Does Testosterone Boost Your Immune System?

By Dr. Farhan Abdullah, DO | Medical Director, Magnolia Functional Wellness | Southlake, TX

Every cold and flu season, someone asks me a version of the same question. "Doc, if I get my testosterone up, will I stop catching everything my kids bring home?" It's an understandable hope. Testosterone has this reputation as the ultimate vitality hormone, the thing that makes men stronger, faster, more resilient. So surely a stronger man has a stronger immune system, right?

Not so fast. This is one of those areas where the popular story and the actual science point in nearly opposite directions, and it's worth slowing down to get it right. Because the honest answer isn't a simple yes or no. Testosterone doesn't so much boost your immune system as it reshapes it, and whether that reshaping helps you or hurts you depends entirely on what you're up against. Let me walk you through what we actually know, because it's genuinely fascinating, and because the truth here is more useful than the myth.

The Uncomfortable Truth: Testosterone Tends to Dampen Immune Responses

Here's the finding that surprises most people. Across a wide range of research, higher testosterone is associated with a more subdued immune response, not a more aggressive one. Women, on average, mount stronger immune reactions than men. They produce more antibodies after vaccination and clear certain infections more efficiently. And a chunk of that difference traces back to sex hormones.

The most striking demonstration came from a Stanford team led by David Furman, published in the Proceedings of the National Academy of Sciences back in 2014. They gave the seasonal flu vaccine to a group of men and women and then measured, in exhaustive detail, how each person's immune system responded. Women generated more protective antibodies. That part wasn't shocking. But when they dug into the men, they found something specific: the men with the highest testosterone levels mounted the weakest antibody responses to the vaccine. The researchers even identified a cluster of testosterone-associated genes tied to that blunted response. They titled the paper around an "immunosuppressive role for testosterone." Read that again. Immunosuppressive, not immune-boosting.

So if your mental model was "more testosterone equals stronger defenses," this is the moment to update it. At least when it comes to antibody-driven responses like vaccination, the relationship often runs the other way. This is also part of why men, as a group, tend to fare worse with certain viral infections than women do. It's not the whole explanation, genetics and behavior matter too, but hormones are in the mix.

Why "Dampening" Isn't Always a Bad Thing

Now, before anyone panics and concludes testosterone is bad for immunity, let me complicate the picture in the other direction, because this is where it gets clinically interesting.

A weaker inflammatory response isn't automatically worse. Sometimes it's exactly what saves you. A lot of the damage from serious infections doesn't come from the pathogen itself. It comes from your own immune system overreacting, flooding tissue with inflammation and causing collateral damage. We saw this vividly during the COVID era, where much of the worst lung injury came from runaway inflammation rather than the virus directly.

This is where a 2020 study by Vom Steeg and colleagues in PLoS Pathogens changed how I think about it. Working with mice infected with influenza, they found that testosterone actually reduced the severity of the infection. But here's the mechanism, and it's the key to everything: testosterone didn't help the mice kill the virus faster. Viral levels were the same. What testosterone did was calm the pulmonary inflammation. It accelerated the cleanup of inflammatory immune cells in the lungs, so the animals suffered less self-inflicted damage and recovered better. Male mice with normal testosterone did better than those with it stripped away, and giving the androgen back restored the protection.

Sit with that for a second, because it reframes the whole question. Testosterone can make you slightly worse at generating antibodies and slightly better at avoiding an inflammatory overreaction. It's not a booster or a suppressor. It's a modulator. It shifts the immune system's temperament from hair-trigger toward measured. Whether that's good or bad depends on whether your real threat is the infection or your own response to it.

It's a Dial, Not a Switch

The best summary of this whole field I've come across is a 2023 review by Sciarra and colleagues in the International Journal of Molecular Sciences on how sex hormones shape the immune system. Reading through it, the recurring theme is that testosterone is broadly anti-inflammatory and immunomodulatory. It tends to tamp down the activity of certain immune cells and the production of inflammatory signaling molecules.

What I try to get patients to understand is that "modulate" is the operative word, not "boost." Your immune system isn't a muscle that simply gets stronger with more hormone. It's more like a thermostat, and testosterone is one of the hands that adjusts the setting. Nudge it one way and you get less inflammation, which is protective in some contexts and a liability in others. There's no universal "better." There's only better for a particular situation.

