Yes, levonorgestrel is a synthetic progestin.
Levonorgestrel is definitively classified as a synthetic progestin (also called progestogen) used in various contraceptive formulations including emergency contraception, combined hormonal contraceptives, intrauterine devices, and progestin-only pills. 1, 2, 3, 4
Classification and Clinical Use
Multiple authoritative guidelines consistently identify levonorgestrel as a progestin across different contraceptive applications:
Emergency contraception: Levonorgestrel 1.5 mg is available as a dedicated progestin-only emergency contraceptive product 2, 5, 4
Combined hormonal contraceptives: Levonorgestrel is paired with ethinyl estradiol in various oral contraceptive formulations and transdermal patches 1, 3
Progestin-only methods: Available as progestin-only pills (POPs or "mini-pills") and in levonorgestrel-releasing intrauterine devices (LNG-IUD) 2, 6
Hormone replacement therapy: Used in combination with 17β-estradiol in transdermal patches for sequential or continuous combined regimens 3
Mechanism of Action
As a synthetic progestin, levonorgestrel works through progestogenic mechanisms:
- In emergency contraception, it delays or inhibits ovulation by preventing the release of an egg from the ovary 4
- In progestin-only pills, it primarily thickens cervical mucus rather than consistently inhibiting ovulation 2
- In combined formulations, it provides the progestogenic component necessary for endometrial protection and contraceptive efficacy
Important Clinical Distinction
The FDA drug labels explicitly state that levonorgestrel "contains a higher dose of levonorgestrel than birth control pills and works in a similar way to prevent pregnancy" 4, confirming its identity as a progestin compound used across different dosing regimens and delivery methods.
The classification is unambiguous across all guideline sources: levonorgestrel is a synthetic progestin, distinguishing it from natural progesterone and from other drug classes like selective progesterone receptor modulators (e.g., ulipristal acetate) 1, 2.