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10 Most Harmful Chemicals Found In Your Shampoo


For as long as people have been trying to prevent hair damage, the hair care industry has been claiming to fix it. But, how often has shampoo failed you as a hair loss treatment? This is because people are too quick to find a solution through shampoo, which contains ingredients that do more harm than good to the hair and body. How do we know who’s telling the truth? Let’s find out.

Function Of A Shampoo

Even though most of these famous shampoo brands reduce hair - breakage, nourish hair right from the first wash and most of all add shine and luster to the hair. But did you know most of these shampoo brands contain a composition of some of the most harmful chemicals. Well, we don’t blame you since you weren’t aware of how these harmful ingredients in shampoo actually work.

Here’s how shampoos actually work. A Shampoo contains molecules called surfactants also known as soap. Now, just like sperm, this soap contains a head and a tail. When this soap is mixed with water, the head of the soap attaches to the water end while the tail binds to the oil, grease and dirt in the hair. In this manner when the water washes out the soap, the dirt from the hair attached to this soap is also washed away. While shampoos help to clean the scalp from the dirt and dust, they also contain some chemicals that do more bad than good for the hair and health.

10 Chemicals In Shampoos To Watch Out For

Instead of telling you which brands are good and which are bad, we want you to start taking a closer look at the back of the bottle, which is the INCI list or the ingredients in the shampoo. So, here’s a list of 10 harmful chemicals in shampoos to avoid.


Number 1 would always be Sulfates. Commonly known as the SLS (Sodium Lauryl Sulfate) and the SLES (Sodium Laureth Sulfate). These are basically detergents that are meant to bring out the lathering effect or more over the bubbles in the shampoos. Most of us feel that the hair does not get clean if the shampoo does not lather well enough but in reality, the truth is that you do not need lather for hair to get clean. Sulfates are just harsh cleansing agents that while cleansing tends to remove excess sebum and natural oils from the scalp leaving the hair brittle, increasing dryness and frizz, and eventually causing hair damage. In some cases, they also cause severe allergic reactions in people with sensitive skin. These include inflammation, redness, dryness, and severe itching. This is where sulfates get their bad reputation from. 

There’s a very common myth that sulfates cause cancer. However, that's not true since there is no clear scientific evidence to prove these claims but what is backed by research is that SLS or Sodium Lauryl Sulfates can have more of a mutagenic property and also cause toxic effects on the human body. Among the three commonly used sulfate compounds in the beauty sector are Sodium Lauryl sulfate, Sodium laureth sulfate, and ammonium laureth sulfate which are basically used in the cosmetic industry as a facial cleansing agent or even toothpaste, although they are used in different concentrations and intensities, the “-eth” versions (laureth sulfate) are milder on your skin and hair than the “-yl” version.  “And the ammonium version is milder than the sodium version.”

While we and most other researchers out there are trying to push and make everyone aware to use sulfate-free shampoos, in some cases sulfate shampoos might not be all that bad. For example, people who have recently colored their hair, need to really consider ditching their sulfate shampoo because due to the detergent effect, they make very harsh cleansers and will strip off the color. People with experience in coloring their hair will always advise you to stay away from sulfate shampoo post-coloring. Even people that already have dry and frizzy hair, must always opt for sulfate-free shampoos as mentioned they strip off the natural oils that are most crucial for people with dry hair. Curly-haired individuals should also step away from this ingredient as this type of shampoo will not retain moisture and curly will not be hydrated. And most importantly, people with sensitive skin should definitely stay away from sulfate shampoos as it could cause severe eczema. However, if your hair is on the oilier side and, if your hair and scalp oil up fast within just a day of washing, or even if you have dandruff that is sticky with an oily scalp, you must consider using a sulfate shampoo. This will efficiently help in cleaning the scalp with minimum effort required. This sulfate shampoo will help to absorb the scalp and quickly get rid of the oils in your scalp.


Another shampoo chemical to be aware of, parabens are technically used as a preservative in cosmetics to stop bacteria from growing which is a good thing but what generally happens is that this paraben is likely to be absorbed into the skin when applied topically. Sometimes they are also used as a common ingredient when meant to keep processed or canned food still fresh. This paraben is said to disrupt the normal functioning of the hormones in the body in both males and females. This also leads to severe hair and health damage and hair loss. This chemical can mimic the hormone called estrogen from the body and is also linked to being an increasing factor in the growth of breast cancer cells. Many experiments have also shown that women tend to have a greater concentration of paraben stored in the body in comparison to men which has resulted in severe cosmetic use and hair and skin care products. Lastly, there are also several studies that have linked parabens to fertility issues and reproductive issues in the organs. They are also said to affect birth-related issues and also increase the risk of cancer. 

