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PCT & hormone control

Enclomiphene (Androxal)

The clean clomiphene isomer - raises testosterone without the estrogenic mood baggage.

1 min read 9 sources

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White tablet bottle with a black TPD label for Enclomiphene on a white podium, next to it a large glossy blue 3D molecule with branching rings in a bright lab
Phase 3 · not approved

Summary

At a glance

Sources checked on 26 Oct 2026

Testosterone after 6 weeks
604 ng/dl

highest dose in the trial, testosterone gel in comparison 500 ng/dl, baseline below 3502

With recovered sperm
7 of 7

Men previously on testosterone gel, after 3 months of enclomiphene, with gel 0 of 54

LH versus placebo
+4.66 U/l

Meta-analysis of randomised trials with clomiphene or enclomiphene5

Phase 3 trials in the registry
9 trials

all completed, as of 26 Oct 20268

  • Clomiphene is a mixture of two isomers, zuclomiphene and enclomiphene. Enclomiphene is the isolated trans isomer and acts as a modulator at estrogen receptor alpha.47
  • In the hypothalamus it blocks the feedback by estrogen. LH and FSH rise and the testes make more testosterone themselves.23
  • In men with secondary hypogonadism testosterone rose about as much as with testosterone gel. Unlike with the gel, sperm count stayed in the normal range.13
  • A meta-analysis of randomised trials found on average 273.8 ng/dl more testosterone than placebo and clearly higher LH and FSH levels.5
  • Nine phase 3 trials have been completed, there is no approval. Everything here is the state of research, not a recommendation.87
Profile

Updated June 2026

How long does it stay in the body?

Share left after one dose, calculated with a half-life of ~10 hours

Half-life ~10 hours
After 20 hours: 25 %
Hour 10 · 50 %Hour 20 · 25 %Hour 24, next dose · 18.9 %Hour 30 · 12.5 %Hour 50 · 3.1 %

Simplified model without an absorption phase, half-life from the TPD lexicon.

Class
SERM

pure trans-isomer of clomiphene

Use
Oral

1x per day

Half-life
about 10 hours
Status
Research

phase 3 completed

Sizes
12.5 to 25 mg

2 sizes in the shop

Contents 13 sections
  1. At a glance
  2. What is Enclomiphene?
  3. How it works
  4. Enclomiphene vs Clomid
  5. Dosing
  6. What the research shows
  7. Research status
  8. Side effects
  9. Storage
  10. Related compounds
  11. FAQ
  12. Glossary
  13. Sources

What is Enclomiphene?

Clomiphene consists of two isomers: zuclomiphene (long-acting, estrogenic) and enclomiphene (short-acting, anti-estrogenic). Enclomiphene is the isolated, "clean" trans-isomer of clomiphene - it keeps the HPTA-stimulating effect but drops the estrogenic, mood-lowering part (the zuclomiphene).

This information is for research and educational purposes only. No medical advice.

How it works

Like clomiphene, enclomiphene blocks the estrogen receptors in the hypothalamus and thereby drives LH and FSH up - boosting the body's own testosterone production. The difference: without the long-acting zuclomiphene, estrogenic side effects (mood, vision) occur less often. The substance also clears faster.

Where it acts

Where enclomiphene acts

Tap a point or a card. Colour = receptor, grey = observed in trials.

  1. Hypothalamus and pituitary

    Blocks estrogen feedback, LH +4.66 and FSH +4.59 U/l versus placebo5

    ERα
  2. Testes

    More own testosterone, sperm production is preserved3

    Observed in trials

Targets in the ChEMBL database7

Compound CHEMBL954: one recorded mechanism, Modulator, direct binding.

Estrogen receptor alpha
Gene
ESR1
UniProt
P03372
ChEMBL
CHEMBL206
Action
Modulator, direct binding
Transparent glass cell with round docking sites where two blue 3D molecules dock, a glowing strand leads from the cell to a group of glass tubes
Enclomiphene blocks estrogen feedback and the hormone axis ramps up. Symbolic image.

Enclomiphene vs Clomid

  • Enclomiphene: cleaner profile, fewer mood and vision side effects, shorter half-life - also popular as an ongoing TRT alternative because fertility is preserved.
  • Clomid: cheaper and more widely available, but with the estrogenic zuclomiphene part.

Comparison

Stimulate or replace own testosterone

Compounds around the hormone axis, as described in the TPD lexicon. Tap a card to open its entry.

