Types of HRT Explained: Estrogen, Progestogen, Combined, Bioidentical and Body-Identical

Searches for the types of HRT have climbed sharply since November 2025, when the US Food and Drug Administration announced it would remove the boxed warning about heart disease, breast cancer and dementia from menopausal estrogen products, a warning that had sat on every pack since 2003. Within days, social feeds filled with confident slogans: patches are ‘risk free’, ‘bioidentical’ creams are ‘natural’, tablets are ‘dangerous’. As of January 2026, the evidence supports almost none of those claims in the form they circulate.

Picture a 52-year-old sitting in a parked car after an appointment, two leaflets on the passenger seat. One describes an estradiol patch, the other a progesterone capsule. A friend has told her to ask for ‘bioidentical’ instead. Her mother stopped hormones in 2002 after a single alarming headline. She has no idea which of these facts still matters.

Most of them do, just not in the way they are repeated online. The menu of hormone therapy is smaller and more logical than it looks, and the two questions that organize it are simple: do you still have a uterus, and how does the hormone enter the body?

What are the main types of HRT?

Hormone replacement therapy, now more often called menopausal hormone therapy, replaces the estrogen that the ovaries stop producing around menopause. Every product on the market can be sorted along two axes: which hormones it contains, and how those hormones get into the body.

By content, the types of HRT fall into four groups. Estrogen-only therapy contains estradiol or conjugated estrogens and nothing else. Combined therapy adds a progestogen, the collective name for the natural hormone progesterone and its synthetic cousins, whose job is to stop estrogen from overstimulating the lining of the uterus. Local vaginal estrogen delivers a very small amount of hormone to the vaginal and urinary tissues and barely enters the bloodstream. A fourth, smaller group covers add-ons and alternatives: testosterone, which some clinicians prescribe for low sexual desire, and tibolone, a synthetic steroid used in the UK and Europe but not approved in the United States.

By route, systemic estrogen arrives as a tablet, a skin patch, a gel, a spray, or, in some countries, an implant placed under the skin. Progestogen arrives as a capsule, a tablet, a combination patch, or a hormone-releasing intrauterine device. Vaginal estrogen comes as a cream, a small tablet or a flexible ring.

The labels ‘bioidentical’ and ‘body-identical’ cut across these categories rather than forming a separate one. Both describe hormones whose molecules match the ones the human body makes, which is why they confuse so many readers; the difference lies in regulation, not chemistry, and this article returns to that distinction below.

What matters most, in my view, is not which brand name appears on the box. It is whether the regimen protects the uterus when it needs protecting, whether the route suits the person’s medical history, and whether the person is still having periods. Those three facts drive nearly every prescribing decision.

Estrogen-only HRT: who it is for and why the uterus matters

Estrogen is the hormone that relieves hot flashes, night sweats, sleep disruption and the vaginal dryness of menopause. Taken alone, it is also the simplest regimen available, which is exactly why it is reserved for a specific group.

In mainstream guidance from the NHS, Mayo Clinic and the US National Institute on Aging, estrogen-only therapy is prescribed for people who have had a hysterectomy, the surgical removal of the uterus. The reason is a tissue called the endometrium, the inner lining of the womb that thickens each month under the influence of estrogen and is shed when progesterone falls. Give estrogen with no progestogen to someone who still has a uterus and that lining keeps building. Over months and years the risk of endometrial cancer rises, and the risk grows with the duration of unopposed estrogen. Observational data from the 1970s onward documented this clearly, and it remains the one warning regulators kept on US estrogen labels in 2025.

Two estrogens dominate prescribing. Estradiol is the same molecule the ovaries make before menopause. Conjugated equine estrogens are a mixture derived from pregnant mares’ urine and were the estrogen used in the Women’s Health Initiative, the large US trial that reshaped prescribing after 2002.

That trial had an estrogen-only arm of roughly 10,700 women who had undergone hysterectomy. After about seven years, the estrogen-only group showed no increase in breast cancer, and in longer follow-up published by the WHI investigators the rate was modestly lower than in the placebo group. The same arm did show a small rise in stroke and blood clots in the leg veins, particularly among older participants. These are randomized-trial findings, the strongest type of evidence, though they apply to one estrogen given as a tablet to women whose average age was 63.

