Enclomiphene
PharmaceuticalThe small divergence reflects the overall alignment between clinical studies and the community: enclomiphene measurably raises testosterone and gonadotropins [s1, s2], but users report variable subjective benefit and relevant side effects such as estradiol elevation and mood changes [c3, c4], keeping both scores moderate.
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TL;DR
Enclomiphen demonstrably raises testosterone, LH, and FSH in men with secondary hypogonadism — supported by multiple Phase II RCTs and a 2024 meta-analysis. Critically: the EMA rejected its approval, it is not a licensed medication in Germany, and purchasing it without a prescription is a legal offense. Despite normalized lab values, many users report no improvement in libido or energy; elevated estradiol and mood swings are common complaints. Without regular lab monitoring (testosterone, estradiol, PSA, liver enzymes), self-administration is not justifiable.
Description
Enclomiphene is the trans-isomer of clomiphene, a SERM that increases LH, FSH, and endogenous testosterone in men with secondary hypogonadism without suppressing fertility [s1, s2].
Enclomiphene (also enclomifene) is the trans-stereoisomer of clomiphene citrate. Clomiphene citrate consists of approximately 62% enclomiphene and approximately 38% zuclomiphene (the cis-isomer) [s3]. Enclomiphene is considered the pharmacologically active component for stimulation of the gonadotropin axis in men, while zuclomiphene, as a weak estrogen agonist, is thought to account for some of the adverse effects of the combination preparation (e.g., mood swings, persistently elevated estradiol) [s3]. The company Repros Therapeutics developed enclomiphene as a pure substance under the brand name Androxal for the treatment of secondary hypogonadism in men. Several Phase II and Phase III studies were completed; however, the FDA declined approval, and the EMA also refused marketing authorization for the preparation EnCyzix [s9, s11]. The key difference compared to testosterone replacement therapy (TRT) is that enclomiphene stimulates endogenous testosterone production while preserving spermatogenesis, whereas exogenous testosterone suppresses gonadotropins via negative feedback, leading to oligospermia or azoospermia [s4, s5]. Clinical studies demonstrated normal sperm concentrations under enclomiphene, while testosterone gel was associated with a marked decline in spermatogenesis [s4]. Despite lacking regulatory approval, enclomiphene is available in the DACH region through grey-market and research chemical suppliers as well as select mail-order pharmacies without a prescription, which is legally problematic [s10]. In the biohacking and bodybuilding communities, the substance is used as PCT (post-cycle therapy) following anabolic steroid cycles [s12].
Legal Status (DE)
In Germany, enclomiphene is not an approved medicinal product. The EMA refused marketing authorization (EnCyzix) [s9]. As a single isomer of prescription-only clomifene, enclomiphene is likewise to be classified as prescription-only. Purchase without a prescription constitutes a regulatory offense; illegal mail-order trade is a criminal offense [s10]. Comparable legal status applies in Austria and Switzerland. Use as a dietary supplement is not permitted.
Mechanism of Action
Enclomiphene is a selective estrogen receptor modulator (SERM) that acts as an estrogen receptor antagonist in the hypothalamus and pituitary gland [s1, s3]. By blocking negative estrogenic feedback on the hypothalamus, pulsatile GnRH secretion is disinhibited. This leads to increased release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary [s1, s2]. LH stimulates Leydig cells in the testes to synthesize testosterone; FSH supports Sertoli cells and thereby spermatogenesis [s1, s2]. In contrast to TRT, the hypothalamic-pituitary-gonadal (HPG) axis remains intact and even enhanced under enclomiphene, rather than being suppressed [s4, s5]. Unlike the parent compound clomiphene citrate, enclomiphene lacks the zuclomiphene isomer, which acts as an estrogen agonist at other tissues (e.g., uterus, liver) and possibly in the CNS. Whether this results in fewer mood-related side effects than clomiphene has not been conclusively demonstrated in clinical studies [s3, s6]. Pharmacokinetically, enclomiphene has a short half-life (hours), whereas zuclomiphene accumulates for weeks. This explains why enclomiphene is cleared more rapidly after discontinuation than clomiphene citrate [s3].
Dosing
Sekundärer Hypogonadismus (Testosteronrestauration)
- Dose
- 12.5–25 mg daily
- Frequency
- 1× täglich oral
- Route
- oral
- Duration
- 3–6 Monate (Studiendauer), Langzeitdaten fehlen
- Timing
- Morning, fasted or with a meal
- With food
- optional
Post-Cycle-Therapie (PCT) nach Anabolika-Zyklus
- Dose
- 12.5–25 mg daily
- Frequency
- 1× täglich oral
- Route
- oral
- Duration
- 4–6 Wochen
- Timing
- Begin after anabolic levels have subsided
- With food
- optional
Pharmacodynamic/PK-Studie (niedrigste wirksame Dosis)
- Dose
- 6.25 mg daily
- Frequency
- 1× täglich oral
- Route
- oral
- Duration
- 4–6 Wochen
- Timing
- Morning
- With food
- optional
In clinical studies, doses of up to 50 mg/day were tested; 25 mg/day is considered the upper standard dose with an acceptable safety profile [s1]. Higher doses increase the risk of visual disturbances and estradiol elevation. No official upper limits have been established by regulatory authorities, as the substance is not approved.
