Low Sperm Count: Causes and Solutions

Seeing the numbers on a semen analysis report can feel like a verdict. When they're lower than expected-lower than "normal"-it's natural to feel a mix of shock, confusion, and worry. What does this mean? Is fatherhood still possible? What went wrong?

First, take a breath. A low sperm count diagnosis is concerning, but it's not a dead end. Most causes of low sperm count are treatable, and even when the count can't be improved, modern reproductive technology offers paths forward that didn't exist a generation ago.

Second, know this: you're not alone. According to the American Urological Association and ASRM, a male factor is the sole cause in about 20% of infertile couples and contributes in another 30-40%, and low sperm count is one of the most common findings. It's not a reflection of your masculinity, your worth, or your future as a father. It's a medical condition-and like most medical conditions, there's much that can be done. For a broader perspective on male fertility issues, see our comprehensive male infertility guide.

Understanding Sperm Count: What's Normal?

Before discussing "low" count, let's establish what normal looks like.

The Numbers

The current World Health Organization (WHO) laboratory manual (6th edition, 2021) gives these lower reference limits. They are the values below which only the lowest 5% of men whose partners conceived within a year fall:

You may still see the older 2010 figures (1.5 ml, 15 million/ml, 40% and 32%) on some reports; the differences are small.

Low sperm count (oligozoospermia, often called oligospermia) is generally taken to mean a concentration below the WHO lower reference limit of 16 million/ml.

There is no single official grading of severity. A concentration below 5 million/ml is often called severe, and it is also the level at which guidelines suggest considering a chromosome (karyotype) test. Below 1 million/ml, guidelines recommend testing for Y chromosome microdeletions.

Azoospermia means no sperm detected in the ejaculate-a separate condition requiring different investigation.

Important Context

A few things to understand about these numbers:

One test isn't definitive. Sperm counts can vary substantially from one sample to the next. A single abnormal result should always be confirmed with a repeat test; NICE suggests ideally about 3 months later, or as soon as possible if the count is very low or zero.

"Low" is relative. The WHO itself stresses that its reference limits alone cannot diagnose infertility. Men with counts below the limits have conceived naturally-it's harder, not impossible. Conversely, men with normal counts sometimes struggle.

Count isn't everything. Motility (how sperm swim) and morphology (shape) matter too. A man with slightly low count but excellent motility may have better fertility than someone with normal count but poor motility.

Causes of Low Sperm Count

Understanding potential causes guides treatment. Sometimes a reversible factor is identified; other times, the cause remains unexplained.

Varicocele

One of the most common identifiable causes of low sperm count, varicocele is an enlargement of veins within the scrotum-similar to varicose veins in the legs.

How it affects sperm: The enlarged veins may raise testicular temperature and impair blood flow, both of which can reduce sperm production.

Prevalence: Found in about 15% of all men, but around 40% of men with infertility.

Treatment: For a varicocele that can be felt on examination in a man with abnormal semen results, repair (surgical or by radiological embolisation) is associated with improved semen parameters and higher natural pregnancy rates, although evidence on live birth is more limited. Varicoceles seen only on ultrasound are not usually treated.

Hormonal Imbalances

Sperm production requires proper hormonal signals-primarily from the brain (FSH and LH) telling the testes to produce testosterone and sperm.

Conditions that disrupt hormones:

• Low FSH/LH from pituitary problems
• Elevated prolactin (can suppress testosterone)
• Thyroid dysfunction
• Testosterone replacement therapy (suppresses natural production-a common iatrogenic cause)

Treatment: Often correctable with medication when a specific hormonal cause is found. If you're on testosterone therapy and want to conceive, discuss alternatives with your doctor; guidelines say testosterone should not be prescribed to men who want current or future fertility.

Genetic Factors

Klinefelter syndrome (47,XXY): An extra X chromosome affects testicular function, often causing very low or absent sperm production.

Y-chromosome microdeletions: Missing segments of the Y chromosome can impair sperm production. The severity depends on which region is deleted.

Cystic fibrosis gene mutations: Can cause absence of the vas deferens (the tubes that carry sperm), resulting in no sperm in the ejaculate despite normal production.

Treatment: Genetic causes are generally not reversible, but sperm may still be retrievable surgically for use with IVF/ICSI.

