What Ingredients Are Bad For Your Hair In Shampoos: 10 Most Harmful Ingredients In Shampoos

Imagine you are washing your hair with your favorite shampoo. 

But do you even know what is inside of the bottle? 

Most likely, there are tons of harmful ingredients ready to wreak havoc on your hair and scalp.

In the US, many of these toxic ingredients are still allowed in products. So it is important for you to be aware of what you are putting in your hair.

So what ingredient is bad for your hair?

Our skin experts have put together this list of hair product chemicals to avoid. If you notice any of these ingredients in your shampoo, you should reconsider buying the product.

Let’s dive in!

The 10 Most Harmful Ingredients In Shampoos

#10. Synthetic Chemicals and Dyes

Synthetic Color and Dyes
Synthetic Color and Dyes

If you wonder why each shampoo or hair care product you try is a different color, it is because of one thing.

Synthetic coloring dyes.

Yes, shampoos and conditioners use a huge amount of dyes to make their product look unique and different from competitors.

The bad part is that these chemicals are toxic and can hurt your hair follicles. Making your hair weak and open to oxidative stress.

Also, these synthetic colors are made of coal tar. This tar can include arsenic and other heavy metal salts which leave toxic chemicals on your scalp and potentially cause allergic reactions.

#9. Alcohol


No, not the type of alcohol that you can drink after a long day of work. This is alcohol added to shampoos to help your hair stay hydrated.

Ironically, alcohol causes a drying effect which can damage weaker hair follicles.

This means if you see alcohols higher up on the ingredient list then your hair is more likely to have breakage.

As a tip, any alcohol with “prop” in the name can cause severe damage to your hair. For example, shampoo ingredients to avoid include propanol and isopropyl alcohol.

#8. Formaldehyde


This bad hair ingredient is a carcinogen. And that means this chemical can cause cancer.

Awful stuff.

Formaldehyde, like parabens, have been tested on animals and have shown that they can be absorbed through your skin.

If this chemical can get through your skin, it can cause some major health risks.

The reason manufacturers add this to shampoo and other hair care products is because it acts as a preservative.

Formaldehyde allows products to be left on shelves for months without going bad.

#7. Parabens


Similar to formaldehyde, parabens are also preservatives. They are used to extend the shelf life of products and prevent them from expiring.

However, parabens are also endocrine disruptors and they can be absorbed easily into the human body.

This means the chemical can affect your reproductive system and other organs when absorbed.

Cosmetic ingredients that are considered parabens include methylparaben, ethylparaben, propylparaben, etc.

As a tip, next time you are shopping look for hair products labeled as paraben free.

#6. Phthalates


Another type of endocrine disrupter are phthalates.

The endocrine system can impact different hormones within your body. Impacted hormones include testosterone, cortisol, estrogen, insulin, and thyroid hormones.

The worst part is any time hormones are changed your hair growth cycle is interrupted.

This is bad news.

Interruptions to our hair cycles could mean potentially more hair loss, less hair growth, or more grey hair.

Manufacturers are tricky and usually hide phthalates under the name of “fragrance”. They use these synthetic fragrances to give products a liquid feel and reduce stiffness.

#5. Benzene


Benzene is one more bad hair chemical that has cancer causing effects.

This ingredient is known to disrupt your immune system’s signaling ability.

That means your body will not respond well to outside invaders such as viruses, toxins, and fungi.

Furthermore, benzene is known to cause cancer like leukemia, according to the American Cancer Society.

Unfortunately this chemical is one of most widely included ingredients in shampoos and conditioners in the US.

Hopefully this reminds you that it is important to read the label of products before you buy them.

#4. Polyethylene Glycol

Polyethylene Glycol
Polyethylene Glycol

Sometimes shampoos and hair products are watery. And you can never really get enough onto your hair.

On the other hand, there are shampoos that are much thicker.

The reason why they are thicker is because of polyethylene glycol (PEGs).

Included as a thickening agent, PEGs are harmful because that can strip hair and take away natural hydration to make your hair extremely dry.

This makes your hair prone to breakage. Especially if you already have dry hair.

Additionally, the International Journal of Toxicology reported that PEGs are carcinogenic and can cause human development problems.

#3. Petroleum Jelly

Petroleum Jelly
Petroleum Jelly

Petroleum jelly which is also known as petrolatum is made from oil.

When you use shampoos with petroleum jelly, they will coat the hair shaft and will not allow the product to remove the oil properly. 

Over time, this will lead to an accumulation of oil on the scalp and will cause dandruff outbreaks.

Furthermore, this chemical ingredient on your hair can lead to dry, brittle, and damaged hair. 

It can also cause scalp irritation making your skin feel dry and itchy.

#2. Mineral Oil

Mineral Oil
Mineral Oil

This ingredient found in shampoos is used for its smoothing properties.

When your hair is smoother it doesn’t become tangled up or get into knots.

Sounds great, right?

Actually, these mineral oils have high levels of polyaromatic hydrocarbons (PAHs).

PAHs have been linked to nonmelanoma skin cancer.

Also, when mineral oil is absorbed into your skin, it can affect your body’s ability to defend itself.

Even in small amounts, this can lead to inflammation which can damage healthy hair follicles.

#1. Sodium Lauryl Sulfate And Sodium Laureth Sulfate


Also known as SLS or “sulfates” is a harmful hair ingredient that is used to create the foaming or cleansing action in shampoos.

What this ingredient does to your hair and scalp is that it strips natural oils and dehydrates your skin. 

This can cause skin irritation, itchiness and dandruff.

The problem is even worse for those who have sensitive skin, dry skin, or other skin conditions.

To date, the U.S. Food and Drug Administration (FDA) hasn’t officially called SLS as harmful. 

However, the negative effects have been widely discussed in the Hair Society.

Therefore, try to focus on sulfate free shampoo if you want to avoid this harmful ingredient.


You might not realize it, but the shampoos you put in your hair on a regular basis are doing more harm than good.

These products are loaded with bad hair ingredients that can affect your immune system, cause hormone imbalance, and potentially even cause cancer.

We recommend that you read the ingredients label before buying a shampoo or hair care product.

Looking at how high the ingredient is on the list will give you an idea of how much of the above harmful chemicals are in there.

By taking some precaution with the products you use, you will be able to keep your hair much longer.

Read More:

Product Reviews:

Fact Checked by our Director of Dermatology We know that understanding how your skin and hair work can seem scary, so my team and I devote our time to thoroughly researching every single topic and product we write about. We hope you find our reviews helpful and informative.

Leave a Reply

Your email address will not be published. Required fields are marked*