Enclomiphene

Why there is no syringe

There is no syringe and there is no tablet either, in the sense that matters: there is no FDA-approved enclomiphene product of any kind, so there is no labelled dosage form to describe. What people are handed is a compounded oral capsule, and the FDA is explicit that compounded drugs are not FDA-approved and are not reviewed for safety, effectiveness or manufacturing quality before they are dispensed. The strength printed on that capsule is a figure a prescriber chose and a compounding pharmacy prepared; nothing on this page proposes, confirms or converts it. The only enclomiphene doses that can be cited at all are the arms of named published trials, and those are reported below as trial arms rather than assembled into a regimen.

Administration

1. 1

   Start from the regulatory position, because it governs everything else

   Enclomiphene is not an approved drug in the United States. A DailyMed query for “enclomiphene” and for “enclomiphene citrate” returns zero Structured Product Labels. A Drugs@FDA query for products whose active ingredient is enclomiphene returns no matches. The only place the word appears in FDA labelling is inside clomiphene labels, describing one of the two isomers clomiphene is made of.

2. 2

   Know what happened to the application that was filed

   Repros Therapeutics filed an NDA for enclomiphene for secondary hypogonadism and received a Complete Response Letter dated 1 December 2015. The company’s own announcement states that “the FDA stated that, based on recent scientific developments, the design of enclomiphene Phase 3 studies is no longer adequate to demonstrate clinical benefit and recommended that Repros conduct an additional Phase 3 study or studies to support approval in the target population”, and that “the FDA also noted concerns regarding study entry criteria, titration and bioanalytical method validation in the Phase 3 program.” The additional studies were never run and the application was never approved.

3. 3

   Understand what enclomiphene is chemically

   It is one half of clomiphene. The CLOMID label states: “Clomiphene citrate is a mixture of two geometric isomers [cis (zuclomiphene) and trans (enclomiphene)] containing between 30% and 50% of the cis-isomer,” and adds that “some data suggest that zuclomiphene has greater estrogenic activity than enclomiphene.” Separating the trans-isomer is the entire premise of the drug; it does not make the resulting product approved.

4. 4

   Read published trial arms as trial arms, not as a dose

   Dose figures for enclomiphene exist only inside named studies. Wiehle et al., BJU Int 2013, was a randomised single-blind phase II study that compared three arms — 6.25 mg, 12.5 mg and 25 mg of enclomiphene citrate daily — against transdermal testosterone in 48 men with secondary hypogonadism. Kim et al., BJU Int 2016, reported two parallel phase III studies (ZA-304 and ZA-305) evaluating “two doses of enclomiphene citrate” against testosterone gel over 16 weeks; the published abstract does not name which two, and this page does not guess. Reporting what a trial gave is not the same as recommending it, and no starting dose, maintenance dose or titration schedule for enclomiphene exists because no regulator has ever set one.

5. 5

   Treat the monitoring as the prescriber’s, not the label’s

   There is no label to specify baseline tests, intervals or stopping rules. Any monitoring on enclomiphene is a clinical protocol your prescriber has assembled, and it should be written down before the first capsule, not reconstructed afterwards.

Storage

• —There is no labelled storage condition, because there is no approved product. A compounded capsule’s storage and its beyond-use date are set by the pharmacy that prepared it and are printed on that pharmacy’s own label.
• —The FDA states that compounded drugs are not FDA-approved: the agency does not verify their safety, effectiveness or quality before they are marketed.
• —Product bought from an online seller without a prescription is outside even that. Its identity, strength and purity are unverified by anyone.

Monitoring

Frequently asked questions

Is enclomiphene FDA-approved?

No, and it never has been. There is no Structured Product Label for enclomiphene on DailyMed — the query returns zero results — and no enclomiphene product in Drugs@FDA. Repros Therapeutics filed an NDA under the brand name Androxal and received a Complete Response Letter on 1 December 2015; the FDA said the phase III study design was “no longer adequate to demonstrate clinical benefit” and asked for additional phase III work, which was never done. Anything sold as enclomiphene in the United States today is a compounded preparation, and the FDA states that compounded drugs are not FDA-approved and are not reviewed for safety, effectiveness or manufacturing quality before dispensing.

Does an SPL or an NDC number mean a drug is approved?

No, and that gap is worth understanding before you evaluate any claim about this compound. FDA listing databases publish what registrants submit; approval is a separate process recorded in Drugs@FDA. Building a page on retatrutide we found ten SPLs from one cross-border e-commerce registrant, every one filed under marketing category “Export only” — product that may not lawfully be sold in the US and whose content FDA does not review — all typed as HUMAN PRESCRIPTION DRUG LABEL, so they read as manufacturer labels at a glance. For enclomiphene the situation is simpler and starker: there is no SPL of any category. Where one does turn up for something else, read the approval block’s marketing category before you read the dose.

