TL;DR: A new study suggests that sildenafil, the active ingredient in Viagra, may help slow the spread of cancer by disrupting how cancer cells use cholesterol. Researchers found that the drug interferes with a newly identified pathway involved in metastasis, and its effects may be even stronger when combined with cholesterol-lowering statins. While the findings are promising, experts stress that Viagra is not a cancer treatment, and clinical trials are still needed before it could become part of cancer care.

Cancer treatment has advanced dramatically over the past two decades, but one challenge remains stubbornly difficult: preventing cancer from spreading.

Now, researchers believe a familiar drug sitting in millions of medicine cabinets may offer an unexpected advantage. According to a new study published in Cancer Research, sildenafil—the active ingredient in Viagra—could interfere with the biological processes that allow cancer cells to spread throughout the body.

The research, led by scientists at Israel’s Weizmann Institute of Science, points to an entirely new way of thinking about metastasis. Rather than targeting the cancer cells directly, the findings suggest that changing how those cells access cholesterol could make it significantly harder for them to establish new tumors.

The discovery is still in its early stages, and researchers caution that Viagra should not be viewed as a cancer treatment. But the study opens the door to a new area of cancer research built around repurposing existing medicines.

What did researchers discover about Viagra and cancer?

The new research focuses on metastasis, the process in which cancer cells leave the original tumor, travel through the bloodstream or lymphatic system, and establish tumors elsewhere in the body.

Metastatic disease accounts for the vast majority of cancer-related deaths because once cancer spreads, it becomes far more difficult to treat.

Scientists identified a previously unknown biological pathway that metastatic cancer cells use to obtain cholesterol—an essential building block for creating new cell membranes.

Their findings suggest that sildenafil disrupts this pathway, making it harder for cancer cells to access the cholesterol they need to survive and multiply after spreading.

Rather than killing cancer cells outright, the drug may reduce their ability to establish themselves in new organs.

Why is cholesterol so important for cancer cells?

Cholesterol is more than a heart health issue

Most people associate cholesterol with cardiovascular disease, but cholesterol is also critical for every cell in the human body.

Cells use cholesterol to:

• Build and repair cell membranes
• Produce signaling molecules
• Support cell growth and division

Cancer cells have especially high cholesterol demands because they multiply rapidly.

When cancer spreads, newly migrated cells face a hostile environment. To survive, they must quickly rebuild themselves, and cholesterol becomes one of the key resources that enables that process.

The researchers found that blocking access to cholesterol could make metastatic cells significantly less capable of forming new tumors.

How could Viagra interfere with cancer spread?

Sildenafil was originally developed to improve blood flow before becoming one of the world’s most widely prescribed treatments for erectile dysfunction.

Its primary action is inhibiting an enzyme known as phosphodiesterase type 5 (PDE5), which relaxes blood vessels and improves circulation.

The new research suggests that sildenafil may also influence how metastatic cancer cells process and use cholesterol.

Instead of directly attacking tumors like chemotherapy or immunotherapy, sildenafil appears to alter the metabolic environment that cancer cells depend on.

This represents a growing area of oncology research that looks beyond genetic mutations and focuses on the body’s metabolism.

Why researchers think statins could make the effect stronger

One of the study’s most intriguing findings involves statins—the medications commonly prescribed to lower cholesterol.

Researchers believe the two drugs may complement one another because they work in different ways.

Sildenafil may:

• Limit cancer cells’ ability to use available cholesterol
• Reduce the resources metastatic cells need

Statins may:

• Lower the body’s production of cholesterol
• Reduce the overall cholesterol supply available to cancer cells

Together, they could create what researchers describe as a “double hit” against metastatic cancer cells.

The team also analyzed electronic health records and observed that patients taking sildenafil appeared to have better survival rates. Those who were also taking statins appeared to fare even better.

However, these findings represent an association, not proof that the medications caused the improved outcomes.

Does this mean Viagra treats cancer?

The short answer is no.

Although the study is promising, several important questions remain unanswered.

Researchers still need to determine:

• Which cancer types respond to sildenafil
• What dosage would be effective
• When treatment should begin
• Whether benefits outweigh potential side effects
• Which patients are most likely to benefit

The current evidence comes from laboratory research and analysis of health records.

Only carefully designed clinical trials can determine whether sildenafil can safely reduce cancer spread in real patients.

Experts emphasize that people should not begin taking Viagra to prevent or treat cancer unless it is prescribed within a clinical trial or by their physician for an approved medical condition.

Why this research matters beyond Viagra

One of the biggest takeaways from the study isn’t necessarily the drug itself.

Instead, it highlights the growing importance of drug repurposing.

Developing an entirely new cancer medication can take more than a decade and cost billions of dollars.

Repurposing existing medications offers several advantages:

• Their safety profiles are already well understood.
• Manufacturing systems already exist.
• Costs are often significantly lower.
• Clinical testing can move more quickly than with brand-new drugs.

Several successful cancer treatments today originated as medications developed for entirely different diseases.

If sildenafil ultimately proves effective in clinical trials, it could become another example of how existing medicines find new life in oncology.

What researchers say

Lead researcher Ayelet Erez says the findings reinforce an increasingly important concept in cancer biology.

Rather than being driven solely by genetic mutations inside tumors, cancer progression is also influenced by the patient’s metabolism and even medications taken for unrelated health conditions.

That broader perspective could help researchers identify additional therapies that indirectly affect cancer growth without targeting tumors directly.

What happens next?

The next step is human clinical trials.

Researchers will need to determine whether sildenafil:

• Actually reduces metastasis in patients
• Improves overall survival
• Works across multiple cancer types or only specific ones
• Can safely be combined with statins and existing cancer therapies

Until those studies are completed, sildenafil remains an interesting research candidate—not a recommended cancer treatment.

Still, the discovery adds to growing evidence that metabolism plays a much larger role in cancer progression than previously understood.

If future trials confirm these findings, a medication best known for treating erectile dysfunction could eventually become part of a broader strategy to prevent cancer from spreading—the deadliest aspect of the disease.

Key takeaways

• Researchers identified a new pathway that metastatic cancer cells use to access cholesterol.
• Sildenafil appears to interfere with that process, potentially slowing cancer spread.
• Combining sildenafil with statins may produce stronger effects because each targets cholesterol differently.
• Current evidence comes from laboratory research and observational health data.
• Clinical trials are required before sildenafil can be recommended for cancer treatment.
• Patients should not self-medicate with Viagra to prevent or treat cancer.