Low sperm count, medically known as oligozoospermia, is one of the common findings associated with male infertility.
It means that the concentration of sperm in a man’s semen is lower than the reference range used during semen analysis.
Quick Answer
Low sperm count, medically known as oligozoospermia, means that the concentration of sperm in semen is lower than the reference range used during semen analysis. It can have many causes, including hormonal problems, varicocele, testicular conditions, certain medications, anabolic steroids, lifestyle factors and genetic conditions. A low sperm count does not automatically mean permanent infertility, and some causes can be treated.
However, a low sperm count does not automatically mean that a man is infertile.
Fertility depends on several factors, including sperm concentration, total sperm number, sperm movement, sperm shape and the reproductive health of both partners.
Key Takeaways
- Low sperm count means a reduced sperm concentration in semen.
- A low sperm count does not automatically mean that a man is infertile.
- Sperm concentration is only one part of a complete semen analysis.
- Hormonal disorders, varicocele, testicular problems and genetic conditions can reduce sperm production.
- Testosterone and anabolic steroid use can significantly suppress sperm production.
- Smoking, excessive alcohol use, obesity and some environmental factors may affect sperm health.
- Semen analysis is the primary test used to assess sperm concentration and other semen parameters.
- An abnormal semen analysis may need to be repeated because sperm parameters can naturally fluctuate.
- Some causes of low sperm count are treatable.
- IVF, ICSI and sperm-retrieval procedures may provide options for men with severe sperm abnormalities.
What Is a Low Sperm Count?
Sperm concentration refers to the number of sperm present in one millilitre of semen.
Semen analysis also measures other characteristics, including sperm motility, morphology, semen volume and total sperm number.
The WHO provides standardized laboratory methods for examining semen and interpreting its characteristics. (World Health Organization)
What Sperm Count Is Considered Low?
A semen report can contain several different sperm measurements, so “sperm count” can sometimes be confusing.
A laboratory may report:
- Sperm concentration
- Total sperm number
- Progressive motility
- Total motility
- Sperm morphology
- Semen volume
- Sperm vitality
Earlier WHO reference data reported a fifth-percentile sperm concentration of approximately 15 million sperm per millilitre among men whose partners had achieved pregnancy within a defined period.
However, reference values should not be treated as a strict line separating fertile and infertile men. (Cooper et al. 2009)
A man with a sperm concentration below a reference value may still father a child naturally, while a man with a concentration within the reference range may still experience fertility difficulties.
Does Low Sperm Count Mean Infertility?
Not necessarily.
A reduced sperm concentration can decrease the probability of conception, particularly when the reduction is substantial.
However, sperm concentration alone cannot determine whether a man is fertile or infertile.
Doctors consider the complete semen analysis together with medical history, physical examination, reproductive history and, when appropriate, hormonal or genetic testing.
What Causes Low Sperm Count?
Low sperm production can have many different causes.
Common contributors include:
- Hormonal disorders
- Varicocele
- Testicular injury
- Undescended testes
- Previous testicular surgery
- Genetic conditions
- Certain infections
- Chemotherapy or radiation
- Anabolic steroid use
- External testosterone use
- Certain medications
- Obesity and metabolic problems
- Smoking
- Excessive alcohol consumption
- Certain environmental or occupational exposures
Sometimes, however, no clear cause can be identified.
Can Hormonal Problems Cause Low Sperm Count?
Yes.
Sperm production depends on communication between the hypothalamus, pituitary gland and testes.
Hormonal disorders affecting this system can reduce sperm production and, in some cases, severely impair or stop it.
This is why hormonal evaluation may be considered when sperm counts are very low or when other symptoms suggest an endocrine problem.
Can Testosterone Treatment Lower Sperm Count?
Yes.
This is particularly important for men who are trying to have children.
External testosterone can suppress the hormonal signals that stimulate sperm production inside the testes.
As a result, sperm production may decrease significantly in some men.
