Rare post-orgasm illness causes days-long flu-like symptoms, but research into its cause remains limited

A rare and poorly understood condition known as post-orgasmic illness syndrome, or POIS, causes a wide range of flu-like and allergic symptoms following ejaculation. These symptoms, which can include exhaustion, difficulty concentrating, and muscle weakness, often begin within minutes to hours after orgasm and can persist for several days. Although the condition has been largely observed in men, there is growing, albeit limited, evidence that it may also affect women. A new scientific review published in Sexuality & Culture offers the most up-to-date summary of what is currently known about POIS, highlighting its symptoms, possible causes, and a wide range of treatment attempts—none of which has proven universally effective.

The researchers conducted the review because POIS remains an under-recognized condition with no established diagnostic criteria in medical manuals and no agreed-upon treatment approach. Since it was first described in 2002, only a handful of studies have attempted to systematically explore its causes and potential treatments. The review authors aimed to provide a clearer overview of the scientific literature to help both clinicians and patients better understand the condition and guide future research efforts.

To carry out the review, the authors searched the PubMed database for articles with references to POIS in their titles, abstracts, or keywords. This initial search produced 429 results, which were then narrowed down to English-language studies published between 2020 and 2025. After removing irrelevant or duplicate entries, the authors were left with 29 articles that met their inclusion criteria. These papers formed the basis for their review of the latest knowledge surrounding POIS.

The authors began by reviewing the symptoms and diagnostic criteria most commonly associated with POIS. Because the condition is not formally recognized by diagnostic systems like the International Classification of Diseases or the Diagnostic and Statistical Manual of Mental Disorders, researchers have had to rely on informal criteria. The most widely accepted standards were developed by Dutch psychiatrist Marcel Waldinger and his team, based on reports from 45 male patients. These criteria include flu-like symptoms such as fatigue, feverishness, and irritability; onset of symptoms shortly after ejaculation; recurrence in nearly every ejaculation; and a duration of symptoms typically lasting between two and seven days.

Later research has expanded upon these findings. In what remains the largest study of POIS to date, researcher Natale and colleagues in 2020 surveyed 302 men, 268 of whom met at least three of Waldinger’s diagnostic criteria. The most commonly reported symptoms were difficulty concentrating (reported by 84% of participants), extreme fatigue (83%), irritability (74%), and muscle weakness (70%). Many participants said they avoided sexual activity, masturbation, or even romantic relationships to prevent the debilitating symptoms.

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While POIS has historically been viewed as a male-only condition, newer reports suggest it may also affect women. However, these cases are rare and under-documented, and more research is needed to understand how the condition manifests in female patients.

The cause of POIS remains a subject of intense debate. Early studies proposed that it might be an allergic or autoimmune reaction to a person’s own semen. Waldinger’s research supported this hypothesis through allergy skin tests, which showed positive results in a large majority of POIS patients. A few case studies even documented successful treatment through desensitization therapy using diluted samples of the patient’s semen.

Yet more recent studies have cast doubt on the allergic explanation. Some patients do not show typical allergy responses, and semen-specific antibodies are not always present. Other researchers have proposed alternative explanations, including the idea that POIS may stem from a chemical imbalance in the brain, a dysregulated immune or hormone response, or nervous system dysfunction. A particularly novel theory suggests that POIS results from minor nerve damage in the pelvic muscles responsible for ejaculation, similar to conditions that cause delayed muscle pain.

The varied and sometimes conflicting findings suggest that POIS may have multiple causes. Different patients may experience the condition due to different underlying mechanisms, making it difficult to define a one-size-fits-all explanation.

In addition to physical symptoms, POIS is frequently associated with mental health problems. Studies have reported high rates of depression, anxiety, and obsessive-compulsive disorder in those affected. One study found that 87.5% of POIS patients had at least one of these conditions. Another found a lower, but still significant, rate of 45%. Many individuals also experience premature ejaculation, likely due to low sexual activity or anxiety about triggering symptoms.

Because the exact cause of POIS remains unknown, treatment has been inconsistent and largely experimental. Doctors have tried a wide range of medications and therapies, targeting the suspected underlying causes. In the 2020 Natale study, some of the more commonly used medications included antihistamines, selective serotonin reuptake inhibitors (commonly used to treat depression), and non-steroidal anti-inflammatory drugs. Of these, niacin and anti-inflammatory drugs appeared to be most effective for the highest number of participants, but still only helped a portion of those who tried them.

Other approaches have included hormone therapy, especially in men with low testosterone levels, and psychological interventions like relaxation techniques. A few cases have reported positive outcomes from desensitization therapy or immunotherapy. In one recent and unusual case, a man underwent surgery to block semen from interacting with immune cells in his body and reportedly saw his symptoms disappear. Another case reported improvement after undergoing a microbiota transplant to alter gut bacteria, though it’s unclear whether this treatment played a direct role in his recovery.

Due to the limited number of documented cases and the diversity in symptom expression and treatment outcomes, no official guidelines exist for treating POIS. Most medical professionals are unfamiliar with the condition, and some patients report difficulty discussing their symptoms due to embarrassment or stigma around sexual health. The authors of the review stress the need for personalized approaches to treatment and encourage clinicians to work closely with patients to identify potential triggers and helpful interventions.

While earlier reviews on POIS exist, this new article includes a larger and more recent body of research. The authors recommend that POIS be considered for inclusion in formal disease classification systems like the ICD or DSM to promote awareness and improve clinical recognition. They also emphasize the importance of continuing to explore the condition in both men and women and testing treatment strategies in larger patient samples.

The paper, “Postorgasmic Illness Syndrome: Insights from Recent Literature on a Rare but Fascinating Disorder,” was authored by Krystian Wdowiak, Agnieszka Maciocha, and Julia Wąż.