For someone with a uterus, the equation changes, and the next type of HRT explains why.

Progestogen in HRT: what it is and why it is added

Progestogen is the quiet partner in combined therapy. It does not relieve hot flashes. Its purpose is almost entirely protective: it keeps the endometrium thin so that estrogen can be used safely by anyone who still has a uterus.

The word covers two families. Progesterone is the body-identical hormone, supplied as micronized progesterone, meaning the molecule has been milled into fine particles so that the gut can absorb it. Progestins are synthetic compounds that act on the same receptor. The most familiar in the US are medroxyprogesterone acetate, the progestin used in the WHI combined arm, and norethindrone. Levonorgestrel is delivered by a hormone-releasing intrauterine device. Dydrogesterone is widely prescribed in the UK and Europe but is not marketed in the United States.

Do these differences matter clinically? Here the evidence is suggestive rather than settled. A large French cohort known as E3N followed more than 80,000 postmenopausal women and found that estrogen combined with micronized progesterone or dydrogesterone was associated with a smaller increase in breast cancer risk than estrogen combined with other progestins over several years of use. UK observational data have pointed the same way. No randomized trial has compared progestogens head to head on breast cancer, so this is observational evidence that can be confounded by who chose which product. The Menopause Society describes micronized progesterone as a reasonable first choice while stating the data are not definitive.

Side-effect profiles differ in ways people notice. Micronized progesterone can cause drowsiness, which some find helpful for sleep. Synthetic progestins are more often linked to bloating, breast tenderness and low mood in the days they are taken.

The levonorgestrel intrauterine device deserves its own sentence. In the UK it is licensed to provide the progestogen component of HRT; in the US that use is not on the label, so its suitability is a judgment for the treating clinician.

Combined HRT: sequential or continuous?

Combined therapy comes in two rhythms, and the choice depends on where a person is in the menopause transition rather than on preference alone.

Sequential combined HRT, sometimes called cyclical, delivers estrogen continuously while the progestogen is added for part of each cycle. The withdrawal of progestogen triggers a predictable bleed, much like a period. Clinicians usually choose this pattern for people in perimenopause, the years of irregular cycles before the final period, or for those within about a year of their last period. Starting a continuous regimen while the ovaries are still active tends to produce erratic bleeding that is hard to interpret.

Continuous combined HRT delivers both hormones every day. After an adjustment phase there should be no bleeding at all, which many people prefer. NHS guidance reserves it for postmenopausal use, generally meaning at least 12 months since the last period or after a year or more on a sequential regimen. Spotting in the first few months is common and expected; bleeding that persists beyond roughly six months, or that returns after it had stopped, needs investigation because the endometrium must be checked.

Combination products exist in both patterns: tablets containing estrogen plus a progestin, and patches that release both. Many prescribers instead pair a separate estradiol patch or gel with a separate progesterone capsule, which lets each component be adjusted independently. That flexibility is the reason the ‘two leaflets’ scenario in the opening is so common.

Tibolone is a different animal. It is a single synthetic molecule that the body converts into substances with estrogen-like, progestogen-like and weak androgen-like activity, so it serves as a combined regimen in one tablet. It is prescribed in the UK and much of Europe for postmenopausal women and has randomized-trial data on fracture reduction, but the FDA has never approved it, and it has been associated with a higher stroke rate in older women in trials.

Bioidentical hormones vs body-identical HRT: what the labels really mean

Few words in women’s health carry more marketing weight than ‘bioidentical’. The term simply means a hormone whose molecular structure is identical to one made in the human body: estradiol, estriol, estrone, progesterone, testosterone. By that definition, the estradiol patch dispensed by any hospital pharmacy is bioidentical, and so is the micronized progesterone capsule next to it.

In everyday use, however, ‘bioidentical hormones’ has come to mean something narrower and more problematic: custom-mixed preparations made by compounding pharmacies, often sold as creams, troches or pellets, sometimes with the promise that they are ‘tailored’ to a saliva or blood test. The Cleveland Clinic and Harvard Health both describe this double meaning, and it is the source of most confusion.

