Enclomiphene
Enclomiphene citrate
Enclomiphene citrate is the trans-isomer of clomiphene citrate, a selective estrogen receptor modulator. It blocks estrogen feedback at the hypothalamus and pituitary, which raises luteinising hormone and follicle-stimulating hormone signalling, and in turn stimulates the testes to produce more of the body's own testosterone.
- Drug class
- Selective Estrogen Receptor Modulator (SERM)
- Route
- Oral
- Common form
- Capsule / tablet
- Regulatory status
- Not FDA-approved [NEEDS CITATION]
- Prescription status
- Prescription only
- Controlled substance
- No
Educational reference. Nothing on this page is a prescription, a diagnosis, or a promise of an individual result.
Enclomiphene Basics
What the drug is, how it is taken, and the facts a clinician establishes before prescribing it.
Clomiphene citrate is a mixture of two isomers: zuclomiphene and enclomiphene. Enclomiphene is the shorter-acting, more estrogen-antagonistic of the two. Isolating it is the reason it is discussed separately from clomiphene in the men's health literature — the zuclomiphene fraction accumulates over weeks and carries most of the estrogenic activity.
Because enclomiphene works upstream on the hypothalamic-pituitary-gonadal axis rather than supplying hormone from outside the body, testosterone produced under it is endogenous. That distinction is the central reason it appears in discussions of secondary hypogonadism in men who wish to preserve testicular function and fertility.
Enclomiphene is taken orally, typically once daily or on an alternating-day schedule, and is dosed by a clinician against baseline and follow-up laboratory values [NEEDS CITATION]. It is not an over-the-counter supplement and it is not appropriate for every man with low testosterone — primary testicular failure, for example, does not respond to upstream signalling.
- Axis targeted
- Hypothalamic-pituitary-gonadal
- Hormone source
- Endogenous (own production)
- Typical monitoring
- Total & free testosterone, LH, FSH, estradiol, CBC
How Enclomiphene Works
Enclomiphene acts on the signals involved in testosterone production. Here is how that process is understood.
Estrogen feedback is blocked centrally
Enclomiphene occupies estrogen receptors in the hypothalamus and pituitary. The brain reads circulating estrogen as lower than it is and stops suppressing gonadotropin release.
LH and FSH signalling rises
Gonadotropin-releasing hormone pulses increase, and the pituitary secretes more luteinising hormone and follicle-stimulating hormone [NEEDS CITATION].
The testes respond
Leydig cells increase testosterone synthesis under LH; Sertoli cells support spermatogenesis under FSH. Output is the body's own, which is why testicular volume and sperm parameters are generally maintained.
Enclomiphene Uses
Understanding the difference between an approved medicine, an unapproved product and a research finding helps you ask informed questions.
Approved uses
United States, as of the review date above.- Enclomiphene citrate has no current FDA-approved indication as a single agent [NEEDS CITATION].
- Clomiphene citrate — the isomer mixture — is FDA-approved for ovulation induction in women, not for men [NEEDS CITATION].
Clinical evaluation
Enclomiphene is not an FDA-approved drug. An individual evaluation is essential.- A clinician evaluates the cause of low testosterone before discussing treatment options.
- Fertility goals should be part of the discussion before starting hormonal treatment.
- Tell your clinician about prior testosterone, anabolic steroid and other hormone use.
Studied / investigational
Reported in the literature; not a treatment recommendation.- Testosterone response versus topical testosterone in overweight men with secondary hypogonadism [NEEDS CITATION].
- Sperm concentration and semen parameters during treatment [NEEDS CITATION].
- Metabolic markers, including insulin sensitivity and lipids [NEEDS CITATION].
Drug Category
Where enclomiphene sits pharmacologically, and which drugs it is most often confused with.
Selective Estrogen Receptor Modulator (SERM)
A selective estrogen receptor modulator binds estrogen receptors and acts as an antagonist in some tissues and an agonist in others. That tissue selectivity is the defining feature of the class: enclomiphene antagonises estrogen signalling in the hypothalamus and pituitary, which is where its effect on gonadotropins comes from.
- Clomiphene citrate
- Isomer mixture containing enclomiphene
- Tamoxifen
- SERM, primarily oncology use
- Raloxifene
- SERM, bone and breast tissue selectivity
Enclomiphene Side Effects
The potential effects below need to be discussed with your clinician. Some concerns come from clomiphene or other SERMs and cannot establish how often they occur with enclomiphene.