Infections

Past or current infections can affect sperm production or transport:

• Sexually transmitted infections (chlamydia, gonorrhea) can scar the reproductive tract
• Mumps orchitis (mumps affecting the testicles after puberty) can damage tissue
• Chronic prostatitis may affect semen quality

Treatment: Treating active infections prevents further damage; past scarring may be permanent.

Lifestyle and Environmental Factors

Heat exposure: Testicles hang outside the body for temperature regulation-they need to be slightly cooler than body temperature. Frequent saunas, hot tubs, tight underwear, or occupational heat exposure can impair production.

Smoking: Reduces sperm count, motility, and morphology.

Heavy alcohol use: Lowers testosterone and impairs production.

Recreational drugs: Marijuana, cocaine, and anabolic steroids all negatively affect sperm.

Obesity: Alters hormone levels and may directly affect sperm.

Certain medications: Some blood pressure medications, antidepressants, and others can affect sperm.

Treatment: These factors are often reversible with lifestyle changes.

Testicular Issues

Undescended testicles: Testicles that didn't descend during childhood may have impaired function.

Testicular injury or torsion: Trauma can damage sperm-producing tissue.

Tumors: Both benign and malignant growths can affect testicular function.

Unknown Cause (Idiopathic)

In about 30-40% of cases, no clear cause is identified despite thorough evaluation, according to European urology guidelines. This is frustrating but doesn't preclude treatment.

Diagnosing Low Sperm Count

If a semen analysis shows low count, further evaluation helps identify causes and guide treatment.

The Diagnostic Process

Repeat semen analysis: Confirming the finding with a second test is essential.

Medical history: Reviewing childhood conditions, surgeries, infections, medications, and lifestyle.

Physical examination: A urologist examines the testicles, epididymis, and vas deferens, looking for varicocele, abnormalities, or absence of structures.

Hormone testing: Blood tests for FSH, LH, testosterone, prolactin, and thyroid function.

Genetic testing: Karyotype (chromosome analysis) is considered when the count stays below about 5 million/ml, and Y-chromosome microdeletion testing when it is below 1 million/ml or zero.

Scrotal ultrasound: Imaging to identify varicocele, tumors, or other structural issues.

Treatment Options

Treatment depends on the identified cause and your specific situation.

Lifestyle Modifications

If lifestyle factors are contributing, address them:

• Stop smoking
• Reduce alcohol to moderate levels or less
• Eliminate recreational drugs (especially steroids and marijuana)
• Lose weight if overweight
• Reduce heat exposure: Avoid saunas/hot tubs, switch to loose underwear, keep laptops off your lap
• Review medications with your doctor

Timeline: Making sperm takes roughly two to two and a half months (one tracer study measured about 64 days on average), so changes take around 3 months to show up in a semen analysis.

Medical Treatment

Hormonal therapy: If a clear hormone problem exists, medication can help. Options include:

• hCG and FSH injections (gonadotropins): Recommended for men whose pituitary does not send enough hormonal signals (hypogonadotropic hypogonadism), where they can restart sperm production
• Clomiphene citrate or similar medicines: Raise FSH, LH and testosterone and are sometimes used in men with low testosterone, but evidence that they improve pregnancy rates in men without a clear hormonal cause is limited, and NICE (2026) advises using them for that purpose only within clinical trials
• FSH injections for unexplained low counts: American guidance says they may be considered, but the benefit is modest

Stopping testosterone replacement: If you're on testosterone therapy, stopping it (often with fertility-preserving alternatives, under medical supervision) usually allows sperm production to recover, although this takes months.

Treating infection: Antibiotics for active infections, though past scarring may persist.

Surgical Treatment

Varicocele repair: One of the most common fertility-related surgeries for men. Performed through a small incision (often with a microscope), laparoscopically, or by blocking the veins radiologically, it redirects blood flow away from the enlarged veins.

• Recommended for consideration when a varicocele can be felt and semen results are abnormal
• Changes take several months to appear in semen analysis
• Associated with higher natural pregnancy rates in studies, though not every couple benefits

Sperm retrieval: If no sperm are in the ejaculate but production exists, sperm can be surgically extracted:

• TESE (testicular sperm extraction)
• Micro-TESE (microsurgical version, the preferred approach when sperm production is very low)
• PESA/MESA (extracting from epididymis)

Retrieved sperm are used with IVF/ICSI.

