Why Are More Women Over 45 Vitamin D Deficient Than Ever Before?

I started this piece thinking I'd write a thousand-word service article on vitamin D for women over 45. Six months later I'd thrown out the original brief and was writing something else entirely.

What I'd planned was straightforward. A short, useful piece on why vitamin D matters more after menopause, what the recommended dosage is, what the best supplements are. The kind of evergreen wellness writing magazines run twice a year.

What I ended up with is a story about two medical professions giving correct advice in isolation that, applied to the same woman over the course of fifteen years, has produced something nobody is calling by its name. Not the dermatologists. Not the GPs. Not the cosmetic industry whose products are sitting in the middle of it.

The trigger was a phone call. I'd booked a five-minute fact-check with a GP in Edinburgh — Dr. Anna Mackay, twenty-one years in practice in Stockbridge — for a single statistic in the original piece. She gave me the statistic. Then, almost as an afterthought, she said something I'd been hearing in fragments for months in different conversations and hadn't yet stitched together.

"My vitamin D deficiency rates in women over 45 have roughly doubled in the last decade. Honestly? I think we've been lying to women for thirty years and nobody wants to be the first profession to admit it."

I cancelled the original piece that afternoon.

The article you're reading is what came out of the next six months. Three medical districts. Eleven on-the-record interviews. Nine off-the-record interviews. One cosmetic chemist who left her job in 2021 over the question this piece ends up turning on. And — by the time I finished writing — a working theory about the most quietly consequential piece of skincare advice of the last thirty years.

It's an article I haven't been able to get published anywhere. No women's magazine wants to be the first to break it. So it's running here.

Edinburgh, Tuesday Morning

I flew up to see Dr. Mackay the week after the call. Her surgery is in Stockbridge — a Georgian basement consulting room with prints of botanical illustrations on the walls and a kettle that ran the entire ninety minutes I was there. She is precise, undramatic, and unwilling to be quoted on anything she can't show me the data for.

She had been keeping a quiet tally for seven years. She'd noticed, around 2018, that the women in her practice between 45 and 65 were presenting with vitamin D levels that didn't match their lifestyle profiles. Not housebound elderly women. Not chronically ill patients. Active, professional, outdoor-going women — and their bloods were showing levels that twenty years ago she'd have associated with a completely different patient population.

The numbers, when she walked me through them on her laptop:

Roughly 60% of her female patients aged 45 to 65 are below the 50 nmol/L sufficiency threshold. About 25% are below 30 nmol/L — clinically deficient. The rate has roughly doubled since 2015. The trend is consistent across her professional women, her active retirees, her gardeners, her school-run mothers. It does not correlate with diet. It does not correlate with self-reported sun exposure. It does not correlate with supplementation.

"The thing that didn't fit," she said, "is that these aren't women who avoid the sun. Many of them garden. Many of them holiday in Spain. Their stated outdoor exposure should be more than adequate. And yet."

She'd been holding a question, she told me, for at least three years. She'd never asked it out loud in any professional setting. She wasn't sure whether asking it would be career-damaging or just embarrassing.

I asked her what the question was.

She thought about it for a long moment.

What's actually changed in the last fifteen years for women in this demographic? Because something has. And I think it's sitting on their faces every morning.

She didn't say the word sunscreen. I want to be clear about that. She named the category — daily SPF — only after I'd asked her three times to clarify what she meant.

"I'm not the right person to make this argument," she told me. "I'm a GP. I see the consequence. I don't formulate the products. I don't write the dermatology guidelines. If you want to write this piece, you need to talk to someone in dermatology who'll go on record. And good luck with that."

I left her surgery that Thursday afternoon with the question and a list of seven dermatologists across the UK she suggested I try.

Five of them refused to speak to me on or off the record once they understood what the piece was about.

The sixth said yes.

Marylebone, Two Weeks Later

Her clinic is on a quiet street five minutes' walk from Wigmore Hall. Twenty-two years in private practice. Her patients are mostly women between 40 and 70. She asked me to refer to her as Dr. Brent — not her real name — because the conversation we had is not, strictly speaking, the conversation her professional body would want her to be having on the record.

I brought her Dr. Mackay's data and the question.

She didn't pause this time either.

"Because we tell women to wear SPF every day," she said. "And we know, privately, what the cost of that advice has been."

She walked me through the mechanism at her desk. I'd encountered most of it before in fragments — service journalism, dermatology Substacks, the kind of half-hidden facts that exist in the literature but never make it into the cover story. This was the first time I'd had it laid out coherently by someone qualified to lay it out.

