Hormones · synthetics & newer drugs
Not all "hormones" are the same drug, and one of the newest options isn't a hormone at all
A lot of the older fear about HRT is fear of a specific old combination. A lot of the newer marketing about 'bioidentical' hormones is selling you something the regulated version already does, more safely. And NK3 receptor antagonists are starting to give people who can't take estrogen a real lever for hot flashes for the first time. Worth knowing the names so the appointment isn't a vocabulary test.
Six families, plainly
Drug class
Progestins (synthetic progesterone-likes)
Also known as: Medroxyprogesterone acetate (MPA, Provera), norethisterone, levonorgestrel (Mirena coil), drospirenone, dydrogesterone, desogestrel, etonogestrel.
What it is
A whole family of synthetic molecules designed to mimic SOME of progesterone's effects — usually the uterine-lining-protecting effect — without being chemically identical. Different progestins behave very differently in the body, in the breast, and in the brain.
Why it matters
Most hormonal contraception uses a progestin, not progesterone. So does some older HRT (like Premique or Provera-based regimens). The headline-grabbing breast-cancer signal in the 2002 Women's Health Initiative trial was specifically tied to MPA paired with conjugated equine estrogen — not to body-identical micronized progesterone, which more recent evidence treats as a lower-risk option. If your prescription says 'progestin' or names one of the molecules above, you're not on body-identical progesterone, and that's a fair thing to ask about.
Where you'll see it
The Mirena coil (levonorgestrel) is often used as the progestogen half of MHT — convenient, very effective for heavy bleeding, but a synthetic. Older oral combination HRT often uses MPA. The progestogen-only mini-pill, the implant, the injection — all progestins.
Drug class
Conjugated equine estrogens (CEE)
Also known as: Premarin. The 'old HRT' the WHI study made famous.
What it is
A mixture of estrogens extracted from pregnant mares' urine. Chemically not identical to the estradiol your ovaries make, and not the same molecule as transdermal body-identical estradiol used in most modern UK and Canadian prescribing.
Why it matters
Most of the cardiovascular and clotting risk that lives in the public memory of 'HRT' came from oral CEE plus MPA in older readers — a specific drug combination, an older average age at start, and an oral route that loads the liver with first-pass metabolism. Transdermal estradiol (patches, gels, sprays) does NOT carry the same clot signal. Conflating the two is what 'HRT myths' pages spend most of their time correcting.
Where you'll see it
Still prescribed in some countries, especially in North America. If your prescription is for Premarin and you'd prefer body-identical, that's a reasonable conversation to have at your next review.
Drug class
Ethinyl estradiol
Also known as: The estrogen in most combined contraceptive pills.
What it is
A potent synthetic estrogen designed to survive oral dosing and reliably suppress ovulation. Not the same drug as the estradiol used in MHT, and not interchangeable with it.
Why it matters
Some people in late perimenopause are kept on the combined pill (or moved onto it) to manage cycle chaos and contraception together. That's a legitimate option, and for some it works well — but ethinyl estradiol carries a higher clot risk than transdermal estradiol, and it's a higher dose of estrogen than typical MHT. It's a contraceptive that happens to mask perimenopause, not MHT in disguise.
Where you'll see it
Microgynon, Yasmin, Rigevidon and most other combined oral contraceptives. The patch (Evra) and the ring (NuvaRing) too.
Drug class
Tibolone
Also known as: Livial. A synthetic that does three jobs in one molecule.
What it is
A synthetic steroid that breaks down in the body into compounds with estrogen, progesterone and weak androgen activity. Taken as a single daily tablet, mostly used after periods have stopped (postmenopause).
Why it matters
Useful when someone wants a single tablet, doesn't want bleeding, and would benefit from the libido lift that the weak androgen action can give. Not first-line in most countries, but worth knowing the name exists if a prescriber mentions it.
Where you'll see it
More common in UK and European prescribing than in North America. Less commonly used in the first 12 months after the final period.
Drug class
NK3 receptor antagonists (the newest option, and not a hormone)
Also known as: Fezolinetant (Veozah, approved 2023). Elinzanetant (approval pending in several markets at the time of writing).
What it is
A non-hormonal drug that targets the KNDy neurons in the hypothalamus — the temperature-control wiring that goes haywire when estrogen drops. By calming that specific signal, it reduces hot flashes and night sweats without touching estrogen anywhere else in the body.
Why it matters
It's a real option for people who can't take MHT — after certain breast cancers, with active liver disease, or where the personal preference is non-hormonal. Trial data show meaningful reductions in moderate-to-severe hot flashes within weeks. Costs and access vary widely; insurance coverage in 2026 is still patchy. Liver function monitoring is required for fezolinetant.
Where you'll see it
Specialist menopause clinics, oncology survivorship clinics, and increasingly primary care in countries where it's reimbursed. Worth knowing the name if your situation rules out MHT.
Drug class
Compounded 'bioidentical' hormones
Also known as: BHRT. cBHT. The custom-mixed creams and pellets you see advertised online.
What it is
Hormones mixed by a specialty pharmacy into a custom cream, lozenge, or implanted pellet, often based on a saliva or blood test. Marketed as 'natural' and 'personalized'. The actual hormone molecule (estradiol, progesterone) is often the same one used in regulated MHT — but the dose, the absorption, and the manufacturing oversight are not.
Why it matters
Major menopause societies (NAMS, IMS, BMS, Endocrine Society) have repeatedly cautioned against custom-compounded hormones for routine use, because dose accuracy is variable, batch-to-batch consistency isn't required, and the marketing often promises individualisation that the underlying science doesn't support. Body-identical regulated MHT (transdermal estradiol + oral micronized progesterone) is the same molecule, with quality control. If someone is selling you a custom pellet on the basis of a saliva test, that's worth a second opinion.
Where you'll see it
Wellness clinics, telehealth-style menopause brands, some private specialists. Less common in NHS / public-system prescribing.
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