Sulfate-free shampoos may get all the buzz, but like many hair-care ingredients, the opinions behind the pluses and minuses of the trending term are split.

PROS

Sulfates get rid of product buildup well.

For those with more oily scalps, shampoos with sulfates are generally advisable, unless the hair is color-treated. Trichologist and hair expert Shab Reslan recommends a weekly clarifying shampoo with sulfates for those prone to oil and buildup. She notes that this can help control the production of oil on the scalp. Following the use of a sulfate-containing shampoo, celebrity hairstylist Justine Marjan says, “The hair feels clean, the residue is removed and the buildup is gone.”

Sulfates cleanse hair thoroughly.

One of the biggest benefits of sulfates is how well they grab onto sebum, says Reslan, adding that sulfates also allow the product to rinse off easily, regardless of hard or soft water conditions. If your hair ever has that squeaky-clean feeling, Marjan says it’s likely thanks to sulfates. Due to this, Reslan suggests these shampoos for those who wash their hair infrequently. “Most natural shampoos and those formulated without sulfates do not sufficiently cleanse the scalp and are not ideal for those with oily scalps or infrequent washers.”

Sulfates produce a nice lather.

Cosmetic chemist Krupa Koestline says the experience of using a shampoo with sulfates is more luxurious, as it promotes plenty of lather. Marjan explains that, at their root, “sulfates are basically a salt that is added to shampoos to help them suds up,” and the lather sulfates “incite the feeling of cleanliness—sulfates are often a big part of the sensory experience of washing your hair.”

Less product is needed when sulfates are in the formula.

With their top-tier lathering abilities, less product can go a longer way than products made without sulfates. Koestline notes that sulfates can also help provide a thicker consistency. “This can quickly add up to sulfate products being cheaper than those with non-sulfate surfactants,” she says.

CONS

Sulfates may fade colored hair.

Sulfates are amazing at ridding hair of excess oil and product buildup, but, in the process, they tend to take color with them. Anyone with dyed hair recalls their colorist encouraging the use of color-safe shampoo and conditioner without sulfates. Koestline says sulfates can “strip or fade colored hair,” although she notes that there is some contradictory evidence of this out there.

Sulfates can lead to acne or rashes.

Yes, sulfates are great for cleansing the hair and scalp, but sometimes they can overdo it. Koestline warns that for those with sensitive skin or scalp, certain sulfates can be irritating. Marjan says they can “even lead to acne or skin irritation if you have sensitive skin.”

Sulfates can strip skin of necessary oils.

Sulfates “may disturb the scalp microbiome and lead to other scalp issues,” warns Koestline. This is a problem because “if a sulfate removes too much oil, your natural barrier to your skin’s protective layer is removed,” says master hairstylist and colorist Paul Labrecque. “This can leave someone more vulnerable to irritation, rashes and swelling of the skin. This can also result in dermatitis of the scalp.”

Labrecque agrees that while shampoos with sulfates can be great for those with overly oily hair and scalps, they must be used sparingly. “Your own oil is a natural conditioner for your hair follicle, and it is needed to create a healthy scalp environment,” he says.

Sulfates may dry hair out and cause scalp flaking.

Marjan notes that as a known “degreaser,” sulfates can be drying. ”They can make the hair and skin feel parched due to the natural oils and buildup being stripped. This is why it’s essential to follow with a moisturizing conditioner to replace the moisture.”

Reslan warns that sulfates in shampoo can also result in flaking. “Those with shorter hair who tend to shampoo their hair daily most commonly suffer from flaking because they shampoo their hair much more often, and flaking can fall right off instead of getting stuck in the hair.” Luckily, in most cases, Reslan says flaking can be addressed quickly by switching to a sulfate-free shampoo.