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How Laundry Detergent Works

Essentially, there are four main types of surfactants, with the first three used the most in laundry detergents, and their actions depend on their interactions with ions. Ions are charged particles due to the gain or loss of electrons. Ions can be positive such as calcium, Ca2+, or negative such as chloride, Cl-.

Anionic surfactants are negatively charged in solution. However, they do not work as well by themselves in hard water. This is because hard water has many positively charged ions present such as calcium (Ca2+) and magnesium (Mg2+). Since anionic surfactants are negative they are attracted to the positive ions and bind, making them unable to bind to other molecules in solution.

Nonionic surfactants have no charge. Therefore, they are not as easily impaired under hard water conditions, since they are not attracted to the positive ions.

Cationic surfactants are positively charged in solution. They help the anionic surfactant molecules pack in at the water/dirt interface thereby allowing the anionic surfactants to pull more dirt away.

Amphoteric or zwitterionic surfactants are both positively and negatively charged. These surfactants are very mild and are often found in gentler cleansers such as hand soaps, shampoos, and cosmetics.



Researchers at Wright State University examined the extent to which mites and mite allergens were removed when washing clothes in water alone and with detergents. Interestingly, they found that both methods were equally effective in removing mite allergens. The researchers suggest that washing in water alone is equally effective as washing with detergent because allergens and mites are water-soluble, so contact with water removes them.

Additional Components of Laundry Detergent

Although surfactants are at the heart of laundry detergent’s ability to clean fabrics, other ingredients can help detergents clean better, brighten clothes or smell better. As described previously, some types of surfactants typically do not work well in hard water due to the excess positive ions present. Additives called builders can help detergents to work better under hard water conditions. Builders accomplish this feat by removing calcium (Ca2+) and magnesium (Mg2+) ions in hard water by binding to them. This allows the surfactants, especially anionic surfactants, to bind to more grime, rather than the positively charged ions in the wash water. Builders also are bases, so they work to neutralize acid and can help disrupt chemical bonds. Another benefit of adding builders to laundry detergents is that manufacturers can use less surfactant since the builders make the surfactant more efficient. Some examples of builders include sodium tripolyphosphate (STTP) and zeolites.


Detergents can also include components that make clothes whiter or brighter. The most common whitening agents are bleaches. Bleaches contain peroxides, which can oxidize fabrics. Fluorescent whiteners and brighteners are also added to some laundry detergents because they minimize the yellowing of fabrics. These additives work by absorbing ultraviolet light and emitting back visible blue light, which can mask the yellow that may make colors appear faded and whites appear dingy.

Enzymes are naturally occurring biologic agents present in many detergents in varying concentrations. These enzymes are typically classified into the following categories and are similar to the enzymes used by your body to digest food:

Proteases: help break down proteins

Lipases: help break down fat

Amylases: help break down starches

These enzymes help break down food particles that are present on clothing by catalyzing, or speeding up, the decomposition process. A point to consider is that enzymes are biological products that can break down over time. Therefore, detergents can also contain enzyme stabilizers, which protect the enzymes and help them function.

Some other components include fragrance and coloring, which give laundry detergents their distinctive scents and appearance. Detergents sometimes contain trace amounts of dye, which is not enough to dye your actual clothing. However, on top of making your laundry detergent more visually appealing, dyes can show you when there is still detergent left on your clothes after the wash cycle.

Lastly, fillers help dilute and distribute the active ingredients to their proper dosages. Powder and liquid detergents use different fillers. The major filler in powder detergents is sodium sulfate, which provides the granular powdery texture. The primary filler in liquid detergents is water.



Soaps and detergents both act as cleansers. In fact, prior to the development of detergents, people used lye-based soaps to wash clothes. However, lye laundry soap could lead to dull colors, graying whites, and rings of soap scum in washing machines. Though soap is a surfactant, the major difference between it and detergent is that soaps don’t contain many of the additional components such as builders, enzymes, whiteners and brighteners that make laundry detergent better at cleaning clothes.

Laundry detergent manufacturers have come a long way since the first box of Tide was produced more than 60 years ago. Currently, the two main types of laundry detergent are powders and liquids. For the most part, powder and liquid detergents share the same active ingredients except for the filler used. Additionally, powder and liquid detergents both have pros and cons, and since they have similar cleaning power, people usually choose which type to use based on personal preference.

Here are some of the advantages and disadvantages of using powdered detergents:

Pro: They’re generally cheaper.

Pro: The cardboard packaging is more eco-friendly.

Con: Some people think they don’t dissolve as well in water. This may have been a problem with some of the first powdered detergents, but these days, most powders are designed to readily dissolve in water.

