Low Sperm Count: Causes, Symptoms, and Treatment Options
Low sperm count, medically called oligozoospermia or oligospermia, is one of the conditions that can make it harder to conceive. It means that the concentration or total number of sperm in a semen sample is below the laboratory’s reference range. However, a low sperm count does not automatically mean infertility, and a single abnormal semen analysis does not necessarily predict whether a man can father a pregnancy.
Male fertility depends on several factors, including sperm concentration, total sperm number, sperm movement, sperm shape, semen volume, reproductive anatomy, hormones, sexual function, and the fertility of the other partner. The American Urological Association (AUA) and American Society for Reproductive Medicine (ASRM) therefore recommend evaluating the male and female partners concurrently when a couple is experiencing infertility.
The World Health Organization (WHO) estimates that about 1 in 6 people of reproductive age experience infertility during their lifetime. WHO identifies male infertility as potentially involving problems with semen or sperm, including low or absent sperm, abnormal sperm movement, abnormal sperm shape, or problems with ejaculation.
This guide explains what low sperm count means, the current WHO semen reference values, common causes and symptoms, how doctors diagnose the condition, evidence-based treatment options, lifestyle factors, and when specialist fertility care may be appropriate.
What Is a Low Sperm Count?
Sperm are microscopic reproductive cells produced in the testicles. They are released in semen during ejaculation and must survive, move through the female reproductive tract, and ultimately reach and fertilize an egg for natural conception to occur.
A low sperm count generally refers to a sperm concentration below the lower reference value used when interpreting semen analysis. The current WHO sixth edition laboratory manual provides reference distributions based on men whose partners achieved natural conception within 12 months. Its lower fifth-percentile reference value for sperm concentration is approximately 16 million sperm per milliliter, while the lower fifth-percentile value for total sperm number is approximately 39 million sperm per ejaculate.
Other WHO sixth-edition lower reference values include approximately:
| Semen parameter | WHO sixth-edition lower reference value |
| Semen volume | 1.4 mL |
| Sperm concentration | 16 million/mL |
| Total sperm number | 39 million/ejaculate |
| Total motility | 42% |
| Progressive motility | 30% |
| Vitality | 54% |
| Normal morphology | 4% |
These numbers need to be interpreted carefully. They are not absolute boundaries separating fertile men from infertile men. WHO emphasizes that semen measurements overlap substantially between men who achieve pregnancy and those who experience infertility. A man can have a value below a reference level and still contribute to a natural pregnancy, while someone with values above the reference levels may still experience fertility problems.
This is why doctors should not diagnose male infertility simply because one number on a semen report is low.
Low Sperm Count vs Male Infertility: What’s the Difference?
Low sperm count and infertility are related, but they are not interchangeable terms.
A low sperm count describes a semen-analysis finding. Infertility describes difficulty achieving pregnancy despite regular unprotected intercourse over a defined period.
WHO defines infertility as failure to achieve pregnancy after 12 months or more of regular unprotected sexual intercourse. It can result from male factors, female factors, a combination of both, or sometimes no identifiable cause.
For example, a man with moderately reduced sperm concentration may still father a child naturally, particularly if other semen parameters are favorable and there are no significant fertility problems in his partner.
Conversely, a man with a sperm concentration within the laboratory reference range could have impaired fertility because of very poor sperm motility, abnormal morphology, reproductive tract obstruction, sexual dysfunction, or other factors.
AUA/ASRM guidance specifically notes that individual semen parameters such as concentration, motility, and morphology are not highly predictive of fertility when considered alone. The probability of infertility tends to increase when multiple semen parameters are significantly abnormal.
How Common Is Male-Factor Infertility?
Infertility is a major global reproductive-health issue. WHO’s current estimate is that approximately 17.5% of adults, or around 1 in 6 people, experience infertility during their lifetime.
Male factors can contribute substantially to infertility, although the exact proportion varies depending on the population and definition used. Male reproductive problems can involve sperm production, sperm transport, ejaculation, hormones, genetics, sexual function, or structural abnormalities.
Importantly, fertility should not automatically be treated as a problem belonging to one partner. AUA/ASRM recommends concurrent evaluation of both partners because pregnancy depends on reproductive factors on both sides.
What Causes Low Sperm Count?
Low sperm count can have many causes. Some are temporary or potentially reversible, while others involve genetic, hormonal, anatomical, or testicular conditions requiring specialist management.