What doses were used in the enclomiphene trials?

Wiehle et al. (BJU Int 2013) ran a randomised, single-blind, two-centre phase II study in 48 men with secondary hypogonadism comparing three daily oral arms — 6.25 mg, 12.5 mg and 25 mg of enclomiphene citrate — against a 5 g dose of transdermal testosterone, with 24-hour testosterone and LH profiles at day 1 and day 42. Kim et al. (BJU Int 2016) reported two parallel randomised, double-blind, placebo-controlled phase III studies, ZA-304 and ZA-305, comparing two doses of enclomiphene citrate against testosterone gel over 16 weeks; the abstract does not state which two doses, so this page does not name them. Those are the arms studies used. They are not a starting dose, a maintenance dose or a titration schedule — none of those exists for an unapproved drug.

How is enclomiphene different from clomiphene?

Clomiphene is a mixture of two isomers and enclomiphene is one of them. The CLOMID label states: “Clomiphene citrate is a mixture of two geometric isomers [cis (zuclomiphene) and trans (enclomiphene)] containing between 30% and 50% of the cis-isomer,” and notes that “some data suggest that zuclomiphene has greater estrogenic activity than enclomiphene.” The argument for the isolated trans-isomer is that it drops the more oestrogenic, longer-lingering half. That argument is plausible and it is not an approval: clomiphene has one (for ovulation induction in women) and enclomiphene has none.

What do the guidelines say about using a SERM in men?

The Endocrine Society's 2018 testosterone guideline carries one technical remark and it is cautious: “Clomiphene citrate has been used empirically in men with hypogonadotropic hypogonadism; however, neither its efficacy nor its safety has been demonstrated in randomized trials.” The AUA's guideline is more permissive but draws the line that matters here — statement 27 says clinicians “may use aromatase inhibitors, human chorionic gonadotropin, selective estrogen receptor modulators, or a combination thereof in men with testosterone deficiency desiring to maintain fertility”, a Conditional Recommendation at Evidence Level Grade C, and then adds: “Clinicians should understand that of these agents, only hCG has been approved by the FDA for use in males.” Enclomiphene is not even in the SERM group those statements were written about, because the statements were written about approved drugs used off-label, and enclomiphene is not approved at all.

Sources

1. [1]DailyMed SPL query for “enclomiphene citrate” — returns zero Structured Product Labels. Run 2026-09-19 against the DailyMed v2 services API (database published 18 Sep 2026)
2. [2]openFDA drug label query for “enclomiphene” — 30 matching label records, every one of them a clomiphene citrate product whose DESCRIPTION section names enclomiphene as the trans-isomer. No product is branded or generically named enclomiphene. A parallel Drugs@FDA query for products whose active ingredient is ENCLOMIPHENE returns “No matches found”
3. [3]Repros Therapeutics Inc., “Repros Therapeutics Receives Complete Response Letter From FDA for Enclomiphene”, 1 December 2015, filed with the SEC. “In the letter, the FDA stated that, based on recent scientific developments, the design of enclomiphene Phase 3 studies is no longer adequate to demonstrate clinical benefit and recommended that Repros conduct an additional Phase 3 study or studies to support approval in the target population.”
4. [4]Wiehle R, Cunningham GR, Pitteloud N, et al. Testosterone Restoration by Enclomiphene Citrate in Men with Secondary Hypogonadism: Pharmacodynamics and Pharmacokinetics. BJU Int. 2013;112(8):1188–1200 (PMID 23875626). The phase II study whose three arms — 6.25 mg, 12.5 mg and 25 mg daily — are the dose figures cited on this page
5. [5]Kim ED, McCullough A, Kaminetsky J. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement. BJU Int. 2016;117(4):677–685 (PMID 26496621). The two parallel phase III studies, ZA-304 and ZA-305; the abstract states “two doses of enclomiphene citrate” without naming them
6. [6]Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol. 2018;200(2):423–432 (PMID 29601923). Statement 27 and its discussion — the source of both quoted sentences, including “Clinicians should understand that of these agents, only hCG has been approved by the FDA for use in males.”
7. [7]Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744 (PMID 29562364). Source of the clomiphene technical remark under recommendation 2.1. Read in full on 2026-09-19: the guideline contains no mention of aromatase inhibitors, anastrozole or letrozole
8. [8]U.S. Food and Drug Administration. Compounding and the FDA: Questions and Answers — “compounded drugs are not FDA-approved”, meaning FDA does not verify their safety, effectiveness or quality before they are marketed

Related

• Clomiphene — the approved parent molecule
• hCG — the one with an approved male use
• Testosterone cypionate — the labelled comparator
• TRT — how it works and what it costs
• Compare online TRT providers
• Testosterone vs. enclomiphene