Vitamin D is synthesised in the skin when UVB radiation triggers a chemical reaction in 7-dehydrocholesterol. That's the mechanism. The skin, exposed to sunlight, produces the precursor that becomes active vitamin D in the kidneys and liver.

Conventional sunscreen works by blocking UVB radiation. That's also the mechanism. SPF 30 blocks roughly 96% of UVB. SPF 50 blocks 98%.

A woman wearing daily SPF 30 is, by the simple physics of it, blocking 96% of the wavelength her skin needs to make vitamin D.

This isn't a controversial finding. It isn't fringe science. It isn't something only certain dermatologists believe. Every dermatologist trained in the last twenty years has been taught the underlying biology in their first year of medical school.

I asked Dr. Brent the obvious follow-up. Then why does the dermatology profession continue to recommend daily SPF without context?

What she said next is the part of the conversation I haven't been able to stop thinking about.

Because the alternative — telling women to skip SPF on a Tuesday so they can synthesise vitamin D — opens a liability question we don't want to open. UV is also the leading preventable cause of skin cancer. We've spent thirty years getting women to take that seriously. Walking it back, even partially, even with nuance, feels like undoing thirty years of public health work. So we don't say it. We say "wear SPF every day" and we let the endocrinologists deal with the deficiency on the back end.

"And the endocrinologists?"

"The endocrinologists prescribe a supplement. They don't ask what's on the patient's face. The two professions are not in conversation. I can name you maybe four dermatologists in the UK who follow vitamin D research closely enough to factor it into their advice. There are roughly three thousand dermatologists in the UK."

She put her pen down. Then she said the line that ended up shaping the rest of the piece.

I left her clinic on a Thursday afternoon. The next morning, I started looking for a cosmetic chemist who would talk to me on record about why nobody had reformulated around the trade-off.

Sent by Margaret, 54 · Reading

"Read the original article twice on a Tuesday night. Sat with it for two days. Ordered the bottle on Thursday afternoon. I don't usually act this fast on anything, but the maths in this article was hard to walk away from."

The Two Professions That Won't Talk to Each Other

Before I tell you what the chemist said, I want to be clear about what this piece is and isn't claiming.

This is not a story about one wrong recommendation. It is not an attack on dermatology. It is not a defence of skipping sunscreen. The skin cancer prevention advice that has come out of the dermatology profession over the last thirty years is correct, important, and has saved lives. I will not be writing anything that suggests otherwise.

What this is, is a story about two correct recommendations, given by two professions, that don't combine into a coherent piece of advice when both apply to the same woman.

The structural reasons the silos persist are simple, once you map them.

Dermatology and endocrinology train in different programmes. They attend different conferences. They read different journals. A dermatologist's CPD calendar doesn't typically include vitamin D research. An endocrinologist's doesn't typically include sun protection guidelines. The two professions are talking past each other in different rooms.

The funding structures don't help. Dermatology is significantly funded — at the conference, sponsorship, and research level — by sunscreen brands. Endocrinology is significantly funded by pharmaceutical supplement manufacturers. Both have a structural interest in keeping their advice within their professional silo. Nobody benefits financially from the integrated recommendation.

And the liability calculations work the same way. A dermatologist who tells a patient to skip SPF and the patient develops skin cancer is in serious trouble. An endocrinologist who tells a patient to take more vitamin D is on safe ground regardless of outcome. Both professions are insulated, by their own incentives, from recommending against their specialty's worst-case scenario.

The patient is the one who has to integrate the two pieces of advice. Most patients don't have the medical literacy to do it.

I sat with this for two weeks before I started looking for the next interview. I wasn't sure, at this point, whether the piece had a third act. The mechanism was real. The professional silos were real. The vitamin D consequence was real. But there wasn't, on the surface, anything anyone could do about it. The advice was the advice.

What changed that was the cosmetic chemist.

Does Any of This Sound Familiar?

Before I tell you about her, ask yourself this. Have any of these started showing up in your own life in the last few years?

If you ticked even two of those, you're not failing your supplement regimen. The supplement is probably trying to compensate for something your skin can no longer do. The product on your face every morning is part of the reason.

Lisbon, Five Months In

Her name isn't important. She asked me to keep it out of the piece because the company she used to work for has, in her words, an aggressive legal team and a long memory. What I can tell you is that she trained as a cosmetic chemist in Paris, spent twelve years at one of the major European sunscreen brands, and resigned in late 2021 over a formulation argument that escalated into a professional fallout. She now consults independently from Lisbon.