To cut through it, UK clinicians increasingly use the phrase ‘body-identical’. The NHS applies it to regulated, licensed products containing estradiol and micronized progesterone, molecules identical to the body’s own, manufactured to pharmaceutical standards, tested in trials and approved by regulators. The same products are FDA-approved in the United States, where the Menopause Society prefers the term ‘FDA-approved bioidentical’ to make the same point.

So the honest answer to ‘is bioidentical better?’ splits in two. Body-identical estradiol and progesterone are mainstream, well-studied options that many clinicians now choose first, partly because of the observational signals on blood clots and breast cancer described elsewhere in this article. Compounded bioidentical hormones are a separate category with a separate evidence base, which is to say almost none.

My own view, after years of reading this literature, is that the adjective on the label is close to irrelevant. What counts is whether the product is regulated, whether its dose is consistent from batch to batch, and whether a progestogen is included when the person has a uterus. A regulated body-identical regimen answers all three. A compounded cream labeled ‘natural’ answers none of them with certainty.

Are compounded bioidentical hormones regulated or recommended?

Compounding is the practice of a pharmacist mixing a medicine for an individual patient, usually because a licensed product does not meet a specific need such as an allergy to a dye or a filler. It is legal and sometimes necessary. It is also, for hormones, largely unmonitored.

Compounded bioidentical hormone preparations are not approved by the FDA, are not required to prove safety or effectiveness in trials, and are not subject to the same manufacturing checks as licensed products. The Mayo Clinic, Cleveland Clinic and Harvard Health all state this plainly. In 2020, a committee of the US National Academies of Sciences, Engineering, and Medicine reviewed the evidence and concluded there was insufficient support for the clinical use of compounded bioidentical hormones outside narrow circumstances. The Menopause Society and the American College of Obstetricians and Gynecologists hold the same position.

Three specific concerns recur in the literature. Potency varies: independent laboratory testing of compounded preparations has found hormone content that differed substantially from the label, in both directions. Protection may be missing: creams marketed as ‘estrogen plus progesterone’ deliver progesterone through the skin unreliably, and endometrial overgrowth has been reported in women using them. Testing is unvalidated: the saliva hormone tests used to ‘personalize’ these regimens do not reliably reflect tissue hormone levels, so the tailoring is more theater than science.

Pellet implants of compounded estradiol or testosterone, placed under the skin, carry an additional issue. They cannot be removed if side effects develop and have been associated with hormone levels well above the physiological range in case series.

None of this means a compounding pharmacy is dishonest or that every person who used such a product was harmed. It means the evidence does not exist to say they are safe or effective, and that mainstream bodies recommend regulated products first. Anyone considering a compounded preparation should raise it with a prescribing clinician rather than buy it from an online seller.

Tablets, patches, gels, sprays and rings: does the route change the risk?

For systemic estrogen, the route is probably the single most consequential choice after the uterus question, and it is the one most often skipped in online debates.

Estrogen swallowed as a tablet is absorbed from the gut and passes through the liver before it reaches the rest of the body, a process pharmacologists call first-pass metabolism. The liver responds by producing more clotting factors, more sex hormone-binding globulin and more triglycerides. Estrogen absorbed through the skin, from a patch, gel or spray, enters the bloodstream directly and largely bypasses that liver effect.

The clinical consequence shows up in blood clots. Venous thromboembolism, a clot in a deep vein of the leg that can travel to the lungs, roughly doubled in the WHI combined arm, where estrogen was oral. A large UK case-control study published in 2019, drawing on more than 80,000 women with clots and 390,000 without, found oral estrogen associated with a higher clot risk than non-use, while transdermal estrogen showed no increase. Smaller French studies reported the same pattern. This is observational evidence; no randomized trial has been large enough to settle the question, but the consistency of the signal and the plausible mechanism have persuaded the NHS, the Menopause Society and most specialists to favor transdermal estrogen for people with clot risk factors, including higher body weight, a history of migraine with aura, or a family history of thrombosis.

Stroke follows a similar logic: oral estrogen was linked to a small excess in the WHI, and observational data suggest the lowest transdermal doses are not.

Practical differences count too. Patches are changed once or twice a week and can irritate skin. Gels and sprays dry in minutes but must not be transferred to a partner or child by skin contact. Tablets are the easiest to remember and the only option some people tolerate. Which route suits a given person is a decision for the prescriber, weighing history against preference.

