Can Viagra Curb Alzheimer's?

But the more research progresses, the clearer it becomes that the truly interesting candidate might not be Viagra – but its close relative Cialis (tadalafil).

No, neither of them is approved for Alzheimer's. No one can currently say that they slow down the disease. But research has progressed so far that the question can no longer be dismissed.

Why study Viagra and Cialis at all?

Viagra (sildenafil) and Cialis (tadalafil) belong to the same class of drugs, the so-called PDE5 inhibitors. They were developed to increase blood flow, but researchers have discovered that they also affect several biological mechanisms that may be important in Alzheimer's.

They can improve the brain's microcirculation, strengthen blood vessel function, increase nitric oxide and cGMP signaling, dampen inflammation, and possibly improve nerve cell energy supply. This makes the hypothesis biologically plausible.

Viagra sparked interest

Some years ago, large observational studies made headlines when Viagra users appeared to have a lower risk of developing Alzheimer's.

Cialis has taken over the lead role

In the past year, an increasing number of researchers have instead turned their attention to tadalafil, the active substance in Cialis.

A clinical study showed that six weeks of treatment favorably affected several blood markers linked to Alzheimer's disease. At the same time, a larger one-year, randomized study is now underway, testing tadalafil in people with early Alzheimer's.