Short answer: In label trials, a few weeks. EstroGel and the two higher Divigel doses reduced moderate to severe hot flashes more than placebo by week 4, the first time point checked. The lowest Divigel dose took until week 7. By week 12, women on EstroGel had about 7.6 fewer hot flashes a day, from about 10. Placebo also helped a lot, which is normal in these trials.
The EstroGel 0.06% label (section 14.1) describes a 12-week trial of 145 postmenopausal women using 1.25 g of gel a day (0.75 mg estradiol) or placebo gel. Hot flashes were counted at weeks 4 and 12.
| Time | EstroGel 1.25 g | Placebo |
|---|---|---|
| Start | 10.3 a day | 11.0 a day |
| Week 4 | 4.4 a day (5.9 fewer) | 6.0 a day (5.1 fewer) |
| Week 12 | 2.8 a day (7.6 fewer) | 5.2 a day (5.8 fewer) |
The label says both the number and the severity of hot flashes fell significantly more than on placebo at weeks 4 and 12. The gap between EstroGel and placebo grew from week 4 to week 12.
The Divigel label (section 14.1) describes a 12-week trial of 495 postmenopausal women who had at least 50 moderate to severe hot flashes a week. They applied 0.25 g, 0.5 g or 1.0 g of gel (0.25, 0.5 or 1.0 mg estradiol) or placebo to the thigh each day.
So a lower dose may take longer to show a clear effect. Dose choice is your prescriber's call; the EstroGel label says estrogens should be prescribed at the lowest effective dose for the shortest time consistent with treatment goals and risks.
In the EstroGel trial, women on placebo went from about 11 to about 5 hot flashes a day by week 12. That is why the labels judge the medicine by the difference from placebo rather than by the raw drop alone.
For a person starting treatment, it means early improvement may be part medicine and part natural change, and that judging the effect takes several weeks rather than days.
A simple daily count of hot flashes, and how bad they were, makes a review visit more useful. A count from before the first dose gives a baseline to compare against. Note night sweats and sleep too, since vasomotor symptoms include both.
Gel has to be applied correctly to work as tested; see how to apply estradiol gel and whether it can transfer to others. Dose Track logs each application and lets you note symptoms by day.
Read more on Dose Track: Menopause: what the evidence shows · EstroGel vs Divigel · EstroGel side effects · Divigel side effects · Divigel dosing schedule