Etonogestrel (ENG) is a synthetic progestin derived from testosterone and used in hormonal contraceptives. Etonogestrel is primarily used in implants and vaginal rings, while its prodrug desogestrel (DSG) is primarily used in oral contraceptives.
ENG, ETN, KDG or 3-KDG
DrugBank Accession Number
KEGG Entry Number
Wikipedia Entry Name
Specific Optical Rotation
+85.0 to +95.0° dried, 10 mg/mL in CH2Cl2
GHS Hazard Code(s)
|Carcinogenicity||2||H351||Suspected of causing cancer if inhaled|
|Reproductive Toxicity||1B||H360||May damage fertility or the unborn child|
|Acute Dermal Toxicity||4||H312||Harmful in contact with skin|
|Acute Inhalation Toxicity||4||H332||Harmful if inhaled|
Vaginal inflammation, headache, breast pain, URI, haemorrhage, abdominal pain, pharyngitis, Leukorrhea, weight gain, flu-like symptoms, acne, dizziness, dysmenorrhoea, back pain, nausea
No treatment-related tumorigenic effects seen from administration of desogestrel only.
Not associated with point mutations in the in vitro Ames test and to chromosomal aberrations in a micronucleus test in female rats.
Progesterone Receptor Activity
Androgen Receptor Activity
Listed as "weak" (Jordan) and "active" (Ruan, Lello) agonist.
Estrogen Receptor Activity
Glucocorticoid Receptor Activity
Reports vary: "weak" (Kuhl), "active" (Bartsch), "not active" (Ruan, Lello)
Mineralocorticoid Receptor Activity
Elimination Half-Life (t1/2)
12-24 h, 30 h, 38 +/- 20 h
Serum Protein Binding
95.5-99% bound. 66% to albumin, 32% to SHBG.
Excreted free or as conjugates, primarily via urine (60%) and feces (35%). Small amounts excreted in the breast milk; as a result, 0.01-0.05 ug per kg body weight per day may be ingested by the child.
Apparent Volume of Distribution
Subdermal implant: 7.5 L/h
CYP2C19, CYP3A4: inhibitor
Minimum Contraceptive Threshold
Possibly > 90 pg/mL
Lower Progesterone Receptor and Estrogen Receptor activity than etonogestrel.
Primary metabolite from human hepatic microsome metabolism. Likely formed by CYP3A4, as this enzyme is responsible for 6β-hydroxylation pathways in other steroids.