facial skin. While it is most commonly talked about as a skincare ingredient, salicylic acid has actually been found to be an effective treatment for several conditions of the scalp as well. Studies have shown that salicylic acid has benefits for those with psoriasis, eczema, and even dandruff on the scalp.

Despite the benefits salicylic acid has for these scalp conditions, it may not be something those with curly hair can afford. Zeichner explains that "ingredients like salicylic acid help remove excess oil from the scalp and hair, but can dry out already dry hair." If you are experiencing any of these scalp concerns and your curls are suffering from salicylic acid-based treatments, talk to your dermatologist about what other options might be available to you.

Fragrance

There is no denying that the scent of products plays a major role in whether we choose to use them or not—especially on our hair. Great smelling fragrance may entice you to buy a certain product, but that fragrance could potentially hurt your curls (and your health).

Williams cautions that artificial fragrance can cause skin irritation in some individuals—and if the fragrance is a phthalate, "this particular ingredient has been categorized as a carcinogen and known to interrupt endocrine and reproductive function." Skin irritation can be detrimental to hair and scalp health, with consequences ranging from pain and itching to hair loss. Avoiding ingredients that contain fragrance also prevents exposure to other ingredients needed to preserve them, such as the previously mentioned benzyl alcohol.