Sodium Chloride

Similar to the sulfate family, sodium chloride is also known to strip the hair of its natural oils and sebum. This is why sodium chloride to has made it to the top 10 harmful chemicals in shampoos to avoid. In its true form, sodium chloride is basically a salt. And what salt does in shampoo is it makes the consistency of the shampoo and conditioner thicker and continues to maintain this thickness in consistency. However, salts since they remove the sebum from the scalp and hair strands, tend to make hair and the scalp dry and cause an itch. This is one of the reasons why shampoos cause hair damage leaving hair dry and brittle, eventually leading to hair loss.

Chemical Fragrance 

Natural fragrances definitely do not have a negative impact on the hair but chemical fragrances, on the other hand, tend to cause a big deal when it comes to hair and health. Basically, shampoos that contain the tag “fragrance” on their label contain thousands of hidden chemicals. Basically, even when brands claim to have natural fragrances, they are still allowed to use traces of synthetic ingredients in them. Most of the time, scents are added to shampoos to mask the bitter or pungent smell of other ingredients in the shampoo. Transparency is the issue in most shampoos that are not fragrance-free. What’s the harm in something that smells, one might wonder? They are basically ingredients in these cosmetic products that tend to disrupt the reproductive systems in women. They are said to hamper women's breast milk but are also known to cause cancer and are really bad for those with asthma. Like many ingredients on this list, it is also an irritant to the skin and scalp, which can lead to hair loss.

Propylene Glycol

Propylene Glycol is one of those ingredients in shampoos that act as a solvent for many other ingredients like fragrances, preservatives, etc. Although it has antimicrobial properties, it sometimes acts as an allergen and sometimes as an irritant. This colorless liquid is added into many shampoo bottles to improve and maintain the consistency of the formula and help the active ingredients to penetrate deeply into the scalp more for better results. Studies have shown that propylene glycol is the fifth most common allergen as an ingredient from shampoos, found 38% from a survey that was conducted about shampoos. This propylene glycol is also a known skin irritant. It’s absorbed into the scalp right along with the other ingredients, where it dries the skin and consequently weakens hair right at the root. It’s best to just avoid any shampoos with this harsh ingredient.

Diethanolamine (DEA) and Triethanolamine (TEA)

Diethanolamine and Triethanolamine also known as DEA and TEA are basically emulsifiers or foaming boosters or agents that are meant to reduce the surface tension between substances to make both the oil and water-soluble ingredients blend in perfectly. Again, just like sulfates that are detergents, DEA is also used as a cleanser or a detergent. In 1998, studies revealed a link between the external application of Diethanolamine or DEA and cancer in tests carried out on animals in the labs. According to the Food and Drug Administration, however, there are no proven links between the use of DEA and cancer in humans. DEA is shown to combine with preservatives thereby creating some toxic chemicals known as nitrosamines. NDELA is one such chemical, and it has been linked to the development of cancer in rats and is also thought to be dangerously toxic to humans because it can be easily absorbed through the skin, such as through the scalp.


One of the scariest of all shampoo ingredients has to be formaldehyde. Also known as a human carcinogen, it has been proven to have absorption properties through the skin as revealed from studies done after various animal tests. While many know the benefits of formaldehyde in funeral homes, others might relate it to cosmetic preservatives. However, it can also be released over time through a chemical process from other types of preservatives. These formaldehyde releasers have a variety of listed names and it won’t always be clear what these names are. The most common one is quaternium-15. Believe it or not, it exists in many popular shampoos. When used in smaller concentrations, formaldehyde isn’t usually a problem. But if used in bigger concentrations, it can also be linked to hair loss and severe hair damage. Severe sensitivity towards this formaldehyde is linked to vomiting, allergy attacks, and even cancer. So it’s probably best to avoid shampoos with formaldehyde altogether—even in small amounts. When reviewing the ingredients list, look for “methylene glycol.” This is the dissolved form of formaldehyde that appears in many hair care products.


Polyethylene glycol (or PEG) is just another chemical added in shampoos to help improve and maintain the texture of shampoos. It is also identified as a thickening agent and is often contaminated with byproducts. As a derivative to petroleum, they can be highly harmful to human populations. There has not been sufficient research done to conclude that PEGs themselves are toxic. However, common by-products in the PEGs, like ethylene oxides and 1,4-dioxane are harmful.


