How Drinking Water Affects Skin Hydration
Why do so many people link glowing, hydrated skin with drinking more water? It’s one of those skincare beliefs that feels right, gets repeated endlessly, and slips into “common knowledge” without much interrogation. But when advice sounds that effortless, it usually deserves a closer look.
If increasing your water intake genuinely improves hydration, you should know when it works, who benefits, and when it simply won’t move the needle. And just as importantly, what to do instead.
So let’s untangle the science and separate what water can do for your skin from what it never will.
- How Drinking Water Affects Skin Hydration
- How the Skin Holds Onto Water
- Does Drinking More Water Improve Skin? What Studies Show
- How Water Moves Through the Body to the Skin
- Drinking Water and Skin Elasticity
- Topical care and why it outperforms drinking water for skin hydration
- When extra water helps—and when skincare should lead
- A practical plan for hydrated skin
How the Skin Holds Onto Water
The skin has layers, and the outermost one—the stratum corneum—is where hydration makes the biggest difference to how your skin looks and feels. You can think of this layer as a protective wall. The cells act as the bricks, and the fats (lipids) between them act as the mortar. This wall helps keep water in and prevents irritants from getting through.
Two systems help the stratum corneum stay hydrated:
- Natural moisturising factors (NMFs): small molecules inside the cells, such as amino acids and urea, that attract and hold water.
- Intercellular lipids: a mix of ceramides, cholesterol, and fatty acids that seal gaps and slow water loss.
When these systems weaken, water escapes more quickly. That’s why skin can feel dry even if you drink plenty of fluids. The water simply isn’t being held in place at the surface.
Drinking water is important for your health, but dry skin usually means your skin barrier isn’t keeping moisture in properly.
Does Drinking More Water Improve Skin? What Studies Show
Research shows a consistent pattern: water intake helps most when someone is underhydrated to begin with. Once daily needs are met, increasing fluid intake produces only small changes.
- Palma et al., 2015:
Adding 2 L/day improved surface hydration in women drinking less than ~3.2 L/day. Importantly, it didn’t strengthen the barrier—TEWL stayed the same. - Akdeniz et al., 2018 (review):
Underhydrated individuals saw modest gains in hydration; well-hydrated individuals showed little to no measurable improvement. - Mac-Mary et al., 2006:
An extra litre of mineral water produced small improvements in elasticity and roughness, but effects were mild.
Takeaway:
If you’re not drinking enough water, having more can make your skin look a little fresher. But once you’re properly hydrated, extra water won’t change much. Skincare that strengthens the barrier will always make a bigger difference.
How Water Moves Through the Body to the Skin
After you drink water, it travels through your gut, enters the bloodstream, and eventually reaches the dermis—the deeper layer of your skin. That’s where hydration levels can shift most noticeably.
But here’s the catch: only a fraction of that dermal water reaches the stratum corneum. The outer layer relies largely on its own internal systems—NMFs, lipids, optimal pH—to hold moisture in place.
This explains a common misconception:
People often feel “internally hydrated” yet still develop surface dryness, especially in winter or after using harsh cleansers. The deeper layer may be well supplied, but the surface can’t retain what it receives.
Another nuance: hydration devices used in studies often measure deeper layers rather than just the stratum corneum. So results can look more impressive than what you’d see or feel on the surface.
Drinking Water and Skin Elasticity
Skin elasticity is how easily the skin stretches and springs back. Collagen and elastin in the dermis control most of this property. Hydration plays a smaller role, but it can make the skin feel more supple in some cases.
In Palma et al. (2015), women who added 2 litres of water per day for a month showed slight improvements in stretch and recovery. These changes were only seen in women who had low water intake to begin with. Those already drinking enough saw no difference.
At the surface, elasticity depends on how flexible the stratum corneum is. Flexibility improves when water is held in by NMFs and lipids. If the lipids are depleted, the surface becomes rigid no matter how much water you drink.
| Factor | Where It Acts | Can Extra Water Help? |
| Collagen and elastin | Dermis | No |
| Hyaluronic acid and similar molecules | Dermis | Slightly |
| Water in stratum corneum | Surface | Yes, if starting from low hydration |
| Lipid matrix | Surface | No, needs topical care |
Key takeaway: Drinking more water can make underhydrated skin feel a little more elastic, but strong collagen and a healthy barrier matter more for long-term resilience.
Pro tip: If your skin feels tight, address both sides: drink enough water to meet body needs and use moisturisers with humectants and lipids.
Topical care and why it outperforms drinking water for skin hydration
Staying well hydrated is essential for overall health, but when your skin feels tight, looks dull, or flakes after cleansing, the solution is almost never “drink more water.” The reality is simple: the stratum corneum controls how much water stays in your skin, and it relies on its own internal machinery—not your water bottle—to do the job.
When NMFs are depleted, lipids are disrupted, or the surface pH shifts away from its natural acidity, the barrier can’t hold onto moisture. Water taken in through diet doesn’t correct these issues. That’s why topical care consistently outperforms hydration from within: it delivers the ingredients that directly repair the systems responsible for holding water at the surface.