Con: Sodium sulfate can wreak havoc on septic systems.

Con: Powders contain more chemicals compared with liquids, due to the filler.


People may or may not use liquid detergents for an entirely different set of reasons:

Pro: The detergent is already pre-dissolved.

Pro: You can pre-treat stains by pouring it directly onto clothes.

Con: They’re usually more expensive than powdered detergent.

Con: They have plastic packaging, which is less eco-friendly.



Although detergents are made with harsh chemicals, it is debatable whether these chemicals expedite the breakdown of fabrics. As discussed previously, the detergent’s job is to help pull away the dirt and grime from the clothing and rinse it out with water. The actual “wearing” out of clothes is more likely due to the rubbing of clothes in the washing machine (i.e. the agitation), not from the detergents themselves.


Environmental Considerations with Laundry Detergent

Even though detergents do a tremendous job of getting rid of the dirt and grime in our fabrics, at what cost does this come? Considering the toxicities of their chemical ingredients and carbon cost of production, it’s not surprising that some people have concerns about the impacts of laundry detergents on the environment.


Their carbon footprint alone is significant by many people’s standards. Carbon footprints are an indicator of the amount of carbon dioxide (CO2) produced while making, shipping and using a product. According to the Wall Street Journal, the carbon footprint of using UK detergent brand Tesco, varies from 1.3 pounds (0.6 kilograms) to 1.9 pounds (0.9 kilograms) per load, depending on the form of the detergent that’s used. To put this in perspective, it is estimated that for every mile an average car travels, 1 pound (0.5 kilograms) of CO2 is emitted. Recall that American families on average do 300 loads of laundry per year. This means that the carbon footprint of laundry detergents for one year of laundry is approximately 480 pounds (218 kilograms) per year or about 10 pounds (4.5 kilograms) per week. So, while this may not seem like a lot, especially if your car produces about 5 tons of CO2 per year, this number only reflects the laundry detergent. It does not factor in the extra energy requirements of running the washer and dryer.

Now, add to that the toxic effects of the chemical components in detergents. According to the EPA, some of the major concerns about the chemical ingredients used in laundry detergents include the following:


Toxicity to aquatic organisms and algae

Persistence in the environment

Eutrophication of freshwater, particularly by phosphate-based detergents (now, phosphates have been replaced by zeolites which may be alleviating this problem)

Health problems in people, such as cancer

Another concern relating to laundry detergent is that it can make the wash water acidic, and depending on where that water runs to, it could further impact the environment, having effects similar to acid rain. Read on to the next page to find some green alternatives to regular detergents.



Changing laundry detergents to account for environmental concerns may clear your conscience, but it could also lead to changes in body odor. There have been a few reports in the medical literature about patients suffering from severe body odor after switching their laundry detergent. This is because the new detergents interact with your sweat and can change your natural skin chemistry.

Green Laundry Detergent Options

Given some of these environmental considerations about laundry detergents, there are some greener options available to today’s consumer. Most detergents marketed as environmentally friendly don’t include perfumes or dyes, and they’re typically phosphate-free, biodegradable, and they haven’t been tested on animals.

One eco-conscious option is detergent designed to work well in cold water. On average, 80 to 85 percent of the total energy used washing a load of clothes goes to heating up the water. Washing in cold water saves energy, which can translate to savings on your household energy bills, too.

Another environmental approach is to use concentrated formulas, which cuts down on packaging and on the amount of water it takes to make the detergent. According to Proctor & Gamble spokeswoman Carol Berning, concentrated detergents require “less plastic for bottles, less corrugated cardboard for crating, and less gasoline used, because we need fewer trucks to move the shipments”. The cold water and concentrated options that different companies manufacture may be one step to greener washing practices. However, even in these forms, the detergents still contain some potentially environmentally hazardous chemicals.

An additional green choice — for the benefit of the environment and your wallet — could be making your own laundry detergents. There are a variety of recipes out there, with the common ingredients of water, bar soap, borax, and washing soda. Some environmental benefits of making your own laundry detergent are that they typically use fewer chemicals and additives, and they can save on packaging. However, be aware that clothing washed with homemade detergent may also require bleaching, and it may not get stains out as well as some of the commercially produced detergents.

Clearly, detergents are chemically complex products that are continually being improved upon, whether it is boosting their stain-fighting powers or making them greener. For lots more information on laundry detergents and related topics, follow the links below.


The presence of some of the chemicals in detergents may cause skin irritation. For example, some fluorescent brighteners used in detergents can leave residues on the skin, which could cause irritation. However, one group of researchers found that enzymes present in detergents do not cause skin irritation.