Hormonal health
Iron deficiency in women: The tiredness everyone normalises
Article produced in association with Spital Clinic
Feeling permanently tired has become so normal for so many women that most of us have stopped questioning it. But one of the most common reasons behind it is also one of the easiest to miss – and one of the most satisfying to fix.
The tiredness that gets explained away
There’s a particular kind of tired that a lot of women simply live with. The mid-afternoon slump that no amount of coffee touches. Needing an early night and still waking up flat. Putting it all down to work, kids, stress, age or hormones – anything except a cause you could actually do something about.
Often, though, that’s exactly what it is: a cause you could do something about. Low iron is one of the most common reasons women feel wiped out, and because it builds so gradually, it rarely announces itself. You don’t wake up one morning feeling different. You just slowly get used to running on less, until “exhausted” starts to feel like your baseline.
Why women are far more likely to run low
Iron is what your body uses to carry oxygen around in your blood. When levels fall, everything has to work a little harder to do the same job – which is why feeling tired is usually the very first thing you notice.
The reason this affects women so disproportionately is simple: periods. Every cycle carries a small iron cost, and over months and years that quietly adds up. Pregnancy adds to the demand too, when the body’s iron needs rise sharply.
But heavy periods are the big one – left unchecked, they can steadily drain your iron, which is why the NHS treats them as something worth looking into rather than just putting up with.
So if your periods sit on the heavier side, you’re not just dealing with the inconvenience in the moment – you may be slowly draining your iron stores at the same time, month after month.
The reassuring part is that heavy periods can be treated, so it’s worth having them looked at rather than soldiering on.
What low iron actually feels like
Tiredness is the headline, but it’s rarely the only clue. Low iron can show up as feeling breathless going up stairs you used to manage without thinking, a foggy, can’t-quite-focus feeling, looking paler than usual, or noticing your heart racing or thumping for no obvious reason.
Then there are the stranger signs people almost never connect to iron: brittle nails, more hair than usual collecting in the brush, restless legs at night, and – oddly – craving and crunching ice. On their own, each of these is easy to shrug off. Lined up together, they’re very often the same story.
Why it so often slips under the radar
Part of the problem is that none of these symptoms screams “iron.” They’re vague, they overlap with ordinary life, and they arrive slowly enough that you adjust without realising. Most of us are also remarkably good at minimising our own tiredness – we assume everyone feels like this, so there’s nothing to mention.
The result is that low iron can go unaddressed for years, not because it’s hard to find, but because nobody thinks to look. It’s a genuinely common, genuinely treatable issue that quietly chips away at how good you’re allowed to feel.
When “heavy” periods are actually heavy
Here’s the tricky bit: most women have no real benchmark for what counts as heavy, because the only period we ever experience is our own. A useful rule of thumb is needing to change a pad or tampon every hour or two, bleeding that lasts longer than seven days, or passing clots bigger than a 10p coin.
NICE frames it even more usefully: periods count as heavy if they’re getting in the way of your life – physically, emotionally or socially. You don’t have to measure anything. If you’re planning your week around your period, doubling up on protection, or it’s leaving you drained, that’s reason enough to take it seriously.
And the good part is they don’t have to be permanent. If yours have crept up over time, getting them under control is worth it in its own right – and it often tackles the iron problem at its source, rather than topping you up only to lose it again next month.
How you actually find out
You can’t tell your iron levels from how you feel. Plenty of women feel rough with results that look “borderline fine,” and some feel reasonably okay while their reserves are already running low.
The only way to know is a straightforward blood test that checks both your blood count and your ferritin – the marker that reflects how much iron you’ve actually got stored away.
Ferritin is the one that matters here, because it tends to drop first, before a standard anaemia test would flag anything as wrong. That’s exactly why a woman can be told her bloods are “normal” and still feel exhausted: the headline number looks acceptable, but the reserves sitting behind it have been running down for a while.
The good news: it’s very fixable
This is the part worth holding onto. Iron deficiency is one of the more rewarding things to put right. The NHS approach is usually a course of iron tablets over several months to rebuild your stores, paired with a source of vitamin C – even just a glass of orange juice – to help your body absorb them properly.
Alongside that, dealing with whatever’s causing the loss in the first place is what stops you ending up back at square one.
Most women start to notice the difference within a few weeks, often well before their levels are fully restored. The fog lifts, the stairs get easier, and the version of “normal” you’d quietly resigned yourself to turns out not to have been normal at all.
The takeaway
The exhaustion so many women treat as a fixed fact of life frequently isn’t one. Low iron is common, it’s quick to check, and it’s straightforward to put right – but only if someone actually looks for it.
