Enclomiphene
A selective estrogen receptor modulator (SERM) that raises testosterone while preserving fertility
Quick Answer
Enclomiphene citrate is the trans-isomer of clomiphene that stimulates natural testosterone production by blocking estrogen receptors in the hypothalamus. Clinical trials showed it increased testosterone to ~600 ng/dL at 25mg daily while preserving sperm counts (unlike TRT which suppresses fertility). A 2024 meta-analysis found SERMs significantly improved testosterone by ~274 ng/dL compared to placebo. Enclomiphene is particularly suitable for younger men with secondary hypogonadism who want to preserve fertility.
Medium Evidence
Good studies, but more research needed
Safety: Enclomiphene has shown a favorable safety profile in clinical trials but is not yet FDA-approved. It preserves fertility unlike TRT but has less long-term safety data.
What Is This?
Enclomiphene citrate is a selective estrogen receptor modulator (SERM) that blocks estrogen receptors in the hypothalamus, triggering increased release of GnRH, LH, and FSH, which in turn stimulates natural testosterone production.
How it differs from clomiphene: Clomiphene (Clomid) contains two isomers: enclomiphene (trans) and zuclomiphene (cis). Enclomiphene is the active isomer responsible for testosterone stimulation. Zuclomiphene has estrogenic effects that may cause side effects. Enclomiphene alone may be better tolerated.
Why it preserves fertility: Unlike TRT, which suppresses LH and FSH (shutting down natural production and spermatogenesis), enclomiphene increases LH and FSH. This maintains or enhances sperm production while raising testosterone.
Who it is for:
- Men with secondary hypogonadism (low testosterone due to pituitary/hypothalamic dysfunction)
- Men who want to improve testosterone while preserving fertility
- Men wanting to avoid the commitment of TRT
- Those with borderline low testosterone and symptoms
- Primary hypogonadism (testicular failure), testes cannot respond to increased LH
- Men already on TRT (different mechanism, not additive)
- Women (different indication)
How It Works
Mechanism of Action: Estrogen provides negative feedback to the hypothalamus, suppressing GnRH release. Enclomiphene blocks estrogen receptors in the hypothalamus, removing this negative feedback. The result: increased GnRH → increased LH and FSH → increased testicular testosterone production.
Clinical Trial Evidence: Phase II trials enrolled men with secondary hypogonadism (testosterone <350 ng/dL, LH <12 IU/L). After 6 weeks of enclomiphene 25mg daily:
- Mean testosterone reached 604 ± 160 ng/dL (vs 500 ± 278 ng/dL with testosterone gel)
- LH and FSH increased above normal range
- Effects persisted for at least 1 week after stopping
Meta-Analysis (2024): A systematic review and meta-analysis found SERM therapy (clomiphene/enclomiphene) significantly improved total testosterone by 274 ng/dL, LH by 4.66 IU/L, and FSH by 4.59 IU/L compared to placebo.
Advantages Over TRT:
- Preserves fertility
- Maintains natural hormonal axis function
- Easier to discontinue (natural production not suppressed)
- Lower hematocrit increase risk
How to Start
Confirm secondary hypogonadism
Enclomiphene works for secondary hypogonadism (low testosterone with low or inappropriately normal LH). Get blood work: total testosterone, free testosterone, LH, FSH, estradiol. If LH is already high, testes may not respond.
Tips:
- •Low T + Low/Normal LH = secondary hypogonadism (enclomiphene candidate)
- •Low T + High LH = primary hypogonadism (enclomiphene unlikely to work)
- •Rule out pituitary tumors if LH is very low (prolactin, MRI)
- •Confirm with two morning testosterone tests
Source enclomiphene
Enclomiphene is not FDA-approved, so it must be obtained from compounding pharmacies or research chemical sources. Work with a physician experienced in hormone optimization.
Tips:
- •Compounding pharmacies offer pharmaceutical-grade enclomiphene
- •Some clinics (Defy Medical, Marek Health) specialize in SERM therapy
- •Research chemical sources exist but quality is uncertain
- •Clomiphene (Clomid) is FDA-approved and available but contains both isomers
Start with appropriate dosing
Clinical trials used 6.25mg, 12.5mg, and 25mg daily. Most practitioners start at 12.5-25mg daily. Higher doses produce higher testosterone but may have more side effects.
Tips:
- •12.5-25mg daily is typical dosing
- •Take in the morning to align with natural hormone rhythm
- •Some practitioners use every-other-day dosing
- •Higher is not always better, find your minimum effective dose
Monitor and adjust
Retest testosterone, LH, FSH, and estradiol after 4-6 weeks. Adjust dose based on response and side effects. Monitor for visual disturbances (rare but reported with clomiphene).