Local vaginal estrogen: the type of HRT most often overlooked

About half of postmenopausal women develop what clinicians now call genitourinary syndrome of menopause, a cluster of vaginal dryness, irritation, pain with sex, urinary urgency and recurrent urinary tract infections caused by thinning of estrogen-dependent tissue. Unlike hot flashes, these symptoms do not fade with time. They tend to worsen.

Vaginal estrogen treats them directly. It is available as a cream, a small tablet or insert placed in the vagina, and a soft ring that releases estradiol for about three months. The amount of hormone involved is tiny compared with systemic therapy, and blood estradiol levels in users generally stay within the postmenopausal range. Because so little reaches the uterus, the NHS, Mayo Clinic and the Menopause Society do not require a progestogen alongside it, and it can be continued long term under review.

This matters for a group that systemic HRT often excludes. People with a history of breast cancer, or others for whom systemic estrogen is unsuitable, are frequently able to use vaginal estrogen after discussion with their oncologist, and observational data in breast cancer survivors have not shown an increase in recurrence. That decision belongs to the treating team, since it depends on the type of cancer and the medicines being taken for it.

Two non-estrogen alternatives exist for the same symptoms. Prasterone is a vaginal insert containing DHEA, a hormone precursor that local tissue converts into estrogen and testosterone; it is FDA-approved for painful sex due to menopause. Ospemifene is an oral tablet that acts on estrogen receptors in vaginal tissue without being an estrogen; it is also FDA-approved.

Vaginal estrogen will not relieve hot flashes or protect bone, and systemic HRT does not always fix vaginal symptoms fully. Many people use both. The 2025 US labeling change applied to local products too, acknowledging that the old warning about heart disease and dementia was never supported by data for this route.

Types of HRT compared at a glance

The table below gathers the categories into one view. ‘Evidence note’ summarizes the strongest available data for each row, not a verdict.

Type of HRT	What it contains	Usually prescribed for	Evidence note
Estrogen-only (systemic)	Estradiol or conjugated estrogens	People who have had a hysterectomy	Randomized trial (WHI): no breast cancer increase; small rise in stroke and clots with oral use
Sequential combined	Estrogen daily plus progestogen for part of each cycle	Perimenopause or within about a year of last period	Endometrial protection well established; produces a monthly bleed
Continuous combined	Estrogen and progestogen every day	Postmenopause (12+ months since last period)	Randomized trial (WHI): small rise in breast cancer with oral conjugated estrogen plus medroxyprogesterone after about 5 years
Body-identical (regulated)	Estradiol with micronized progesterone	Either regimen above, any uterus status	Observational data suggest lower clot risk (transdermal) and smaller breast cancer signal; no head-to-head trial
Compounded bioidentical	Custom-mixed hormones, unapproved	Not recommended by major societies	No randomized trials; potency and endometrial protection uncertain
Vaginal estrogen (local)	Low-dose estradiol or conjugated estrogens	Genitourinary symptoms, any age after menopause	Randomized trials for symptom relief; no progestogen needed; minimal systemic absorption
Tibolone	Synthetic steroid with mixed activity	Postmenopausal women (UK and Europe; not FDA-approved)	Randomized trial: fewer fractures; higher stroke rate in women over 60
Testosterone add-on	Testosterone gel or cream	Low sexual desire after other causes addressed	Randomized trials show modest benefit for desire; off-label for women in most countries

Reading down the final column reveals the pattern that should shape any conversation: the regulated products, whichever adjective they wear, have trial or large cohort data behind them. The unregulated ones do not. Within the regulated group, the differences between routes and progestogens are real but rest on observational evidence, which is why a clinician weighs them against a person’s own risk factors rather than applying one rule to everyone.

What changed recently

Three dates explain why this topic is trending, and only one of them is new.

In July 2002, the Women’s Health Initiative stopped its combined-hormone arm early. Among roughly 16,600 women with an average age of 63, five years of oral conjugated estrogens plus medroxyprogesterone acetate produced, per 10,000 women per year, about 8 extra invasive breast cancers, 7 extra heart attacks, 8 extra strokes and 8 extra pulmonary clots, alongside 6 fewer colorectal cancers and 5 fewer hip fractures. The PubMed record for that paper is in the references. Prescriptions fell by more than half within two years, and in 2003 US regulators added a boxed warning to every estrogen product.

