Clomiphene vs Enclomiphene For Low Testosterone Treatment
- Harold Pierre, MD
- 1 day ago
- 10 min read
Is Clomiphene and Enclomiphene Good Options for Testosterone Replacement Therapy?
I've been prescribing testosterone therapy for over 10 years. And I still get some version of this question almost every week: "Do I really have to do injections?" The short answer is no. You don't. Clomiphene, along with its newer relative enclomiphene, can raise your testosterone, relieve your symptoms, and preserve your fertility. For the right patient, this is a real option. Let me explain who that patient is, how this drug actually works, and what the risks are that most articles skip entirely. And of course, why does this matter to a board certified addiction medicine specialist.
Who Should Know About Clomiphene and Enclomiphene?
I have four patient groups who ask about alternatives to traditional testosterone replacement therapy (TRT). The first group: men recovering from opioid addiction. If you were on opioids (prescription painkillers, heroin, methadone, or even Suboxone) your testosterone levels may be extremely low, and there is a good chance no one has checked. This is called OPIAD: Opioid-Induced Androgen Deficiency. It is a form of secondary hypogonadism, meaning low testosterone caused by a failure in the brain's signaling rather than a problem with the testes themselves. It is common and it is underdiagnosed.
The second group: men already on testosterone therapy who are unhappy with the side effects, the cost, or the routine of injections. The third group: men thinking about starting TRT who want to preserve their ability to have children. The fourth group: younger men with low testosterone who do not want to commit to lifelong hormone replacement. If you are in any of these groups, keep reading.
What OPIAD Is (And Why Your Doctor Probably Didn't Check)
Opioids don't just kill pain. They also suppress your body's hormonal command center. This is known to happen in men and women. The hypothalamus sits deep in your brain and acts as the control room for testosterone production. It sends signals down to the pituitary gland, which sends signals down to the testicles, which produce testosterone. Opioids interrupt that chain at the top. The hypothalamus goes quiet, the pituitary stops signaling, and the testicles stop working.
The result is low testosterone, low libido, fatigue, depression, brain fog, sexual dysfunction, and insomnia. Many of these symptoms mimic side effects of substance abuse, withdrawal, and Post Acute Withdrawal Syndrome (PAWS). All the things that make recovery from addiction feel impossible to maintain and may cause your doctor to think it's PAWS, depression, a psychological issue. This happens with all opioids. Short-acting, long-acting, and yes, buprenorphine (Suboxone) too. Methadone may be the worst offender, but virtually no opioid is off the hook. In men on long-term opioid therapy, testosterone disruption is the rule, not the exception.
In my practice, I check testosterone levels on every patient being treated for opioid addiction once I have them stabilized. Most haven't had it checked anywhere else. When the levels come back low, we have a real conversation about options: testosterone therapy, clomiphene, or enclomiphene. The right choice depends on your labs, your medical history, and your long-term goals.
What Clomiphene Citrate Actually Does
Clomiphene citrate (sold under the brand name Clomid) is a SERM, which stands for selective estrogen receptor modulator. The name sounds complex, but the mechanism is straightforward once you understand a bit of basic biology. Your brain monitors estrogen levels and uses that signal to regulate testosterone production. When estrogen is high, the brain tells the system to slow down. Clomiphene works by blocking estrogen receptors in the hypothalamus and pituitary gland, cutting off that signal. The brain thinks estrogen is low. So it releases more LH (luteinizing hormone) and FSH (follicle-stimulating hormone). LH tells the testes to produce more natural testosterone. FSH tells them to keep making sperm. You might wonder, why is the hypothalamus detecting estrogen in a man. Well, testosterone is converted to estrogen in our fat cells. Women aren't the only ones producing estrogen. In essence, you are tricking your brain into thinking it needs to produce more testosterone. And it does.
A 2023 study published in Endocrinology, Diabetes & Metabolism followed 153 hypogonadal men (men with low testosterone levels) on clomiphene citrate. Total testosterone increased from an average of 9 nmol/L to 16 nmol/L. The units aren't important but the effect is. That's over a 70% increase in testosterone. Eighty-nine percent of patients had a measurable biochemical response. Seventy-four percent reported improvement in hypogonadal symptoms. And in patients who stayed on it, the effect held for up to 8 years (Huijben et al., 2023). Those are solid numbers for an oral, off-label medication. In my practice, I've seen men increase their testosterone levels as high as 1000 ng/dL range.
Enclomiphene: The Cleaner Version
Standard clomiphene citrate is a mixture of two isomers: zuclomiphene and enclomiphene. Enclomiphene citrate, when used alone, is derived from isolating just the beneficial half of that compound.
Enclomiphene is the active component. It blocks estrogen receptors cleanly and drives the LH and testosterone response. Zuclomiphene is the other half. It has mild estrogenic activity and clears from the body slowly, sometimes accumulating over months. Some of the mood-related side effects tied to clomiphene (agitation, hot flashes, mood swings) are thought to come from the zuclomiphene component rather than the enclomiphene.