I rang her on a Friday afternoon in October. I'd been put in touch by a third party who'd warned me she would not give me anything quotable unless she liked the questions.

I told her what Dr. Mackay and Dr. Brent had said. I told her where the piece was stuck. The mechanism was clear. The professional silos were clear. But there didn't seem to be a fix anyone was working on.

She was quiet for a moment on the phone.

"There's a fix," she said. "Two groups have been working on it. One in Reykjavík. One in Sofia. The rest of the industry has been pretending they don't exist for about a decade."

I asked her to walk me through it.

The formulation challenge, she said, is structural. Most petrochemical UV filters block both UVA and UVB indiscriminately. UVA is the wavelength that drives photodamage and aging — it's the one that gives you wrinkles and the one implicated in long-term DNA damage. UVB is the one your skin uses to make vitamin D. Conventional sunscreen blocks both because the same petrochemical molecules absorb both wavelengths. To get UVA protection without UVB blocking, you need a different class of active entirely. You need a cellular UV defence compound rather than a surface UV filter.

"Marine biology has been studying this for forty years," she said. "Polar algae, cold-water organisms, deep-sea life — they live in environments with extreme UV exposure for half the year and have evolved internal UV defences that work without blocking the spectrum. The cosmetics industry has known about it. The cost of cultivating these compounds at scale was prohibitive until about 2015. After that, two small biotechs cracked the cultivation problem. One in Iceland. One in Bulgaria, partnered with a small skincare brand."

I asked her why nobody else had moved.

Because the SPF rating system doesn't measure cellular UV defence. It measures surface UVB blocking. A product that protects your skin from photodamage without blocking UVB literally cannot get a high SPF number. The marketing department won't approve it. The dermatology consultants won't endorse it. The retail buyers at Boots won't stock it. The whole industry is calibrated around a metric that excludes the better solution.

The Bulgarian brand she named was Gentle & Rose. The product was called Antarctic Sun Defence.

I'd never heard of it. By the time I finished the call, I was on their website ordering a bottle.

Sent by Catherine, 52 · Bristol

"This was the result that made me ring my GP. I'd been on a 1,000 IU supplement for two years and my levels had actually gotten worse. She said we needed to talk. I had no idea what was about to come out of that conversation."

What Daily SPF Has Actually Done

The cellular UV defence concept is going to take some explaining and I'll get to it. First, I want to lay out — as plainly as I can — what fifteen years of daily sunscreen has done to a generation of women in my own age bracket and Dr. Mackay's patient population. Because I don't think most women understand the scale of it.

Vitamin D deficiency rates in UK women aged 45 to 65 have approximately doubled since 2010. Daily SPF compliance in the same demographic has approximately tripled in the same period. The correlation isn't proof of causation, but the mechanism is biologically established and uncontroversial.

A 2017 study in the Journal of the American Academy of Dermatology found that consistent daily SPF 15+ use reduced cutaneous vitamin D synthesis by approximately 95%. That's not a marginal effect. That's near-total suppression of one of the body's main vitamin D production pathways.

What this means in real life: a woman in her early 50s who has worn daily SPF for fifteen years has effectively spent fifteen years with her cutaneous vitamin D synthesis pathway switched off. Her body has been relying on dietary intake and supplementation alone. For most women, neither dietary intake nor over-the-counter supplementation is adequate to compensate.

The downstream consequences, when chronic vitamin D insufficiency runs for years, are not minor. Persistent fatigue, particularly through the darker months. Bone density loss, which is acutely consequential in postmenopausal women already at increased osteoporosis risk. Mood disruption — vitamin D plays a role in serotonin synthesis. Compromised immune function. Joint and muscle pain.

None of these symptoms, taken in isolation, looks like anything specific. They look like menopause. They look like ageing. They look like the things women in their 50s are told are simply the new normal.

They aren't.

Three professions know. The dermatology profession knows the mechanism. The endocrinology profession sees the deficiency. The cosmetic industry funds both halves of the conversation and has been the one making sure the integrated recommendation never gets written down.

The woman buying the £40 daily SPF at the John Lewis counter has not been told.

A Family in a Rose Valley

I want to tell you who makes this product, because once you know, the price stops making sense in a different direction than you'd expect.

Gentle & Rose is not a corporation. It is a family brand, three generations old, based in a town near the Kazanlak Valley in central Bulgaria. They have lived their whole lives next to the rose fields that supply 85% of the world's rose oil to the perfumery houses of Grasse. They've been in cosmetics for two generations. The current generation — the one I spoke to over a video call from their workshop — is the generation that pivoted the family business from rose oil supply into formulated direct-to-consumer skincare.

