Steam bath: does it really dilate the pores?

Pores are tiny openings located on the surface of the skin, connected to sebaceous glands and to hair follicles. Their role is simple yet essential: they allow sebum to escape, thereby contributing to the skin’s natural balance and protection. However, pore appearance can vary. Over time or due to significant production of sebum, pores can expand and become more noticeable. While this dilation has no direct impact on skin health, it is often perceived as unattractive and leads many people to seek solutions to refine their skin texture, such as steam baths.

Although it is often claimed that hot water – or sometimes cold water – can dilate or constrict pores, this belief has no biological basis.

Let us first recall what steam baths are. This practice involves exposing the skin to a hot water source that releases steam, typically by holding the face over a vessel filled with simmering water, sometimes enhanced with herbs or essential oils. This technique, inherited from traditional skincare rituals, is renowned for providing a deep cleansing and relaxing sensation. By enveloping the skin in moist heat, the steam bath promotes sweating and gives the impression that the skin is purified and that the pores are more open. However, pores are simply the openings of hair follicles that do not contain any muscle fibers capable of contracting. Their diameter is thus determined primarily by genetic factors, the amount of sebum produced, and the skin’s elasticity, rather than by external temperature or exposure to water vapor.

However, while steam does not open pores, the heat it gives off can influence sebum behavior. At higher temperatures, sebum liquefies and flows more easily across the skin’s surface, helping to unclog pores. This effect explains why some people notice clearer skin after a steam bath, even though the pores themselves have not changed in size. A study involving nine volunteers showed that skin temperature significantly influences the sebum excretion rate.

Each 1°C change resulted in approximately a 10% alteration in sebum excretion, whether from warming or cooling.

These rapid changes, observed in under 90 minutes, did not appear to be related to sebum production within the sebaceous glands, but rather to the variation in sebum viscosity on the surface. In other words, heat facilitates its flow by reducing its density, which makes the skin more capable of shedding impurities, without affecting pore dilation.

That said, it is important to recall that temperature variations, whether hot or cold, can weaken the skin. Repeated exposure to very hot water, such as during a prolonged steam bath, can increase the skin’s transepidermal water loss, alter its pH, and cause redness. Conversely, cold water has a less pronounced effect but is not entirely neutral. A study conducted with 50 volunteers whose forearms were immersed for ten minutes in hot water (40 °C) or cold water (10 °C) illustrates these effects and underscores the need for caution.

To reduce the appearance of dilated pores, the optimal approach is based on a consistent, regular skincare routine.

A gentle cleansing every evening is essential to remove excess sebum, pollution residues, and impurities, while avoiding overly harsh detergents that can trigger reactive hyperseborrhea. For the same reason, hydrating your skin daily with a cream suited to your specific skin type is non-negotiable. Additionally, once or twice a week, remember to gently exfoliate your skin. This helps stimulate cellular turnover and refine the skin’s texture. Finally, daily sun protection remains indispensable, since UV rays degrade collagen and elastin, making pores appear more pronounced over time.

Note: If the appearance of your pores is a persistent source of insecurity, certain aesthetic medicine techniques—such as chemical peels, laser treatments, or radiofrequency—can help minimize them. However, it is essential to consult with a healthcare professional to ensure these options are suitable for your skin type and specific needs.