Varicocele
A varicocele is an enlargement of veins around the testicle. It is one of the recognized potentially correctable causes of male infertility.
The mechanism is not always straightforward, but abnormal blood flow around the testicle may contribute to an environment that interferes with normal sperm production.
Not every varicocele requires treatment. Clinical findings, semen parameters, fertility goals, symptoms, and other reproductive factors are considered when deciding whether intervention is appropriate.
Hormonal problems
Sperm production depends on a coordinated hormonal system involving the hypothalamus, pituitary gland, and testicles.
Problems involving follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, prolactin, or other endocrine pathways can interfere with spermatogenesis.
Certain men with hormonal disorders can benefit from targeted medical treatment. The appropriate therapy depends on the underlying diagnosis rather than simply trying to raise testosterone.
Testosterone therapy
One of the most important fertility-related medication issues is exogenous testosterone.
Testosterone replacement can suppress signals from the brain to the testicles. This can reduce or even stop sperm production in some men.
AUA/ASRM guidance states that clinicians should not prescribe exogenous testosterone to men who are interested in current or future fertility. The guideline explains that external testosterone can suppress gonadotropin secretion and consequently decrease spermatogenesis, potentially resulting in azoospermia, meaning no sperm in the ejaculate.
Men taking testosterone who want children should discuss fertility-preserving or fertility-restoring options with an appropriately qualified clinician rather than stopping or changing medication without medical guidance.
Testicular injury or disease
The testicles are responsible for producing sperm. Previous trauma, infection, surgery, inflammation, or other testicular conditions can interfere with sperm production.
A history of undescended testicles, testicular torsion, certain infections, or previous testicular surgery may also be relevant during a fertility assessment.
Genetic conditions
Genetic abnormalities can affect sperm production or the anatomy of the reproductive tract.
Genetic testing is not required for every man with a mildly reduced sperm count. It may be considered in selected men with severe sperm-production abnormalities, particularly when sperm concentration is extremely low or when the clinical history suggests a genetic cause.
AUA/ASRM guidance includes karyotype and Y-chromosome microdeletion testing among genetic evaluations that may be appropriate in selected patients with impaired sperm production.
Obstruction of the reproductive tract
A man may produce sperm normally but have a blockage preventing sperm from entering the ejaculate.
Possible causes include previous surgery, infection, congenital abnormalities, or certain reproductive-tract conditions.
This is an important distinction because treatment may involve restoring the pathway or retrieving sperm rather than trying to increase sperm production.
Infections
Some infections affecting the reproductive tract can interfere with fertility.
The clinical impact depends on the infection, its location, severity, duration, and whether complications developed.
A healthcare professional may investigate infection when symptoms, medical history, semen findings, or examination suggest it.
Medications and medical treatments
Some medications and medical treatments can affect sperm production.
Cancer treatments such as chemotherapy and radiation can have significant effects on spermatogenesis. Certain medications can also affect reproductive hormones or sexual function.
Because the effects vary by medication and dose, patients should review their complete medication and treatment history with a fertility specialist.
Smoking, alcohol, recreational drugs, and anabolic steroids
Lifestyle factors can also influence reproductive health.
WHO identifies smoking, excessive alcohol intake, and obesity as factors associated with higher chances of infertility.
Recreational drugs and anabolic steroids can also interfere with reproductive function. The NHS specifically advises men with low sperm count to avoid anabolic steroids and recreational drugs such as cocaine.
Heat exposure
Normal sperm production requires a temperature environment slightly below core body temperature.
Conditions that substantially increase scrotal temperature may affect sperm production. Heat is therefore considered as part of the history in some fertility evaluations.
However, popular claims that specific underwear types or everyday activities automatically cause infertility are often stronger than the available evidence. The NHS notes an association between increased scrotal temperature and reduced semen quality but also states that evidence is uncertain regarding whether loose-fitting underwear itself improves fertility.
What Are the Symptoms of Low Sperm Count?
Low sperm count usually does not cause obvious symptoms.
Many men discover the condition only after having difficulty conceiving and undergoing semen analysis.
The NHS states that people commonly find out they have low sperm count through fertility testing rather than through a specific physical symptom.
Possible associated signs depend on the underlying cause. These may include:
- Difficulty conceiving
- Reduced libido
- Erectile or ejaculatory problems
- Testicular pain or swelling
- A noticeable scrotal mass or enlarged veins
- Signs of hormonal imbalance
- Reduced facial or body hair in certain hormonal conditions
- History of testicular injury or disease
These symptoms do not prove that sperm count is low. A semen analysis is required to evaluate sperm concentration and other semen characteristics.