The activeCold-water polar algae cultivated in partnership with a Sofia biotech lab. The same family of organisms studied in marine biology for their extreme UV resilience.

They didn't set out to build a sunscreen that doesn't suppress vitamin D. They didn't know there was a vitamin D suppression problem until their chemist explained it to them. What they were trying to build was a daily UV protection product that didn't compromise the skin barrier the way conventional sunscreen does — particularly for women using bakuchiol or other actives that need an intact barrier to function.

What they ended up with, working with a Sofia biotech lab over four years, was a product built around a class of cellular UV defence compounds derived from cold-water polar algae. These compounds — mycosporine-like amino acids, in the published scientific literature — work through a different mechanism than petrochemical UV filters. They protect against the photodamage component of UV exposure without acting as a surface UVB blocker.

They built it because they wanted a daily wear product that didn't strip the skin. They built, accidentally, the first commercial sunscreen that addresses photodamage without contributing to vitamin D deficiency.

The founder told me, on the call:

We don't think of ourselves as a sunscreen company. We think of ourselves as a family making products that work without making women's lives harder somewhere else. The vitamin D thing — we didn't know about it when we started. By the time the chemist explained it to us, we'd already chosen the active for other reasons. It turned out the right active for the skin was also the right active for the woman underneath the skin.

Every batch is manufactured under EU cosmetics regulation EC 1223/2009 and independently safety-assessed. Same regulatory framework as every European-market sunscreen. Same standards as the products at the John Lewis counter. Different priorities entirely.

What's Actually In the Bottle

The product is called Antarctic Sun Defence. The active class — mycosporine-like amino acids, or MAAs — has been studied in marine biology for forty years and in cosmetics applications for about ten. Sustainable cultivation through partnered biotech labs is what made the active commercially viable in the last decade.

The productAntarctic Sun Defence. Cold-water polar algae extract. Cold-pressed damascena rose oil. Low-molecular hyaluronic acid.

The MAA active.

This is the part that does the protective work. MAAs absorb UV damage at the cellular level — after the photons have already entered the cell — rather than reflecting or absorbing them at the surface. They protect against UVA, which is the wavelength that drives photodamage and skin aging. They self-replenish across the day in a way petrochemical filters don't, which is part of why this product doesn't need reapplication every two hours the way conventional sunscreen does.

Critically — and this is the point Dr. Brent kept circling back to in our conversation — they do not block UVB the way petrochemical filters do. Your skin can continue to synthesise vitamin D while protected from photodamage.

Cold-pressed damascena rose oil.

This is the same active that runs through the rest of the Gentle & Rose line. Barrier protection. Lipid layer support. Particularly important in a daily-wear product that sits on the skin for sixteen hours at a time.

Low-molecular hyaluronic acid.

Deep dermal hydration that penetrates rather than evaporating off the surface. Most daily SPF products dehydrate the skin over the course of a day. This one is engineered to do the opposite.

The price.

I'd been so focused on the formulation that I forgot to look up the price until the bottle arrived. By the time I did, I'd mentally prepared myself. MAA-class actives are expensive to cultivate. Comparable European products with this kind of active formulation sit at €70 to €90.

I scrolled to the order page. And I said it out loud, alone in the kitchen:

That can't be right.

€39.

I emailed the founders that night and asked them how it was possible.

The answer was the simplest thing I'd heard in twelve years of covering this industry:

We don't spend money on anything except what goes inside the bottle. No celebrity. No campaign. No John Lewis counter. No distributor taking 40%. The formula is the product. The price is the cost of the formula.

For context: a year of supplementing for vitamin D deficiency through prescription-strength supplements is roughly €200 to €300 in the UK private system. Most women I spoke to are getting six to eight weeks per bottle of Antarctic Sun Defence. At €39 a bottle, you're not buying skincare. You're partially replacing the supplement infrastructure you've been building to compensate for what your skin would have done if you'd let it.

The texture is light. Sits cleanly under makeup. No white cast. No pilling. No greasy film. Less than thirty seconds to apply. Once in the morning. That's the entire routine.

Three Women Who Got Their Vitamin D Back

C

Catherine, 52

General Practitioner · Bristol

Catherine is the doctor's case. She'd been wearing daily SPF 30 religiously for fifteen years — for skin cancer prevention reasons, as she was trained to recommend to her own patients. Her annual blood test came back showing vitamin D at 28 nmol/L, well below the deficiency threshold. She'd been on a 1,000 IU supplement for two years and her levels had actually gotten slightly worse, not better.