Therefore, testosterone replacement should not be considered a fertility treatment.
Men concerned about low testosterone who are also trying to conceive should discuss fertility-preserving options with a qualified clinician.
Can Varicocele Cause Low Sperm Count?
Yes.
A varicocele is an enlargement of veins surrounding the testicle.
It can be associated with impaired testicular function and abnormal semen parameters in some men.
However, having a varicocele does not automatically mean that a man has a low sperm count.
Treatment is generally considered only in selected men based on clinical findings, semen results and fertility goals.
Can Obesity Affect Sperm Count?
Obesity and metabolic health can influence male reproductive function.
Possible mechanisms include hormonal changes, increased oxidative stress and alterations in testicular function.
However, obesity does not mean that a man will necessarily have a low sperm count.
Improving overall metabolic health may be beneficial for reproductive health as well as general wellbeing.
Can Smoking Affect Sperm Count?
Smoking has been associated with poorer semen quality and may affect several sperm characteristics.
Potential effects include changes in sperm concentration, movement, morphology and DNA integrity.
For men trying to conceive, stopping smoking is an important modifiable step toward improving overall reproductive health.
Can Anabolic Steroids Cause Low Sperm Count?
Yes.
This is an important consideration for men who use anabolic steroids for bodybuilding or athletic performance.
External anabolic-androgenic steroids can suppress the body’s natural reproductive hormone signals.
This can substantially reduce sperm production and, in some men, may result in temporary absence of sperm in the ejaculate.
Can Low Sperm Count Cause Symptoms?
Usually, low sperm count does not cause obvious physical symptoms.
A man may have:
- Normal erections
- Normal ejaculation
- Normal sexual desire
- Normal orgasm
- Normal genital sensation
The problem may only become apparent when a couple experiences difficulty achieving pregnancy.
This is why fertility problems can sometimes remain unnoticed until conception is attempted.
How Is Low Sperm Count Diagnosed?
The main initial test is a semen analysis.
The laboratory evaluates characteristics such as sperm concentration, total sperm number, motility, morphology and semen volume.
Because semen parameters can naturally vary between samples, an abnormal result may need to be confirmed with another semen analysis.
The WHO recommends standardized laboratory procedures to improve the quality and consistency of semen examination. (World Health Organization)
What Happens If the Sperm Count Is Very Low?
A very low sperm count may lead a doctor to investigate further.
Depending on the results, evaluation may include:
- Hormone testing
- Physical examination
- Assessment for varicocele
- Medical and medication history
- Genetic testing in selected cases
- Evaluation for previous testicular injury or surgery
- Assessment of possible reproductive tract obstruction
The appropriate tests depend on the severity of the sperm abnormality and the individual’s medical history.
When Should a Man Have His Sperm Tested?
A semen analysis is commonly considered when a couple has been trying to conceive without success.
Evaluation is generally recommended after 12 months of regular unprotected intercourse, although testing may be appropriate earlier when there are known fertility risk factors.
These can include previous testicular problems, reproductive surgery, chemotherapy, anabolic steroid use or significant sexual or reproductive symptoms.
What Other Factors Can Cause Low Sperm Count?
Low sperm count can result from problems affecting the testes, hormones, reproductive tract or overall health.
Sometimes the cause is obvious, such as previous testicular damage or anabolic steroid use.
In other men, several factors may contribute at the same time.
Can Heat Exposure Affect Sperm Production?
The testes function best at a temperature slightly below core body temperature.
Prolonged or repeated exposure to increased scrotal temperature has been investigated as a potential contributor to impaired sperm production.
However, everyday activities should not automatically be considered a cause of infertility.
Can Medications Cause Low Sperm Count?
Yes.
Some medications can interfere with sperm production or reproductive hormones.
Potential examples include certain hormonal treatments, chemotherapy drugs and other medications that affect reproductive function.
