Estradiol Topical (EstroGel)
EstroGel · E2 Gel
Transdermal estradiol for feminizing HRT. Steady low-level delivery.
Key takeaways
- Transdermal 17β-estradiol gel; approved for menopausal symptoms, common off-label in feminizing HRT.
- Apparent ~36-hour half-life from the skin reservoir; once-daily application.
- Skips first-pass liver metabolism, avoiding the clotting-factor shifts of oral estradiol.
- Transfer risk: cover the site, wash hands, let it dry before skin contact with others.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| Menopausal symptoms (label) | 0.75–1.5 mg estradiol (1.25–2.5 g gel) | Transdermal | Once daily | Ongoing |
| Feminizing HRT (community/guideline) | 0.5–1.5 mg | Transdermal | Once daily | Ongoing |
Pharmacokinetic summary
- Model tier
- Advanced (t½ + Cmax + Tmax + F)
- Half-life
- 36 hours
- Cmax
- 2.16558 pg/mL
- Tmax
- 0.2 days
- Bioavailability
- 62%
- Typical dose
- 0.5–1.5 mg
Frequently asked questions
Gel vs patches — what differs?
Same molecule, different delivery. Gels dry fast and dose flexibly but transfer easily to others, and levels vary more day to day. Patches run steadier with less transfer risk but can irritate skin and come in fixed strengths. Blood levels, not the vehicle, drive the effect.
Is transdermal estradiol safer than oral?
For clotting risk, the evidence points that way. Oral estradiol's first-pass effect raises clotting-factor production, while transdermal largely bypasses it; observational studies show little to no VTE signal with transdermal use, unlike oral. It's not risk-free, just metabolically gentler.
How real is the transfer risk?
Real enough to carry a label warning. Documented cases of precocious puberty in children and hormonal effects in partners followed skin contact with recently applied gel. Covering the site, washing hands, and waiting for it to dry removes most of the risk.
References
- PubMed / EstroGel label
- Steady-state PK of estradiol gel (Br J Obstet Gynaecol 1997) — Application-area and washing effects on gel PK in postmenopausal women.
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