These Hair Oils Contain Problematic Chemicals

Hair oil has become a staple in many people’s hair care routines to nourish, add shine, and protect the hair. But behind the golden drops often hide several problematic chemicals. We tested 38 hair oils so you can find a nourishing oil for your hair free from problematic chemicals.

See the test in Danish here

Key Findings of the Test

It is generally difficult to find a hair oil without problematic chemicals for the environment and health.
The particularly problematic chemicals, siloxanes, are widespread in hair oils.
Fragrance ingredients are also found in many hair oils, some of which are suspected endocrine disruptors.
Many products are marketed as “argan oil” but contain only small amounts of argan oil.
Danish brands generally perform well in the test – and Denmark also performs better than four other European countries in the comparison.

Particularly Problematic Chemicals in Hair Oils

One group of chemicals, siloxanes, appears in many of the tested products. They are a type of silicone compound used to give hair a smooth and soft feel, but they have a downside: siloxanes resemble PFAS because they cannot break down in nature. They evaporate from the hair, end up in the air – and eventually in soil and water environments. Many siloxanes are also suspected endocrine disruptors.

Several siloxanes are classified as SVHC substances (Substances of Very High Concern), and the EU has already decided that in the future, cosmetic and personal care products may contain only up to 0.1 percent of the most problematic siloxanes. This means that starting June 2027, you can expect that hair oils with larger amounts of siloxanes will no longer be on the shelves.

These hair oils contain siloxanes:

Alama, Hydra argan oil essence
Aussie, Reconstructor hair oil
Gisou, Honey infused hair oil
Kevin.Murphy, Young.Again treatment oil
Maria Nila, True soft argan oil
Moroccanoil, Treatment for all hair types
Ouai, Hair oil
Redken, All Soft Argan-6 oil
Rituals, Hair oil
Sebastian Professionals, Dark Oil

The siloxanes we found in the test are Cyclopentasiloxane, Cyclohexasiloxane, Trisiloxane, and Cyclomethicone.

Plant Extracts and Fragrance Can Cause Scalp Allergies

Fragrance and plant extracts are in many hair oils to provide a specific scent. 31 hair oils in the test contain fragrance and/or plant extracts.

These scented ingredients can all cause allergies – whether they are natural or chemically produced, especially if you massage the oil well into the scalp.

A few fragrance substances can also have other negative effects. We found the fragrance ingredient benzyl salicylate in seven hair oils in the test and hexamethylindanopyran in one hair oil. Both substances are also suspected endocrine disruptors.

Argan Oil Is Not Always What It Seems

Many hair oils are marketed as “Argan oil,” signaling naturalness and purity. But when you turn the bottle around, the ingredient list tells a different story.

In several products, argan oil makes up less than 25 percent of the content – and in some cases, it is listed at the very bottom of the ingredient list. The further down the list, the smaller the amount. The first three ingredients usually make up the majority of a cosmetic product.

For example, argan oil is listed as number 9 in OGX Renewing+ Argan Oil of Morocco Dry Oil and all the way down at number 14 in Alama Hydra Argan Oil Essence. This indicates that both oils contain minimal amounts of argan oil – and the latter even receives a c-rating for containing the problematic chemicals siloxanes.

Denmark Performs Best in International Test

The test is part of an international comparison in collaboration with Norway, the Czech Republic, Austria, Slovenia, and Denmark. When we look at hair oils in the different countries, Norway performs the worst, and Denmark leads with several good choices.

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These Hair Oils Are Free from Unwanted Chemicals

In the test, seven hair oils receive the best rating, a-rating. All seven hair oils are from Danish brands:

Grå – Elixir hair oil
Hairdo! – Argan oil
Matas Striber – Argan hair oil
Naturligolie – Organic hair oil
Ren Lykke – Organic hair oil
Scandinavian Biolabs – Protection oil hair
ZENZ – Oil Treatment Pure no. 97

How we tested hair oils

We purchased 38 hair oils from physical stores and online on the Danish market.

The test is a declaration test, in which we reviewed the ingredients listed on the packaging.

We examined whether the products contain ingredients that may be allergenic, suspected endocrine disruptors, or problematic for the environment.

Product names and ingredient lists were sent to the manufacturers to ensure that the products have not been discontinued and that the ingredient lists are correct.

These unwanted chemicals we found

Siloxanes are a type of silicone compounds that are often found in hair oils because they can add shine and have a softening effect on the hair.

Siloxanes are classified as SVHC substances (Substances of Very High Concern), and the EU has already decided that from 6 June 2027 only up to 0.1 percent of the most problematic siloxanes may be present in cosmetics and personal care products – including cyclopentasiloxane, cyclohexasiloxane, and cyclomethicone. These substances are already regulated in rinse-off cosmetics – but the ban will now also apply to leave-on cosmetics, such as hair oil.

10 hair oils in the test contain problematic siloxanes. These are:
- Cyclopentasiloxane, 6 products
- Cyclohexasiloxane, 1 product
- Cyclomethicone, 2 products
- Trisiloxane, 2 products
Trisiloxane is not included in the upcoming ban, but it is considered a particularly problematic substance (SVHC).
In the test, we found a number of suspected endocrine disruptors, including:
- Cyclopentasiloxane, 6 products
- Cyclomethicone, 2 products
- BHT, 4 products
- Benzyl salicylate, 7 products
- Ethylhexyl salicylate, 1 product
- Ethylhexyl methoxycinnamate, 5 products
- Hexamethylindanopyran, 1 product
A-rating: 7 hair oils
B-rating: 14 hair oils
C-rating: 17 hair oils