Levonorgestrel vs Clomiphene: side-by-side comparison
Levonorgestrel (Synthetic progestin (emergency contraception)) and Clomiphene (Selective estrogen receptor modulator (ovulation induction)) 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 | Levonorgestrel | Clomiphene |
|---|---|---|
| Therapeutic class | Synthetic progestin (emergency contraception) | Selective estrogen receptor modulator (ovulation induction) |
| CAS | 797-63-7 | 911-45-5 |
| ATC | G03AC03 | G03GB02 |
| Molecular weight | 312.5 g/mol | 405.96 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Levonorgestrel and Clomiphene 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
Levonorgestrel acts by a different mechanism than Clomiphene, 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
Levonorgestrel: In emergency contraception, levonorgestrel works primarily by delaying or inhibiting ovulation when taken before the LH surge. Clomiphene: Clomiphene acts as a competitive antagonist of estrogen receptors at the hypothalamus, blocking the negative feedback that estrogen normally exerts on hypothalamic gonadotropin-releasing hormone production.
Indications compared
Levonorgestrel: Levonorgestrel is approved for emergency contraception (single 1.5mg dose), regular oral contraception (combined with ethinylestradiol or as progestin-only), and as the active component of hormonal intrauterine devices f… Clomiphene: Clomiphene is approved for the treatment of anovulatory infertility in women with intact pituitary-ovarian function — particularly polycystic ovary syndrome (PCOS) — when other causes of infertility have been excluded or…
Safety profile
Levonorgestrel: Common adverse effects of emergency contraceptive use include nausea, headache, fatigue, dizziness, breast tenderness and menstrual cycle changes. Clomiphene: Common adverse effects include hot flashes, mood swings, breast tenderness, ovarian enlargement and visual disturbances (typically reversible on discontinuation).
Frequently asked questions
Is Levonorgestrel better than Clomiphene? ▾
Levonorgestrel and Clomiphene are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Levonorgestrel and Clomiphene 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 Levonorgestrel
Products with Clomiphene
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.