Silicones are basically used to bring out the conditioning effect in the hair strands leaving them feeling all soft, shiny, and smooth altogether. But even after this smoothening effect, silicones and moreover, dimethicones are just plastic that leads to product buildup in the scalp and leaves hair feeling all greasy to give the finishing touch of hair looking shiny. In reality, it weighs the hair down, making it heavy, limp, and lifeless. Hair and scalp that are “coated” with this plastic film stop moisture and nutrients from coming in and can clog pores on your scalp causing skin irritation or hair loss. These silicones are basically the class of liquids that lock in moisture and keep hair looking hydrated. In simple terms, it helps hair with its texture and radiance. Over a period of time, that is with constant use of these silicones in shampoos, they tend to leave the hair looking weak and lifeless. The following are just some of the silicone-based lists to keep away from 

  • Amodimethicone
  • Cetearyl methicone
  • Cetyl dimethicone
  • Cyclomethicone
  • Cyclopentasiloxane
  • Dimethicone - Dimethicone is a type of silicone that is used in a ton of hair products and contributes to product buildup that makes your hair feel greasy. Since it acts as a protective cover on the surface of the hair, it stops moisture and nutrients from coming in and instead collects dirt and residue. It can clog the pores on the scalp and cause skin irritation.
  • Dimethiconol
  • Stearyl dimethicone
  • Trimethylsilylamodimethicone

Synthetic Colors & Alcohol

The dye at the end of most shampoos and conditioners to make them look good is of synthetic colors. These colors are available from petrol or coal-tar and these sources do not good for health either as they can cause severe diseases like even cancer. These ingredients are already illegal in many countries and FD&C or D&C combined with a number. Alcohol on the other hand is a very common component in every shampoo and acts as a solvent many times. Most of the time alcohol is added for the drying effect and if it appears in the first half of the list of ingredients, it means that the particular shampoo contains more alcohol. Some alcohols that are not all bad for dry hair usually start with a “C” or an “S '', like Cetearyl alcohol and Stearyl alcohol. These help to retain hair with the required moisture. The ones that are bad if you already have dry hair usually have a “prop” in their name, like Isopropyl alcohol or propanol.

How To Avoid Shampoos That Are Harmful?

If you want to avoid shampoos that contain these incredible ingredient lists, the best thing to do is read the ingredients. Hair care manufacturers are required by law to disclose the ingredients in their products, and you can find the ingredients list right on the label. Additionally, you can also try the following things: 

  • Look up and read about third-party reviews from both customers. Look for shampoos made with natural, plant-based ingredients and botanicals. A lot of manufacturers are stressing healthier ingredients like tea tree oil, aloe, citrus, and even hemp. 
  • Be suspicious of severely inexpensive shampoos. If the price seems too good to be true, it probably is. 
  • Stop using your existing shampoo right away if you notice any signs of sudden hair damage and hair fall. 
  • More than avoiding anything else, always go for sulfate and paraben-free, silicone-free conditioning, and opt for shampoos infused with natural oils. 

Of course, other aspects of your hair care regimen may also play a role. If you use a lot of harsh dyes or treatments, for example, this can also cause severe damage to your hair over time. So take time to consider all possible causes when determining whether your current shampoo is causing hair loss.


The reality is that it is impossible to avoid all these 10 harmful chemical ingredients in shampoos all at once. It is best to initially start by going sulfate and paraben-free, silicone-free conditioning and look for shampoos that are infused with either natural or essential oils as baby steps towards better hair and health. 


Q1 - What Are The Healthiest Ingredients In Shampoo?

Ans - Natural oils like coconut, olive, and essential oils like bergamot are all considered healthy ingredients in shampoos as long as they are absorbed by the scalp in a manner that they are actually helpful for hair. 

Q2 - What are the harmful chemicals in shampoo?

Ans - Starting from sulfates and parabens to silicones to PEGs to DEAs, TEAs and synthetic colors and fragrances are also considered to be harmful chemicals in shampoos. 

Q3 - What chemicals in shampoo and conditioner are harmful?

Ans - Shampoos and conditioners both contain sulfates and parabens right up to silicones to PEGs to DEAs, TEAs and synthetic colors and fragrances are also considered to be harmful chemicals in shampoos.


Zahra Lokhandwala

Hair Coach

Zahra is the hair coach-in-chief at Traya. She works closely with the doctors to monitor all cases. She is a fitness freak and has not touched sugar in years!

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