How Is Low Sperm Count Diagnosed?
Semen analysis
The primary test for evaluating sperm count is a semen analysis.
A laboratory evaluates the sample for several characteristics rather than looking only at sperm concentration. These can include:
- Semen volume
- Sperm concentration
- Total sperm number
- Sperm motility
- Progressive motility
- Sperm morphology
- Vitality
- Other characteristics when clinically indicated
WHO’s sixth-edition semen manual was developed specifically to standardize laboratory procedures and improve the reliability and comparability of semen analysis between laboratories.
Why one semen test may not be enough
Semen parameters can vary from one sample to another.
An abnormal result therefore does not necessarily establish a permanent problem.
The NHS notes that a repeat semen analysis is usually performed after a possible abnormal result, often around three months later.
This timing is clinically understandable because sperm production is a biological process that takes weeks, so a repeat test can help determine whether an abnormal result persists.
The AUA/ASRM guideline recommends that the initial male fertility evaluation include one or more semen analyses and states that men with abnormal semen parameters should undergo appropriate further evaluation.
Medical history and physical examination
A clinician may ask about:
- Previous pregnancies
- Duration of trying to conceive
- Childhood testicular problems
- Undescended testicles
- Previous infections
- Testicular trauma
- Surgeries
- Medication use
- Testosterone or anabolic-steroid use
- Smoking and alcohol
- Recreational drug use
- Occupational exposures
- Sexual function
- Family history
- Previous cancer treatment
A physical examination may evaluate the testicles, epididymis, vas deferens, scrotum, and other relevant structures.
Hormone testing
Hormone tests are not automatically required for every man.
AUA/ASRM recommends endocrine evaluation in selected circumstances, including men with oligozoospermia, especially when sperm concentration is substantially reduced, or when clinical features suggest hormonal abnormalities.
Tests may include testosterone and FSH, with additional hormones such as LH or prolactin depending on the clinical picture.
Genetic testing
Genetic testing may be appropriate in selected men with severe sperm-production problems.
The purpose is not simply to explain the semen analysis. Genetic results can influence treatment decisions and may have implications for assisted reproduction and potential transmission of genetic conditions.
Imaging and other tests
Ultrasound or other imaging may be recommended when physical examination or history suggests a structural abnormality.
Additional tests may be considered when there is suspicion of reproductive-tract obstruction, hormonal disease, infection, or another specific condition.
Can Low Sperm Count Be Treated?
In many cases, treatment can address a contributing cause or help a couple achieve pregnancy even when the sperm count does not return to a particular reference value.
Treatment should therefore focus on the cause, the severity of the semen abnormality, the duration of infertility, the reproductive goals of the couple, and the fertility status and age of the female partner.
Lifestyle changes
Lifestyle optimization may be recommended as part of fertility care.
This can include stopping smoking, avoiding anabolic steroids and recreational drugs, limiting excessive alcohol intake, achieving a healthy weight when appropriate, exercising regularly, maintaining good sleep habits, and managing relevant chronic health conditions.
The goal is not to promise that lifestyle changes will normalize every abnormal semen analysis. Instead, these measures address modifiable factors associated with overall reproductive and general health.
Treating hormonal disorders
Men with specific hormonal causes of impaired sperm production may be treated with medications that stimulate the body’s own reproductive hormone pathways.
For example, men with hypogonadotropic hypogonadism may be treated with gonadotropins or other appropriate hormonal therapy under specialist supervision.
Treatment is diagnosis-specific. Simply taking testosterone is not a fertility treatment and can suppress sperm production.
Varicocele treatment
In selected men with a clinically significant varicocele and abnormal semen parameters, surgical repair may be considered.
The decision depends on physical findings, semen results, fertility history, and the overall reproductive situation.
Treating reproductive-tract obstruction
When low or absent sperm is caused by obstruction rather than poor sperm production, surgical reconstruction may sometimes restore sperm passage.
AUA/ASRM notes that microsurgical reconstruction can be preferable to sperm retrieval and ICSI in selected cases of acquired or congenital obstruction, depending on the clinical circumstances and the fertility potential of the female partner.
Intrauterine insemination
IUI involves processing a semen sample and placing prepared sperm into the uterus around the time of ovulation.
Its suitability depends on the total number of motile sperm, female reproductive factors, age, diagnosis, and other circumstances.
