Patch, gel, tablet, injection: what changes
Hormone therapy comes in more delivery formats than almost any other treatment, and people frequently move between them. Each format runs on its own schedule and produces its own pattern of levels, which means switching resets a lot of what you had got used to.
Format changes the schedule, not just the product
This is the practical heart of it. A twice-weekly patch, a daily gel and a fortnightly injection are three completely different rhythms, and the mental habits built around one do not transfer.
| Format | Typical rhythm | Level pattern |
|---|---|---|
| Patch | Changed once or twice weekly | Relatively steady while worn; falls to baseline within about a day of removal |
| Gel or spray | Daily | A daily cycle, with a skin depot smoothing it |
| Oral tablet | Daily | A daily rise and fall; subject to first-pass metabolism |
| Injection (ester) | Weekly to fortnightly | Depot release-limited; a longer, slower cycle |
Which format suits you involves clinical considerations well beyond scheduling, and that is a conversation with your clinician. What this guide covers is what changes in your record.
Why the level patterns differ so much
The published elimination figures explain most of it, and they differ by more than an order of magnitude across formats. Oral estradiol is generally reported around 13–20 hours; transdermal gel considerably longer at around 37 hours because a depot forms in the skin; injectable esters longer again, with estradiol valerate reported around 3.5 days and estradiol cypionate around 8–10 days.
The injectable figures are release-limited. They describe how slowly the ester leaves the injection-site depot, not how fast estradiol itself clears — estradiol's own half-life is short. Our Half-Life Data Table carries these entries with an evidence tag and a note on each saying which kind of figure it is.
One honest caveat about patches: a patch delivers at a near-constant rate while worn, which is not a rise-and-fall pattern at all. A curve model fits it poorly, and our data table flags it accordingly rather than pretending otherwise.
What to record through a format change
Switching formats is the moment records most often break, because people start a new log for the new format. Keep one timeline.
- The last dose on the old format — product, strength, date.
- The date of the change itself, as an event you can point to.
- The new format's strength and interval, which will not be comparable to the old one.
- How the following weeks went. This is why you keep the record — a change made in March is assessed against how April and May felt.
- Any labs, with the timing relative to your dose, which matters more for some formats than others.
The Estradiol Tracker handles multiple formats on one timeline with a dose-interval projector for each rhythm.
Progesterone runs on its own schedule
Where progesterone is part of a regimen, it frequently follows a different pattern from the estrogen component — continuous in some regimens, cyclical for part of each month in others. Published half-life figures also vary by route: oral micronized progesterone is reported around 5 hours fasted and roughly double that taken with food, which is an unusually large food effect worth being aware of when reading anything about timing.
Because the two components can run on different rhythms, keeping both on one timeline is what makes the overall pattern legible.
Frequently asked
Which HRT format is best?
Why do injectable esters last so much longer?
Does a patch give steadier levels than a gel?
Should I start a new log when I change format?
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