July 22, 2026, 6:12 pm | Read time: 5 minutes
Viagra has been known for several decades as a potency drug for men. However, the famous blue pills may have another positive effect. Researchers have investigated the impact of Viagra on the spread of cancer–with astonishing results. FITBOOK also inquired with study author Prof. Ayelet Erez about this.
In the late 1990s, Viagra was introduced to the German market as a medication for erectile dysfunction. The small blue pills quickly became the best-known potency drug for men. The active ingredient, Sildenafil, was originally developed to treat high blood pressure and chest pain due to reduced blood flow to the heart. Now, a new study has shown that Sildenafil may have another remarkable effect. Israeli researchers at the Weizmann Institute of Science discovered that the Viagra ingredient could inhibit cancer metastasis through a newly discovered biological mechanism.
How Does Viagra Work?
The active ingredient in Viagra, Sildenafil, belongs to the group of PDE-5 inhibitors. It blocks the enzyme phosphodiesterase type 5 (PDE5), which normally breaks down the messenger substance cGMP. As a result, more cGMP remains available in the smooth muscle cells of the blood vessels in the penis’s erectile tissue. An increased cGMP level relaxes the vascular muscles, the vessels expand, and blood flow to the penis increases. This makes it easier to achieve and maintain an erection under sexual stimulation, making Viagra an effective medication for erectile dysfunction.
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Why Viagra Could Also Help Against Cancer
In the course of the investigation, the Israeli researchers found that the messenger substance cGMP also binds to a protein responsible for cholesterol transport within the cells. This involves the transporter NPC1 in the lysosome membrane. This blocks the export of cholesterol from the lysosomes, effectively trapping the cholesterol there.
For the cell, this means less freely available cholesterol for membranes, lipid rafts, and energy production. Cancer cells are particularly susceptible to this cholesterol deficiency. They are sensitive because they naturally have fewer genes for cholesterol transport in their cellular powerhouses and cannot compensate well for the loss. They rely heavily on cholesterol for growth, movement, and invading other tissues.
In other words, Sildenafil deprives metastasis-prone cancer cells of an important fuel, making it harder for them to detach from the primary tumor, travel through the body, and form new tumor sites in distant organs. This process is known as metastasis. When their access to usable cholesterol is restricted, it becomes more difficult for these cancer cells to form metastases.
Another Active Ingredient Supports the Positive Effect
But there’s more good news. The scientists also found that combining drugs from the Viagra family (PDE5 inhibitors like Sildenafil) with statins–a widely used group of drugs that lower the body’s cholesterol production–can further slow metastasis. In this combination, cancer cells’ access to two central cholesterol sources is hindered:
- PDE5 inhibitors prevent stored cholesterol from being made usable again from the lysosomes.
- Statins, in turn, block the new formation of cholesterol via HMG-CoA reductase.
The interplay of both active ingredients thus creates a double blockade of cholesterol metabolism.
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So, Is Viagra Suitable for Fighting Cancer?
For the study, the researchers used several cancer models in mice. They also examined cultures of tumor cells from human cancer patients. Additionally, they analyzed electronic health data from the Israeli health insurance company Clalit. The data spans 20 years and includes around five million insured individuals. Consistent with the results from mouse models and human cell cultures, the statistical analysis of the Clalit database showed a significantly better survival rate in cancer patients taking Sildenafil. The survival rate increased further when patients also received statins.
Upon inquiry from FITBOOK, Prof. Erez emphasizes that the results do not yet provide proof of a protective effect: “Our work mainly focused on identifying the mechanism of action of Viagra. In cancer patients, we observe a dose-dependent increased survival in those taking Viagra.”
“We have discovered a new biological signaling pathway that connects a known signaling molecule with cholesterol regulation in cells and demonstrated how this pathway can be used to impair cancer cells’ ability to form metastases,” comments Prof. Ayelet Erez from the Weizmann Institute of Science on the results. One must also consider the patient’s metabolic state and medications in cancer therapy. These likely have a strong influence on the development of metastases.
Further Research Needed
“Our study underscores the importance of considering the patient as a whole–and not just the cancer–when selecting the most effective therapy,” explains Prof. Erez. The study may be the first step toward developing new cancer drugs. These could protect cancer patients from metastases by utilizing the newly discovered mechanism of Viagra. However, further in-depth research is needed.
Prof. Erez considers it fundamentally possible that new therapies could indeed develop from this: “I hope so, as both medications are known to have a good safety profile.”
It is important to note: The data from the millions of insured individuals comes from an observational study. While it shows a clear correlation, it does not yet provide definitive proof that Viagra alone extended life.