Zuclomifene
The long-acting, more oestrogenic geometric isomer of clomifene (roughly 38% of Clomid). It is the more strongly agonist enantiomer, with a long tissue half-life, and is relevant to PED users who separate clomifene's isomers.
01 Overview
Clomifene citrate is a mixture of two geometric isomers: zuclomifene (the zu- / cis-isomer) and enclomifene (the en- / trans-isomer). Zuclomifene is the more oestrogen-agonist isomer and clears very slowly, accumulating over weeks of dosing.
Because zuclomifene is the component blamed for some of clomifene's mood, vision and lingering oestrogenic effects, PED users increasingly prefer purified enclomifene. Zuclomifene itself is listed as a WADA-prohibited substance and is not marketed as a standalone drug.
02 Mechanism
Estrogen receptor modulator: the predominantly agonist isomer of clomifene; contributes long-lasting oestrogenic activity while still exerting some central anti-estrogen feedback effect.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| As clomifene component | 19 mg/day | Oral | Approx. 38% of a 50 mg clomifene citrate tablet; not dosed alone. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Estrogenic agonist activityMore agonist than enclomifene, contributing sustained oestrogenic effect after dosing stops. | Long-lasting oestrogenic tone | Clinical | |
| Contributes to gonadotropin riseShares some central feedback antagonism with the parent mixture. | Part of clomifene's LH/FSH effect | Observational |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Visual disturbancesBlurring, floaters and after-images associated with the long-acting isomer. | Moderate | Uncommon | Clinical | |
| Mood disturbanceLow mood and irritability attributed to the accumulating agonist isomer. | Moderate | Uncommon | Observational |