AUA/ASRM notes that IUI success may be reduced when repeated semen analyses show a low total motile sperm count and that IVF/ICSI may be considered in such situations.
IVF and ICSI
In vitro fertilization (IVF) involves fertilizing an egg with sperm in a laboratory before transferring an embryo into the uterus.
Intracytoplasmic sperm injection (ICSI) is an IVF technique in which an individual sperm is injected directly into an egg.
ICSI can be particularly useful when sperm numbers or movement are severely compromised or when previous fertilization problems have occurred.
AUA/ASRM states that assisted reproductive technology can allow couples to achieve pregnancy even when the underlying male-factor condition has not been corrected.
Surgical sperm retrieval
Some men have extremely low or absent sperm in the ejaculate but still produce sperm inside the testicles.
In selected cases, sperm can be retrieved surgically and used with ICSI.
Techniques may include testicular sperm extraction or aspiration and epididymal sperm retrieval, depending on the underlying diagnosis.
This approach demonstrates why “no sperm in semen” and “no sperm production” are not necessarily the same condition.
Do Supplements Increase Sperm Count?
The market for male fertility supplements is extensive, with products containing antioxidants, vitamins, minerals, herbs, and other ingredients.
However, marketing claims often go beyond the quality of clinical evidence.
AUA/ASRM specifically recommends counseling patients that the benefits of supplements such as antioxidants and vitamins have questionable clinical utility for treating male infertility, with insufficient evidence to recommend specific agents for this purpose.
That does not mean every nutrient is irrelevant to reproductive health. Correcting a genuine nutritional deficiency can be medically appropriate. But taking a large collection of fertility supplements without identifying an underlying problem is not an evidence-based substitute for evaluation.
Men should also discuss supplements with a healthcare professional because some products can interact with medications or contain ingredients that are not clearly regulated for quality.
Can You Increase Sperm Count Naturally?
There is no single natural method guaranteed to increase sperm count in every man.
The most sensible approach is to identify potentially modifiable factors while investigating medical causes when appropriate.
Stopping smoking, avoiding anabolic steroids and recreational drugs, reducing excessive alcohol intake, maintaining a healthy weight, exercising regularly, managing chronic diseases, and avoiding unnecessary heat or toxic exposures may support reproductive health. WHO and the NHS both identify several lifestyle and health factors associated with male and overall fertility.
But lifestyle changes should not delay medical evaluation when there is prolonged difficulty conceiving, severe semen abnormalities, testicular abnormalities, or other concerning symptoms.
How Long Does It Take for Sperm Count to Improve?
Sperm production is a continuous biological process rather than something that changes immediately after a lifestyle adjustment.
Because sperm development takes time, changes in health, medication, illness, or environmental exposure may take weeks or months to become apparent in a semen analysis.
This is one reason repeat testing is often performed after an abnormal result rather than judging treatment effectiveness from a test performed only a few days later.
The exact timeline depends on the cause. A man whose low sperm count results from a reversible exposure may respond differently from someone with a genetic condition, severe testicular damage, or an endocrine disorder.
When Should You See a Fertility Specialist?
A medical evaluation is appropriate when a couple has been unable to achieve pregnancy after 12 months of regular unprotected intercourse. Earlier assessment may be appropriate when there are known fertility risk factors, significant reproductive symptoms, previous testicular problems, or concerns about the female partner’s age or reproductive health.
The NHS recommends seeking medical evaluation after one year of trying, with earlier assessment in certain circumstances.
Men should also consider earlier specialist assessment if they have:
- A history of undescended testicles
- Testicular surgery or injury
- Previous chemotherapy or radiation
- Known varicocele
- Very low or absent sperm on a semen analysis
- Significant sexual or ejaculatory dysfunction
- Testosterone or anabolic-steroid use
- A history suggesting hormonal or genetic disease
AUA/ASRM recommends that men with one or more abnormal semen parameters or presumed male infertility receive appropriate evaluation by a male reproductive specialist.
Does Low Sperm Count Mean You Cannot Have Children?
No.
Low sperm count can reduce the probability of conception, but it does not automatically mean that biological parenthood is impossible.
The appropriate next step depends on how low the sperm count is, whether other semen parameters are abnormal, whether sperm are being produced normally, the cause of the problem, and the reproductive factors of both partners.
Some men with reduced sperm concentration conceive naturally. Others may benefit from treatment of an underlying cause. Some may require IUI, IVF, ICSI, or sperm retrieval.
