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Cannabis and Viagra: is it a safe combination?

Cannabis and Viagra: is it a safe combination?

In general, cannabis can be helpful for male sexual function, including getting and maintaining an erection, but also for men with low libido and those who experience early finish. 

Viagra is used to treat erectile dysfunction – that’s a well-known fact. Not so commonly known is that patients will not get an erection just by taking a little blue pill. Rather, Viagra helps a man get and keep an erection only when he is sexually stimulated. 

With that in mind, cannabis directly targets the libido, increasing feelings of arousal by cannabinoids sending neurotransmitters to the brain, interacting with the endocannabinoid system (ECS) that monitors pleasure and relaxation, and ultimately heightening the two. 

“Cannabis and the PDE-5 inhibitors – Viagra and Cialis, for example, that relax muscles and increase blood flow to the penis – are generally safe to use together,” says Jordan Tishler, MD, who is on the faculty at Harvard Medical School, president of the Association of Cannabinoid Specialists, and CEO/CMO at inhaleMD, a patient-focused clinical practice. 

“There is some evidence that THC can interact with Cialis (Tadalafil) specifically but I’ve never seen it become a real-world problem,” he says.  

Tishler goes on to explain that this means some interactions are theoretical (based on the biology) but don’t seem to actually occur in the real world (or at least not noticeably). “I’ve never seen a cannabis-related Cialis adverse event. Could happen, but doesn’t seem to come up.”

However, says Tishler, “cannabis is very dose dependent. A little can be helpful, but too much can backfire and shut down sexual experience. For men with erectile dysfunction (ED), cannabis in too high a dose can cause loss of erection. Overall, cannabis can be wonderfully helpful, but is really best done in conjunction with medical guidance to avoid pitfalls.”

Viagra and cannabis have the potential to work together. However, it is worth noting that Viagra is predominantly metabolized by an liver enzyme known as CYP3A4, which can be inhibited by CBD. This means that when taken together, the effects of sildenafil (Viagra) could be increased, increasing the risk of side effects like headaches and dizziness. 1

Since little research focuses on the specific topic of inhibitors as well as men’s sexual wellness and health in general, more research is needed.

Erectile dysfunction, underlying issues and cannabis

Sexual arousal involves the brain, hormones, emotions, nerves, muscles and blood vessels, and ED can result from a problem with any of these. Stress can also be a  trigger. Often, it is a combination of physical and psychological issues. Cannabis can help. 

The endocannabinoid system helps to regulate erectile function and sexual behavior of males through the binding of receptors in the paraventricular nucleus of the hypothalamus, among other locations. 2

This could also explain why cannabis can improve sexual function in some patients affected by conditions or symptoms such as depression, anxiety disorder and pain. 3 4

Growing evidence, both in animal and human studies, reported a peripheral effect of cannabis on ED, specifically on corpus cavernosum, the erectile tissue forming the bulk of the penis, where cannabinoid receptors are present. 5 6

Not all of the research is in agreement, though. There are some studies associating cannabis-use orgasm disorders in men. In fact, both the inability to finish and finishing too quickly were associated with cannabis use in one survey of Australian men. It remains unclear if this is cannabis related or if common tobacco use alongside cannabis is confounding (altering) this finding. 7

But most agree that the right dose of cannabis can turn an ordinary experience into an extraordinary one – and that includes a sexual experience. 

In fact, according to a 2021 review article looking at cannabis and male reproductive health “some studies have suggested that 70–85% of marijuana consumers experience increased sexual pleasure and satisfaction, 25–40% prolonged duration of intercourse, and 55–70% heightened orgasmic sensation.” 8

THC can slow down time and intensify feelings of sexual pleasure while CBD reduces stress, lessens anxiety and may even relieve depression by activating serotonin receptors in the brain. 9

Some studies suggest cannabis use even increases testosterone levels. However, other studies have found the opposite effect on testosterone and also suggest that THC is a bit of a passion killer (dosage is key, less is better). More research needs to be conducted, including human trials. 

Can cannabis replace Viagra? It probably can’t for the majority of men, but the combination can ensure sexual desire, arousal, orgasm and overall satisfaction.


  1. MacCallum CA, Lo LA, Boivin M. “Is medical cannabis safe for my patients?” A practical review of cannabis safety considerations. Eur J Intern Med. 2021;89:10-18. doi:10.1016/j.ejim.2021.05.002
  2. Argiolas, A., & Melis, M. R. (2005). Central control of penile erection: role of the paraventricular nucleus of the hypothalamus. Progress in neurobiology, 76(1), 1–21. https://doi.org/10.1016/j.pneurobio.2005.06.002
  3. Gobbi, G., Atkin, T., Zytynski, T., Wang, S., Askari, S., Boruff, J., Ware, M., Marmorstein, N., Cipriani, A., Dendukuri, N., & Mayo, N. (2019). Association of Cannabis Use in Adolescence and Risk of Depression, Anxiety, and Suicidality in Young Adulthood: A Systematic Review and Meta-analysis. JAMA psychiatry, 76(4), 426–434. https://doi.org/10.1001/jamapsychiatry.2018.4500
  4. Huang, W. J., Chen, W. W., & Zhang, X. (2016). Endocannabinoid system: Role in depression, reward and pain control (Review). Molecular medicine reports, 14(4), 2899–2903. https://doi.org/10.3892/mmr.2016.5585
  5. Gratzke, C., Christ, G. J., Stief, C. G., Andersson, K. E., & Hedlund, P. (2010). Localization and function of cannabinoid receptors in the corpus cavernosum: basis for modulation of nitric oxide synthase nerve activity. European urology, 57(2), 342–348. https://doi.org/10.1016/j.eururo.2008.12.024
  6. Melis, M. R., Succu, S., Mascia, M. S., Sanna, F., Melis, T., Castelli, M. P., & Argiolas, A. (2006). The cannabinoid receptor antagonist SR-141716A induces penile erection in male rats: involvement of paraventricular glutamic acid and nitric oxide. Neuropharmacology, 50(2), 219–228. https://doi.org/10.1016/j.neuropharm.2005.09.009
  7. Maccarrone, M., Rapino, C., Francavilla, F., & Barbonetti, A. (2021). Cannabinoid signalling and effects of cannabis on the male reproductive system. Nature reviews. Urology, 18(1), 19–32. https://doi.org/10.1038/s41585-020-00391-8
  8. Ibid
  9. Sales, A. J., Crestani, C. C., Guimarães, F. S., & Joca, S. (2018). Antidepressant-like effect induced by Cannabidiol is dependent on brain serotonin levels. Progress in neuro-psychopharmacology & biological psychiatry, 86, 255–261. https://doi.org/10.1016/j.pnpbp.2018.06.002
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