6 Best Shampoo Bars for a Deep Cleanse, According to Hairstylists

Dr. Bowles says shampoo bars are good for hair when they are properly formulated and matched to the right hair type. “Not all shampoo bars are created equal, and some can be too alkaline, leading to irritation or breakage.” Hair that is color-treated, curly, or already dry tends to be more sensitive to formulation differences. “When patients use the right bar and follow with a conditioner, many do very well,” she says.

The answer lies in formulation and delivery, not necessarily effectiveness, says Dr. Bowles. “Shampoo bars are solid cleansers that often use more-concentrated surfactants and fewer preservatives, while liquid shampoos rely on water-based formulas,” she says.

Choosing between a liquid shampoo and a shampoo bar also depends on your hair type and concerns. “Liquid shampoos tend to offer more consistent dispersion and conditioning agents, which can be beneficial for damaged or color-treated hair. Ultimately, formulation quality matters more than format,” Dr. Bowles says. Shampoo bars work best for normal to slightly oily hair and simpler routines, says Rogerio Cavalcante, hairstylist and owner of NYC’s Second Floor Salon. “If hair is dry or color-treated, extra hydration afterward becomes essential, like using a leave-in and a weekly mask.”

“Some shampoo bars can be too alkaline, which may leave hair feeling rough, tangled, or dull. They can also be harder to rinse thoroughly, especially for people with thick or long hair, leading to buildup over time,” says Dr. Bowles. A solid shampoo might make your hair feel a bit dry or tight afterward; if this happens, Cavalcante recommends using a hydrating treatment after the fact, like a hair mask or a leave-in conditioner.

Both experts agree that you should not wash your hair with bar soap. “Using bar soap on hair can strip natural oils, disrupt the cuticle, and leave hair dry, brittle, and prone to breakage. It can also irritate the scalp, leading to itching, flaking, or inflammation,” says Dr. Bowles. If you’re looking for a way to make your routine zero-waste, eco-friendly, or plastic bottle-free, shampoo bars are the way to go.

“Shampoo bars work best as part of a routine, not on their own. Think cleanse first, then hydrate. Leave-ins and masks are what keep hair looking soft and healthy long term,” Cavalcante says.

We evaluated shampoo bars based on ingredients, ease of application, and how well they cleansed without leaving residue behind. Glamour editors and contributors tested ones with hydrating and nourishing ingredients such as honey and plant oils, as well as hair-thickening and strengthening ingredients like biotin and proteins. The ones that made the list gave us a rich lather in our shower—equivalent to a head spa experience—and didn’t leave residue or bubbles behind after we rinsed. They also detangled our strands, leaving our hair deeply cleansed, strong, shiny, and volumized.

• Alexandra Bowles, MD, board-certified dermatologist at Mona Dermatology
• Rogerio Cavalcante, hairstylist and owner of the Second Floor Salon