February 1979; Updated February 3, 1995
Ordinary soap is solely made up of fats and an alkali. In the past, people made their own soap from animal fats and wood ashes.
Today there are very few true soaps in the traditional sense on the market. You might recognize these soaps as products marketed with characteristics such as "pure." "True" soaps are regulated by the Consumer Product Safety Commission, not FDA, and do not require ingredient labeling.
Most body cleansers on the market today are actually synthetic detergent products and come under the jurisdiction of FDA. These detergent cleansers are popular because they make suds easily in water and don't form gummy deposits. Some of these detergent products are actually marketed as "soap" but are not true soap in the common and legal definition of the word.
If a cosmetic claim is made on the label of a "true" soap or cleanser, such as moisturizing or deodorizing, the product must meet all FDA requirements for a cosmetic, and the label must list all ingredients. If a drug claim is made on a cleanser or soap, such as antibacterial, antiperspirant, or anti acne, the product is a drug, and the label must list all active ingredients, as is required for all drug products.
The 1979 FDA Consumer article reprinted below provides additional information on soap products. You also may wish to refer to a related Fact Sheet: Is it a Cosmetic, a Drug, or Both? (Or is it Soap?).
U. S. Food and Drug Administration
ALL THAT LATHERS IS NOT SOAP
by Harold Hopkins
You've been near it all your life, bassinet to bath to boudoir. It was used behind your ears before perfume was used there. It has removed dirt and grime from your face, fingers, and knees. If you've said naughty words your mother may have threatened to wash out your mouth with it. It has cleansed you, made you smell good, added a glow to your complexion, and helped make you feel fresher. But what do you really know about soap?
Well, in the first place the product you regard as soap may not be soap at all, but a synthetic detergent "beauty" or "bath" bar. These and similar names have been used by copywriters to spare the consumer the awful knowledge that she is not bathing herself with real soap, but with a synthetic detergent which, ironically, is for some purposes superior to soap. Some "soap" bars may consist of soap and synthetic detergent.
Soap, as long as we can remember, has enjoyed an enviable respect in polite society and this could be at least a part of the reason why Congress placed soap above the law in enacting the Food, Drug, and Cosmetic Act of 1938. This law exempted soap from regulation as a cosmetic.
So long as no cosmetic representations are made for soap, other than that it cleanses, and no claims are made that it will affect the structure or functions of the body or treat a disease, it is beyond FDA regulation. When such claims are made the soap must meet all FDA requirements for a cosmetic or a drug or both, whichever is appropriate. If it's represented as a drug the label must list all active ingredients; if represented as both a cosmetic and drug or as only a cosmetic the label must list all ingredients.
For instance, if a soap is labeled as a deodorant soap, FDA considers this to be a cosmetic claim and the label must, as with other cosmetics, carry a list of ingredients. If the soap makes a medical claim, such as that it will cure dandruff, it is considered a drug and must carry required drug labeling and also meet FDA safety and effectiveness requirements.
Fortunately, plain soap of the noncosmetic, nondrug variety has earned a good reputation. Apart from the familiar sting from getting soap into your eyes or the peril of slipping on a bar in the bathtub or shower, common bath and hand soap is relatively safe. In fact we often use it to remove other substances from our hands and skin that we think are a lot less safe.
For purposes of excluding ordinary soap from regulation as a cosmetic, FDA defines it as a product in which most of the nonvolatile matter consists of an alkali salt of fatty acids and whose detergent properties are due to these alkali-fatty acid compounds. Our ancestors often made their own soap for laundering, cleaning, and bathing from animal fats and wood ashes. Today's soap may contain perfumes, colors, and oils, but if it is represented only as soap it's out of FDA's regulatory bailiwick.
Ordinary soap is regulated by the Consumer Product Safety Commission under authority of the Hazardous Substances Act. CPSC's jurisdiction covers most noncosmetic, nondrug substances used in the home.
If the bar you use for bathing does not claim to be a soap, it's probably a synthetic detergent product. FDA defines a cosmetic as an article intended to be used on the body for cleansing, beautifying, promoting attractiveness, or altering the appearance; thus, a nonsoap product intended for any of these purposes is automatically classified as a cosmetic.
Soaps and synthetic detergent cleansing agents function in water in somewhat the same way; that is, they break down the resistance barrier between the water and the dirt, grime, oil, or other material, allowing it to be wetted and washed away. Soap works well in soft water, but in hard water, which contains a relatively high amount of calcium in solution, the calcium and soap react to form a gummy material called soap scum, which includes dirt and other matter. This gummy stuff is what forms the familiar ring in the bathtub.
The increasing number of synthetic detergent bars on the market is due largely to their more efficient functioning in water, regardless of hardness, and because they don't form gummy deposits as does soap. There are many types of synthetic detergents, ranging from strong to mild; usually the milder types are used for personal cleansing. Some of the harsher detergents are capable of causing eye irritation or injury and manufacturers normally avoid using these in personal bathing bars. There are consumers who may experience irritation or allergic skin reactions from some synthetic detergents. Some consumers also may be allergic to fragrances, colors, or other substances added to either soaps or synthetic detergent bars.
FDA's file of about 70 reports of adverse reactions during the years 1975 through 1977 from use of bar soaps and synthetic detergent bars that qualify as cosmetics includes consumer complaints about skin rash, redness, inflammation, irritation, itching, and burning among the most common problems. The Consumer Product Safety Commission's file of complaints and injury investigations shows similar effects on the skin and eye irritations. Consumer complaints about adverse reactions to synthetic detergent bars and those soaps classified as cosmetics may be made to any FDA district office or to the Director, Division of Cosmetics Technology, Food and Drug Administration, 200 C Street, SW, Washington, DC 20204. *
Complaints of adverse reactions from ordinary personal cleansing soap not classified as a cosmetic or drug should be sent to the Consumer Complaints Section, Consumer Product Safety Commission, Washington, DC 20207. Complaints may also be made and information obtained on any current recalls, warnings, or bans concerning soap by dialing the toll-free CPSC Hotline for Consumers: 1-800-638-2772.
U. S. Food and Drug Administration
FDA CONSUMER, February 1979