What Causes Low Sperm Count and How to Fix It

Low sperm count — medically known as oligozoospermia — is one of the most common causes of male infertility. It is defined as having fewer than 15 million sperm per milliliter of semen. But a diagnosis of low sperm count is not a dead end. For the majority of men, the underlying causes are identifiable and addressable.

What Is Considered a Low Sperm Count?

According to World Health Organization reference values, a normal sperm count is 15 million sperm per milliliter or more, with a total count of 39 million or more per ejaculate. Below these thresholds, fertility potential decreases — though conception is still possible depending on other sperm parameters like motility and morphology.

Severe oligozoospermia is defined as fewer than 5 million sperm per milliliter. Azoospermia — the complete absence of sperm — is a separate condition requiring medical evaluation.

The Most Common Causes of Low Sperm Count

Varicocele. A varicocele is an enlargement of the veins within the scrotum, similar to varicose veins. It is the most common reversible cause of male infertility, found in approximately 15% of all men and up to 35% of men with fertility issues. Varicoceles raise the temperature of the testicles, disrupting sperm production. Surgical treatment can significantly improve sperm count and quality.

Hormonal imbalances. Testosterone and other hormones — including FSH and LH — regulate sperm production. Low testosterone, elevated estrogen, thyroid disorders, and elevated prolactin can all reduce sperm count. A simple blood test can identify hormonal causes.

Infections. Certain infections — including sexually transmitted infections like chlamydia and gonorrhea, as well as mumps orchitis — can cause inflammation that damages the testicles or blocks sperm transport. Some infections cause no symptoms and are only discovered during fertility testing.

Lifestyle factors. Obesity, smoking, heavy alcohol use, anabolic steroid use, and exposure to environmental toxins such as pesticides and heavy metals are all associated with significantly reduced sperm count. These are among the most modifiable causes.

Oxidative stress. When free radicals exceed the body's antioxidant defenses, sperm cells — which are particularly vulnerable due to their high fat content — suffer DNA damage and reduced production. Poor diet, chronic stress, and environmental exposure all contribute to oxidative stress.

Undescended testicles. In some men, one or both testicles did not descend fully into the scrotum during development. Even after surgical correction, this can affect sperm production long-term.

Medications. Certain medications — including some antibiotics, testosterone replacement therapy, chemotherapy, and anabolic steroids — can suppress sperm production. Always discuss fertility implications with your doctor before starting any new medication.

How to Improve Low Sperm Count

Once medical causes like varicocele or hormonal imbalance have been ruled out or treated, there is a great deal men can do on their own to improve sperm count:

Losing excess weight has been shown to significantly improve sperm parameters in overweight and obese men. Even a 5-10% reduction in body weight can produce measurable improvements.

Quitting smoking is one of the most impactful changes a man can make. Smoking is directly linked to lower sperm count, reduced motility, and increased DNA fragmentation.

Reducing alcohol to moderate levels — or eliminating it entirely — removes a significant source of oxidative stress and hormonal disruption.

Avoiding heat exposure to the testicles — including hot tubs, saunas, and laptops on the lap — protects the temperature-sensitive environment needed for healthy sperm production.

Targeted supplementation with nutrients shown to support spermatogenesis can meaningfully improve sperm count over a 3-month cycle. Zinc and Folate are the most directly linked to sperm production, while CoQ10 and Selenium protect developing sperm from oxidative damage. L-Carnitine supports the energy production sperm need to develop and move properly.

Supersperm Plus combines all of these nutrients in a single daily formula, making it one of the most comprehensive male fertility supplements available for men looking to improve their sperm count naturally.

When to See a Doctor

If you and your partner have been trying to conceive for 12 months without success — or 6 months if your partner is over 35 — it is worth getting a semen analysis. It is a simple, non-invasive test that gives you a clear picture of your sperm count, motility, and morphology, and points to next steps.

The good news is that for most men, low sperm count is not permanent. With the right changes and consistent supplementation, meaningful improvement is achievable within 3 months.