Researchers found that low vitamin D triggers excess superoxide—a damaging molecule that breaks down nitric oxide, essential for erections. This “internal rust” disrupts blood flow, making it harder to maintain erections
Published Apr 22, 2025 | 7:00 AM ⚊ Updated Apr 22, 2025 | 7:00 AM
Synopsis: A new study published in the British Journal of Pharmacology reveals that vitamin D deficiency may directly cause erectile dysfunction (ED). Researchers found that low vitamin D alters body chemistry, reducing penile blood flow. Unlike earlier studies, this one explains the biological mechanism, using human tissue samples and animal models to show how deficiency impairs erectile function
You’ve cleaned up your lifestyle — eating right, exercising regularly, staying away from alcohol and cigarettes — but bedroom troubles still persist? The problem might not be in your head. It could be in your blood. Or more specifically, it could be in your sunlight-starved skin.
A new study has revealed a surprising and potentially life-changing finding: men who are low in vitamin D may be at a higher risk of developing erectile dysfunction (ED).
The research, published in the British Journal of Pharmacology, goes beyond earlier studies that hinted at a connection between vitamin D and sexual health, offering the strongest evidence yet that vitamin D deficiency doesn’t just coexist with ED — it may actually cause it.
What makes this study different is that it doesn’t stop at showing a link. It explains the biological how and why. Using tissue samples from human donors and carefully designed experiments on mice and rats, the researchers found that vitamin D deficiency leads to chemical changes in the body that reduce blood flow to the penis, making it difficult to achieve or maintain an erection.
Erectile dysfunction is a condition that affects millions of men globally, especially those aged over 40. While it’s commonly associated with aging, diabetes, or heart disease, the new study suggests that a simple and often overlooked factor — not getting enough vitamin D — could be playing a bigger role than previously understood.
The team of scientists from several leading Spanish institutions, including the Complutense University of Madrid, used both human and animal models to test their theory. So What Did the Scientists Do?
The researchers didn’t just rely on surveys or patient records. They ran lab tests on human tissue, and did experiments on rats and mice to explore how vitamin D affects the blood vessels and tissues in the penis that are responsible for erections.
They looked at:
In all of these cases, when vitamin D was missing or its signal was blocked, the erectile function of the animals (or human tissue samples) got worse.
Here’s the simple explanation from the study:
For an erection to happen, blood needs to flow into the penis smoothly. This happens because of a chemical called nitric oxide (NO) that relaxes the muscles and blood vessels in the penis.
But in this study, researchers discovered that when there isn’t enough vitamin D, the body makes too much of something called superoxide—a kind of “bad” molecule that cancels out nitric oxide. Without nitric oxide, blood vessels don’t relax properly, and that leads to erectile dysfunction.
So basically, low vitamin D = more superoxide = less nitric oxide = trouble getting or keeping an erection.
So, what’s happening at the molecular level?
The researchers discovered that low vitamin D levels led to an overproduction of superoxide, a harmful molecule that breaks down nitric oxide before it can do its job. The more superoxide in the system, the less nitric oxide remains to support an erection. Think of superoxide as a kind of internal “rust” that interferes with the smooth functioning of the body’s mechanisms for blood flow.
But that’s not all. The study also found that a specific protein called SLPI — short for Secretory Leukocyte Protease Inhibitor — plays a key role in this process. SLPI has protective and antioxidant effects, meaning it helps the body get rid of harmful molecules like superoxide. In men with low vitamin D, SLPI levels were also found to be low. That means their bodies weren’t just producing more of the bad stuff — they were also less able to fight it off.
When the researchers added SLPI back into the mix, erectile function improved — even in the presence of high levels of superoxide. On the flip side, when they blocked SLPI in otherwise healthy tissues, the tissues began to show signs of erectile dysfunction. This strongly suggests that SLPI — and by extension, vitamin D — isn’t just helpful for erections, but necessary.
Here’s the surprising part: animals with low vitamin D also didn’t respond well to sildenafil (the active drug in Viagra).
That’s a big deal. It means that if someone is vitamin D deficient, ED drugs might not work as well, because the whole nitric oxide system isn’t working properly in the first place.
The researchers suggest that checking and treating low vitamin D could help ED medications work better.
The findings of this new study are especially significant for India, where vitamin D deficiency is shockingly widespread—even though the country is bathed in sunlight for most of the year.
According to the Apollo Hospitals’ Health of the Nation 2025 report, a staggering 82 percent of people tested in Telangana and 74 percent in Andhra Pradesh were found to be vitamin D deficient.
This isn’t just a regional problem. Nationally, studies show that 1 in 5 Indians don’t have enough vitamin D in their system. In eastern India, the rates are even higher—nearly 39 percent, despite abundant sun exposure.
The study suggests that air pollution adds another layer of complexity, blocking ultraviolet B (UVB) rays that are crucial for the body to produce vitamin D. Compounding the issue is melanin, the pigment that gives skin its darker tone and naturally limits vitamin D production.
“Studies suggest that individuals with darker skin may require three to six times longer exposure to produce the same amount of vitamin D as those with lighter skin tones,” the report states. The Indian Council of Medical Research (ICMR) notes that just 8–14 percent of Indians consume the recommended amount of dairy.
Vegetarians and those with lactose intolerance, both common in India, face even greater dietary limitations. In such cases, experts say, supplementation or food fortification becomes essential.
“It is difficult to identify the deficiency in the early stages and the cost of testing and treatment is high,” the report notes.
“For a long time, we’ve known that vitamin D is essential for bone health and immunity, but this is evidence yet that it plays a major role in men’s sexual health as well,” Consultant Urologist at Gleangles Hospital in Hyderabad Dr P Narendra Kumar to South First.
“In India, where a large section of the population try to avoid sun exposure, live in polluted cities, and follow diets low in dairy, vitamin D deficiency is almost inevitable,” he adds. “If a man is experiencing erectile dysfunction, especially if medications like sildenafil (Viagra) aren’t working well, checking vitamin D levels should not cause any harm.”
However, Dr Kumar cautions against self-prescribing supplements without testing. “This research is very promising, but most of it has been done in animals and lab settings. We still need strong clinical trials in humans to know how much vitamin D can help, and in what cases. But given how common the deficiency is, and how simple and safe the fix might be, it’s definitely worth discussing with your doctor.”
(Edited by Ananya Rao)
