Bar Soap vs. Body Wash for Men: Which One Should You Use?

Bar soap or body wash? Marketing makes it sound like a big decision. Here is what published research and official sources say, and where the evidence runs out.

The short answer

For most healthy men, bar soap and body wash both do the job, and no source we read shows that one is clearly better for the skin. What matters more is what is in the product (soap or a milder synthetic cleanser, with or without fragrance) and how your skin reacts. Body wash is a bit easier to use in the shower. Bar soap is simpler to pack for a flight.

Is bar soap unhygienic?

A common worry is that a used bar collects germs and passes them on. A lab study tested this. Researchers put high levels of two bacteria (E. coli and Pseudomonas) on bars of soap, then had 16 volunteers wash their hands with them. Afterward, "none of the 16 panelists had detectable levels of either test bacterium on their hands." The authors concluded that "little hazard exists in routine handwashing with previously used soap bars."

Two caveats: it was a small study from 1988, and the authors worked at a soap company. It tested hand washing, not full-body showers. The CDC's advice is simply that "washing hands with soap and water is the best way to get rid of germs in most situations", and it does not say bar or liquid is better.

What the research says about the skin

Here is the part that surprises people. Skin is slightly acidic. A 2022 review gives its pH as 4.0 to 6.0. Soap, bar or liquid, is made with a strong alkali, and the same review says soap has "a pH typically in the range of 8.5-11.0." It also reports that soap-based cleansers tend to disrupt the skin barrier more than synthetic detergent cleansers ("syndets"), which can be made close to skin pH. A review by Dr. Zoe Draelos says the same: syndets cause less irritation and dryness than alkaline soaps.

What this means in practice:

• "Natural" does not change the chemistry. Real soap is alkaline whether it is made by a big company or a small shop.
• Body wash is not automatically gentler or harsher. Some are built on soap, some on syndets, and some on harsher surfactants. The same review calls sodium lauryl sulfate (SLS) a "harsh" surfactant. The label is the only way to tell, and we did not find a source that sorts all body washes into one group.
• Glycerin. Glycerin is made when soap is formed, and a review of research says that glycerol applied to skin can improve hydration. But that research is about products left on the skin. We found no study showing that the glycerin in a rinse-off bar makes a difference, so we make no claim about it.
• Only one trial compared the two formats directly, and it was in newborns. Babies washed with liquid soap had better skin hydration and a more acidic skin surface than babies washed with bar soap. That cannot be applied to adult men, but it shows that the format and formula can matter.

If your skin often feels tight, itchy or red after showering, try a cleanser labeled "fragrance-free" and shorter showers. The American Academy of Dermatology suggests limiting showers to five to ten minutes in warm water, using a gentle cleanser, and seeing a board-certified dermatologist if dryness continues. Fragrance is also a common cause of skin allergy, so it is the first thing to drop when skin is irritated.

Cost

Prices change and depend on size and how fast you use a product, so we do not list any. To compare, take the current Amazon price and divide it by the number of weeks one bar or one bottle lasts you. We found no reliable source on how long bars last compared with bottles.

Travel

The TSA 3-1-1 rule covers "liquids, aerosols, gels, creams and pastes", with containers of "3.4 ounces (100 milliliters) or less per item" in one quart-size bag. A solid bar is none of those, so it is not part of that rule. A body wash bigger than 3.4 oz is.

Which to choose

• Choose bar soap if you like the simplicity, travel often or just prefer it. Read the label if your skin runs dry.
• Choose body wash if you like using it with a washcloth or pouf, or if you find a fragrance-free liquid cleanser that suits your skin.
• See a doctor if you have persistent skin trouble. Product choice cannot replace that.

Sources

1. Heinze JE, Yackovich F. Washing with contaminated bar soap is unlikely to transfer bacteria. Epidemiology and Infection, 1988
2. Mijaljica D, Spada F, Harrison IP. Skin Cleansing without or with Compromise: Soaps and Syndets. Molecules, 2022
3. Draelos ZD. The science behind skin care: Cleansers. Journal of Cosmetic Dermatology, 2018
4. Ramos MCM et al. Effects of Liquid and Bar Soaps on the Skin of Brazilian Newborns: A Randomized Controlled Trial. Skin Pharmacology and Physiology, 2023
5. Cheng J, Zug KA. Fragrance allergic contact dermatitis. Dermatitis, 2014
6. Fluhr JW, Darlenski R, Surber C. Glycerol and the skin. British Journal of Dermatology, 2008
7. American Academy of Dermatology, Dermatologists' top tips for relieving dry skin
8. CDC, About Handwashing with Soap and Water
9. TSA, Liquids Rule (3-1-1)