In September 2017, the WHI investigators published 18 years of follow-up in JAMA: neither the combined nor the estrogen-only regimen was associated with higher all-cause, cardiovascular or cancer mortality compared with placebo. Reanalysis by age showed that women who started hormones in their fifties had a different, more favorable profile than those who started in their sixties or seventies. In 2022 the Menopause Society’s position statement concluded that for symptomatic women under 60 or within 10 years of menopause, benefits generally outweigh risks, while recommending individual assessment and the lowest effective dose for the shortest time consistent with goals.

In November 2024, the UK’s NICE published an update to its menopause guideline, adding structured advice on discussing HRT with women who have a history of breast cancer and on non-hormonal options.

Then, in November 2025, the FDA announced it would remove the boxed warning about cardiovascular disease, breast cancer and probable dementia from systemic and vaginal estrogen products, keeping the endometrial cancer warning for unopposed estrogen in women with a uterus. The agency framed this as aligning labels with the age-stratified evidence.

Nothing about the underlying data changed in 2025. The trials are the same ones summarized by the NIH and Mayo Clinic pages cited below. What changed is the official reading of them, and that is what sent the search curve upward.

What the evidence actually says, graded by strength

Not all claims about the types of HRT stand on the same footing. Sorting them by evidence grade is the most useful thing this article can do.

Strongest, from randomized controlled trials. Systemic estrogen reduces the frequency and severity of hot flashes and night sweats by roughly 75% compared with placebo, a finding replicated across dozens of trials. Both WHI arms showed fewer hip and vertebral fractures. Oral combined conjugated estrogens with medroxyprogesterone, started at an average age of 63, increased breast cancer, stroke and clots. Oral estrogen alone in women after hysterectomy did not increase breast cancer. In women aged 65 and over, the WHI Memory Study found a higher rate of probable dementia with combined therapy; it tested no one younger. The ELITE trial, which randomized women by time since menopause, found less progression of carotid artery thickening in those who started estradiol within six years of menopause, while the KEEPS trial found no effect on arterial measures either way.

Moderate, from large observational cohorts. Transdermal estrogen carries less clot risk than oral. Micronized progesterone and dydrogesterone are associated with a smaller breast cancer signal than synthetic progestins. Vaginal estrogen in breast cancer survivors has not been linked to recurrence. Women who start HRT in their fifties show lower cardiovascular event rates than non-users in many cohorts, consistent with the ‘timing hypothesis’, though healthy-user bias cannot be excluded.

Weak, resting on expert opinion or small series. Claims that compounded bioidentical hormones are safer or more effective than licensed products. Claims that hormone ‘optimization’ by blood or saliva level improves outcomes. Claims that HRT prevents dementia in younger women; observational data are mixed, and a 2023 Danish registry study reported an association in the opposite direction.

Unknown. Whether the breast cancer findings from the WHI’s oral conjugated estrogen plus medroxyprogesterone regimen transfer to transdermal estradiol with micronized progesterone. The observational signals are encouraging; the randomized trial has not been done.

Common myths about the types of HRT

Most of the viral claims of the past few months are old myths wearing new captions. Six come up constantly.

‘Bioidentical means natural and therefore safe.’ The estradiol in a regulated patch is bioidentical and plant-derived; so is the hormone in many compounded creams. Chemistry does not confer safety. Regulation, consistent dosing and trial data do, and only one of those two products has them.

‘Patches carry no risk at all.’ Transdermal estrogen appears to avoid the clot and stroke excess linked to oral estrogen, which is a meaningful advantage. It does not remove the need for progestogen in someone with a uterus, and breast cancer data for transdermal regimens remain observational. ‘Lower’ is not ‘zero’.

‘Any HRT causes breast cancer.’ Estrogen-only therapy in the WHI did not increase breast cancer. Combined therapy did, modestly, after about five years, with oral conjugated estrogen plus medroxyprogesterone; the absolute excess was fewer than one additional case per 1,000 women per year. Lifestyle factors such as alcohol intake and body weight carry risks of a similar order.

