Estriol for menopause
Per Open Targets, estriol is a Phase 2 clinical candidate for menopause acting as an estrogen receptor modulator on estrogen receptor 2.
Hypothesized mechanism
Estriol acts as an estrogen receptor (ERβ) modulator, supplementing declining estrogen activity to address menopausal symptoms.
This is the model’s proposed mechanism from the sources on file, not a demonstrated causal pathway. How well the published record supports it is reflected in the rigor and plausibility dimensions of the score, and traced to the verbatim sources at the foot of the page.
How the score was reached, for this pair
The composite score is the sum of five dimensions, each scored 0 to 2 by the model from the evidence on file. Below is the sub-score this specific pair received on each, with what that dimension measures. It scored 3.8 of 10 overall, a emerging reading, from a pathway rated emerging in strength.
The model’s overall reasoning for this pair is the summary at the top of the page, and the mechanism it proposed is in the section above.
Scored for women. Female representation not stated — applicability to women uncertain (flagged for full text). (band F4, ×0.75).
Corroboration
Only a single source (Open Targets) and a single mechanistic statement are provided. There is no convergence of independent mechanistic lines, just one drug-target-indication annotation.
Rigor
The claim reflects a curated database annotation citing a PHASE_2 clinical stage, which implies human-relevant data exists, but no actual study model, data, or experimental detail is given. The evidence is a registry-level annotation rather than a described model.
Specificity
Estriol is described as an estrogen receptor modulator acting on estrogen receptor 2 (ERβ), which names a specific target. However, estriol is broadly an estrogen agonist acting across estrogen receptors, so action is not highly selective to a single named target.
Plausibility
Estrogen receptor modulation is a well-established and direct mechanistic fit for menopause, a condition of estrogen decline. The target-phenotype relationship (estrogen receptor activity in menopause) is highly coherent.
Consistency
There is only one positive mechanistic signal, so there is nothing contradictory, but consistency across multiple signals cannot be assessed with a single claim. The lone signal points coherently toward an estrogenic mechanism.
Regulatory & development status
Where this candidate sits in the US regulatory landscape: whether the drug is already FDA-approved for menopause (on-label) or approved for something else (off-label), whether the molecule is available as a generic or a single-source brand still under patent, and how far it has been studied as a therapy for this condition. Each fact is drawn from a public US source and reported beside the score; none of it is folded into the score.
This is descriptive context, not regulatory advice. It maps the landscape a 505(b)(2)route would build on (an already-approved active ingredient proposed for a new indication), but it is not a 505(b)(2) viability assessment, and says nothing about whether any particular development path is advisable. “Approved” means FDA-approved (US); approvals elsewhere are out of scope.
Approval relationship No FDA-approved label
Read from the drug’s FDA label via DailyMed, the US National Library of Medicine’s label repository. A label is only counted when it carries an FDA-approved marketing category (an NDA, ANDA, or biologic BLA); dietary supplements, homeopathics, and OTC-monograph products are not FDA-approved drugs and are excluded.
For this pair. No FDA-approved drug label was found for this molecule (it may be a supplement, a biologic, investigational, or approved only outside the US), so any use here is investigational.
Generic & patent supply Not in the Orange Book
Read from the FDA Orange Book (Approved Drug Products with Therapeutic Equivalence Evaluations), using single-ingredient products only so that patents on novel branded combination formulations are never attributed to the base molecule.
For this molecule. Absent from the Orange Book. Biologics (listed in the Purple Book instead), dietary supplements, and drugs not FDA-approved in the US do not appear here.
Clinical-trial stage, for this condition Phase 3
Read from ClinicalTrials.gov (US National Library of Medicine). A trial only counts when the drug appears as an experimental or active-comparator intervention in an interventional study of this condition; mechanistic, drug-interaction, post-marketing (Phase 4), and comparator-background uses are excluded, so this reflects the drug being tested as a therapy for menopause.
For this pair. Studied in 4 qualifying interventional trials · highest stage reached Phase 3 · active trial(s).
Layers not covered for this pair
Not covered for this pair. This layer holds documented sex-specific pharmacokinetics for a limited set of drugs, and this compound is not among them yet. A blank here means the drug is not covered by the layer, not that no sex difference exists.
More on the sex-specific pharmacokinetics layer and its sources →Not covered for this pair. The cycle-phase layer is seeded for the strongest-evidence cases so far (PMDD), and this pair is not among them yet. A blank here means the pair is not covered by the layer, not that the effect was found to be phase-independent.
More on the cycle-phase layer and its sources →Source evidence · what the pipeline ingested
These are the sources the pipeline ingested to detect and score this signal, the published literature the model actually read, each tagged by study type. Where the model combined findings the claim is marked as a synthesis (S), and where the literature disagrees the contradiction is shown (!).
Every source below belongs to this signal’s evidence arm, Pathway insights. Whel reads each drug-condition pair through four such arms, each held to its own inclusion bar; a signal is surfaced through one of them.
- 1Per Open Targets (retrieved 2026-06-16), ESTRIOL (a Small molecule) is a clinical candidate for menopause (maximum clinical stage PHASE_2); its mechanism of action is Estrogen receptor modulator on target estrogen receptor 2. Open Targets · mechanistic ↗
These are the verbatim sources the pipeline surfaced and read; they may not be the full published record for a pair, and the score reflects the strength and agreement of the evidence rather than its volume. The strength of these source types is what the rigor dimension of the score reads off. MATRIX, sex-specific pharmacokinetics, and cycle phase are separate layers the pipeline does not ingest, external cross-references reported beside the score, and they link to their own sources in their sections above.
The primary sources and pipelines this evidence is drawn from →