Assisted Reproduction

When count can't be improved sufficiently for natural conception, assisted reproduction offers excellent options:

IUI (Intrauterine Insemination): Concentrates and washes sperm, placing them directly in the uterus. Can be useful for mild low count, but only works if enough moving sperm are left after washing; clinics use different minimum thresholds, so ask yours what it uses.

IVF with ICSI: The definitive treatment for severe male factor. The ICSI procedure requires only one viable sperm per egg-even men with counts in the hundreds of thousands can become fathers. With surgically retrieved sperm, even men with no sperm in their ejaculate can father biological children.

Success Rates and Outcomes

With Treatment for Underlying Cause

When a reversible cause is identified and treated:

• Varicocele repair improves semen quality and natural pregnancy rates for many, but not all, couples
• Hormonal treatment restores sperm in men with a clear hormonal cause such as hypogonadotropic hypogonadism
• After stopping testosterone, sperm production usually recovers: in studies of healthy men given testosterone, about two-thirds recovered within 6 months and about 90% within 12 months, though recovery can take longer after long-term use

With Assisted Reproduction

When moving to IVF/ICSI for severe male factor:

• ICSI overcomes most sperm-related barriers to fertilization
• The UK fertility regulator (HFEA) reports that ICSI success rates tend to be very similar to IVF, so the female partner's age and embryo quality become the main drivers of success
• Many couples with male factor infertility go on to have a baby with IVF/ICSI, although success is never guaranteed

Important Perspective

Low sperm count was once a devastating diagnosis with few options. Today, between treating underlying causes and using ICSI, many men with low sperm count can become biological fathers.

Emotional Considerations

Male infertility carries psychological weight that's often underacknowledged.

Common Feelings

Inadequacy: Fertility is culturally tied to masculinity for many men. A diagnosis can feel like an attack on identity.

Guilt: If male factor is the primary issue, you might feel responsible for your partner's need for treatment.

Isolation: Men often don't discuss fertility with friends the way women might.

Pressure: Expectations-internal and external-to be "strong" and support your partner while suppressing your own feelings.

What Helps

Acknowledge your feelings: They're valid. This is hard.

Talk about it: With your partner, a trusted friend, or a therapist.

Remember: Sperm count has nothing to do with your worth as a person, partner, or potential father.

Seek support: Fertility counselors understand these specific challenges.

Key Takeaways

Low sperm count is one of several conditions that can affect a couple's fertility journey. Explore our fertility conditions hub for information on other factors that may be relevant to your situation.

• Low sperm count is common and contributes to many couples' fertility challenges.

• One low result needs confirmation-sperm counts vary significantly between samples.

• Causes range from reversible (varicocele, lifestyle factors, hormonal imbalances) to genetic (Y-chromosome deletions, Klinefelter syndrome).

• Treatment options exist at every level-lifestyle changes, medication, surgery, and assisted reproduction.

• ICSI has transformed outcomes-even severe male factor can be overcome with modern techniques.

• Many men with low sperm count can become biological fathers with appropriate treatment.

Sources

• WHO laboratory manual for the examination and processing of human semen, 6th edition (2021) (checked October 2026)
• Boitrelle et al. The sixth edition of the WHO manual for human semen analysis: a critical review. Life, 2021 (checked October 2026)
• NICE NG257: Testing for male factor fertility problems (2026) (checked October 2026)
• NICE NG257: Management of male factor fertility problems (2026) (checked October 2026)
• AUA/ASRM: Diagnosis and Treatment of Infertility in Men (guideline, amended 2024) (checked October 2026)
• EAU Guidelines on Sexual and Reproductive Health: Male infertility (checked October 2026)
• Misell et al. Measuring human spermatogenesis kinetics in vivo. J Urol, 2006 (checked October 2026)
• Liu et al. Spermatogenic recovery after hormonal male contraception. Lancet, 2006 (checked October 2026)
• HFEA: Intracytoplasmic sperm injection (ICSI) (checked October 2026)

This content is for educational purposes only and should not replace professional medical advice. If you've received a low sperm count result, consult with a urologist or reproductive specialist for personalised evaluation and treatment.