Enclomiphene used alone avoids that problem. It clears faster and has no estrogenic activity. For patients who notice mood changes or other side effects on standard clomiphene, enclomiphene is worth discussing. Neither is FDA-approved for male hypogonadism. Both are used off-label in men, but enclomiphene is the more targeted option.
What SHBG Is and Why It Changes Everything
This is the part most articles skip. I am not going to skip it. SHBG stands for sex hormone-binding globulin. It is a protein your liver produces that binds to testosterone in your bloodstream and locks it up. Bound testosterone cannot do anything. It is biologically inactive. Only free testosterone, the fraction not bound to SHBG or albumin, is actually available to your cells. You can have a total cholesterol of 1000 ng/dL and still have low T if the SHBG bounds a lot of the testosterone. I've seen this exact scenario. If your doctor doesn't check SHBG, you may be misdiagnosed.
Clomiphene raises total testosterone. That is well established. But it also raises SHBG. In the Huijben study, SHBG climbed from a median of about 30.5 nmol/L at baseline to over 36 nmol/L during treatment, continuing to rise in some patients over years. When SHBG goes up alongside total testosterone, the net gain in free testosterone may be smaller than the total testosterone number suggest.
This does not mean clomiphene does not work. Seventy-four percent of patients still felt better, and free testosterone did increase by almost double (from about 178 pmol/L at baseline to around 340 pmol/L). But it means you cannot just check total testosterone and feel confident things are working. Free testosterone needs to be measured. If you are on clomiphene and not feeling the improvements you expected, ask your doctor to check both free testosterone and SHBG. That tells the real story. And the most accurate test is the LCMS test.
The Thrombosis Risk You Need to Understand
Clomiphene is not risk-free, and I want to be direct about that. Fortunately, this is something I've never seen in practice but the risks are there. The most significant risk to be aware of is blood clots. In the Huijben study, one patient developed a pulmonary embolism (a clot in the lung) while on clomiphene during the fourth year of treatment. That patient had a prior history of lower extremity blood clots before starting the medication.
One patient out of 153 is a low number. But it is not zero. And the relevant detail is that prior clotting history or family history of blood clots is a serious concern that needs to be discussed with your doctor. Clomiphene may amplify clotting risk in patients who already have a predisposition to it.
In my practice, patients with a history of deep vein thrombosis, pulmonary embolism, or a known clotting disorder are not candidates for clomiphene or enclomiphene. Other side effects reported in the studies were relatively minor: hot flashes in about 3% of patients, agitation in another 3%, and occasional visual changes, nipple tenderness, or mood shifts. No meaningful changes in PSA, red blood cell count, or liver enzymes were found. That safety profile is a real advantage compared to injectable testosterone, which commonly raises hematocrit (red blood cell count) and can require blood donation.
Cardiovascular Risk of Clomiphene No One Talks About
Clomiphene increases desmosterol. Desmosterol is a direct precursor to cholesterol, one step back in the synthesis chain. When clomiphene interferes with that pathway, desmosterol can accumulate in the blood. That is a problem because desmosterol is atherogenic. It has been found deposited inside arterial plaques. The FDA's prescribing information for clomiphene actually acknowledges this, noting that patients on prolonged therapy may show elevated desmosterol levels. Whether enclomiphene causes the same effect is not settled. Some researchers suspect zuclomiphene is the main culprit, since enclomiphene does not contain it, but that has not been proven. If you have existing cardiovascular risk factors, this is a conversation worth having with your doctor before you start.
How Clomiphene Compares to TRT
Traditional testosterone therapy (injections, gels, or pellets) works by replacing your testosterone from the outside. Levels go up and symptoms often improve. But there are meaningful trade-offs. Testosterone shuts down your body's own production through negative feedback on the HPG axis (the hypothalamic-pituitary-gonadal axis, the hormonal chain that runs from your brain down to your testicles). Both LH and FSH drops. Sperm production stops or falls to nearly zero. Sperm count can drop dramatically. This leads to male infertility that is sometimes temporary and sometimes surprisingly prolonged, even after stopping TRT. What the man notices is significant testicle shrinkage.
Clomiphene does the opposite. It works with your natural system. LH and FSH go up, not down. Sperm production is preserved or improved. If having children is desired, now or in the future, this difference is enormous. You may seriously want to discuss the clomiphene option with your doctor.
There is also the estrogen conversion issue. Injectable testosterone at higher doses can convert (aromatize) to estrogen in fat tissue, which creates its own problems: gynecomastia, mood changes, water retention. Clomiphene does not add testosterone to your body. It stimulates your body to produce more of its own, which tends to be processed more naturally.
For patients with OPIAD (Opioid Induced Androgen Deficiency), clomiphene is often a logical first step when the underlying opioid problem is being treated at the same time. The goal is to restore the hormonal axis, not just substitute the missing hormone.