Enclomiphene is not an approved medicinal product in Germany. Self-medication without medical supervision and laboratory monitoring (LH, FSH, testosterone, estradiol, PSA) is not recommended [s9, s10].
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Hitzewallungen (Hot Flashes) Estrogen receptor antagonism in the hypothalamus can trigger vasomotor responses, similar to women undergoing anti-estrogenic therapy [s6]. | gelegentlich | leicht |
| Stimmungsschwankungen, Reizbarkeit, Angst Both clinical and user reports describe mood changes; unclear whether caused by estradiol fluctuations or direct CNS effects [s6, c3]. | gelegentlich | moderat |
| Kopfschmerzen Described in clinical studies and case reports; mechanism unclear [s6]. | gelegentlich | leicht |
| Übelkeit Gastrointestinal complaints were recorded as an occasional adverse effect in Phase II studies [s6]. | gelegentlich | leicht |
| Sehstörungen (verschwommenes Sehen, Lichtempfindlichkeit) Known class-effect adverse reaction of clomiphene derivatives (SERMs). Reported less frequently with enclomiphene than clomiphene, but documented. Discontinuation is recommended immediately upon occurrence [s6, s3]. | selten | moderat |
| Erhöhtes Östradiol (E2) Stimulation of Leydig cells increases aromatase activity alongside testosterone production, leading to measurable E2 elevation [s1, s4]. Clinically relevant in individuals with genetic predisposition to gynecomastia. | häufig | leicht |
| Erektionsstörungen (vereinzelt berichtet) Individual user reports describe erectile dysfunction with enclomiphene, possibly due to an unfavorable testosterone/estradiol ratio [c3]. | selten | moderat |
| Erhöhung von Cortisol und Prolaktin (vereinzelt) One user reported increases in cortisol and prolactin at 25 mg/day [c3]. Mechanism unclear; no systematic data available. | selten | leicht |
Contraindications
Clomiphene derivatives are hepatically metabolized; impaired liver function may reduce clearance and lead to accumulation of toxic metabolites [s6].
Enclomiphene can cause visual disturbances; in the presence of pre-existing ocular conditions, the risk of irreversible damage may be increased [s6].
As a SERM with tissue-specific estrogenic activity, theoretically contraindicated in hormone-sensitive malignancies; no specific clinical data in males [s3].
In primary hypogonadism, Leydig cells are non-functional; stimulation of the HPG axis by enclomiphene is ineffective [s1, s2].
Clomiphene is approved for female fertility, but uncontrolled hormonal effects from unintentional exposure of the female partner should be avoided [s3].
Interactions
Synergistic
Combined use may additively increase testosterone and sperm production; used in PCT protocols, however without sufficient clinical evidence [c2].
Combination may attenuate excessive estradiol rise under enclomiphene; used in clinical protocols, evidence from small studies [s7].
Zinc supports endogenous testosterone production and is frequently used alongside enclomiphene in clinical protocols to enhance hormonal optimization. The combination is included in compounded formulations such as Elevate-T.
Magnesium glycinate is recommended alongside enclomiphene in hormone optimization protocols to support muscle function and sleep quality. No direct pharmacokinetic interaction has been established.
DIM may attenuate excessive estrogenic effects under enclomiphene by directing estrogen metabolism toward weaker estrogen metabolites. The combination is used in practice, however clinical data are limited.
Ashwagandha KSM-66 may additively increase LH levels and testosterone and is mentioned alongside enclomiphene in testosterone optimization protocols. Clinical combination studies are currently lacking.
DHEA as a hormone precursor can be used together with enclomiphene in testosterone optimization formulations. Since DHEA is converted to testosterone and estrogen, estradiol levels should be monitored.
Gonadorelin and enclomiphene act at different levels of the HPG axis and can be used together to maintain endogenous testosterone production. Gonadorelin dosing must be pulsatile to avoid pituitary desensitization.
Boron can support testosterone levels by inhibiting SHBG and influencing hormone metabolism, and is used in testosterone optimization protocols. A direct combination with enclomiphene is anecdotally reported, but clinical data are lacking.
Enclomiphene increases testosterone and lowers IGF-1, while GHRH peptides promote growth hormone secretion and increase IGF-1. The combination may enable more comprehensive hormonal optimization.
Caution
Concurrent administration suppresses the HPG axis and negates the mechanism of action of enclomiphene [s1, s4].
Additive estrogen receptor blockade possible; no clinical data on the combination [s3].
Enclomiphene is metabolized via CYP3A4; inhibitors may increase plasma levels and potentiate side effects [s3].
Since DHEA can be aromatized to estrogen, concurrent intake with enclomiphene carries a risk of elevated estradiol levels when aromatase activity is high. Regular lab monitoring is recommended.