The important point is that treatment decisions should be based on the complete fertility assessment rather than a single sperm-count number.
Low Sperm Count and Male Sexual Health
Another common misconception is that sperm count directly determines sexual performance.
In most cases, sperm count does not determine whether a man can achieve an erection, experience sexual desire, or have an orgasm.
However, some underlying conditions can affect both fertility and sexual function. Hormonal disorders, certain medications, chronic diseases, psychological stress, and reproductive conditions may influence both.
AUA/ASRM recommends assessing erectile dysfunction, ejaculatory dysfunction, and reduced libido in men presenting with infertility concerns because these issues can affect the ability to conceive and may require separate treatment.
Key Takeaway
Low sperm count is a common and treatable component of male fertility problems, but it should not be interpreted as a simple pass-or-fail fertility test.
The current WHO sixth-edition reference data place the lower fifth-percentile sperm concentration at about 16 million sperm/mL and total sperm number at about 39 million per ejaculate. These figures are statistical reference values rather than a definitive boundary between fertility and infertility.
The most useful approach is to investigate why the sperm count is low. Depending on the individual, the cause may involve varicocele, hormonal disorders, genetic factors, testicular disease, reproductive-tract obstruction, medication or testosterone exposure, infections, lifestyle factors, or other medical conditions.
A semen analysis provides important information, but it is only one part of the fertility assessment. When abnormalities persist, a male reproductive specialist can determine whether additional hormone testing, genetic evaluation, imaging, treatment of an underlying condition, sperm retrieval, IUI, IVF, or ICSI may be appropriate.
Most importantly, a low sperm count does not automatically mean that biological parenthood is impossible. The appropriate treatment depends on the complete reproductive picture of both partners.
Frequently Asked Questions
What is considered a low sperm count?
The WHO sixth-edition laboratory manual gives a lower fifth-percentile reference value of approximately 16 million sperm per milliliter and 39 million sperm per ejaculate. These are reference values, not absolute definitions of infertility.
Is 10 million sperm per mL considered low?
A concentration of 10 million sperm/mL is below the WHO sixth-edition lower reference value of 16 million/mL. However, the number alone cannot determine whether natural conception is possible. Other semen parameters and the fertility of both partners also matter.
Can a man with low sperm count get someone pregnant?
Yes. Low sperm count can reduce fertility, but it does not automatically prevent natural conception. Some men with reduced sperm concentration can father a pregnancy without assisted reproductive treatment.
What are the main symptoms of low sperm count?
Low sperm count usually has no specific symptoms. Difficulty conceiving is often the first indication. Symptoms such as testicular swelling, pain, hormonal changes, erectile problems, or reduced libido may point toward an underlying condition rather than the low sperm count itself.
How is low sperm count diagnosed?
The primary test is a semen analysis. It measures sperm concentration and evaluates other parameters such as total sperm number, motility, morphology, and semen volume. An abnormal result may be followed by repeat testing and additional investigations.
Can low sperm count be cured?
Sometimes the underlying cause can be treated or corrected, but there is no universal cure. Treatment depends on whether the cause involves varicocele, hormones, obstruction, medication, testicular disease, genetics, lifestyle factors, or another condition.
Does testosterone increase sperm count?
Exogenous testosterone can actually suppress sperm production. AUA/ASRM advises against prescribing testosterone to men who are interested in current or future fertility.
Do fertility supplements increase sperm count?
Evidence for routine antioxidant and vitamin supplementation as a treatment for male infertility is uncertain. AUA/ASRM states that the clinical utility of these supplements is questionable and that available evidence is inadequate to recommend specific agents.
How long does it take to improve sperm count?
The timeframe depends on the cause. Because sperm production takes time, changes are generally evaluated over weeks to months rather than days. A repeat semen analysis is commonly used to determine whether an abnormal result persists.
Can IVF or ICSI help with very low sperm count?
Yes. IVF and particularly ICSI can allow fertilization when sperm numbers or quality are substantially impaired. In selected cases where sperm are absent from the ejaculate, sperm may also be retrieved surgically for use in assisted reproduction.
Should both partners be tested for infertility?
Yes. AUA/ASRM recommends concurrent evaluation of both partners because infertility may involve male factors, female factors, a combination of both, or unexplained causes.
Is low sperm count the same as azoospermia?
No. Low sperm count means sperm concentration or total sperm number is reduced. Azoospermia means sperm are absent from the ejaculate. The causes and treatment approaches can be different.