Why Has My Ejaculate Volume Decreased?

A Common Concern

Men often come into clinic with concerns about reduced semen volume and/or ejaculatory force. This can feel distressing with some patients worried about underlying malignancy and others simply bothered by decreased sexual performance.

The most important starting point in any discussion with a man suffering from decreased ejaculate volume is to clarify that it is a benign occurrence. While many patients simply want to know that they do not have an underlying cancer or tumor, most wish to investigate further in order to establish a cause and potentially recover their previous volume.

Most Common Cause: Medication

1. Tamsulosin (and other alpha blockers)

By far, the most common cause I encounter is the use of Tamsulosin, a medication prescribed to help men suffering from prostatic enlargement to urinate more easily. This medication works by relaxing smooth muscle fibers in the prostate and bladder neck to lessen the blockage caused by an enlarged prostate.

Why does this matter?

To ejaculate, a man’s body must:

• Emit semen into the prostatic urethra
• Close the bladder neck to prevent retrograde flow
• Contract the pelvic floor to propel semen outward

When the bladder neck stays too relaxed (as it does with alpha blockers), semen is redirected backward into the bladder. This results in retrograde ejaculation—or what appears to be a decrease or absence in ejaculatory volume.

Good news:

Retrograde ejaculation due to tamsulosin use is completely reversible within a few days of medication discontinuation. Many men can pause the medication for a day or two before a planned encounter and experience a return of normal ejaculatory volume.

2. Finasteride / Dutasteride (5-alpha reductase inhibitors)

These medications—used for benign prostatic hyperplasia (BPH) or male-pattern hair loss—can also cause some reduction in ejaculatory volume. However:

• The effect is usually mild and gradual
• Most men do not notice a significant change
• Unlike alpha blockers, the side effect is not quickly reversible

Medical Causes

1. Poorly Controlled Diabetes

In men with diabetes, especially long-standing or poorly managed cases, neuropathy can affect bladder neck control. This can lead to the same retrograde ejaculation seen with medication use.

2. Neurologic Conditions

Spinal cord injuries, neurodegenerative diseases, and post-surgical nerve trauma can all affect the various steps and processes involved in emission, bladder neck closure and pelvic floor contraction necessary for ejaculation. Spinal cord injuries, neurodegenerative diseases, and post-surgical nerve trauma can all affect these steps leading to decreased or absent ejaculation.

Surgical Causes

1. Prostatectomy

The prostate contributes the majority of ejaculatory volume. During the process of emission semen is deposited into the segment of the urethra that passes through the prostate. If you’ve had your prostate removed for prostate or bladder cancer the primary source of semen production is no longer present and ejaculation is no longer possible.

2. Prostate Procedures for BPH

Various procedures are performed in order to increase the dimensions of the prostatic urethra in men who suffer from prostatic enlargement (otherwise known as BPH). These procedures involve the removal of a portion of the prostatic tissue surrounding the urethra and, in many cases, some of the bladder neck. While rates of decreased or absent ejaculation vary by procedure, most men having undergone any of the following procedures will experience significant decrease in ejaculatory volume:

• TURP (Transurethral Resection of the Prostate)
• GreenLight Laser Therapy
• HoLEP (Holmium Laser Enucleation)
• Aquablation

Although traditionally the cause of decreased ejaculate volume has been attributed to disruption of the smooth muscle fibers at the bladder neck, an alternative thought places blame on disruption of the network of ducts that carry seminal fluid within the prostate. In any case, these patients undergoing these procedures should expect permanent loss or reduction in ejaculatory volume.

Anatomic Causes

As noted above, semen is deposited into the prostatic urethra during the process of emission. The semen enters the prostatic urethra through a structure known as the verumontanum. Although rare, patients may experience a narrowing or stricture of the verumontanum resulting in decreased or absent ejaculatory volume. Patients suffering from such obstruction often have notably distended seminal vesicles on transrectal US. This condition may be treated through the transurethral unroofing of the obstructed verumontanum.

Other Common Factors

1. Age-Related Changes

Even in healthy men with no medications or major diagnoses, semen volume naturally decreases over time.

2. Situational & Psychological Variables

Younger men, new partners, higher excitement levels, or longer periods of arousal often produce larger, more forceful ejaculations. Over time or in more routine settings, this may naturally decline without any medical cause.