Bigger is better, and that’s why we love Viagra. But turns out the drug may actually be able to shrink us — in a good way. Researchers from the University of Bonn fed mice Viagra and found that it reduced belly fat and lessened the risk for health issues associated with obesity.

What’s the Deal?

Viagra, aka sildenafil, has been used to treat erectile dysfunction since the FDA approved the drug in 1998. It basically works by stopping the breakdown of cGMP, a molecule that regulates blood flow in men’s nether regions Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. Boolell, M., Allen, M.J., Ballard, S.A., et al. Pfizer Central Research, Sandwich, Kent, UK. International Journal of Impotence Research 1996 Jun;8(2):47-52.. But scientists now know that sildenafil doesn’t just heat things up in the bedroom — it can also help get us ready for swimsuit season. Earlier research suggested the drug can reduce inflammation in adipose (or fatty) tissue and prevent insulin resistance in mice eating a high-fat diet Reduced vascular nitric oxide-cGMP signaling contributes to adipose tissue inflammation during high-fat feeding. Handa, P., Tateya, S., Rizzo, N.O., et al. Department of Medicine, University of Washington, Seattle, WA. Arteriosclerosis, thrombosis, and vascular biology 2011 Dec;31(12):2827-35..

In this latest study, scientists actually figured out how sildenafil helps prevent obesity Increased cGMP promotes healthy expansion and browning of white adipose tissue. Mitschke, M.M., Hoffmann, L.S., Gnad, T., et al. Institute of Pharmacology and Toxicology and Pharma Center, University of Bonn, Bonn, Germany. FASEB Journal 2013.. Again, scientists tested the drug on mice (of unspecified gender) that were fed a high-fat diet. It seems the drug converts white, or “bad,” fat cells to beige fat cells. The beige stuff fights weight gain by burning the energy from food and converting it to heat. But the drug doesn’t just help prevent obesity — it can also put the brakes on other issues associated with being seriously overweight, including risk factors linked to cardiovascular disease Obesity and cardiovascular disease: risk factor, paradox, and impact of weight loss. Lavie, C.J., Milani, R.V., Ventura, H.O. Cardiac Rehabilitation, Exercise Laboratories, Ochsner Medical Center, New Orleans, Louisiana. Journal of the American College of Cardiology 2009 May 26;53(21):1925-32.. When white fat cells grow, they release hormones that can cause inflammation, and sildenafil seems to stop that process.

Is It Legit?

Still unclear. No offense to the mice, but they aren’t exactly human, so it’s not clear if the same findings apply to people looking to shed a few pounds. And even if they do, researchers still need to figure out exactly what dosage is safe and effective for humans.

It’s also worth noting that sildenafil has some side effects (though they’re all unlikely), including headache, stomach ache, back pain, and shortness of breath. And it doesn’t look like scientists have reached the point where they can figure out whether women can take the drug for weight loss, or whether men who take the drug for weight loss will have to put up with constant rolls of quarters in their jeans.

Until researchers figure out whether sildenafil can safely help humans lose weight, we may just be stuck watching some skinny mice get it on in their cages.

If the drug were approved for human use, would you consider taking Viagra to lose weight? Let us know in the comments below or tweet the author @ShanaDLebowitz.

Photo: Simon Willison

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