Men should not stop prescribed medication on their own. Instead, they should discuss possible fertility effects with their doctor.
Can Chemotherapy Affect Sperm Production?
Yes.
Some chemotherapy treatments can damage sperm-producing cells in the testes.
The effect may be temporary or permanent depending on the specific drugs, doses and individual circumstances.
Men who may undergo chemotherapy and want children in the future should discuss fertility preservation, including sperm banking, before treatment whenever possible.
Can Previous Testicular Injury Cause Low Sperm Count?
Yes.
Because the testes are responsible for sperm production, significant injury or conditions affecting testicular function can potentially reduce sperm production.
A history of testicular trauma, torsion, surgery or undescended testes can therefore be important during a fertility evaluation.
Can Genetic Conditions Cause Low Sperm Count?
Yes.
Genetic abnormalities can interfere with sperm production in some men.
Examples include Klinefelter syndrome and Y-chromosome microdeletions.
Genetic testing may be considered in men with severe oligozoospermia or azoospermia when the clinical findings suggest a genetic cause.
Can Infections Affect Sperm Count?
Certain infections and inflammatory conditions can affect male reproductive function.
They may interfere with sperm production, sperm movement or the passage of sperm through the reproductive tract.
Some sexually transmitted infections can also cause inflammation or scarring that may interfere with fertility if left untreated.
Can Diabetes Affect Male Fertility?
Diabetes can affect several aspects of male reproductive health.
Poorly controlled diabetes may be associated with changes in sperm quality, oxidative stress and reproductive hormone regulation.
It can also contribute to erectile or ejaculation problems, potentially making conception more difficult.
Can Stress Affect Sperm Count?
Severe or prolonged psychological stress may influence reproductive health through hormonal and behavioral pathways.
Stress can also affect sleep, exercise, alcohol consumption and other lifestyle factors that may indirectly influence sperm health.
However, stress should not automatically be assumed to be the sole cause of an abnormal semen analysis.
Can Lack of Sleep Affect Sperm Health?
Sleep and reproductive health have increasingly been studied together.
Poor sleep may be associated with hormonal changes and lifestyle patterns that could influence semen quality.
Maintaining adequate, regular sleep is therefore a reasonable part of an overall approach to reproductive health.
Can Alcohol Lower Sperm Count?
Excessive alcohol consumption can negatively affect male reproductive health.
Heavy alcohol use may interfere with testosterone regulation, testicular function and semen quality.
Reducing excessive alcohol intake can therefore be an important lifestyle step for men trying to optimize reproductive health.
Can Smoking Affect Sperm Quality?
Smoking exposes the reproductive system to numerous chemicals and oxidative stress.
Research has associated tobacco use with adverse effects on several semen parameters and sperm function.
Stopping smoking is therefore an important modifiable step for men concerned about reproductive health.
How Is a Low Sperm Count Confirmed?
An abnormal semen analysis does not automatically mean permanent infertility.
Semen parameters can vary between samples because of factors such as illness, abstinence duration and biological variation.
For this reason, repeat semen analysis may be recommended when an initial result is abnormal.
A complete evaluation considers sperm concentration together with motility, morphology and total sperm number.
The AUA and ASRM recommend semen analysis as a key component of the initial male infertility evaluation and emphasize that semen parameters should be interpreted in the context of the complete clinical picture. (AUA/ASRM)
What If the Sperm Count Is Extremely Low?
Very low sperm concentration requires more detailed evaluation.
A doctor may assess:
- Hormonal function
- Testicular size and consistency
- Varicocele
- Previous surgery or injury
- Medication and anabolic steroid use
- Genetic factors
- Possible reproductive tract obstruction
The European Association of Urology recommends a structured evaluation of men with abnormal semen parameters, including assessment of medical history, physical findings and relevant hormonal or genetic factors when indicated. (EAU)
What Is Azoospermia?
Azoospermia means that no sperm are detected in the ejaculate.
