Detox Your Wardrobe: Synthetic Dyes vs. Natural Dyes

Natural dyes
Posted in Content Beauty

Unlike food and beauty, our clothing doesn’t come with an itemised list of ingredients that have gone into its manufacturing. Instead, chemicals such as dyes and fabric finishes, are undisclosed and well hidden within the fabric.

No matter what they’re made from, your clothes have been through a long and complex process to get to you. About 8,000 chemicals1 are used throughout the fashion supply chain, from fertilisers and pesticides in fibre production; bleaches, metals and synthetic or natural dyes used to colour materials; to finishing chemicals that provide properties such as crease resistance and waterproofing. Chemical processing can also use vast quantities of water, which if left untreated and released into rivers will contaminate water supplies and may cause loss of aquatic life and soil damaging in the agricultural yields of local farmers. Many of the chemicals used also persist in the environment and accumulate over time, meaning we may not yet know the full impact of them.

Some of these chemicals are still present in our clothes when we buy them, both intentionally and unintentionally. There is no strict global regulation on the use of chemicals in the textile industry, and in many garment producing countries there is little to no regulation at all, so it can be difficult to know just what is hidden in our clothing. As with beauty, we prefer to know what we are putting on our body, so here are some synthetic chemicals we watch out for:

Synthetic Chemicals to Avoid

AZO Dyes

AZO dyes are commonly used to colour fabric. According to industry organisation Common Objective, around 60-80% of all fabric colourants in use today are AZO dyes2. They produce a long lasting and vibrant colour, which makes them appealing to manufacturers. However, some AZO dyes release chemicals known as aromatic amines, some of which have been associated with cancer and skin allergies in workers employed in the manufacture of AZO dyes3. Luckily, the EU has restricted the use of AZO dyes that release amines in any textiles that come into contact with human skin.

Phthalates and Plasticisers

These chemicals are used to make plastic more flexible and durable, and are commonly used in screen-printing processes. They can also be used to dye and soften leather, rubber and PVC in footwear and accessory manufacture. Phthalates are known endocrine disruptors.

PFCs (Perfluorinated Chemicals)

PFCs are used to make clothing and footwear products waterproof and stainproof. According to the Guardian, two of the most widely studied PFCs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have been linked in epidemiological studies to multiple types of cancer in humans and other health impacts. PFCs are so ubiquitous that they’ve been detected in the blood of polar bears. Furthermore, a study from EWG found PFC pollution in the tap water supplies used by 15 million Americans in 27 states4.


Formaldehyde is mainly applied to fabric to create wrinkle-free finishes. According to a study by the U.S. National Cancer Institute, prolonged exposure to formaldehyde can cause serious respiratory issues, allergies and skin conditions5.

NPEs (Nonylphenol Ethoxylate)

These are cleaning agents that are applied to textiles, and they’ve been found to be hazardous to our health even at low levels. When we wash our clothes, NPEs are released into local water supplies where wastewater treatment plants are unable to remove them. They accumulate in the environment and are highly toxic to aquatic life. According to the U.S. Environmental Protection Agency, NPEs accumulate in the tissues of the body, and are endocrine disruptors, meaning they can interfere with the work of our hormones and lead to negative reproductive function6.

Heavy Metals e.g. Lead, Cadmium, Mercury, Copper

Heavy metals are used as mordants to fix dyes. They are easily absorbed through our skin or by inhaling dust which contains residues, and have toxicity profiles that can affect our immune system, alter our genetic and enzyme systems, and damage our nervous system. Mercury is particularly damaging to developing embryos, which are 5 to 10 times more sensitive than adults.

How to Choose Natural Dyes in Clothes


Look for garments with certifications for assurance that harmful chemicals are not present. GOTS, Cradle to Cradle, EU Ecolabel, Standard 100 by OEKO-TEX and Bluesign all restrict the use of synthetic chemicals in garment supply chains or textile products. Organic textiles, specifically GOTS-certified, gives you assurance that the product is organic, from farm to finished garment. Look out for products on our site with these Ethos Badges to easily identify non-toxic products: Certified Organic (CO) and Certified Materials (CM).

Natural Dyes

Before you buy, do your research. Look for companies that use non-toxic natural dyes, such as those approved by GOTS, and have wastewater treatment processes in place (Mud Jeans are an example of this), because neither natural dyes nor synthetic dyes (plus the associated mordants etc. used in the dyeing process) should ever be returned to the local waterways.

Natural dyes are having a resurgence and we can see why. The natural dyeing process relies on nature and is usually done by hand by small makers. The slight variations in colour that are created lead to garments that are rich in both colour and story. Natural dyes are derived from sources such as flowers, leaves, insects, bark roots and minerals without any chemical treatment.

However, keep in mind that  “natural” does not necessarily mean safe. Some natural dyes are perfectly safe, while others can be quite toxic. For example, natural indigo is a skin, eye and respiratory system irritant. A second consideration is that “natural” does not necessarily equate to sustainable or organic, and therefore hidden chemicals such as pesticides or herbicides might be present. With the vast quantities of dyestuff required for natural dyeing, it is likely that this will remain a bespoke process which adds to its unique appeal.

Wash Before Wearing

Lastly, always wash your new clothes before wearing them using a non-toxic laundry detergent to remove excess chemicals that may still be present – try Dr Bronner’s Pure Castile Liquid Soap or The Gentle Label Laundry Liquid. Avoid claims such as “wrinkle-resistant” and “stain-resistant” to ensure that nothing is being added to your clothes that you don’t want there.

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