Please enable JavaScript
Bain de vapeur pour dilater les pores.

Steam bath: does it really dilate the pores?

Often recommended for purifying the skin, a steam bath is based on the idea that it dilates the pores. But do pores actually open in response to heat? Let us explore the scientific reality behind this long-held belief.

Published on August 25, 2025, by Pauline, Chemical Engineer — 6 min of reading

Can hot steam open the pores?

Pores are tiny openings located on the skin’s surface, connected to the sebaceous glands and to hair follicles. Their role is simple yet essential: they allow sebum to be expelled, thus contributing to the skin’s natural balance and protection. The appearance of pores can, however, vary. Over time or due to substantial production of sebum, pores may enlarge and become more noticeable. While this enlargement has no direct impact on skin health, it is often considered unsightly and leads many people to seek solutions to refine their skin texture, such as steam baths.

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

Let us first recall what steam baths are. This practice involves exposing the skin to a source of hot water that emits steam, typically by holding the face above a vessel of simmering water, sometimes infused with herbs or essential oils. This technique, inherited from traditional care rituals, is renowned for inducing a sensation of relaxation and deep cleansing. By enveloping the skin in moist heat, the steam bath promotes perspiration and gives the impression that the skin is purified and that the pores are more open. However, pores are merely the openings of hair follicles that do not possess muscular fibres capable of contracting. Their diameter is therefore determined primarily by genetic factors, the amount of sebum produced and the skin’s elasticity, rather than by external temperature or steam exposure.

Nevertheless, while steam does not open the pores, the heat it emits can influence sebum behaviour. At elevated temperatures, sebum liquefies and flows more readily to the surface of the skin, helping to clear the 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 has a significant influence on the rate of sebum excretion.

Each 1°C variation led to an approximately 10% change in sebum excretion, whether due to warming or cooling.

These rapid changes, observed in under 90 minutes, did not appear to be linked 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, making the skin better able to rid itself of impurities, without however affecting pore dilation.

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

ParameterControlHot waterCold water
TEWL (g·h⁻¹·m⁻²)25.7558.5834.96
pH6.336.656.62
Erythema (a.u.)209.07286.34Non-significant difference
Effects of temperature variations on the skin (TEWL, pH and erythema).
Source: ARIAS-SANTIAGO S. & al. Impact of water exposure and temperature changes on skin barrier function. Journal of Clinical Medicine (2022).

Effective methods to minimise the appearance of dilated pores.

To reduce the visibility of dilated pores, the most effective strategy lies in maintaining a consistent and regular skin care routine.

A gentle cleanse each evening is essential to remove excess sebum, pollution residues and impurities, while avoiding overly harsh products that can trigger reactive hyperseborrhoea. For the same reason, daily moisturisation with a cream suited to one’s skin type is non-negotiable. Moreover, once or twice a week, don’t forget to gently exfoliate your skin. This helps stimulate cell renewal and refine the skin’s texture. Finally, daily sun protection remains indispensable, as UV rays degrade the collagen and elastin, making pores more visible over time.

Note: If the appearance of your pores is a genuine concern, certain aesthetic medicine techniques, such as chemical peels, laser therapy or radiofrequency, can help to minimise their appearance. However, it is essential to discuss these options with a healthcare professional to ensure they are appropriate for your skin type and specific needs.

Sources

Diagnostic

Understand your skin
and its complex needs.

Read more