‘You must stop at 60, or after five years.’ No major guideline sets a fixed stopping age. The NHS and the Menopause Society advise an annual review of symptoms and risks, with the decision to continue made individually.

‘Vaginal estrogen is as risky as the tablet.’ Systemic absorption from local products is minimal, no progestogen is required, and regulators removed the systemic warnings from these products in 2025 for exactly that reason.

‘HRT just delays menopause, so symptoms come back worse.’ Menopause is the permanent end of ovarian function; hormones do not postpone it. Symptoms can recur when therapy stops because the underlying deficiency is still there, not because treatment made it worse. Tapering under supervision is commonly suggested, though trials comparing gradual and abrupt stopping found similar recurrence rates.

Side effects of different types of HRT in the first three months

Whatever type of HRT a person starts, the first weeks tend to be the bumpiest, and the pattern of side effects often points to which component is responsible.

Estrogen-related effects include breast tenderness, nausea, bloating, headaches, leg cramps and a feeling of fluid retention. They usually ease within six to eight weeks as the body adjusts. Progestogen-related effects, which cluster in the days a sequential progestogen is taken, include irritability, low mood, acne-like skin changes and breast discomfort; switching from a synthetic progestin to micronized progesterone, or changing the delivery method, resolves these for many people, although that is a prescriber’s call.

Route-specific issues are predictable. Patches can cause redness or itching where they sit, and some fall off in hot weather or after swimming. Gels and sprays need time to dry and must not be shared by skin contact. Oral tablets are the most likely to cause nausea, which taking them with food often reduces. Vaginal products occasionally cause mild local irritation or discharge in the first week.

Bleeding deserves its own paragraph. On sequential combined therapy a regular bleed is expected. On continuous combined therapy, irregular spotting during the first three to six months is common and usually settles. Persistent or heavy bleeding, bleeding that returns after it stopped, or any bleeding on estrogen-only therapy or vaginal estrogen is not something to wait out; it is a reason to be seen, because the endometrium must be assessed.

The NHS recommends a review about three months after starting or changing HRT, then yearly. That first review is where most adjustments happen, and it is a better forum than social media for comparing notes. Serious adverse events such as clots or stroke are rare in people under 60 using transdermal estrogen, but they are the reason the warning signs in the next section are worth memorizing.

When to see a doctor

Every decision about starting, switching or stopping HRT belongs with the prescribing clinician. Some situations, though, call for an urgent appointment or emergency care rather than waiting for the next scheduled review.

Seek emergency help for chest pain, sudden breathlessness, or coughing up blood, which can signal a clot in the lungs; for sudden weakness or numbness on one side of the body, facial drooping, slurred speech, or a severe headache unlike any before, which can signal a stroke; and for a swollen, painful or warm calf, which can signal a deep vein clot.

Book a prompt, non-emergency appointment for any of the following:

• Vaginal bleeding that is heavy, lasts beyond six months on continuous combined therapy, returns after it had stopped, or occurs at all on estrogen-only or vaginal estrogen.
• A new breast lump, skin dimpling, nipple discharge or persistent breast pain in one area.
• Yellowing of the skin or eyes, dark urine, or pain in the upper right abdomen, which can indicate a liver problem.
• A first migraine with aura, meaning visual disturbances such as flashing lights before a headache, or a marked change in an existing migraine pattern.
• Blood pressure readings that have climbed since starting treatment.
• Low mood, anxiety or sleep disruption that is new or worsening rather than easing.

Before starting any type of HRT, a clinician will want to know about a personal history of breast, ovarian or endometrial cancer, blood clots, stroke, heart disease, liver disease, unexplained vaginal bleeding or untreated high blood pressure, and about any family history of clots or breast cancer. None of these automatically rules HRT out; they shape which type and route are appropriate, and in some cases whether non-hormonal options come first.

If symptoms are not controlled after three months, or side effects persist, the answer is a conversation about adjusting the regimen, not stopping abruptly or adding something bought online. That conversation is also the right place to ask about ‘bioidentical’ or compounded products, so that the person prescribing can explain what the evidence does and does not support.

