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Avoid this ingredient in your cosmetic products

Once you see it, you cannot un-see it. It’s everywhere: in your eyeliner, foundation, deodorant, hair serum and moisturizer. It’s often the first or second ingredient listed, which means that it is predominant in the product.

What is it? Cyclopentasiloxane, a type of silicone.

Its purpose: To improve application by providing a silky feeling and by repelling water.

The good

Aesthetically, we have come a long way in developing formulas: hair is smooth and shiny, makeup is cake free and skin looks dewy all day long. Further, cyclopentasiloxane is relatively inexpensive. The result is oftentimes more affordable products that “work.”

Or so we’re led to believe.

The bad

Unfortunately, this ingredient is found to be harmful to your health. cyclopentasiloxane (also known as D5) is toxic, can bioaccumulate in aquatic organisms and has been shown to cause uterine tumours.

The Scientific Committee on Consumer Safety (SCCS) by the European Commission considers cyclopentasiloxane to be irritating to the skin and eyes when applied topically, damaging to the liver when ingested (think: lipstick) and harmful to the lungs and uterus when inhaled (such as hair aerosol sprays).

The European Chemicals Agency (ACHA) includes cyclopentasiloxane in the Candidate List, which is a list of substances that may have serious effects on human health or the environment. (For reference, substances on the Candidate List are nominees for eventual inclusion in the Authorization List, which requires that industry apply for permission to continue using the substance).

The ugly

The Government of Canada determined cyclopentasiloxane to be harmful to the environment, but not human health. That was in 2009. The Silicones Environmental, Health and Safety Council of North America objected to the assessment, and, after consideration, in 2012 the Government of Canada concluded that D5 does not pose a danger to the environment. This is grounded on the assurance that D5 does not enter the environment in large enough quantities to cause an issue.

What about accumulation in the environment?

Further, the study conducted by the SCCS did not cover the potential toxicity of cyclopentasiloxane in antiperspirant deodorants. Regularly shaving underarms can result in micro cuts, which allow substances applied over the area to be introduced into the bloodstream. This has already been studied, potentially linking antiperspirants and underarm shaving to breast cancer.


There are various perspectives on cyclopentasiloxane’s toxicity and its harm to human health and the environment. While some suggest that it is highly toxic, all sources seem to be cautious of the ingredient.

So, why take the risk?

We suggest seeking out products that do not contain cyclopentasiloxane. There are many great alternatives on the market – but they require some digging. In foundation, for example, toxic-free companies will use natural serums or plant-based oils. These provide the same smooth texture without the risk.

Have you discovered any silicone-free products? We’d love to hear about it!