It is different from oligozoospermia, where sperm are present but their concentration is reduced.
Azoospermia may occur because the testes produce little or no sperm, or because sperm are produced but cannot reach the ejaculate because of an obstruction.
The distinction is important because treatment options can differ considerably between these conditions.
Can Low Sperm Count Be Improved Naturally?
Sometimes lifestyle changes may help, particularly when modifiable risk factors contribute to poor sperm health.
Helpful measures can include:
- Maintaining a healthy weight
- Regular physical activity
- Avoiding tobacco
- Limiting excessive alcohol
- Avoiding anabolic steroids
- Managing chronic diseases
- Getting adequate sleep
- Eating a balanced diet
However, lifestyle changes cannot correct every cause of low sperm count.
Genetic conditions, severe testicular damage and certain hormonal disorders may require specialized medical treatment.
Can Supplements Increase Sperm Count?
Many supplements are marketed for male fertility, including antioxidants, vitamins, minerals and herbal products.
However, evidence for fertility supplements is mixed.
Taking large doses of individual nutrients can also be harmful, so men should not assume that a supplement is automatically safe or effective simply because it is marketed for fertility.
Can Frequent Ejaculation Cause Low Sperm Count?
Frequent ejaculation can temporarily reduce the amount of sperm present in an individual ejaculate, particularly when ejaculations occur close together.
This does not necessarily mean that sperm production is impaired.
For fertility testing, the laboratory may provide specific instructions regarding sexual abstinence before collecting a semen sample.
Can Low Sperm Count Be Treated?
Yes. Treatment depends on why the sperm count is low.
Some men may improve after treating an underlying medical condition, while others may need medication, surgery, sperm retrieval or assisted reproductive techniques.
The goal is not simply to increase the sperm count but to improve the couple’s overall chance of achieving pregnancy.
Can Hormonal Treatment Improve Sperm Production?
In selected men, yes.
When low sperm production is caused by certain hormonal disorders, treatment directed at the underlying hormonal problem can sometimes stimulate sperm production.
However, testosterone replacement is not a fertility treatment.
External testosterone can suppress the hormones required for sperm production and may substantially reduce sperm production in some men. (EAU)
Can Varicocele Treatment Improve Sperm Count?
In appropriately selected men, varicocele repair may improve semen parameters and potentially fertility outcomes.
Treatment is generally considered when an infertile man has a clinically detectable varicocele and abnormal semen parameters, rather than simply because a varicocele is present.
The decision should take into account the man’s examination, semen results and reproductive goals.
Can Surgery Treat Low Sperm Count?
Sometimes.
Surgery may be useful when low sperm availability is related to an anatomical problem.
For example, selected men with reproductive tract obstruction may undergo surgical reconstruction.
Varicocele repair may also be considered in appropriately selected patients.
Not every man with a low sperm count requires surgery.
What If There Are Very Few or No Sperm?
Very severe sperm abnormalities do not necessarily mean that biological fatherhood is impossible.
If sperm are being produced inside the testes but cannot reach the ejaculate because of an obstruction, sperm retrieval may sometimes be possible.
In selected men with extremely poor sperm production, sperm can also sometimes be retrieved directly from testicular tissue.
These sperm may then be used for assisted reproductive treatment.
Can IVF or ICSI Help With Low Sperm Count?
Yes.
In vitro fertilization (IVF) may be considered when natural conception is difficult.
Intracytoplasmic sperm injection (ICSI) involves injecting a single sperm directly into an egg and can be particularly useful when sperm numbers or movement are severely impaired.
The choice between natural conception, IUI, IVF, ICSI or sperm-retrieval procedures depends on the severity and cause of male-factor infertility as well as factors affecting the female partner.
Can Lifestyle Changes Improve Sperm Health?
Lifestyle changes can be useful, particularly when modifiable risk factors are present.