Pure trans isomer Enclomiphene (Androxal) ERα
Mixture of two isomers Clomid (Clomiphene) ERα Estrogen receptor modulator Tamoxifen (Nolvadex) ERα Acts directly on the testes like LH HCG LH receptor Testosterone from outside Testosterone Enanthate AR

Simplified: enclomiphene and clomiphene stimulate own production via LH and FSH, testosterone from outside suppresses it. In the trials enclomiphene kept sperm in the normal range, the gel did not. 34

Dosing

Dosing

Dosing, titration and syringe

Loading the dosing information …

  • Getting started and stepping up, drawn as a staircase
  • Units on the U-100 syringe for every step
  • How long one vial lasts

What the research shows

Wiehle et al. showed in several studies (BJU International 2013, Fertility and Sterility 2014) that enclomiphene reliably raises testosterone in secondary hypogonadism while - unlike topical testosterone - preserving sperm production. That makes it an interesting option when fertility is a concern.

Study results

What the trials measured

Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.

Testosterone in the blood25

In ng/dl, men with secondary hypogonadism

Morning level after 6 weeks2 44 men, baseline below 350
Testosterone gel 500 ng/dl
Enclomiphene, highest dose in the trial 604 ng/dl
More than on placebo5 Meta-analysis of randomised trials
Clomiphene or enclomiphene 274 ng/dl

In the 6-week trial enclomiphene and gel did not differ significantly, the gel varied more and suppressed LH. In the meta-analysis testosterone did not differ between the modulators and testosterone gel.

Control hormones versus placebo5

Mean difference in U/l, meta-analysis of randomised trials

LH5
Clomiphene or enclomiphene 4.66 U/l
FSH5
Clomiphene or enclomiphene 4.59 U/l

On testosterone gel LH and FSH fall, on enclomiphene they rise. The two phase 3 trials also showed this after 16 weeks.

Sperm after switching from testosterone gel4

Share of men with more than 20 million sperm per ml after 3 months

After 3 months4 Gel 0 of 5, enclomiphene 7 of 7
Testosterone gel 0%
Enclomiphene 100%

Percentages calculated from the case numbers in the abstract, very small trial with 12 men. After 6 months 6 of 6 with enclomiphene, 2 of 5 with gel. In the phase 3 trials sperm concentration stayed in the normal range with enclomiphene and fell markedly with gel.

Row of tall glass tubes with clear liquid, each holding a glowing translucent organ model on a metal rail in the lab
Trials in men with secondary hypogonadism. Symbolic image.

Research status

Where the research stands

Enclomiphene has nine completed phase 3 trials in men with secondary hypogonadism, yet there is no approval. As of 26 Oct 2026. 8

  1. Preclinical Modulator at estrogen receptor alpha
  2. Phase 1 9 trials, 9 completed
  3. Phase 2 1 trial, 1 completed
  4. Phase 3 9 trials, 9 completed
  5. Approval not yet
1,535 participants in phase 3 Planned figures for running trials Not approved. ChEMBL lists enclomiphene with phase 3 as the highest phase and no approval year. Clomiphene, the mixture of both isomers, is a separate compound.7
Show all 10 phase 2 and 3 trials on a timelineHide timeline 10 completed 0 running 1 with results
Phase 2
Phase 3

Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026. Phase 1: 9 trials on safety and pharmacokinetics, not shown as bars.

Side effects

  • Overall milder than Clomid due to the missing zuclomiphene.
  • Rarely headache, nausea.
  • Visual disturbances much rarer than with clomiphene.

Storage

Store dry and protected from light. Out of reach of children.

Three white tablet bottles and a folded light blue towel on a white shelf
Store dry and protected from light. Symbolic image.
Level · Enclomiphene (Androxal)

How the level builds up

One dose per day: each dose adds to what is left of the previous one.

Lexicon: Oral, 1x per day
Peak 1.23×Trough 0.23×
Day 1 · 2. dose
1.19× of the first dose
Plateau
from Day 1

96 % of the plateau after dose 2

Peak
1.23×

of the first dose

Trough
0.23×

before the next dose

Simplified model, values relative to the first dose, no dosing information. Dashed: the first dose alone, green: the plateau.

Related

Related compounds

Same targets, blends with Enclomiphene (Androxal) or a different path: all in the TPD lexicon.

Enclomiphene (Androxal)
Clomid (Clomiphene) Contains enclomiphene and zuclomiphene Tamoxifen (Nolvadex) Another estrogen receptor modulator Arimidex (Anastrozole) Lowers estrogen via aromatase, a different route HCG Stimulates the testes directly Testosterone Enanthate Replaces testosterone, suppresses own production

FAQ

Common questions about Enclomiphene (Androxal)

Short answers, each backed by the sources below.

Is enclomiphene approved?

