Canadian MHT reference

Estrogen Doses in Canada: Why Patch, Gel & Pill Numbers Don’t Match

One box says 1 mg. Another says 50 μg/day. A gel says 0.06% or 1 mg/g. They may all be estrogen products, but those numbers are not meant to match.

This Canadian reference explains what the labels mean, which systemic and vaginal estrogen products are currently marketed, and how clinicians use approximate dose categories when comparing routes. It is not a prescribing calculator.

First: estrogen is a family, not one molecule

Estrogen is the category. Estradiol, estrone and estriol are individual estrogens. They interact with the same broad hormone system, but they are not chemically identical or interchangeable milligram for milligram.

• Estradiol (E2) is the principal estrogen during the reproductive years. Regulated 17β-estradiol used in Canadian patches, gels, tablets and vaginal products has the same molecular structure as human estradiol.
• Estrone (E1) is another human estrogen. Estragyn vaginal cream is a Canadian local estrone product.
• Estriol (E3) is a weaker estrogen that rises greatly in pregnancy. No marketed Health Canada-authorized systemic menopause product was identified in the current product database for this comparison. It may appear in compounded preparations, which are a separate category.
• Conjugated estrogens are a mixture of several estrogenic compounds rather than a single estradiol molecule. Premarin is the familiar Canadian example.

“Bioidentical” does not automatically mean compounded. Health Canada-authorized estradiol and micronized progesterone are regulated products whose molecules match human hormones. A custom-compounded mixture is prepared for an individual patient and is not a Health Canada-approved finished drug. The broader Canadian MHT/HRT guide explains that distinction in detail.

Why 1 mg does not equal 1 mg across products

The number on a label can describe the amount in a tablet, the concentration in a gram of gel, the amount released by a patch over 24 hours, or the total amount held in a vaginal ring. Those are different measurements.

So, 1 mg oral estradiol is not automatically equivalent to 1 mg/g gel, a 50 μg/day patch, 0.625 mg conjugated estrogens or any vaginal-estrogen dose. The route changes absorption and metabolism; the formulation changes what the number represents.

Approximate systemic estrogen dose categories

A 2024 Government of Canada clinician guide, drawing on SOGC and Canadian Menopause Society guidance, groups common systemic products into low, standard and high clinical dose bands. This is useful for a supervised switch—but it does not prove that every person will absorb or respond identically.

Exact caveat: these are approximate clinical dose bands, not exact mathematical conversions. Do not use this comparison to change or substitute your own prescription. Individual absorption, product formulation, indication, symptom response, tolerability and endometrial-protection needs matter.

No reliable direct equivalency established: this source does not establish an exact conversion between Divigel packets and EstroGel pump actuations, between one gel and every patch product, or between systemic estrogen and vaginal/local estrogen. Custom-compounded estrogen also cannot be assigned a dependable category from its label alone.

Systemic estrogen products currently marketed in Canada

Health Canada’s Drug Product Database was checked for current “Marketed” status in September 2026. A marketed product can still be temporarily unavailable at a particular pharmacy or affected by a shortage.

Local and vaginal estrogen products in Canada

These products are used for genitourinary syndrome of menopause (GSM)—including vaginal dryness, irritation, painful sex and some urinary symptoms. They are not interchangeable with systemic estrogen for hot flashes and should not be placed in the systemic equivalency table.

• Vagifem 10: estradiol 10 μg vaginal tablet; local.
• Imvexxy: estradiol 4 μg or 10 μg vaginal insert; local.
• Estring: estradiol 2 mg vaginal ring designed for extended local release; the 2 mg is the ring’s total content, not a systemic daily dose.
• Estragyn vaginal cream: estrone 0.1% (1 mg/g); local.
• Premarin Vaginal Cream: conjugated estrogens 0.625 mg/g; local treatment with formulation-specific dosing.

Low-dose vaginal estrogen generally has much lower systemic exposure than systemic MHT and, in standard low-dose use, does not usually require a progestogen for endometrial protection. Individual circumstances still belong with a clinician. See Vaginal Dryness, GSM & Sex After Menopause for the fuller treatment discussion.

Estrogen is only one part of an MHT regimen

If you have a uterus and use systemic estrogen, an appropriate progestogen is generally required to protect the uterine lining. Canadian options include regulated oral micronized progesterone—Prometrium 100 mg and several marketed generics—as well as prescribed progestins such as medroxyprogesterone acetate, norethindrone acetate and, in selected regimens, a 52 mg levonorgestrel intrauterine system.

The estrogen dose, progestogen choice and continuous or cyclic schedule form one plan. Do not select or increase systemic estrogen as if it were independent of endometrial protection. New, heavy or persistent unscheduled bleeding needs clinical assessment; any bleeding after menopause should not be self-explained as “just hormones.”

Why might a clinician choose—or switch—a formulation?

The goal may be similar, but the practical fit can differ. A decision can reflect:

• the indication: systemic symptoms versus local GSM treatment;
• medical history and route-related considerations;
• skin sensitivity, gastrointestinal effects or other tolerability;
• dosing flexibility, convenience and patient preference;
• clinician experience and follow-up capacity;
• provincial or territorial coverage, private insurance and out-of-pocket cost;
• pharmacy or wholesaler availability and reported shortages.

MHT means menopausal hormone therapy; HRT means hormone replacement therapy. Both terms are used in Canada. A prescribed product is not necessarily the only medically reasonable option, but alternatives are not automatically dose-equivalent.

If your usual MHT product is unavailable

Another manufacturer, strength, formulation, route or medication may sometimes be clinically reasonable. The pharmacist can investigate local and wholesaler supply, confirm the exact product and identify options that exist. The prescriber can decide whether an option fits your history and the overall regimen.

A supervised switch may begin with an approximate dose band, then use symptom response, side effects, bleeding pattern and follow-up—not package-label arithmetic—to judge the fit. Do not ration, stretch, stop or self-convert a prescription.

Questions worth taking to the appointment

• Is this product systemic or intended mainly for local vaginal/urinary symptoms?
• What does the number on this particular label measure?
• If we switch routes, which approximate dose band are you using—and when will we reassess?
• If I have a uterus, what provides endometrial protection in this regimen?
• What bleeding or side effects should prompt earlier review?
• Is coverage or a shortage affecting this recommendation?

Use Maple’s appointment-preparation checklist, Canadian care-navigation guide and menopause glossary if you want the terminology and questions in one place.

Sources and review notes

• Health Canada Drug Product Database—medicinal ingredients, routes, strengths and current Canadian marketing status.
• Government of Canada, Medical Management of Menopause Symptoms: Clinician Practice Support (2024)—Canadian systemic dose bands and local estrogen/progestogen tables.
• Yuksel N, et al. SOGC Guideline No. 422a: Menopause—Vasomotor Symptoms, Prescription Therapeutic Agents, Complementary and Alternative Medicine, Nutrition, and Lifestyle. J Obstet Gynaecol Can. 2021.
• Johnston S, et al. SOGC Guideline No. 422b: Menopause and Genitourinary Health. J Obstet Gynaecol Can. 2021.

Editorial note: Brand names help Canadian readers identify prescriptions; inclusion is not an endorsement. This page contains no affiliate links. Product status and source review completed September 1, 2026.