Check Your Shampoo for These 6 Carcinogenic Ingredients

Learn which shampoo ingredients may pose health risks and how to choose safer, non-toxic options for daily hair care.

Many of us choose our shampoo based on how it smells or what it promises to do for our hair. We might look for volume, shine, or frizz control without giving much thought to what’s actually in the bottle. However, it also pays to be more discerning about the ingredients in your shampoo to ensure it’s safe for daily use. What you put on your scalp and hair can affect not just your hair health but your overall well-being, especially if the product contains harmful chemicals.

Check Your Shampoo for These 6 Carcinogenic Ingredients

Photo by Polina Tankilevitch

Some shampoos, particularly those that have not undergone proper safety checks or inspections, may contain carcinogenic ingredients or byproducts. Carcinogenic means these substances have the potential to cause cancer or increase the risk of developing it over time.

Being exposed to such chemicals regularly, even in small amounts, can pose long-term health risks. This is why it’s important to be selective with the shampoos you use and to make better-informed choices. If you’re not sure what to look out for, here are some carcinogenic ingredients and byproducts you’ll want to be aware of:

1) Nitrosamines

Nitrosamines are not intentionally added to shampoos, but they can form as a byproduct when certain chemicals react during manufacturing or storage. They often appear when amine-based foam boosters or surfactants come into contact with nitrites, especially if the ingredients are contaminated or not processed correctly.

Because nitrosamines are not listed on ingredient labels, it can be difficult to know if your shampoo contains them. Using products with a natural foam booster, such as the Suframide line from Natura Aeropack, can help reduce the risk of exposure, allowing you to enjoy a rich lather while minimizing any potential long-term health concerns.

2) Formaldehyde and Formaldehyde-Releasing Preservatives

Some shampoos contain preservatives that release small amounts of formaldehyde over time, including DMDM hydantoin, quaternium-15, imidazolidinyl urea, and diazolidinyl urea. These ingredients help prevent bacterial or fungal growth, but repeated exposure can irritate the skin and scalp.

Opting for formaldehyde-free shampoos or products using natural preservatives can help lower exposure. Checking labels carefully can make a difference, especially if you use shampoo daily, and will allow you to maintain both your hair health and your overall well-being.

3) Parabens

Parabens such as methylparaben, propylparaben, and butylparaben are widely used to extend shampoo shelf life. However, they can mimic estrogen in the body and have been linked to hormone disruption over time, though studies are still ongoing. Some research suggests that parabens at the levels typically found in shampoos may be safe, but long-term exposure and cumulative effects remain under investigation. Daily use of products containing parabens may increase overall exposure, so it is still wise to exercise caution.

Switch to paraben-free shampoos to reduce this risk. Many modern formulas perform just as well without parabens, so you don’t have to compromise on hair shine, volume, or smoothness while making a safer choice.

4) 1,4-Dioxane

1,4-Dioxane is a byproduct that can appear in shampoos containing sodium laureth sulfate (SLES), a common foaming agent. It is not intentionally added, but forms during the chemical process used to produce SLES. Regular exposure over time, even at low levels, may pose health risks.

Choose shampoos labeled 1,4-dioxane-free or those made with natural sulfate alternatives like decyl glucoside, coco-glucoside, or potassium cocoate to reduce exposure. These ingredients will provide a gentle, safe lather while avoiding potential harmful byproducts.

5) Synthetic Fragrances

Shampoos often include synthetic fragrances to give them a pleasant smell. These fragrance blends can contain dozens of undisclosed chemicals, some of which may pose health risks. Because the full composition is rarely listed on the label, it can be hard to know what chemicals are present.

A safer approach is to choose fragrance-free or naturally scented shampoos. Scents from essential oils or botanical extracts can provide a pleasing aroma without exposing your scalp and skin to potentially harmful synthetic chemicals.

6) Polyethylene Glycols (PEGs) and Contaminated Solvents

PEGs are used in shampoos as thickeners, emulsifiers, or moisture carriers. While PEGs themselves are generally safe, they can sometimes be contaminated with ethylene oxide or 1,4-dioxane during manufacturing. Both of these contaminants are potentially harmful.

To reduce exposure, look for PEG-free shampoos or products from brands with strict purity standards. This ensures that you can enjoy smooth, hydrated hair while minimizing contact with potentially risky byproducts.

How to Protect Yourself from Harmful Ingredients

Ultimately, being aware of potentially carcinogenic ingredients and byproducts in shampoos is the first step toward safer hair care. To protect yourself, always check the ingredient list and choose products from reputable brands that prioritize safety and transparency.

Beyond the label, take time to research brands, read reviews, and look for any reported issues or recalls. This extra step can help you avoid products that may contain harmful chemicals or have a history of safety concerns.

In addition, using shampoo in moderation and rinsing thoroughly can help reduce cumulative exposure over time. Pay attention to what goes into your hair and onto your scalp, and you’ll be able to enjoy healthy hair without compromising your overall well-being.