No. Nine phase 3 trials in men with secondary hypogonadism have been completed, but ChEMBL lists it with phase 3 as the highest phase and no approval. Only clomiphene, the mixture of both isomers, is approved.87

How does enclomiphene differ from clomiphene?

Clomiphene is a mixture of zuclomiphene and enclomiphene. Enclomiphene is the isolated trans isomer. In an analysis of 66 men who switched from clomiphene to enclomiphene testosterone rose similarly, estradiol rose less and side effects such as lower libido, lower energy and mood swings occurred less often. The odds ratio for side effects was 0.18.46

How does enclomiphene raise testosterone?

It acts as a modulator at estrogen receptor alpha and blocks the feedback by estrogen in the hypothalamus. The pituitary releases more LH and FSH and the testes make more testosterone. In a 6-week trial the morning level with the highest dose was 604 ng/dl, with testosterone gel 500 ng/dl. The effect lasted at least one week after stopping.72

What happens to sperm?

In two 16-week phase 3 trials sperm concentration stayed in the normal range with enclomiphene and fell markedly with testosterone gel. In a small trial in men who had used gel before, all 7 on enclomiphene were above 20 million per ml after 3 months, none of 5 on gel.34

What does a meta-analysis say?

A meta-analysis of randomised trials with clomiphene or enclomiphene found on average 273.8 ng/dl more testosterone, 4.66 U/l more LH and 4.59 U/l more FSH than placebo. Compared with testosterone gel testosterone did not differ, LH and FSH were clearly higher.5

Which side effects have been described?

The checked abstracts give no frequencies. In the 6-week trial thyroid, stress hormones, blood lipids and bone markers stayed unchanged, IGF-1 fell more than on gel. Compared with clomiphene side effects occurred less often in one analysis.26

Glossary

Terms explained briefly

Dotted words in the text open these explanations directly.

FSH
Follicle-stimulating hormone. Drives sperm production in men.
HPTA
Axis of hypothalamus, pituitary and testes that controls natural testosterone production.
Isomer
Molecule with the same formula but a different spatial arrangement. It can act quite differently.
LH
Luteinising hormone from the pituitary. Signals the testes to make testosterone.
Oligospermia
Too few sperm in the ejaculate.
PCT
Post cycle therapy, the phase after stopping in which own hormone production is meant to restart.
Secondary hypogonadism
Too little testosterone because the control from pituitary and hypothalamus is too weak, not the testes themselves.
SERM
Selective estrogen receptor modulator. Acts like estrogen or against it depending on the tissue.
TRT
Testosterone replacement therapy with outside testosterone. Suppresses own production and sperm.
Zuclomiphene
The second isomer in clomiphene, besides enclomiphene.

Evidence

Sources

Show all 9 sourcesHide sources 6 Studies1 Trial registry2 Database checked 26 Oct 2026

Studies

  1. Phase 2: testosterone rises, sperm is preserved

    Wiehle et al., Fertility and Sterility, 2014

    DOI 10.1016/j.fertnstert.2014.06.004 PMID 25044085 NCT01270841
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed, ClinicalTrials.gov
  2. Three doses against testosterone gel over 6 weeks

    Wiehle et al., BJU International, 2013

    DOI 10.1111/bju.12363 PMID 23875626
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  3. Two phase 3 trials against testosterone gel in overweight men

    Kim et al., BJU International, 2016

    DOI 10.1111/bju.13337 PMID 26496621
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  4. Sperm after switching from testosterone gel, 12 men

    Kaminetsky et al., Journal of Sexual Medicine, 2013

    DOI 10.1111/jsm.12116 PMID 23530575
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  5. Meta-analysis: clomiphene or enclomiphene in hypogonadism

    Hohl et al., Archives of Endocrinology and Metabolism, 2025

    DOI 10.20945/2359-4292-2025-0093 PMID 41066380
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  6. Enclomiphene against clomiphene in 66 men, analysis

    Saffati et al., Translational Andrology and Urology, 2024

    DOI 10.21037/tau-24-238 PMID 39434750
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed

Trial registry

  1. Trials on ClinicalTrials.gov

    ClinicalTrials.gov, U.S. National Library of Medicine

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2

Database

  1. Mechanism and development status in ChEMBL

    ChEMBL, EMBL-EBI (CHEMBL954)

    Checked 26 Oct 2026 via ChEMBL
  2. Structure of enclomiphene in PubChem

    PubChem, U.S. National Library of Medicine (CID 1548953)

    Checked 26 Oct 2026 via PubChem

In the shop

Enclomiphene (Androxal) in the catalog

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