What goes into an effective moisturiser
The most reliable way to improve skin hydration is with a moisturiser that combines different ingredient types. Each plays a role in mimicking how healthy skin manages water:
| Ingredient type | What it does for your skin | Examples |
| Humectants | Pull water into the outer layers so skin feels more supple | Glycerine, sodium PCA, urea |
| Emollients | Smooth rough edges and fill tiny gaps, improving texture | Squalane, fatty alcohols |
| Occlusives | Form a light seal that slows water loss | Petrolatum, dimethicone |
| Barrier lipids | Replace the ceramides, cholesterol, and fatty acids your skin naturally uses to build its structure | Ceramide-rich creams |
Pro tip: Apply a humectant serum first, then layer a moisturiser with emollients and an occlusive. This sequence draws water in and then helps keep it there.
Fun fact: In controlled tests, people who washed with regular soap developed more stiffness and dryness, while those who used a mild syndet (synthetic detergent, a cleanser formulated with milder surfactants than traditional soap) cleanser maintained softer, better-hydrated skin. Even small daily choices like cleanser type matter.
Why pH matters
Your skin’s surface operates best in a mildly acidic environment. This acidity allows the enzymes responsible for assembling barrier lipids to work efficiently. When cleansers or leave-on products push the pH toward alkaline levels, those enzymes slow down—and lipid organisation falters.
The result? More water escape, more dryness, and more vulnerability.
Choosing products formulated with a skin-friendly pH helps your barrier repair itself more effectively, amplifying the benefits of your moisturiser rather than working against it.
How hydration is measured
Clinics often measure hydration with two kinds of tools. One tracks water escaping through the skin (TEWL), the other measures how much water is present in the surface layers. Drinking more water can sometimes raise surface hydration readings, but TEWL usually stays the same. That means the skin’s barrier hasn’t become stronger—only slightly more hydrated in deeper layers.
Key takeaway: Moisturisers improve hydration where it matters most—on the surface where you feel the difference. Drinking water supports your body overall, but topical care directly addresses dryness.
When extra water helps—and when skincare should lead
Not everyone responds the same way to increased water intake. Here’s the practical breakdown:
- If you normally drink very little, adding extra water can make your skin appear slightly more hydrated and subtly more elastic.
- If you already meet daily fluid needs, extra water produces minimal changes.
- Ageing alters how skin handles water, which is why older adults may need more targeted topical support.
- Environmental factors—dry air, heating, harsh cleansers—accelerate water loss, making topical care the primary defence.
In every scenario, moisturisers consistently outperform extra hydration from drinking alone.
Water vs moisturiser: a practical comparison
| What changes | Adding more water | Using a moisturiser |
| Surface hydration | Slight increase, strongest in people with low baseline intake | Consistent, visible increase |
| Water loss (TEWL) | Little to no change | Reduced when occlusives and lipids are present |
| Elasticity | Small improvement in low-intake groups | Noticeable improvement when dryness is reduced |
| Roughness and feel | Mixed results | Softer, smoother skin, especially when paired with mild cleansers |
Pro tip: If your routine includes strong actives or frequent cleansing, balance it with a ceramide-rich moisturiser and a gentle, low-pH syndet (synthetic detergent, a cleanser formulated with milder surfactants than traditional soap) cleanser. These two steps alone can improve hydration and comfort within days.
Drinking water helps when your intake is low, but moisturisers consistently outperform it for tackling dryness. Combine the two approaches, but lean on topical care for real change.
A practical plan for hydrated skin
Think of this as a two-step system: give your body enough water, then give your skin the topical support it needs.
Start with a mild syndet (synthetic detergent, a cleanser formulated with milder surfactants than traditional soap) cleanser that respects your skin’s natural acidity. This reduces the tightness and flaking that come from harsher soaps.
Next, apply a serum with humectants like glycerin or sodium PCA to pull water into the outer layer. Follow immediately with a moisturiser that contains ceramides, cholesterol, and fatty acids, alongside an occlusive such as dimethicone or petrolatum, to slow down evaporation.
Stick with products that stay in the slightly acidic range. This supports the enzymes that keep your barrier functioning well.
Check your progress after 2 to 4 weeks. Signs that the plan is working include less tightness after washing, smoother skin texture, and fewer visible flakes—even if clinical barrier measurements haven’t shifted.
Quick reference routine:
| Step | What to choose | Why it helps |
| Cleanser | Mild syndet (synthetic detergent, a cleanser formulated with milder surfactants than traditional soap), pH-aware | Prevents extra dryness and stiffness |
| Serum | Humectants (glycerin, sodium PCA, urea) | Pulls water into the surface |
| Moisturiser | Lipids plus emollients and an occlusive | Locks water in and repairs structure |
| Routine | Twice daily and after cleansing | Maintains a healthy hydration gradient |
Key takeaway: Lasting hydration comes from meeting your body’s fluid needs and supporting your skin barrier every day with the right products.
If you already drink enough water but still feel dry or tight, shift your focus to the barrier. Start with a gentle cleanser, add a humectant serum, and lock it all in with a moisturiser that combines lipids and an occlusive. Track your skin over the next month and notice the change.
If you’re new here and want skin advice backed by science rather than marketing, this is the best place to start. Take the first step toward skin that feels comfortable, resilient, and well hydrated.
Talk to you soon!
Dr Bozica