Who Responds Best to Clomiphene and Enclomiphene for Hypogonadism
Based on the research and my own clinical experience, the patients most likely to see a strong response are men with secondary hypogonadism, specifically hypogonadotropic hypogonadism. That means low testosterone combined with low or low-normal LH. This is exactly the pattern seen in OPIAD, and it is what clomiphene citrate is designed to correct. Men with secondary hypogonadism respond far better than men with primary testicular failure. If your LH is already very high (a sign your testicles are not responding to the signal despite adequate stimulation), clomiphene has less room to work. The treatment is less likely to be effective in primary testicular failure.
Age, body weight, and testicular history also matter. Men who have had orchiectomy (removal of testicle) or who have primary testicular damage tend to respond less. But for the typical patient with functional low testosterone (the recovering addict, the man on opioid maintenance, the younger man with idiopathic low T): clomiphene is worth a serious conversation.
What to Expect When Starting
The typical starting dose for men is 25 mg every other day. Some physicians use 25 mg daily. Response is usually evaluated at 6 to 12 weeks with a full panel: total testosterone, free testosterone, LH, FSH, SHBG, and estradiol.
If the response is inadequate, the dose can be increased to 50 mg daily. That said, higher doses do not always mean better results. Some patients get more side effects at higher doses without additional benefit. Give it at least three months before concluding it is not working. Testosterone production takes time to ramp up, and symptom improvement often lags behind the lab improvements by several weeks. Anecdotally, I've seen every other week dosing after a 3 month maintenance further increase testosterone levels. It's like the testicles continue to work after the dose stops. But the reason is clomiphene's long half-life of 5-7 days. Meaning, even 3-4 weeks later, there is still a significant amount of clomiphene in the body. However, men using every other week dosing report lower side effects.
If you are dealing with OPIAD, the situation is slightly different. You may see faster improvement as the opioid's suppressive effect wears off and the HPG axis starts to recover. But do not expect results in weeks. Think in months. Regardless, I hope this article gave you a great starting point to have that conversation with your doctor to determine if clomiphene or enclomiphene is right for you.
Frequently Asked Questions
Can clomiphene replace testosterone therapy entirely?
For many patients, yes. It raises testosterone through your body's own production, relieves symptoms, and avoids the fertility suppression that comes with exogenous testosterone. Whether it is the right choice depends on your baseline hormone levels, fertility goals, and medical history. Patients with primary testicular failure or very high LH are less likely to respond.
Is clomiphene FDA-approved for low testosterone in men?
No. It is used off-label for male hypogonadism. The FDA approved it for ovulation induction in women. That said, clomiphene has been prescribed for low testosterone in men for over 30 years and has a well-documented safety profile in this population, including long-term follow-up data.
What is OPIAD and how often does it affect men on opioids?
OPIAD stands for Opioid-Induced Androgen Deficiency. Opioids suppress the hypothalamic-pituitary-gonadal axis, reducing LH, FSH, and testosterone production. It affects a significant portion of men on long-term opioid therapy, including those on buprenorphine (Suboxone) and methadone. Most are never tested because physicians do not routinely screen for it. If you are being treated for opioid addiction and feel fatigued, depressed, or have low libido, ask your doctor to check your testosterone.
What makes enclomiphene different from standard clomiphene?
Standard clomiphene contains two isomers: enclomiphene (anti-estrogenic, the active component) and zuclomiphene (mildly estrogenic, slowly cleared). Enclomiphene isolates the beneficial part and avoids the estrogenic effects of zuclomiphene. Some patients tolerate enclomiphene better, particularly those who experience mood-related side effects on standard clomiphene.
References
Huijben M, Lock MTWT, de Kemp VF, Beck JJH, De Kort LMO, van Breda HMK. Clomiphene citrate: A potential alternative for testosterone therapy in hypogonadal males. Endocrinol Diabetes Metab. 2023;6(3):e416. https://doi.org/10.1002/edm2.416
Ross LS, Kandel GL, Prinz LM, Auletta F. Clomiphene treatment of the idiopathic hypofertile male: High-dose, alternate-day therapy. Fertil Steril. 1980;33(6):618-623. https://doi.org/10.1016/s0015-0282(16)44775-8
About the Author
Harold Pierre, MD, is a board-certified anesthesiologist, board-certified addiction medicine specialist, and a concierge addiction doctor with over 27 years of experience. He is board-certified by the American Board of Anesthesiology, the American Board of Preventive Medicine and has extensive experience managing hormones. He is licensed in Florida, Texas, Oklahoma, Louisiana, and Arizona, with a pending Missouri license. If you are seeking care, you may schedule an appointment with him by calling or texting 918-518-1636. LinkedIn
Disclaimer: This blog post is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your doctor or other qualified health provider with any questions you may have regarding your health or a medical condition.
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