Tips:
- •Target testosterone in mid-normal range (500-800 ng/dL)
- •LH and FSH should increase, if not, testes may not be responding
- •Estradiol may rise, monitor for symptoms of excess
- •Report any visual changes immediately (rare but serious)
What to Expect
LH/FSH begin rising
Enclomiphene blocks hypothalamic estrogen receptors quickly. LH and FSH begin increasing within days to weeks.
Testosterone rises
As LH increases, testosterone production rises. Clinical trials showed significant increases by week 2-4. Symptom improvement may begin.
Steady state reached
Testosterone levels stabilize at new higher baseline. Clinical trials measured endpoints at 6 weeks with testosterone reaching 500-600 ng/dL on 25mg daily.
Sperm production maintained/improved
Unlike TRT, sperm counts remain normal or increase. Studies showed sperm concentrations of 75-334 × 10⁶/mL at 3-6 months.
Practical Details
Timing
Take once daily, typically in the morning. Some practitioners split doses or use every-other-day dosing.
Duration
Can be used long-term, though long-term data is limited. Unlike TRT, stopping does not suppress natural production (you return to baseline).
Cost
$30-$100/month
Compounding pharmacy enclomiphene costs $30-100/month depending on pharmacy and dose. Research chemical sources are cheaper but quality is uncertain.
Risks & Considerations
Potential Risks
- •Visual disturbances (rare, more common with clomiphene than enclomiphene)
- •Mood changes in some users
- •Headaches
- •Less potent testosterone elevation than TRT
- •Long-term safety data limited compared to TRT
Possible Side Effects
- •Generally well-tolerated in trials
- •Possible headaches
- •Mood changes (variable, some improve, some worsen)
- •Hot flashes (uncommon)
- •Visual symptoms (rare, more associated with zuclomiphene in clomiphene)
Who Should Avoid This
- •Primary hypogonadism (testicular failure), will not work
- •Pituitary tumors (need evaluation first)
- •Liver disease (SERM metabolism)
- •History of blood clots (theoretical concern with SERMs)
Key Research
Enclomiphene citrate stimulates testosterone production while preventing oligospermia: a randomized phase II clinical trial
Fertility and Sterility, 2014
Phase II trial found enclomiphene increased testosterone, estradiol, and LH comparable to testosterone gel while preserving sperm production. Addresses both hallmarks of secondary hypogonadism: low testosterone and low/inappropriately normal LH.
View StudyTestosterone Restoration by Enclomiphene Citrate in Men with Secondary Hypogonadism: Pharmacodynamics and Pharmacokinetics
BJU International, 2013
After 6 weeks, 25mg enclomiphene produced mean testosterone of 604 ± 160 ng/dL. LH and FSH increased above normal range. Effects persisted for at least 1 week after stopping treatment.
View StudyClomiphene or enclomiphene citrate for the treatment of male hypogonadism: a systematic review and meta-analysis
Andrology, 2024
Meta-analysis found SERM therapy significantly improved total testosterone (MD: 274 ng/dL), LH (MD: 4.66 IU/L), and FSH (MD: 4.59 IU/L) compared to placebo. SERMs are effective for secondary hypogonadism.
View StudyFrequently Asked Questions
How does enclomiphene differ from clomiphene (Clomid)?
Clomiphene contains two isomers: enclomiphene (active, anti-estrogenic) and zuclomiphene (estrogenic, causes side effects). Enclomiphene alone may be better tolerated with fewer mood-related side effects. However, clomiphene is FDA-approved and more accessible.
Will enclomiphene work as well as TRT?
Enclomiphene raises testosterone significantly but typically not as high as TRT can achieve. Clinical trials showed ~600 ng/dL on 25mg daily. TRT can achieve higher levels. However, enclomiphene preserves fertility and natural axis function.
Can I switch from TRT to enclomiphene?
Yes, but it takes time. TRT suppresses natural production, so you need to allow the axis to recover. Some practitioners use hCG during the transition. It may take weeks to months for natural production to restart.
Why is enclomiphene not FDA-approved?
Enclomiphene completed phase III trials but has not received FDA approval. The regulatory path has been complex. It is available through compounding pharmacies, and clomiphene (which contains enclomiphene) is FDA-approved for other indications.
Sources
Related Interventions
Disclaimer: This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider before starting any new health practice or supplement. Evidence levels and recommendations can change, this content was last updated December 2025.