Massive New Study Links Viagra Use to Reduced Risk of Alzheimer’s Disease

You know Viagra® as the world’s most popular treatment for erectile dysfunction, but new research out of the U.K. indicates that it may also be useful in the treatment of Alzheimer’s disease.

The cohort study, released this week by researchers at the University College of London School of Pharmacy, analyzed data from nearly 270,000 patients who were diagnosed with erectile dysfunction from 2000 to 2017 and found that men who were prescribed Viagra (or its generic version, sildenafil) were a staggering 18 percent less likely to develop Alzheimer’s disease than men who weren’t.

Even more surprising, the research concluded that there may be a correlation between how much Viagra men took and their susceptibility to Alzheimer’s—men who received 20 or more prescriptions of Viagra or sildenafil over the study’s five-year follow-up period were even less likely to develop Alzheimer’s. 

"Despite the fact that Alzheimer's disease is the most common form of dementia, we still know so little about it,” says Jessica Yu, Ph.D., a clinical psychologist and Senior Director of Patient Experience at Hims & Hers.

According to data from the  National Institutes of Health (NIH), Alzheimer’s disease is the single-most common form of dementia, and by the year 2050 is expected to affect as many as 16 million Americans. 

“We don't know what causes it, and we don't have a cure for it,” says Dr. Yu. “This study may represent a huge leap in our ability to reduce the incidence and burden of this disease.”

Alzheimer’s is a progressive neurodegenerative disease that not only affects a person’s memory, but also interferes with bodily functions and quality of life. According to the Alzheimer’s Association, it kills more people every year than breast and prostate cancer combined.

One thing that makes this new study so compelling, however, is its size. It’s one thing to say that sildenafil can reduce the risk of Alzheimer’s in mice or a small sample size of humans, but to look at the health records of almost 270,000 men and compile real-world data? That’s big.

And these weren’t just self-reports, either. Researchers looked at primary care data with prescription records and diagnosis codes, which offers a more robust — and accurate — look into the relationship between Viagra and Alzheimer’s disease treatment.

This isn’t the first time researchers have poked around at a relationship between Viagra—a member of the phosphodiesterase-5 (PDE5) inhibitors class of medication—and Alzheimer’s disease.

A 2020 study featured in the Journal of Alzheimer’s Disease Reports found that just one dose of sildenafil increased cerebral blood flow, decreased spontaneous neural activity, and increased the cerebral metabolic rate of oxygen in the brains of mice with Alzheimer’s disease. 

“Viagra, and similar drugs used to treat erectile dysfunction, work by increasing blood flow to the penis, so it’s not surprising that they also appear to increase blood flow to the brain,” says Dr. Daniel Lieberman, Clinical Professor of Psychiatry and Behavioral Sciences at George Washington University and SVP of Mental Health at Hims & Hers.

And a 2017 study, in which researchers administered single doses of sildenafil to 12 human patients with Alzheimer’s disease, noted similar observations.

This type of population-based research study is similar to another large recently published study that linked use of PDE5 inhibitors to improved long-term cardiovascular health, according to Dr. Peter Stahl, SVP of Sexual Health at Hims & Hers. “Although they do not prove cause and effect,” Dr. Stahl says, “recent population-based studies on the potential brain and heart benefits of PDE5-inhibitors are exciting developments that hint at the potential of these drugs to do much more than support sexual function.”