Frequently asked questions

What are the different types of HRT?

The main types are estrogen-only therapy, combined estrogen and progestogen therapy in either a sequential or continuous pattern, and low-dose vaginal estrogen for local symptoms. Within those groups, hormones can be body-identical or synthetic and delivered as tablets, patches, gels, sprays, rings, capsules or an intrauterine device. Tibolone and testosterone are less common additions. A clinician chooses among them based on uterus status, menopause stage and medical history.

Are bioidentical hormones safer than regular HRT?

Not as a category. Regulated body-identical products such as estradiol and micronized progesterone are mainstream HRT with trial and cohort data behind them, and observational evidence suggests transdermal estradiol carries less clot risk than oral estrogen. Compounded bioidentical hormones, by contrast, are not FDA-approved, have no randomized trials, and show variable potency in independent testing. Major societies recommend regulated products first and advise discussing any compounded option with a prescriber.

What is the difference between body-identical and bioidentical HRT?

Chemically there is none; both terms mean hormones with the same molecular structure as those the body makes. The difference is regulation. ‘Body-identical’ is the term the NHS uses for licensed, pharmaceutical-grade estradiol and micronized progesterone. ‘Bioidentical’ is often used in marketing for compounded preparations that are not approved by regulators, are not standardized, and have not been tested in clinical trials.

Who can take estrogen-only HRT?

Estrogen-only HRT is prescribed for people who have had a hysterectomy, since without a uterus there is no endometrium to protect. In the Women’s Health Initiative, this regimen did not increase breast cancer over seven years, though oral estrogen raised stroke and clot risk slightly in older participants. Anyone who still has a uterus needs a progestogen alongside estrogen. The prescribing clinician confirms which regimen fits.

What does progestogen do in combined HRT?

Progestogen protects the lining of the uterus from overgrowth caused by estrogen, which lowers the risk of endometrial cancer. It does not relieve hot flashes. Options include body-identical micronized progesterone, synthetic progestins such as medroxyprogesterone or norethindrone, and the levonorgestrel intrauterine device. Observational studies suggest micronized progesterone carries a smaller breast cancer signal than synthetic progestins, but no randomized trial has compared them directly.

Is sequential or continuous combined HRT better?

Neither is better in general; they suit different stages. Sequential therapy, with progestogen for part of each cycle and a monthly bleed, is used during perimenopause or within about a year of the last period. Continuous therapy, with both hormones daily and no bleed after settling, is used once a person is at least 12 months past their last period. Irregular spotting in the first months of continuous therapy is common; persistent bleeding needs assessment.

Are HRT patches safer than tablets?

For blood clots, the evidence favors patches, gels and sprays. Oral estrogen passes through the liver and raises clotting factors; a large UK study found oral estrogen linked to higher clot risk while transdermal estrogen showed none. This is observational data, not a randomized trial, but it is consistent enough that guidelines favor transdermal routes for people with clot risk factors. Breast cancer data for transdermal regimens remain observational. Route choice belongs with the prescriber.

Does vaginal estrogen need a progestogen?

No. Low-dose vaginal estrogen as a cream, tablet or ring delivers very little hormone to the bloodstream, and blood estradiol levels generally stay in the postmenopausal range. The NHS, Mayo Clinic and the Menopause Society do not require a progestogen alongside it. In November 2025 US regulators also removed the systemic warnings from these products. Any bleeding while using vaginal estrogen should still be reported to a clinician.

What changed about HRT warnings in 2025?

In November 2025 the US Food and Drug Administration announced it would remove the boxed warning about cardiovascular disease, breast cancer and probable dementia from systemic and vaginal estrogen products, while keeping the endometrial cancer warning for unopposed estrogen in women with a uterus. The agency cited age-stratified analyses of the Women’s Health Initiative and its 18-year follow-up. The underlying trial data did not change; the official interpretation did.

How long can you stay on HRT?

No major guideline sets a fixed limit. The NHS and the Menopause Society recommend reviewing symptoms, benefits and risks about three months after starting and then every year, with the decision to continue made individually. Risks such as breast cancer with combined therapy rise with longer duration, so the review matters. Stopping or changing a regimen should always be discussed with the prescribing clinician rather than done abruptly.

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.