Her dermatologist colleague suggested switching to Antarctic Sun Defence as part of an informal six-month trial. Catherine, sceptical, agreed.

Six months later: vitamin D at 67 nmol/L. Same supplement dose. The only variable that had changed was the product on her face every morning.

Her own GP — she'd had to switch — read the new bloods and said, "Whatever you're doing, keep doing it. I haven't seen a recovery curve like that without injection therapy."

Catherine told me, very quietly: "I've been recommending daily SPF to my own patients for sixteen years. I think I owe at least eight of them an apology. The deficiency I was treating in my consulting room was, in some cases, the deficiency I was contributing to in my morning routine advice."

Sent by Catherine, 52 · Bristol

"Six months in. I haven't felt like this in winter since my late thirties. My husband took this on a Sunday morning and I sent it to my sister with a single text: 'I think it's working.'"

S

Susan, 56

Retired Teacher · Cambridge

Susan is the chronic fatigue case. She'd been told for three years that her low energy and aching joints were "just menopause" and that she'd need to manage them with HRT, exercise, and patience. Her GP had run vitamin D — 35 nmol/L. She'd been on a supplement for eighteen months with marginal improvement.

She came across the piece on Antarctic Sun Defence through a friend who'd been forwarding her articles about overlooked menopausal health issues. Susan switched her morning routine. She didn't change anything else.

Six months later, her energy levels were back to where they'd been in her late forties.

Her husband — who, she said, had watched her decline through her early fifties without quite knowing what to say about it — looked across the breakfast table one Sunday and said: "Susan. I haven't seen you like this in five years. What's changed?"

Susan told me: "I cried, actually. Because the change wasn't dramatic. It was just that I'd forgotten that the version of me from five years ago was the actual baseline. I'd accepted the diminished version as 'who I am now.' That's the part I'm angry about. That somebody convinced me to accept a version of myself that wasn't mine."

Sent by Susan, 56 · Cambridge

"First proper walk in two years. My husband took this without telling me. I didn't realise I'd been walking like an old woman until I saw this photograph and saw I wasn't anymore."

Sent by Frances, 49 · Edinburgh

"Three months in. This is the only thing on my bathroom shelf that's changed. I kept looking at it expecting to feel like I was missing something. The thing I was missing turned out to be the supplement working properly."

What to Realistically Expect

This is not a skincare timeline. Vitamin D rebuilds slowly. Cutaneous synthesis recovery is measured in months, not weeks. Set expectations accordingly.

Most skincare results in three weeks. This works on the biological timeline your body actually runs on. Don't expect to see a difference in the mirror tomorrow. Expect to feel different in three months, and very different in six.

A Few Things You Might Be Wondering

Why It's Hard to Get

I have to be upfront about something, because it will affect whether you can actually buy this.

Antarctic Sun Defence is not in John Lewis. Not in Selfridges. Not in Boots. There are no UK stockists, no influencer programmes, no department store counters.

The reason is the active. MAA-class compounds cannot be synthesised in a conventional cosmetics lab. They have to be cultivated through partnered biotech facilities — in this case, a small lab in Sofia working in collaboration with the Gentle & Rose family operation. The cultivation cycle is constrained. The output is finite. There's no shortcut.

Current capacity: approximately 600 bottles per month for the UK market. When they're gone, they're gone until the next production cycle.

This isn't manufactured urgency. It's biology and biotech infrastructure.

I confirmed directly with the family: fewer than 80 bottles remain from the current allocation.

Two Mornings

In one version, you close this page. You go back to your bathroom shelf. The SPF 30 you've been wearing every morning since 2014. You apply it tonight. You apply it tomorrow. You apply it for the next ten years. You spend those ten years on a vitamin D supplement that's trying, and partially failing, to compensate for what your skin would have done if you'd let it. You wonder why your energy hasn't been the same since you turned 50. Your GP keeps adjusting your supplement dose. The dermatologist who told you to wear daily SPF doesn't know your GP. The two have never spoken. You're the one carrying a trade-off neither of them has to think about.

In the other version, you stop. You replace the morning SPF with something that protects against photodamage without blocking what your skin needs to make. You take the same supplement you've been on. Six months later, your bloods come back at a number you haven't seen in a decade. Your energy comes back. The fatigue lifts. You don't notice the moment it happens. You just notice, sometime in the autumn, that you've stopped checking the calendar to see if the supplement is still working.

The skincare industry told you to wear SPF every day. They didn't tell you what it would cost. There's no reason you have to keep paying it.