Men can support reproductive health by:
- Maintaining a healthy body weight
- Exercising regularly
- Avoiding smoking
- Limiting excessive alcohol
- Avoiding anabolic steroids
- Managing chronic diseases
- Getting adequate sleep
- Eating a balanced diet
- Discussing potentially fertility-affecting medications with a doctor
Obesity, smoking, excessive alcohol consumption and low physical activity have all been investigated as potentially modifiable factors associated with male reproductive health. (Salas-Huetos et al. 2017)
However, lifestyle changes should not delay medical evaluation when a semen analysis is significantly abnormal.
Do Fertility Supplements Work?
This is an area where caution is important.
Antioxidants, vitamins and other supplements are widely marketed for improving sperm count and quality.
However, evidence has not established that antioxidant supplementation consistently improves the chance of achieving a live birth.
A Cochrane review found that evidence regarding antioxidants for male subfertility remained uncertain, highlighting the need for better-quality research. (Smits et al. 2019)
This means supplements should not be considered a guaranteed treatment for low sperm count.
How Long Does It Take to Improve Sperm Count?
Changes in sperm production generally take weeks to months, rather than just a few days.
This is because sperm development is a multi-stage biological process.
Therefore, when an underlying problem is treated or lifestyle changes are introduced, a follow-up semen analysis may be scheduled after an appropriate interval rather than immediately.
Can Low Sperm Count Be Reversed?
Sometimes.
If the underlying cause is treatable, sperm production may improve after appropriate management.
For example, addressing certain hormonal disorders, stopping fertility-suppressing substances under medical supervision or treating selected reproductive conditions may improve semen parameters.
However, some causes, including certain genetic conditions or severe testicular damage, may not be completely reversible.
Did You Know?
A man’s sperm count is not necessarily a fixed number. Semen parameters can vary between tests because of biological variation, recent illness, abstinence duration and other factors. This is one reason why a single abnormal semen analysis does not always provide the complete picture of male reproductive health.
Lesser-Known Fact About Low Sperm Count
Sperm Count Can Change Between Two Semen Tests
A man’s sperm count is not necessarily a fixed number.
Semen parameters can fluctuate because of illness, fever, abstinence duration, lifestyle factors and normal biological variation.
This is why one abnormal semen analysis does not always provide the complete picture.
A repeat test can sometimes provide a better understanding of a man’s usual semen parameters.
Does Low Sperm Count Affect Sexual Performance?
Usually, no.
A man can have a very low sperm count while maintaining normal:
- Sexual desire
- Erections
- Ejaculation
- Orgasm
- Penile sensation
Fertility and sexual performance involve different physiological processes.
Therefore, normal sexual function does not necessarily mean that sperm production is normal.
When Should You See a Doctor?
A man should consider a fertility evaluation if:
- Pregnancy has not occurred after 12 months of regular unprotected intercourse
- A previous semen analysis was abnormal
- There is a history of testicular injury
- There has been testicular or reproductive surgery
- There is a history of undescended testes
- He has used anabolic steroids or testosterone
- He has undergone chemotherapy or radiation
- There are erectile or ejaculation problems
- There is a known hormonal or genetic condition
Earlier evaluation may be appropriate when a known fertility risk factor is already present.
Low Sperm Count: Myth vs Fact
| Myth | Fact |
|---|---|
| Low sperm count means a man is completely infertile. | Low sperm count can reduce the chance of conception, but it does not automatically mean permanent infertility. |
| A man with normal erections has normal sperm. | Sexual performance and sperm production are different processes. A man can have normal erections and still have a low sperm count. |
| One abnormal semen test proves infertility. | Semen parameters can fluctuate, so repeat testing may sometimes be recommended. |
| Low sperm count is always caused by lifestyle. | Lifestyle can contribute, but hormonal, genetic, testicular, anatomical and medical causes are also possible. |
| Taking testosterone increases fertility. | External testosterone can suppress sperm production and may reduce fertility. |
| Varicocele always causes low sperm count. | Varicocele can affect sperm production in some men, but not every man with a varicocele has infertility. |
| Frequent ejaculation permanently lowers sperm production. | Frequent ejaculation can temporarily reduce sperm numbers in an individual ejaculate, but this is not the same as permanently impaired sperm production. |
| Fertility supplements can always fix low sperm count. | Evidence for fertility supplements is mixed, and treatment should focus on identifying the underlying cause. |
| Low sperm count cannot be treated. | Some causes can be treated medically or surgically, while assisted reproductive techniques may help selected couples. |
What Should You Do After an Abnormal Semen Analysis?
