The Truth About Hydration and Moisturisers: Can Drinking More Water Really Improve Your Skin?

Drinking Water vs. Topical Moisturising: Which is Better?

In this South Korean study, researchers invited 43 healthy female participants to partake in a 4-week experiment. The participants were divided into four sub-groups, each instructed to follow one of the following routines:

．High Water Intake Routine: Drink an additional 2 litres of water

．Moisturiser Routine: Apply moisturiser three times

．Combined Routine: Follow the “High Water Intake + Moisturiser”

．Control Group: No

Throughout the study, South Korean researchers conducted assessments of the participants’ skin hydration levels and Transepidermal Water Loss (TEWL) every two weeks.

Surprising Results

The findings from the study revealed that while drinking water is advantageous for your organs, its direct effect on skin hydration is surprisingly limited. The research indicated that merely increasing water intake resulted in only a slight improvement in skin condition on the lower legs, with no significant moisturising effect observed on the rest of the body.

Conversely, participants who regularly applied moisturiser demonstrated significant improvements within just two weeks. By the four-week mark, the results were even more pronounced, illustrating that topical moisturisers are considerably more effective for short-term skin hydration:

．Increased water content in the skin of the

．Smoother and softer skin on the backs of the

．Significant reduction in dryness on the lower

“1 + 1” Does Not Equal “2”

Interestingly, participants who both increased their water intake and used moisturiser did not exhibit statistically significant differences compared to those who only used moisturiser. This suggests that combining the two did not yield a “double” boost in skin hydration levels as one might have expected.

Does Avoiding Water Lead to Drier Skin?

The researchers initially hypothesised that individuals who drink less water would exhibit drier skin. However, the baseline skin conditions of both the high and low water intake groups were found to be quite similar.

That said, individuals with naturally high-water intake demonstrated more favourable hydration trends in the forearms and cheeks. This improvement is likely attributable to a long-term balance in internal water metabolism, suggesting that habitual hydration may contribute to better skin condition over time.

Why Are Moisturisers So Effective?

The outermost layer of the skin, also known as the stratum corneum, contains approximately 30% water and serves as a natural protective barrier. Skin hydration relies not only on internal water supply but also on preventing moisture from evaporating into the environment.

Moisturisers are effective because they:

．Create a protective film that reduces water evaporation from the

．Contain humectants (substances that attract and retain moisture) that directly hydrate both the epidermis and dermis.

As a result, compared to drinking water, topical products offer a much quicker solution to skin dryness.

The Most Effective Way to Improve Dry Skin

．For Short-term Relief: Prioritise the use of

．For Long-term Health: Maintain a balance of sufficient water intake alongside consistent skincare.

The conclusions drawn from the South Korean study emphasises that drinking water cannot “instantly” remedy dry skin; however, consistent hydration contributes to the overall health of the skin barrier over time.

The most effective approach is simply holistic: ensure daily hydration while using a moisturiser tailored to your skin type.

References: Seol JE, Cho GJ, Jang SH, et al. Effect of Amount of Daily Water Intake and Use of Moisturizer on Skin Barrier Function in Healthy Female Participants. Ann Dermatol. 2024;36(3):145-150. PMID: 38816975; PMCID: PMC11148315.