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Large human trials Hormones and Reproductive Health

Enclomiphene

Also called Enclomiphene citrate; Androxal (investigational name)

A pill that raises a man's own testosterone by signaling the brain to make more LH and FSH. Studied as an alternative to TRT that preserves sperm production. Not FDA approved.

Overview

What it is

A small molecule, not a peptide. It is one of the two mirror-image forms that make up clomiphene (Clomid), the fertility drug. Enclomiphene is the form that blocks estrogen at the brain.

How it works

Estrogen tells the brain to slow testosterone production. Enclomiphene blocks those estrogen receptors in the hypothalamus and pituitary, so the brain releases more LH and FSH, which tell the testicles to make more testosterone and sperm.

What the research shows

Phase 2 and phase 3 trials in men with secondary hypogonadism found daily enclomiphene (12.5 to 25 mg) raised testosterone into the normal range while maintaining sperm counts, unlike testosterone gel. FDA declined to approve it in 2015, raising concerns about the trial design and endpoints. It is now available only from compounding pharmacies.

Studied for

  • Secondary hypogonadismlow testosterone with low or normal LH
  • Preserving sperm counts compared with testosterone therapy

Safety and regulatory status

Safety and side effects

Reported side effects include headache, hot flashes, nausea, and mood changes. Vision changes have been reported with clomiphene and should be reported right away. Not for men with primary testicular failure, where the testicles cannot respond.

Regulatory status

Not FDA approved. Available only as a compounded medicine prescribed by a licensed provider.

Common questions

How is it different from TRT?

TRT replaces testosterone from outside and usually shuts down sperm production. Enclomiphene prompts the body to make its own, and trials showed sperm counts were maintained.

Is it the same as Clomid?

Clomid is a 50/50 mix of enclomiphene and zuclomiphene. Enclomiphene is the active, shorter-acting half.

Related in Hormones and Reproductive Health

EstradiolFDA approved GonadorelinEarly human data hCGFDA approved HMG (Menotropins)FDA approved KisspeptinEarly human data OxytocinFDA approved
Sources and further reading (3)
  1. Kim ED, et al. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement. BJU Int, 2016.
  2. PubMed: phase 3 trials of enclomiphene in secondary hypogonadism.
  3. Earl JA, Kim ED. Enclomiphene citrate: a treatment that maintains fertility in men with secondary hypogonadism. Expert Rev Endocrinol Metab, 2019.
Educational information only. This content summarizes published research for general education. It is not medical advice, not a recommendation to use any substance, and not an instruction for human or animal use. It does not describe any Research Product sold on this site.