Viagra has spent nearly three decades known for one specific thing. New research out of Israel’s Weizmann Institute of Science suggests its active ingredient, sildenafil, may have a second, unrelated talent: disrupting how cancer cells access the cholesterol they need to spread through the body.
The study, led by Dr. Yarden Ariav in the lab of Prof. Ayelet Erez, was published in the journal Cancer Research and involved collaborators from the US National Cancer Institute and Clalit Health Services, Israel’s largest healthcare provider.
Key Takeaways
- Sildenafil appears to trap cholesterol inside cancer cells, potentially limiting their ability to break away from a tumor and spread to other organs.
- In mouse models of breast, lung, and colon cancer, sildenafil reduced metastasis, and pairing it with a statin worked even better than either drug alone.
- An analysis of health records from more than 40,000 male cancer patients in Israel found that men who used both sildenafil and a statin had a 31% lower risk of death within five years compared to those who used neither.
- This remains lab and animal research plus observational health data — not a clinical trial — and the researchers are explicit that it’s not ready for real-world use.
How a Blood Pressure Mechanism Ended Up Fighting Cancer
Sildenafil works by blocking an enzyme called PDE5, which normally breaks down a molecule called cGMP. Blocking that enzyme lets cGMP build up — the same chemistry that relaxes blood vessels and gives Viagra its original effect. But the research team found cGMP does something else entirely inside a cancer cell: it binds to a protein called NPC1, which normally acts like a delivery system, moving cholesterol out of the cell’s internal recycling compartment (called a lysosome) to wherever the cell needs it. When cGMP builds up and jams that delivery system, cholesterol gets stuck inside the compartment instead of reaching the rest of the cell. Cancer cells try to compensate by manufacturing their own cholesterol, but it isn’t enough — the cell’s outer membrane grows flimsier and its energy production falters, making it harder for the cell to migrate or invade new tissue.