Commonly reported
- Headache
- Nausea
- Hot flashes or flushing
- Mood changes or irritability
- Fatigue
- Increased haematocrit
Less common or more serious considerations
- Visual disturbance, including blurred vision or floaters — reported with clomiphene and a reason to stop and seek review
- Elevated liver enzymes
- Thromboembolic events, reported rarely with SERMs
- Gynecomastia or breast tenderness
- Testicular discomfort
Contraindications
Health conditions to discuss before treatment. Your clinician considers your individual risks.
Contraindications
- Known hypersensitivity to enclomiphene, clomiphene, or their excipients
- Active or prior hormone-sensitive malignancy without oncology clearance
- Uncontrolled liver disease
- History of thromboembolic disease without specialist review
- Primary testicular failure, where upstream stimulation cannot work
Relevant health conditions
- Erythrocytosis or baseline haematocrit above range
- Untreated obstructive sleep apnoea
- Depression or bipolar disorder — mood effects are reported
- Migraine with visual aura
Medication Interactions
Medicines and supplements to discuss with your clinician before treatment.
- Exogenous testosterone
- Suppresses the axis enclomiphene acts on; concurrent use requires a clear clinical rationale.
- Aromatase inhibitors
- Overlapping effect on estradiol; combined use can drive estradiol too low.
- hCG and gonadotropins
- Additive stimulation of testosterone production; monitor haematocrit and estradiol.
- Anticoagulants
- Reported interaction risk with SERMs; monitoring may be required [NEEDS CITATION].
Warnings & Precautions
Safety considerations and the follow-up to discuss with your clinician.
- Baseline and follow-up laboratory testing
- Treatment decisions rest on morning total and free testosterone, LH, FSH, estradiol, and a complete blood count, repeated on schedule [NEEDS CITATION].
- Visual symptoms
- Blurred vision, spots, or flashes should prompt discontinuation and clinical review rather than continued dosing.
- Fertility is not contraception
- Preserved or improved sperm parameters mean fertility is possible during treatment. It is not a fertility treatment and it is not birth control.
- Not for use in women or anyone under 18
- This profile addresses adult men. Use outside that population is a separate clinical question.
What the Research Shows
Summaries of published work, kept plain. Numbers are reported as the authors reported them; nothing here predicts an individual outcome.
- Testosterone levels
- BJU International2016[NEEDS CITATION]
- Randomised comparison of enclomiphene citrate against topical testosterone in overweight men with secondary hypogonadism reported that both raised morning total testosterone into the normal range.
- LH and FSH response
- Journal of Clinical Endocrinology & Metabolism2014[NEEDS CITATION]
- Enclomiphene raised luteinising hormone and follicle-stimulating hormone, consistent with central estrogen-receptor antagonism, whereas exogenous testosterone lowered both.
- Sperm concentration
- Fertility and Sterility2015[NEEDS CITATION]
- Sperm concentration was maintained in men on enclomiphene over the treatment period, while the topical-testosterone comparator group showed reductions.
- Comparison with exogenous testosterone
- Translational Andrology and Urology2019[NEEDS CITATION]
- Reviews of oral SERM therapy versus testosterone replacement describe similar total-testosterone effects with preservation of gonadotropin signalling, and call for longer-duration trials.
Straight answers.
Understand the options, the evaluation and what happens next.
Sources & References
Research and reference material for this educational draft. Clomiphene labeling is not an enclomiphene product label.
- 1
Kim ED, et al. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone.
BJU International2016Primary research - 2
Wiehle RD, et al. Enclomiphene citrate stimulates testosterone production while preventing oligospermia: a randomized phase II clinical trial.
Fertility and Sterility2014Primary research - 3
Clomiphene citrate — FDA prescribing information.
U.S. Food and Drug Administration[NEEDS CITATION]Prescribing information - 4
Endocrine Society clinical practice guideline: testosterone therapy in men with hypogonadism.
Journal of Clinical Endocrinology & Metabolism2018Clinical guideline - 5
American Urological Association guideline: evaluation and management of testosterone deficiency.
AUA2018Clinical guideline
Editorial & Medical Notice
Caesar publishes educational reference material. It is not a diagnosis, a prescription, or a promise of an individual result. Treatment decisions belong to you and a licensed physician who has reviewed your history and laboratory work. This review draft requires source verification and medical-director sign-off before publication.
