Soap, by definition, is clean. But unfortunately, that doesn’t mean it’s environmentally friendly, or even that it’s free from harmful chemicals. That’s discouraging news about a product that you coat your entire body in daily, like body wash or shower gel. But you can’t just skip the shower if you want to continue living in human society. There are lots of ways to make your hygiene routine more sustainable, and some soap choices are clearly better than others.
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Soap vs. Detergent
You might be surprised to find out that most people don’t shower with soap. Body washes, bath gels, and even some bar soaps are technically detergents. The difference is more than just semantics; soaps and detergents are chemically different, and as a result, their environmental impacts are, too.
Every cleanser contains surfactants to dissolve water and wash away dirt and oil. The surfactants in soap come from the reaction between a strong base, such as sodium hydroxide, and a fatty acid or triglycerides from vegetable oils or animal fats. In contrast, shower gels and body washes contain surfactants that are usually derived from petroleum. The most common plant-based surfactants are sodium laureth sulfate or sodium cocoamphoacetate from palm or coconut oil.
Soaps and synthetic detergents are regulated differently. The Consumer Product Safety Commission regulates true soaps. But the U.S. Food & Drug Administration regulates soaps containing moisturizers or perfumes as cosmetics. The FDA also regulates medicated soaps and soaps that are marketed as non-prescription drugs to treat acne or other skin conditions. Unfortunately, none of these sets of regulations is particularly strong. When it comes to cleansers, it’s buyer beware.
Soap is usually better than detergent, which is almost always petroleum-based. There are plant-based detergents, such as those made by Honest Company or the cosmeceutical First Botany’s Tea Tree Body Wash. But if you’re shopping for plant-based body washes, beware that unsustainable palm oil is a common ingredient.
Soap is also less likely to contain sodium laureth sulfate, one of the Suzuki Foundation’s Dirty Dozen cosmetic chemicals to avoid. However, many soaps contain animal products such as goat’s milk or even tallow. The Leaping Bunny app identifies companies that do not perform or employ animal testing, and there are numerous vegan certifications. Soaps like Kiss My Face and Hugo Naturals do not contain animal products or byproducts and have not been tested on animals.
Liquid vs. Bar
Liquid cleansers require five times more energy to manufacture and have 10 times the carbon footprint of bar soaps. Liquids are also packaged in plastic that is not always recyclable and contributes to ocean pollution. One life cycle analysis also found that solid soaps contain fewer ingredients harmful to human health and the environment than liquid soaps. The British website Ethical Consumer confirms that bar soaps are less likely to contain petroleum, use less plastic packaging, and have lower emissions from transportation than liquid soap. Among their recommended brands, Bentley Organic and Lush are available in the U.S.
Cleansers of all kinds can contain untested chemicals (or worse, known carcinogens and toxins). The Environmental Working Group’s Skin Deep database provides detailed information about individual products. Verified products are those with the fewest toxicity concerns, like Codex Beauty’s BIA bar and Bravo Sierra.
The FDA encourages consumers to avoid antibacterial soaps. Antibacterial soaps do not provide any added protection against viruses like COVID-19, nor is there any evidence that their ingredients are safe and effective. The overuse of antibiotics contributes to the rise of antibiotic-resistant strains of bacteria.
Because water treatment systems cannot effectively filter out microbeads, they end up as microplastic pollution. The Microbead-Free Waters Act of 2015 prohibits the manufacturing, packaging, and distribution of rinse-off cosmetics containing plastic microbeads. However, many product formulae still contain plastics under the names acrylate copolymer and polypropylene. If you want an exfoliating soap, look for one with a high EWG rating like Ethique’s face scrub. Or, use regular soap with a renewable loofah sponge (you can even grow your own).
Multiple LCAs note that the way we use soap contributes significantly to its footprint. One found that consumers use more than six times more liquid soap than bar soap per wash. Use this knowledge to either switch from body wash to bar soap or become more mindful of how much liquid soap you squeeze out of the bottle. When you switch to bar soap, try to store it dry so it doesn’t dissolve between uses.
Also, be sure to set your water heater to 120F degrees and use a low-flow showerhead. Be mindful of how much time you spend in the shower. Even an efficient showerhead uses more than a gallon of water per minute. In the end, the water and energy you use washing have a much bigger impact on your personal carbon footprint than your choice of soap.