There is a particular glow that only comes from truly hydrated skin. It looks plump and dewy, it moves softly when you smile, and it feels comfortable from morning to night. Some of that comfort begins deep in the epidermis, where tiny water channels called aquaporins help supply your skin from within. Once you understand aquaporins in skincare, you start to see why a heavier cream isn't always the answer.

One aquaporin in particular, Aquaporin-3 (AQP3), has captured the attention of researchers and skincare formulators. In this guide, I'll explain what AQP3 does, how it works alongside your skin barrier, why it changes as we age, and which ingredients may help support it.

What Are Aquaporins?

Aquaporins are protein channels built into cell membranes that allow water, and in some cases other small molecules, to move in and out of cells. There are several types throughout the body. In the epidermis, Aquaporin-3 is one of the most important.

AQP3 is an aquaglyceroporin, which means it transports both water and glycerol. That glycerol piece matters. Glycerol is a natural humectant that helps skin hold onto water, and AQP3 helps deliver it to the upper layers of the epidermis.

The research on this is fascinating. Mice bred without AQP3 had about one third of the normal water content in the outermost layer of their skin. Their skin was also less elastic, and it recovered more slowly after the barrier was disrupted. When researchers restored glycerol levels, each of those problems was corrected. Glycerol-like molecules such as xylitol did not produce the same result.

So when we talk about aquaporins and hydrated skin, we're talking about something far more sophisticated than putting water on the surface. We're talking about a hydration system your skin already has.

Aquaporins and Your Skin Barrier Do Different Jobs

Aquaporins help move water and glycerol within the living layers of the epidermis. Your skin barrier helps keep that moisture from escaping. Healthy, comfortable skin needs both working well.

Dry vs. Dehydrated Skin

This distinction explains something we see every day as estheticians: dehydrated skin and oil-dry skin are not the same thing.

You can absolutely be both. And when you are, adding more hydration alone won't solve it. If skin can't hold onto water, it also needs lipids and a more protective layer to slow moisture loss.

That's why my approach is simple:

Hydrate first. Then seal it in.

What Happens to Aquaporins as We Age?

Human studies show that AQP3 expression decreases with age, and research has found lower AQP3 levels in sun-exposed skin than in protected skin. That doesn't mean our aquaporins simply switch off. Skin biology is far more complex than that.

But it does give researchers another piece of the puzzle when studying why hydration and barrier function change over time. I feel this personally. At 63, my skin behaves differently than it did in my forties, and I've learned that it needs smarter support, not just more product. (Estrogen-Deficient Skin: What Really Happens to Your Skin During and After Menopause.)

That's the heart of our pro-aging philosophy at Art of Skin Care. Rather than trying to make skin behave like younger skin, we're looking for ways to support the skin you have now and help it function at its best.

Aquaporin Skincare: Can Ingredients Support AQP3?

Potentially, yes. But aquaporin skincare doesn't put aquaporins into your skin. Instead, these formulas use ingredients that may support the skin's own AQP3 expression and hydration pathways.

Two ingredients stand out to me in professional skincare right now.

Acetyl Hexapeptide-37

Acetyl Hexapeptide-37, sold to formulators under the name Diffuporine, is a peptide developed to support AQP3 and the skin's natural water flow. Most of the evidence comes from the ingredient supplier's own testing, so I think of it as promising rather than proven. In a well-built moisturizer, it works best alongside humectants and barrier lipids.

Isosorbide Dicaprylate (IDC)

Isosorbide Dicaprylate has published research behind it. In a laboratory skin model, IDC increased AQP3 expression along with other proteins involved in healthy epidermal function.

Researchers then tested it on human skin:

• A lotion with 2% IDC improved hydration and reduced transepidermal water loss (TEWL), a measurement of how much water escapes through the skin.
• In a direct comparison, 2% IDC produced three times the hydration improvement of 2% glycerol.
• Combining 2% IDC with 2% glycerol improved hydration by 133% in severely dry skin and 35% in moderately dry skin.

Those numbers are impressive. Two details keep them in perspective. The study was conducted by the ingredient's developer, and results apply to those specific concentrations. A finished product may use a different percentage.

Aquaporins Are One Piece of the System

No single ingredient is the secret to hydrated skin. AQP3 moves water and glycerol. Humectants attract and hold water. Ceramides, cholesterol and fatty acids support the barrier. Emollients and occlusives slow water loss. The best results come from a routine that addresses each of these, based on what your skin actually needs.

The Bottom Line

Hydrated skin isn't simply skin with moisturizer sitting on top of it. Healthy hydration depends on what happens within the epidermis, where aquaporins move water and glycerol, and on how well your barrier keeps that moisture in.

That's what I love about modern professional skincare. We're learning more about how skin naturally functions, and finding smarter ways to support it at every age. Once you know whether your skin needs more water, more lipids or both, choosing the right products gets so much easier.

Not sure what your skin needs? Start a complimentary consultation, and one of our estheticians will help you build a routine made for your skin.

References

1. Bollag WB, Aitkens L, White J, Hyndman KA. Aquaporin-3 in the epidermis: more than skin deep. American Journal of Physiology-Cell Physiology. 2020;318(6). doi:10.1152/ajpcell.00075.2020.
2. Draelos ZD. Aquaporins: an introduction to a key factor in the mechanism of skin hydration. Journal of Clinical and Aesthetic Dermatology. 2012;5(7):53-56.
3. Hara M, Verkman AS. Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice. Proceedings of the National Academy of Sciences. 2003;100(12):7360-7365. doi:10.1073/pnas.1230416100.
4. Li J, Tang H, Hu X, Chen M, Xie H. Aquaporin-3 gene and protein expression in sun-protected human skin decreases with skin ageing. Australasian Journal of Dermatology. 2010;51(2):106-112. doi:10.1111/j.1440-0960.2010.00629.x.
5. Is aquaporin-3 a determinant factor of intrinsic and extrinsic aging? An immunohistochemical and morphometric study. American Journal of Dermatopathology. PMID: 26509906.
6. Chaudhuri RK, Bojanowski K. Improvement of hydration and epidermal barrier function in human skin by a novel compound isosorbide dicaprylate. International Journal of Cosmetic Science. 2017;39(5):518-526. PMID: 28543784.
7. Bellemère G, et al. Retinoic acid increases aquaporin 3 expression in normal human skin. Journal of Investigative Dermatology. 2008;128(3):542-548.
8. Schrader A, et al. Effects of glyceryl glucoside on AQP3 expression, barrier function and hydration of human skin. Skin Pharmacology and Physiology. 2012;25(4):192-199.
9. Filatov V, Sokolova A, Savitskaya N, et al. Synergetic effects of aloe vera extract with trimethylglycine for targeted aquaporin 3 regulation and long-term skin hydration. Molecules. 2024;29(7):1540. doi:10.3390/molecules29071540.
10. Gunia-Krzyżak A. Aquaporins in the skin: molecular regulators of hydration and potential targets for cosmetic applications. Cosmetics. 2025;12(6):263. doi:10.3390/cosmetics12060263.