Scientists find hot showers may have hidden risks

For millions of people, a steaming hot shower offers a moment of bliss—a daily ritual that soothes tired muscles and washes away stress. However, emerging research suggests that this comfort may come at a cost to skin and hair health, forcing scientists and dermatologists to reconsider the impact of this common habit.

According to dermatologists and researchers who study the effects of water temperature on skin health, a 2022 study found that hot water exposure weakens the skin's protective barrier, increases water loss, and leads to redness.

"There are benefits to warmer showers or baths, so I do not want to discount that," said Dr. Victoria Barbosa, associate professor of dermatology at the University of Chicago. "But none of those benefits are for your skin."

While research specifically examining water temperature effects remains limited, dermatologists report that high-temperature showers can strip away essential oils and moisture-retaining substances from both skin and hair.

Dr. Paola Baker, a Boston dermatologist who studies skin barrier function, explained that the skin's protective barrier consists of dead skin cells surrounded by fatty substances called lipids, including ceramides, fatty acids, and cholesterol. These lipids help maintain skin moisture and protect against environmental irritants.

A thin protective layer called the acid mantle sits atop this barrier, Baker said. This layer contains amino acids, sweat-derived acids, and sebum — an oily substance released by glands near hair follicles that helps retain moisture and maintain barrier strength.

Dr. Trinidad Montero-Vílchez, a dermatologist at Virgen de las Nieves University Hospital in Granada, Spain, led research showing how hot water disrupts these protective mechanisms. The study demonstrated that hot water caused more damage than cold water when participants submerged their hands, resulting in increased water loss, weakened skin barriers, and elevated pH levels.

"The tightly packed lipids in the skin barrier may lose their organized structure," Montero-Vílchez said, explaining that this disruption allows moisture to escape more easily through the skin.

The effects of hot water on hair appear similar, though research in this area is more limited. Dr. Elika Hoss, assistant professor of dermatology at the Mayo Clinic in Arizona, explained that sebum-producing glands are particularly concentrated on the scalp and face.

Hoss said, "What's keeping our hair moisturized and protected?" can be removed when hot water strips away the sebum-coating hair strands.

Dr. Blair Jenkins, clinical assistant professor of dermatology at Michigan Medicine, noted that research on bathing effects on skin health has focused primarily on cleansers rather than water temperature. However, she said hot water combined with fragranced soaps and harsh ingredients may compound damage to the skin's outer layer.

The impact of hot showers varies among individuals. "People exist on a spectrum," Jenkins said, "and some people can tolerate hot showers and not have any issues."

The effects may be more pronounced for those with existing skin conditions. Dr. Brittany Craiglow, an adjunct associate professor of dermatology at the Yale School of Medicine, indicated that conditions like eczema or psoriasis might be aggravated by hot water exposure.

Dermatologists emphasize that while occasional hot showers likely won't cause lasting damage in most people, making them a daily habit could lead to ongoing skin and hair issues. Barbosa suggested that "a hot bath or shower should be a treat, not a daily occurrence."

The medical consensus recommends lukewarm water for regular bathing. This recommendation stems from evidence that extreme temperatures can disrupt the skin's natural protective mechanisms while maintaining hygiene.

This growing understanding of how water temperature affects skin and hair health represents an evolution in dermatological knowledge, though researchers acknowledge that more studies are needed to understand the mechanisms involved fully.

The findings highlight the complex relationship between personal comfort, hygiene practices, and skin health, suggesting that individuals may need to balance the psychological benefits of hot showers against potential effects on their skin and hair.

These insights come at a time when increasing attention is being paid to the role of everyday habits in long-term skin and hair health. Dermatologists are working to provide evidence-based guidance for optimal bathing practices.

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