The blue dish soap. The green all-purpose cleaner. The pink hand wash. These colors exist because decades of marketing taught consumers to associate color with cleaning power. Synthetic dyes are petroleum-derived compounds that add zero cleaning or care function to a product. They exist for shelf appeal. Several dyes permitted in the United States are restricted in the European Union. And yet they remain among the most common ingredients in household cleaning products. No Nines™ products are formulated without synthetic dyes of any kind, as part of the No Nines™ Standard™.
What are synthetic dyes in cleaning products?
Synthetic dyes are colorants manufactured from petroleum-derived aromatic hydrocarbons through chemical processes such as sulfonation, nitration, and condensation. In household and personal care products, they are categorized as FD&C dyes (approved for food, drugs, and cosmetics) and D&C dyes (approved for drugs and cosmetics only).
The most common synthetic dyes in cleaning and personal care products include FD&C Blue No. 1 (Brilliant Blue), FD&C Yellow No. 5 (Tartrazine), FD&C Red No. 40 (Allura Red), and D&C Red No. 33. These are the ingredients that make your glass cleaner blue, your dish soap green (blue plus yellow), your hand soap pink, and your laundry detergent a vivid, unnatural shade of whatever color the brand decided communicates "clean."
On product labels, synthetic dyes may be listed by their FD&C or D&C name, by a CI (Colour Index) number, or simply as "colorant." In cleaning products specifically, manufacturers are not always required to disclose colorants by name. A product may contain multiple synthetic dyes with no specific identification on the label at all.
The functional contribution of these dyes to product performance is zero. They do not clean. They do not preserve. They do not disinfect. They do not deodorize. They exist to make a product look a certain way on a shelf or in your hand.
What the research says
The health concerns around synthetic dyes are more modest than those of other Nasty Nine categories like formaldehyde releasers or bleach. That distinction matters, and this post will not overstate the case. But the concerns are real, documented, and relevant to a product category where the ingredient provides no benefit.
The most significant body of research concerns behavioral effects in children. In 2007, McCann et al. published a randomized, double-blinded, placebo-controlled trial in The Lancet involving 153 three-year-old and 144 eight- and nine-year-old children. The study found that children who consumed drinks containing mixtures of artificial food colors, including FD&C Red No. 40 and FD&C Yellow No. 5, showed statistically significant increases in hyperactive behavior compared to the placebo group. The effect was observed in both age groups.
The 2007 McCann et al. study in The Lancet found statistically significant increases in hyperactive behavior in children exposed to artificial color mixtures, across both three-year-old and eight- to nine-year-old age groups.
That study prompted regulatory action in Europe. Under Regulation (EC) No. 1333/2008, the European Union now requires that any product containing one of the six dyes studied (the "Southampton Six," including Red No. 40 and Yellow No. 5) must carry a warning label stating: "may have an adverse effect on activity and attention in children." Rather than print that warning on packaging, most European manufacturers reformulated their products to remove the dyes entirely. The dyes are not technically banned in the EU, but the labeling requirement effectively removed them from the market.
FD&C Yellow No. 5 (Tartrazine) is a known contact allergen. It can trigger urticaria (hives), asthma, and other hypersensitivity reactions in susceptible individuals. This sensitivity is well documented in the medical literature and is one reason Yellow No. 5 is one of the few colorants that the FDA requires to be listed by name on food labels.
The environmental dimension is straightforward. Synthetic dyes are petroleum-derived and are not readily biodegradable. Research published in environmental science journals has consistently identified synthetic dyes as persistent in aquatic environments, resistant to conventional wastewater treatment, and contributing to long-term pollution. A cleaning product that goes down the drain carries these dyes into the water system, where they persist.
The risk-benefit calculation
Every ingredient in a product should be justifiable by its function. A preservative prevents microbial growth. A surfactant lifts dirt from surfaces. An acid dissolves mineral deposits. Each ingredient earns its place by doing something the product needs done.
Synthetic dyes do not meet this standard. They do not clean. They do not preserve. They do not improve the product's performance in any measurable way. They exist because of a marketing convention established decades ago: blue means glass cleaner, green means all-purpose, yellow means degreaser, pink means gentle. These color associations were invented by brands to differentiate products on a shelf. They were never functional requirements.
When an ingredient adds zero functional value and carries any level of concern, the rational decision is exclusion. You do not need to prove that FD&C Blue No. 1 causes serious harm to justify removing it from a glass cleaner. You need to prove it does something useful to justify including it. It does not.
A cleaning product ingredient should earn its place by performing a function. Synthetic dyes perform none.
This is the simplest cost-benefit analysis in the Nasty Nine series. The benefit column is empty. The concern column, while not alarming, is not empty. Petroleum derivation. Potential allergenicity. Environmental persistence. Behavioral concerns in children. A product that is better without an ingredient should not contain it.
The color of a cleaning product tells you nothing about its efficacy. A blue glass cleaner does not clean glass better than a clear one. A green all-purpose cleaner does not cut grease better because it is green. The color is a signal to your brain, not to the surface you are cleaning.
What No Nines uses instead
Nothing. No Nines products are not colored. There is no replacement ingredient for synthetic dyes because there is nothing to replace. A function that does not exist does not need an alternative.
What you see when you look at a No Nines product is the formula itself, without cosmetic manipulation. The Whole Home HOCl Cleaner is clear. The Foaming Hand Wash looks like what it is: a simple, functional formulation. The Laundry Rinse, Pet Deodorizer, Baby Skin Mist, and Face + Body Mist contain no FD&C or D&C dyes.
This is a deliberate choice, not an oversight. It reflects a broader principle: if an ingredient does not serve the person using the product, it does not belong in the formula. That principle applies to the dramatic cases, like preservatives that release a known carcinogen, and it applies equally to the quiet cases, like dyes that make a cleaner look more like what advertising taught you a cleaner should look like.
Every No Nines product excludes synthetic dyes. No FD&C dyes. No D&C dyes. No "colorant" listed or unlisted. The formula contains only what does the work.
The bottom line
Synthetic dyes are the clearest example in the Nasty Nine series of an ingredient that exists for marketing, not function. They are petroleum-derived. They are not readily biodegradable. Some are associated with hypersensitivity reactions. The EU requires warning labels on products containing certain synthetic dyes based on research linking them to behavioral effects in children. And they add precisely zero cleaning, preserving, or care function to any product they appear in.
The Nasty Nine series has covered ingredients with well-documented health consequences: phthalates that disrupt hormones, formaldehyde releasers that generate a known carcinogen, ammonia that irritates lungs and creates mixing hazards. Synthetic dyes are a different kind of problem. They are not the most dangerous ingredient on this list. They are the most unnecessary.
No Nines includes only ingredients that serve a purpose. Synthetic dyes do not serve a purpose. So they are not included. A cleaner does not need to be blue.
Read the full No Nines Standard: all nine categories explained.
This is post 9 of 9 in the Nasty Nine series. Read more about synthetic fragrance in cleaning products (Post 2) and phthalates in cleaning products (Post 3).
