By the time we reach our seventies, the oil glands in our skin produce roughly sixty percent less sebum than they did when we were twenty. That number, drawn from decades of dermatology research and most recently reviewed in the 2019 Journal of the American Academy of Dermatology paper on xerosis in older adults, is not a small statistic. It is the reason a woman who never once owned a bottle of lotion at forty finds herself, at seventy-five, scratching at her shins through her stockings on a January evening.
We tend to talk about dry skin the way we talk about gray hair: a cosmetic detail, a sign of years passing, something to mention to the dermatologist if there is time at the end of the appointment. It is something else. It is a structural change in one of the body's most important organs, and it deserves a more careful explanation than the one most of us were given.
What's actually happening under the surface
The outermost layer of our skin, the stratum corneum, is built like a brick wall. The bricks are dead, flattened cells called corneocytes. The mortar is a mix of lipids: ceramides, cholesterol, and free fatty acids arranged in tight, ordered sheets called lipid lamellae. That mortar is what keeps water inside the body and irritants outside it. When the wall is intact, the skin feels supple. When the mortar thins, the wall begins to leak.
As we age, the mortar thins on a measurable schedule. A 2020 review in Skin Pharmacology and Physiology documented declines in stratum corneum lipid content with each decade after fifty, alongside a steady rise in transepidermal water loss, which is the rate at which water evaporates out of the skin. Filaggrin, a protein that breaks down inside the corneocytes themselves into what dermatologists call the natural moisturizing factor, also drops off. The bricks dry out. The mortar crumbles. Water leaves.
This is not a process we can stop. It is one we can work with, once we understand what we are working with.
Why the old advice often misses
For years, the standard guidance for dry skin has sounded something like this: drink more water, use a moisturizer, take shorter showers. None of it is wrong. All of it is incomplete.
The drink-more-water advice, in particular, gets repeated far past its useful life. Hydration matters for many things, including circulation, kidney function, and cognition. But the skin's water content is governed largely by what the barrier can hold, not by what we pour into the glass. If the lipid mortar is thin, the water leaves regardless. This is why a person can drink eight glasses a day and still have flaking, itchy shins by February.
What I have found, in my years of working with families through long winters in the Blue Ridge mountains, is that dry skin worsens precisely when we stop paying attention to it. We notice it only when it itches at night, or when a thin patch of skin on the forearm splits open from a bump against a doorframe, or when a daughter visiting from out of town gently mentions that her mother's hands look papery. By then, the barrier has been failing for months.
The medications and conditions that quietly make it worse
Older adults take more prescriptions than any other group, and several common ones dry the skin further. Diuretics, taken by a significant share of people managing blood pressure, pull water from the body. Statins have been associated with xerosis in patient surveys. Topical retinoids prescribed for sun damage thin the stratum corneum on purpose. Some chemotherapy drugs strip the barrier almost completely. Even antihistamines, often taken nightly for sleep, can contribute to a drier mouth and drier skin.
Medical conditions matter too. Diabetes affects skin in several ways, including elevated glucose levels that draw water out of cells and reduced microcirculation that slows barrier repair. Hypothyroidism reduces sebum production. Kidney disease changes the way the skin metabolizes urea, which is itself a natural humectant. The American Academy of Dermatology's position statements on geriatric dermatology emphasize that persistent itching in an older adult is worth a workup, not a shrug, because the cause may be sitting in the medicine cabinet or in lab work nobody has ordered recently.
If the dryness is severe, asymmetric, weepy, or accompanied by a rash, it is no longer a question of moisturizer. It is a question for a dermatologist, and the National Institute on Aging recommends bringing it up rather than waiting it out.
What actually rebuilds the barrier
The science here has gotten more specific in the last decade. We now know that the most effective topical products are the ones that work with the lipid lamellae rather than around them. The label matters. The price tag does not, particularly.
Look for three ingredients. Ceramides are the same lipids the skin is losing, and replacing them directly helps rebuild the mortar between corneocytes. Glycerin is a humectant that pulls water into the stratum corneum and is one of the most studied moisturizing agents in dermatology. Petrolatum, plain white petroleum jelly, remains the most effective occlusive ever measured for reducing transepidermal water loss. It is unglamorous. It works. A jar of it costs less than a coffee.
The timing matters as much as the ingredient. Apply moisturizer within three minutes of getting out of the shower, while the skin is still damp. This is sometimes called the soak-and-seal method and has been recommended by the American Academy of Dermatology for managing eczema and xerosis for years. Pat the skin almost dry, then trap that moisture in. Doing this once a day, consistently, will do more than an expensive cream applied once a week.
A few practical notes I have gathered from the women and men who actually live this:
- Hot water feels wonderful and strips lipids faster than warm water. Lukewarm is the compromise. Ten minutes in the shower is enough.
- Bar soaps with high pH tend to disturb the barrier. Syndet cleansers, which are synthetic detergents sold as fragrance-free body washes, are gentler.
- A humidifier in the bedroom during winter, set to around forty to fifty percent humidity, will do more for the skin overnight than most lotions do during the day. Indoor heating in cold climates can drop humidity below twenty percent, which the skin cannot keep up with.
- Soft cotton next to the skin matters more than people expect. Wool over a cotton layer in winter, not directly against the calf or the forearm where the skin is thinnest.
- Fragrance-free is not the same as unscented. Unscented products often contain masking fragrance. The label to look for says fragrance-free.
The role of food and supplements, smaller than you might think
There is genuine evidence that omega-3 fatty acids, from fatty fish, flaxseed, walnuts, or a supplement if needed, support skin barrier function. Studies published in The British Journal of Dermatology have shown improvements in barrier integrity with regular intake. Vitamin D status, often low in older adults, correlates with skin health in observational studies, though the direct causal picture is still being worked out. A diet that consistently includes good fats, enough protein, and colorful produce is worth more than any single supplement claim on a bottle.
But diet alone will not rebuild a barrier that is already thinning. Topical care is the first line. Nutrition is support work. I have watched too many people invest in expensive collagen powders while skipping the petroleum jelly that would actually help them.
When the itch is the warning sign
Dry skin in older adults is not always cosmetic, and it is not always simple. Persistent itching that wakes a person at night, skin that bleeds easily, patches of redness that do not respond to a week or two of consistent moisturizing: these are signs to make an appointment. Pruritus in older adults can flag iron deficiency, thyroid dysfunction, liver or kidney disease, or, less commonly, a hematologic condition. It is worth taking seriously rather than scratching through.
So is the skin tear. The thinning of the dermis with age makes older skin more vulnerable to small, shallow injuries that take longer to heal and offer a foothold for infection. A 2018 study in the Journal of Wound, Ostomy and Continence Nursing found that consistent moisturizer use significantly reduced skin tear incidence in older adults in long-term care. A well-maintained barrier reduces that risk meaningfully. This is one of the quiet reasons dermatologists treat xerosis in older adults as preventive care, not vanity.
A gentler way to think about it
There is something instructive about how the skin ages. It does not fail. It changes. The systems that kept water in and the world out for sixty or seventy years begin to need help, and the help is mostly small, mostly daily, mostly unspectacular: a warm shower instead of a hot one, a fingertip of plain ointment on the shins before bed, a humidifier humming through a January night, a cotton sleeve under the wool sweater.
We do not need to make a project of our own bodies. We need to pay attention to what they are telling us and respond with the kind of steady care we would give a friend. The skin, like the rest of us in this season of life, asks for less than we think and gives back more than we expect when we listen.