Studies
Tier A — High Evidence
Outcome: Morning serum testosterone, E2, LH in obese hypogonadal men vs. testosterone gel
Effect Size: Enclomiphene increased testosterone and sperm concentration; testosterone gel suppressed spermatogenesis.
Outcome: 24-h LH and total testosterone profiles (enclomiphene 6.25/12.5/25 mg vs. transdermal testosterone)
Effect Size: All enclomiphene doses increased LH; testosterone normalized (12.5 mg: 412 ng/dL; 25 mg: 520 ng/dL). Testosterone gel completely suppressed LH.
Outcome: Sperm concentration and testosterone levels compared to testosterone gel
Effect Size: Enclomiphene maintained normal sperm concentrations; testosterone gel significantly reduced sperm count (p<0.001).
Outcome: Total testosterone, LH, FSH compared to placebo and testosterone gel
Effect Size: Significantly elevated LH, FSH, and total testosterone values vs. placebo; LH and FSH significantly higher than under testosterone gel.
Tier B — Moderate Evidence
Outcome: Mechanism, efficacy, and safety profile of enclomiphene in clinical practice
Effect Size: Summary of available data; no primary endpoint.
Outcome: Clinical recommendations for the potential use of enclomiphene in male hypogonadism
Effect Size: Recommendation for use under medical supervision; no independent effect size.
Tier C — Low Evidence
Outcome: Practice protocol for enclomiphene, clomiphene, and anastrozole in male hypogonadism and fertility
Effect Size: No primary study data; clinical recommendations.
Community Evidence
Top reported benefits
- Marked testosterone increase (doubling of baseline values in multiple reports)
- Preservation of fertility / sperm production compared to TRT
- Increased libido and motivation in responders
- Effective PCT option after anabolic steroid or SARM cycles
- Rapid onset of action (1–4 weeks)
Top reported issues
- Elevated estradiol with associated symptoms (water retention, mood swings)
- Limited improvement in libido and body composition despite normalized lab values
- Erectile dysfunction and anxiety in individual users
- Loss of efficacy in some users after several months
- Unclear long-term safety and lack of medical supervision
In German-speaking regions, enclomiphene is distributed without a prescription through grey-market pharmacies, despite not being an approved medicinal product [s10]. Some bodybuilding forum users assess the benefit-risk ratio more critically than English-language communities, as the anabolic effect is perceived as markedly inferior compared to TRT [c4]. Lack of medical monitoring (PSA, liver enzymes, eyes) is a repeatedly cited concern [c1, c4].
Scientific Sources
- Testosterone restoration using enclomiphene citrate in men with secondary hypogonadism: a pharmacodynamic and pharmacokinetic study
Wiehle R, Cunningham GR, Pitteloud N, et al. (2013). BJU InternationalAPMID:24131556DOI - Strafbarkeit bei Online-Bestellung von Clomifen und Enclomifen im Inland
frag-einen-anwalt.de (Rechtsanwalt) (2022). frag-einen-anwalt.deBLink - Androxal (enclomiphene): FDA approval history
Drugs.com editorial (2023). Drugs.comBLink - Illegal and falsified medicines self-administrated in not approved post-cycle therapy after the cessation of anabolic-androgenic steroids – qualitative analysis
Frontiers in Chemistry authors (2025). Frontiers in ChemistryBDOI - Clomiphene or enclomiphene citrate for the treatment of male hypogonadism: a systematic review and meta-analysis of randomized controlled trials
Santos MAS, Oliveira R, Bessa J, et al. (2024). Archives of Endocrinology and MetabolismAPMID:41066380DOI - Enclomifene – Wikipedia
Wikipedia contributors (2024). WikipediaDLink - Enclomiphene citrate stimulates testosterone production while preventing oligospermia: a randomized phase II clinical trial comparing topical testosterone
Wiehle RD, Fontenot GK, Wike J, et al. (2014). Fertility and SterilityAPMID:25044085DOI - Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement
Kim ED, Crosnoe L, Bar-Chama N, et al. (2016). BJU InternationalAPMID:26496621DOI - Enclomiphene in Clinical Practice: Mechanism, Efficacy, and Safety Consideration
News-Medical Life Sciences (Review) (2024). News-Medical.netBLink - Fertility-Friendly Hormone Therapy in Men: Guide to Enclomiphene, Clomiphene, and Anastrozole
Men's Reproductive Health (clinical review) (2023). mensreproductivehealth.comBLink - British Society of Sexual Medicine: Position Statement for the Potential Use of Enclomiphene in the Treatment of Male Hypogonadism
BSSM Working Group (2025). World Journal of Men's HealthADOI - EnCyzix – Wissenschaftliche Schlussfolgerungen und Begründung der EMA für die Versagung der Marktzulassung
European Medicines Agency (2018). European Commission – Community RegisterALink
Community Sources
Storage
Unopened
Store in a dry place at room temperature (15–25 °C), protected from light and moisture.
Opened
Keep packaging tightly closed; do not remove tablets or capsules from the original packaging.
Notes
As enclomiphene is not approved in Germany, no official storage guidance from regulatory authorities is available. Follow manufacturer specifications.