Norethindrone vs Tibolone: side-by-side comparison
Norethindrone (Progestin) and Tibolone (Synthetic steroid (STEAR)) belong to different therapeutic classes and are rarely substitutes for each other. The comparison is useful when a single patient is weighing both options for adjacent or overlapping needs.
| Property | Norethindrone | Tibolone |
|---|---|---|
| Therapeutic class | Progestin | Synthetic steroid (STEAR) |
| CAS | 68-22-4 | 5630-53-5 |
| ATC | G03DC02 | G03CX01 |
| Molecular weight | 298.42 g/mol | 312.45 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Norethindrone and Tibolone share the common regulatory framework for prescription active ingredients, bioequivalence standards for generics, and pharmacist oversight. Beyond that, points in common are limited.
Key differences
Norethindrone acts by a different mechanism than Tibolone, with indications that barely overlap. Comparing the two is useful when a clinician has mentioned both in the same context or the patient wants to understand why one was prescribed instead of the other.
Mechanisms compared
Norethindrone: Norethindrone binds to progesterone receptors and exerts progestational effects: thickening cervical mucus, suppressing the LH surge, thinning the endometrium and inhibiting ovulation (at sufficient doses). Tibolone: Tibolone is a prodrug; on absorption it is rapidly converted to three active metabolites (3α-OH-tibolone, 3β-OH-tibolone and Δ4-tibolone) with different tissue-selective activity.
Indications compared
Norethindrone: Norethindrone is approved for prevention of pregnancy (progestin-only and combined formulations), secondary amenorrhoea, abnormal uterine bleeding, endometriosis-associated pain, and as part of menopausal hormone replace… Tibolone: Tibolone is approved (in countries where licensed) for treatment of moderate-to-severe vasomotor menopausal symptoms and prevention of postmenopausal osteoporosis in women at least 12 months past their last natural menst…
Safety profile
Norethindrone: Common adverse effects include breakthrough bleeding, breast tenderness, nausea, mood changes and headache. Tibolone: Common adverse effects include vaginal bleeding or spotting (especially in the first 3 months), breast tenderness, weight changes, headache and dizziness.
Frequently asked questions
Is Norethindrone better than Tibolone? ▾
Norethindrone and Tibolone are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Norethindrone and Tibolone be combined? ▾
Whether they can be combined depends on the indications and the interaction profile of each. If both are in a single prescription, the prescriber has weighed it; in self-medication they should never be combined.
Do they have the same side-effect profile? ▾
No — they belong to different classes and have distinct side-effect profiles. Each has its own prescribing information.
Products with Norethindrone
Products with Tibolone
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.