If you’ve been tired for longer than you can remember, especially if your periods are heavy, it’s worth getting your iron checked rather than explaining it away for another year. Speaking to a GP is usually all it takes to get that started – and more often than not, the fix turns out to be far simpler than the months of tiredness would suggest.
Disclaimer: This article is produced for informational purposes only and does not constitute medical advice, diagnosis or treatment. Clinical guidance referenced reflects published NHS and NICE information as at May 2026. Individual circumstances vary; readers are advised to consult a qualified healthcare professional before acting on any information in this article. This piece was produced in association with Spital Clinic, which provided background clinical information for editorial purposes. Hyperlinks to external sources are included for reference only and do not represent an endorsement of any product, service or organisation.
Supermarket loyalty card data suggests more than a quarter of women buying menstrual products also buy pain relief at the same time.
The findings also suggest women in lower-income areas are significantly less likely to do so, pointing to disparities in access to over-the-counter pain relief across England.
The study was led by Dr Victoria Sivill of the University of Bristol and colleagues.
The authors said: “The study highlights the need for greater awareness and policy interventions to address the high prevalence of menstrual pain as well as socioeconomic dimensions of menstrual pain.
“Public health initiatives should incorporate menstrual pain relief as part of broader efforts to improve health equity.”
Researchers analysed anonymised loyalty card data from a major UK health and beauty retailer, covering 211m transactions by 3.4m people between 2006 and 2015.
The study examined how often shoppers bought menstrual products and pain relief in the same transaction, and compared this with a customer’s usual rate of buying pain relief.
It found that 26.7 per cent of customers who bought menstrual products also bought pain relief at the same time.
These customers were nearly four times more likely to buy pain relief when buying menstrual products than on other shopping trips.
As a check on the approach, researchers found the most common interval between consecutive menstrual product purchases was exactly 28 days, consistent with the average menstrual cycle.
Menstrual pain is common and can affect daily activities, including school and work attendance.
Regional income was the strongest predictor of menstrual pain purchases.
Customers in the lowest-income areas were 32 per cent less likely to buy pain relief at the same time as menstrual products than those in the highest-income areas.
The authors said lower rates of pain relief purchases in deprived areas are likely to reflect an inability to afford over-the-counter medication rather than lower rates of menstrual pain itself.
Co-author Dr James Goulding said: “It is wonderful that smart data research in the UK is able to bring issues which may have once been overlooked in scientific settings, such as the sheer scale and impact of menstrual pain, to light. This is well overdue.
Co-author Dr Anya Skatova said: “Like many women, I was aware of how common menstrual pain is, but the scale of painkiller purchases alongside menstrual products was still striking.
“Using shopping data, we can see just how widespread the need for pain relief really is. This kind of evidence helps make menstrual pain visible at a population level and provides a strong foundation for systemic change in how it is recognised, treated, and prioritised in public health.”
Wearable technology could revolutionise how women understand and manage their menstrual and hormonal health, according to a major new review that assessed dozens of studies involving data from millions of participants.
The review, which examined 40 studies with cohorts ranging from small pilot groups to nearly 19 million participants, found that devices such as the Oura Ring, Apple Watch, Fitbit, WHOOP band and Garmin watches are capable of detecting meaningful physiological changes across the menstrual cycle – and could one day help identify conditions far sooner than current methods allow.
The findings come as growing attention is being paid to the economic and personal toll of menstrual health problems.
Up to 90 per cent of women report cycle-related symptoms including pain, bloating and mood swings, while up to 40 per cent suffer from premenstrual syndrome.
A more severe condition, premenstrual dysphoric disorder, affects up to 8 per cent of women. In economic terms alone, menstrual and perimenopausal symptoms are estimated to cost the United States more than US$26 billion a year.
Researchers found that wearables were able to reproduce well-established hormonal patterns in real-world settings.
Skin temperature was found to be lower in the first half of the cycle before ovulation, and higher afterwards, consistent with known effects of progesterone.
Resting heart rate rose by around two to four beats per minute from the pre-ovulation phase to the days following it.
Heart rate variability, a marker of nervous system activity, was highest in the early cycle and lowest in the premenstrual phase, with lower readings linked to symptoms of PMS and PMDD.
The review also challenged some long-held assumptions.
Digital data suggested that ovulation tends to occur later and more variably than previously thought, with the pre-ovulation phase averaging 15 to 17 days rather than the 13 to 14 days typically cited.
