Hard flaccid syndrome (HFS): what is it, causes, symptoms, treatment

Felix Gussone, MD - Contributor Avatar

Reviewed by Felix Gussone, MD, Ro, 

Written by Gina Allegretti, MD 

Felix Gussone, MD - Contributor Avatar

Reviewed by Felix Gussone, MD, Ro, 

Written by Gina Allegretti, MD 

last updated: Feb 08, 2022

4 min read

It may seem like a simple process: you feel aroused, you get an erection. But there’s a  surprising number of glitches that can happen in the process. 

There’s erectile dysfunction (ED), in which your erections aren’t hard enough or long-lasting enough for satisfying sex. There’s also priapism, a potentially dangerous condition in which you get painfully hard and can’t get soft, even when no longer aroused. If this wasn’t enough, there’s a newly recognized player in the game that falls somewhere in between these issues—introducing: hard flaccid syndrome. 

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What is hard flaccid syndrome? 

Hard flaccid syndrome (HFS) is a new(ish) diagnosis reported since 2018 but has only recently gained more recognition. HFS is a condition in which your penis is semi-erect even when you’re in a flaccid state. This causes symptoms like erectile dysfunction, penile and perineal pain, and psychological distress. It may have a significant impact on your overall quality of life (Abdessater, 2020). 

HFS usually affects people in their 20s and 30s. Some online forums compare it to chronic pelvic pain syndrome (CPPS), since it causes continuous pain in the pelvic region. It’s unclear how many people have the condition since it’s not well-defined, but many online discussion boards and support groups discuss it (Gül, 2020). 

What are the symptoms of hard flaccid syndrome? 

Since HFS has only been recognized by some organizations recently, researchers aren’t sure yet what causes HFS symptoms. Possible symptoms include (Gül-b, 2019): 

  • Erectile dysfunction (ED): Since your penis is half-hard but half-flaccid, it’s difficult to have a fully rigid erection or last long enough for satisfying sex. You may even notice that you don’t have morning wood or get erections during the night. 

  • Penile pain: People with HFS often have pain in the penis or the perineum (the space between the scrotum and the anus). It’s usually worse when you’re standing up. Sometimes the pain feels better after you urinate or when you’re lying on your back. 

  • Painful erections and pain during ejaculation: While there isn’t a clear reason for this, it may be related to pelvic floor spasms, which are painful irregular contractions in your pelvic floor muscles. 

  • Weak urine stream and pain during urination 

  • Decreased libido (sex drive): You may feel less interested in sex or find that you need more stimulation to get aroused than you used to.

  • Numb, cold, or “hollow” feeling in your penis

  • Decreased sensitivity in your penis

  • Soft, flaccid glans (head of the penis)

  • Penis feels “like rubber”

  • Psychological distress: You may experience anxiety and depression, ranging from mild to severe. 

People with HFS usually have no signs in their laboratory tests, so a healthcare provider usually diagnoses this condition based on their symptoms. 

What causes hard flaccid syndrome?  

The exact cause of HFS has yet to be determined, but researchers suspect that it involves multiple factors. 

HFS usually begins a few days after you experience some type of trauma to the penis. The traumatic event may be anything that puts stress on the penis—getting a physical injury, using a vacuum pump or penis pump, jelqing, or even a particularly rigorous bout of masturbating or sex (Gül-b, 2019). 

Physical trauma may damage blood vessels in the penis. Blood flows in but not out, keeping you in a constant semi-erect state. Trauma can also damage nerves in the penis, causing symptoms like pain, numbness, and pelvic floor spasms (Gül-a, 2019). 

HFS symptoms can cause emotional and psychological distress and raise your stress hormones like adrenaline, contributing to pelvic floor spasms. Spasms tighten the pelvic floor muscles, exacerbating HFS symptoms and creating a “vicious cycle” (Gül-b, 2019). It gets more challenging to break as the cycle continues, but that doesn’t mean you’re out of luck. 

How do you treat hard flaccid syndrome? 

There’s no standard treatment for HFS, but there may be different things you can do to treat the symptoms. Since HFS is related to both physical and psychological causes, it’s a good idea to incorporate treatment for both. Working with a therapist and using cognitive behavioral therapy (CBT) are important components of HFS treatment (Hughes, 2018).  

Stress, anxiety, and depression exacerbate HFS, so treating them may help alleviate your symptoms. This may involve breathing exercises, yoga, and mindfulness activities (Abdessater, 2020). Healthy behaviors like eating nutritious foods, maintaining good sleep hygiene, and getting regular exercise also offer many mental health benefits. 

Some people with HFS benefit from treating pelvic floor dysfunction. For example, your healthcare provider might recommend doing pelvic floor physical therapy, massaging pelvic floor muscles with a Z wand device, or using a muscle relaxation technique called reverse Kegel exercises (Hughes, 2018). 

What’s the recovery time for hard flaccid syndrome? 

It’s not entirely clear how long HFS lasts. Some case reports suggest that it lasts for months (Gül, 2020). In some online discussion boards and support groups, people with HFS report that their symptoms lasted weeks to months. However, there’s not enough data to determine the recovery time.  

Viagra for hard flaccid syndrome

There’s not much evidence that Viagra is effective for treating HFS. Small case studies report that people with HFS who took either 50 mg of Viagra (generic name sildenafil) or 5 mg of Cialis (generic name tadalafil) did not improve and eventually stopped taking the medication (Gül, 2020). 

Many people with HFS report in online forums that they were treated with pain relievers, antidepressants, or phosphodiesterase-5 inhibitors like Viagra. Though the treatment wasn’t helpful most of the time, a few individuals had some symptom relief with treatment (Gül-b, 2019; Gül, 2020). 

HFS is not well understood, but it’s starting to get more attention. If you have symptoms of HFS, it’s a good idea to talk to a healthcare provider to discuss the best treatment options for you. 

Viagra Important Safety Information: Read more about serious warnings and safety info.

Cialis Important Safety Information: Read more about serious warnings and safety info.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

  • Abdessater, M., Kanbar, A., Akakpo, W., & Beley, S. (2020). Hard flaccid syndrome: state of current knowledge. Basic and Clinical Andrology, 30,

  1. doi: 10.1186/s12610-020-00105-5. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271516/

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

February 08, 2022

Written by

Gina Allegretti, MD

Fact checked by

Felix Gussone, MD

About the medical reviewer

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.

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