Enclomiphene and clomiphene: what separates them

How both drugs raise testosterone

Your brain monitors estrogen and testosterone and adjusts LH and FSH, the hormones that tell the testes to make testosterone and sperm. Clomiphene and enclomiphene are selective estrogen receptor modulators (SERMs). They block estrogen's feedback at the brain, so the pituitary releases more LH and FSH and the testes respond by making more testosterone.

Because the testes are being stimulated rather than bypassed, sperm production is generally maintained. That is the key difference from testosterone replacement, which suppresses LH and FSH and often lowers sperm counts. These drugs only work if the testes can respond, which is why they are mainly considered for secondary hypogonadism, where the signal from the brain is the weak link.

What the isomer difference means

Clomiphene citrate is roughly a blend of two isomers, molecules with the same atoms arranged as mirror images. Enclomiphene is the one that drives the rise in LH and testosterone. Zuclomiphene has weaker and partly estrogen-like effects and a much longer half-life, so it accumulates with ongoing use.

The argument for enclomiphene alone is that removing zuclomiphene might reduce side effects linked to that accumulation. That idea is plausible, but it has not been proven in large head-to-head trials in men.

What the evidence shows

Enclomiphene was studied in phase 3 trials in overweight men with secondary hypogonadism. In those trials, oral enclomiphene raised testosterone and increased LH and FSH while keeping sperm concentration in the normal range, whereas testosterone gel lowered LH, FSH and sperm output.

Clomiphene has a longer history of off-label use in men and is widely prescribed by urologists. The American Urological Association guideline notes that SERMs may be used in men with testosterone deficiency who want to preserve fertility. Neither drug has robust long-term safety data in men.

Regulatory status

Clomiphene is FDA-approved to induce ovulation in women. Use in men is off-label, which is legal and common but means FDA has not reviewed it for that purpose.

Enclomiphene is not FDA-approved for any indication. In June 2022, FDA's Pharmacy Compounding Advisory Committee voted 8 to 4 against adding enclomiphene citrate to the list of bulk substances for 503A compounding, with several members citing a lack of clinical efficacy evidence. As of FDA's May 2026 category list, enclomiphene citrate remains in Category 1, meaning it is still under evaluation and can be compounded under the interim policy while FDA reaches a final decision.

Side effects to know about

MedlinePlus advises that clomiphene can blur vision and that people should avoid driving in poor light until they know how it affects them. If you notice any visual change on either drug, stop and contact your clinician.

• Headache, hot flashes and nausea
• Mood changes or irritability
• Breast tenderness, since some estrogen rises along with testosterone
• Visual disturbances such as blurring, spots, flashes or double vision, which are uncommon but need prompt attention
• A rise in hematocrit in some men as testosterone increases

Who is unlikely to benefit

Men with primary hypogonadism, where the testes themselves are not working, usually do not respond, because higher LH cannot make damaged testes produce more testosterone. Men with very high baseline LH are in this group. Men whose low testosterone is driven by a correctable cause, such as untreated sleep apnea, heavy drinking or opioids, may do better addressing that cause first.

These medicines are also not for women outside fertility care, or for anyone with liver disease, uncontrolled thyroid or adrenal problems, or a history of blood clots without specialist advice.

How monitoring usually works

After starting, your clinician typically rechecks testosterone and estradiol within the first couple of months, along with hematocrit and a symptom review. If testosterone rises but symptoms do not improve, that is useful information too. Periodic checks continue for as long as you take the medicine, and any visual symptom prompts an immediate review rather than waiting for the next appointment.

Which might be considered

The choice depends on availability, cost, your clinician's experience and how you respond. Clomiphene has a longer track record in men; enclomiphene is the more targeted molecule but is compounded and not FDA-approved. Both require monitoring of testosterone, estradiol, hematocrit and symptoms.

HealifyMD's Enclomiphene / DHEA / Boron / Pregnenolone ODT is a compounded product that is not FDA-approved and not equivalent to any branded drug. It starts at $129/month, labs are priced separately, and your price is confirmed at the eligibility review.