Skin temperature was also found to dip most sharply more than five days before ovulation – not immediately before it – a finding the authors said could have practical implications for women using cycle tracking for contraception or conception.
Large datasets revealed that cycle patterns vary considerably between individuals and across a lifetime.
Nearly 20 per cent of women showed significant cycle-to-cycle variability, and both low and high body weight were linked to longer and less predictable cycles.
The data also pointed to racial differences in menstrual characteristics that had previously gone largely undetected in smaller laboratory studies.
On contraception, the review found that combined hormonal contraceptive users showed flatter, inverted heart rate variability patterns across the cycle, while progestin-only methods produced trends closer to natural cycles.
The authors cautioned that most research has been conducted in the United States and Europe, with predominantly white participants, and called for broader, more diverse studies.
They also flagged significant gaps in research on perimenopause, partly because many studies excluded women with irregular cycles.
Despite these limitations, researchers concluded that wearable devices hold genuine promise for helping women monitor their health and enabling earlier identification of conditions that might warrant medical attention – provided privacy safeguards and standardised research methods are put in place.
Sweden is exploring domestic production of oestrogen patches as shortages continue to disrupt menopause treatment.
Two government agencies have been asked to examine whether transdermal oestrogen patches could be made in the country.
Transdermal treatments deliver medicine through the skin, most commonly through patches, gels or sprays. They provide a continuous low dose of hormones.
The move follows a long-running shortage of oestrogen treatments that has left women struggling with menopause symptoms and forced pharmacists to look for alternatives.
Hot flushes, mood swings and depression are among the well-documented effects of menopause.
Jakob Forssmed, the health and social affairs minister, has asked the Swedish Medical Products Agency and the Dental and Pharmaceutical Benefits Agency to examine whether the patches could be produced in Sweden.
Speaking to Dagens Nyheter, Forssmed described the assignment as “very urgent”, citing recurring shortages affecting women who “need these medications to lead a functional life”.
The Swedish Medical Products Agency will examine whether a national operator could produce bulk transdermal formulations of oestrogen medicines and, where possible, prepare a process for production.
One possible manufacturer is the state-owned Apotek, Produktion & Laboratorier, which makes medicines tailored to the needs of the Swedish health system.
In 2025, about 205,000 women aged over 45 in Sweden were using systemic oestrogen treatment, according to a report from the Board of Health and Welfare.
That represents 8 per cent of women in the age group.
Transdermal oestrogen has become increasingly popular among menopausal women in Sweden. When patches are unavailable, some women switch to sprays and gels, which can then also run out of stock.
There is no shortage of oestrogen pills. However, experts say they are not a suitable option for everyone because of side effects that patches, sprays and gels do not have.
Angelica Lindén Hirschberg, professor of obstetrics and gynaecology at Karolinska Institutet, told Läkemedelsvärlden: “The pills affect the liver’s production of proteins and increase the risk of blood clots. For many women, the transdermal option, administered through the skin, is the only medically appropriate choice.”
Demand for hormone treatment has risen sharply in Sweden and globally, contributing to shortages.
Manufacturing constraints, supply chain bottlenecks and rising production costs are also said to play a role.
Läkemedelshandlarna, the Swedish association for parallel importers, has said access could be improved by allowing importers to buy hormone patches from other European countries at higher prices.
In response, representatives of the Swedish Medical Products Agency and the Dental and Pharmaceutical Benefits Agency said the causes of shortages needed to be seen “in a more nuanced light”.
They said: “The price level in Sweden is not the only explanation for the shortage of transdermal oestrogens, that is, oestrogen medications administered through the skin, most commonly via patches, gels, or sprays.
“Increased global demand and production issues are also affecting international supply.”
Estradot is among the oestrogen patches affected by shortages.
Some dosage strengths have been removed from Swedish benefit schemes by manufacturer Sandoz after authorities did not approve higher prices.
Under the government’s instruction, the Medical Products Agency will also consider whether access could be secured through EU mechanisms, including public procurement.
The Dental and Pharmaceutical Benefits Agency will examine whether more companies could hold marketing authorisations for transdermal oestrogen medicines, as well as whether parallel trade could be promoted.
The agencies are due to report back to the government by 30 October.
The Board of Health and Welfare report also found disparities in access to hormone patches across areas with different socioeconomic conditions.
In areas facing major socioeconomic challenges, 3.2 per cent of women collected hormone replacement therapy. In areas with very good socioeconomic conditions, the figure was 12.1 per cent.
Maja Österlund, an investigator at the agency, said: “These differences reflect a healthcare system that is currently unequal, and where we also know there is a shortage of certain medicines.”
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