Do not panic after receiving one abnormal result.
A low sperm count is a finding that requires context, not automatically a diagnosis of permanent infertility.
The next step may involve repeat semen testing and, depending on the results, physical examination, hormonal testing, genetic testing or evaluation for conditions such as varicocele.
A urologist, andrologist or fertility specialist can help determine the appropriate next steps.
Final Thoughts
A low sperm count can be concerning, but it does not automatically mean permanent infertility. Several different factors can affect sperm production, and some of these causes can be treated or managed.
If a semen analysis shows a low sperm count, the most important step is to identify the underlying cause rather than relying on supplements or internet remedies. A qualified urologist, andrologist or fertility specialist can help determine the appropriate next steps.
Conclusion
Low sperm count is a common male reproductive concern, but it does not automatically mean that a man cannot father a child.
Sperm concentration is only one part of a semen analysis, and fertility also depends on sperm movement, morphology, total sperm number and the reproductive health of both partners.
Causes can range from hormonal disorders and varicocele to medications, anabolic steroids, genetic conditions, infections and lifestyle factors.
The good news is that some causes are treatable, and even men with very low sperm counts may have options through medical treatment, surgery, sperm retrieval or assisted reproductive techniques such as IVF and ICSI.
If a semen analysis shows a low sperm count, the most useful step is not to rely solely on supplements or internet remedies.
Instead, seek a proper medical evaluation to identify the underlying cause and determine the most appropriate treatment.
Frequently Asked Questions About Low Sperm Count
1. What is considered a low sperm count?
A low sperm count means that sperm concentration is below the reference range used when interpreting a semen analysis. Sperm concentration should be considered together with other semen parameters.
2. Can a man with low sperm count have a baby?
Yes. A low sperm count does not automatically mean that natural conception is impossible. The likelihood depends on sperm concentration, motility, morphology and other reproductive factors.
3. What causes low sperm count in men?
Possible causes include hormonal disorders, varicocele, testicular conditions, genetic abnormalities, infections, certain medications, anabolic steroids, external testosterone and some lifestyle or environmental factors.
4. Can testosterone cause low sperm count?
Yes. External testosterone can suppress the hormones that stimulate sperm production and may significantly reduce sperm production in some men.
5. Can obesity affect sperm count?
Obesity and metabolic problems may affect male reproductive health through hormonal and metabolic changes, although not every man with obesity will have a low sperm count.
6. Can smoking reduce sperm count?
Smoking has been associated with poorer semen quality and may affect sperm concentration, movement, morphology and other aspects of sperm function.
7. Can varicocele cause low sperm count?
Yes. A varicocele can affect testicular function and sperm production in some men, although not every man with a varicocele has impaired fertility.
8. Can low sperm count be treated naturally?
Lifestyle improvements may help when modifiable factors contribute to poor sperm health, but they cannot correct every cause. Medical evaluation is important when the sperm count is significantly abnormal.
9. Can low sperm count be reversed?
Sometimes. Treating an underlying hormonal, medical or reproductive problem may improve sperm production, while some genetic or severe testicular conditions may not be completely reversible.
10. When should a man see a doctor for low sperm count?
A man should consider medical evaluation after an abnormal semen analysis, when pregnancy has not occurred after 12 months of regular unprotected intercourse, or earlier when known fertility risk factors are present.
