A dermatologist reveals 5 toxic shampoo chemicals to avoid — and how to pick a natural alternative that won't damage your scalp

• Social media users — including Cardi B — are crediting their healthy hair to natural alternatives to shampoo.
• Dr. Alexander Dane, a board-certified dermatologist, said some natural alternatives like rice water can benefit the hair.

Growing awareness of how pervasive toxic chemicals are in personal care products might be incentivizing people to buy shampoo made with fewer, all-natural ingredients.

Indigenous people have used natural ingredients like yucca roots and chickpea flour to wash their hair for centuries, but social media sparked renewed interest in these shampoo-alternatives.

Cardi B jumped on the trend, telling her Instagram followers this week that she washes her hair with boiled onion water.

"My last 2 washes I been boiling onions and using the water to wash my hair," she said in an Instagram post. "It's odorless and I notice that it's been giving a shine to my hair."

A post shared by Cardi B (@iamcardib)

Shampoo-naysayers may have a point, said Dr. Alexander Dane, a New Jersey-based board-certified plastic surgeon. Chemicals in shampoo can strip away the hair's natural oil, and some are even known to cause cancer or disrupt your body's hormones.

"People are becoming more aware of what they're putting into and on their bodies, and we're starting to see people reach for natural alternatives as an alternative to using these store-bought, synthetic shampoos that can actually sometimes cause more damage than good," Dane told Insider.

Shampoos can contain chemicals that strips your hair of color, natural oils, and moisture

The "clean beauty" trend likely has to do with Americans becoming more cognizant of the dangerous health effects chemicals in their beauty products can have, according to Dane.

"If you went into your local drug store and you pick up any bottle of shampoo and you turn it around to see the ingredient, oftentimes you see there's 20 to 30 ingredients listed, most of them being synthetic with numerous chemicals that actually are banned in other countries," Dane said.

The dermatologist said some of these chemicals include:

• Sulfate, a foaming agent in haircare products that strip the hair of natural oils and coloring, and may cause irritation.
• Triclosan, a chemical added to prolong shelf-life in anti-bacterial products that can interfere with the body's hormones and might be linked to cancer and reproduction problems.
• Parabens, a chemical that strips the color out of hair, and can lead to dryness and irritation. Researchers are studying the effects of parabens on breast cancer.
• Benzene, a known human carcinogen that may have contaminated Procter & Gamble's shampoos products in 2021, leading to a recall.
• Formaldehyde, a known human carcinogen that is still used in some shampoos.

Natural shampoos that damage your scalp

1. Baking soda, though touted on social media as a way to exfoliate your hair and scalp, contains a high pH balance, which can irritate the scalp and strip the hair, Dane said. He would avoid using baking soda as a standalone hair treatment.
2. Dane also warned against castor oil. Excess amount of castor oil in the hair can lead to "acute hair felting," or when the hair becomes matted, twisted, and so entangled it resembles a birds nest, according to a 2017 paper in the International Journal of Trichology.
3. The acidity in lemon juice can help restore dry or frizzy hair, but using too much can lead to excessive dryness and brittle hair. Plus, if lemon juice leaks out of your hair and onto other parts of your skin, interaction with the sun can cause a rash or discoloration.

Dane said while hair can benefit from natural alternatives to shampoo, overdoing it can cause negative effects on the skin and hair. "Just because something is natural, you don't wanna overdo it," Dane said.

Homemade washes you should try, from eggs to chickpea flour — but in moderation

1. Chickpea flour mixed with milk. Dane said research backs up the use of this centuries-old homemade shampoo in India. Chickpea flour, as well as rice flour, contains proteins that can help strengthen keratin — the protein that keeps your hair and nails strong.
2. Rice water. Many people in China, Japan, and parts of Southeast Asia use the starchy water from soaked rice as a hair cleanser. Dane said it is "filled with nutrients" like folate, vitamin B, vitamin E, amino acids, and antioxidants that increase the moisture in your hair and scalp, adding volume and definition. Limit use to once or twice a week, he said — too often can cause flakiness.
3. Eggs — whether applied topically or eaten as part of your diet — can help produce shiny and healthy hair, Dane says. That's because they contain biotin, iodine, and vitamins A, D, E, and B12. The sulfur in eggs work as an antimicrobial, and yolks contain vitamins that can make brittle hair more resistant to damage. Apply and wash out an egg-and-water mixture once or twice a week, Dane says.
4. Coconut oil spray is fast emerging as a promising natural haircare product. One study found it may treat head lice better than chemical treatment. Studies also indicate coconut oil protect hair from sun damage by filtering UV rays. And a paper published last year found it can treat dandruff. Dane said not to use too much coconut oil, as the buildup can clog pores in your scalp, but using it once in a while and fully rinsing it out can help maintain healthy hair and scalp.