That nuance also explains why you can't reason your way from "testosterone is anti-inflammatory" to "everyone should take testosterone for their immune system." Chronic inflammation genuinely does drive a lot of age-related disease, and there's real interest in how healthy hormone levels fit into that larger picture. But that is a completely different claim from "testosterone will keep you from catching a cold." One is a serious question in aging biology. The other is a marketing slogan.

Then Why Do Men Seem to Get Sicker?

If you've ever rolled your eyes at "man flu," you've bumped into the real pattern underneath the joke. Men do tend to fare worse with a number of infections, from certain respiratory viruses to some parasitic and bacterial illnesses. Part of that traces right back to what we've been discussing. A more restrained antibody response and a quieter early immune reaction can mean a virus gets a bit more of a head start.

But I'd caution against blaming testosterone for the whole thing, because it isn't that clean. Men's worse infection outcomes also ride on genetics, on higher rates of smoking and cardiovascular disease, on the fact that men statistically delay seeking care, and on occupational exposures. Hormones are one thread in a thick rope. And remember the flip side we just covered: in the influenza work, testosterone's inflammation-calming effect actually improved outcomes. So the hormone isn't a straightforward liability during infection. It's context-dependent, which is the theme of this entire piece. The useful takeaway isn't "testosterone makes you sick." It's that biological sex shapes immunity in layered ways, and no single hormone is the hero or the villain.

The Autoimmune Flip Side

There's another angle to all of this that rarely makes it into the vitality-hormone conversation, and I find it clarifying. If testosterone dials the immune system down, and estrogen tends to rev it up, you'd predict that conditions caused by an overactive immune system would hit women harder than men. And that's exactly what we see.

The overwhelming majority of autoimmune disease burden falls on women. Lupus, Hashimoto's thyroiditis, rheumatoid arthritis, multiple sclerosis, Sjogren's, the list runs long, and in most of these the female-to-male ratio isn't close. Some of that is genetic, tied to the X chromosome. But sex hormones are woven through it. The same review by Sciarra and colleagues that I mentioned lays out how testosterone's broadly anti-inflammatory, immune-quieting influence appears to be part of why men are relatively protected from many autoimmune conditions. A more restrained immune system is less likely to turn its weapons on your own tissue.

I bring this up not to hand anyone a new thing to worry about, but because it drives home the central idea. There is no such thing as a simply "stronger" or "better" immune system in the abstract. A hair-trigger immune system fights infections aggressively and is also more prone to friendly fire. A calmer one is gentler on your own body and a little slower on the draw against invaders. Testosterone pushes toward the calmer end. For an aging man, whose bigger long-term risks often come from chronic inflammation and its slow damage rather than from failing to clear a virus, that temperament isn't obviously a bad hand to be dealt. It's just a different one, with its own trade-offs.

What This Actually Means for You

Let me bring this back to the exam room, because that's where it counts. If you're a man with genuinely low testosterone and real symptoms, fatigue, low libido, loss of muscle, mood changes, then restoring your levels to a healthy range through properly monitored therapy is worthwhile for all the reasons we talk about at our testosterone replacement therapy program. Better energy, better body composition, better quality of life. Those benefits are real and well documented.

But I want to be straight with you about the immune piece specifically, because this is where I see men get misled. Optimizing your testosterone is not a strategy for building a superhuman immune system, and pushing your levels artificially high in pursuit of that goal is a bad idea. Supraphysiologic testosterone, the kind chased in gyms and shady clinics, doesn't buy you extra immunity. If anything, based on what we've just walked through, it may blunt certain protective responses. More is not better. The goal is a healthy, balanced range, the level a well-functioning body would produce on its own, not the highest number you can force.

What genuinely supports your immune resilience is unglamorous and familiar, and I'll say it anyway because it's true. Sleep, and enough of it. Real physical activity. A diet that isn't drowning in ultra-processed junk. Managing stress and blood sugar. Getting your recommended vaccines, and yes, that advice holds even knowing testosterone might slightly blunt the antibody response, because a slightly smaller shield is still a shield. Those fundamentals do far more for your defenses than any hormone ever will. Testosterone therapy, used correctly, is about restoring healthy function, not gaming your immune system.

So does testosterone boost your immune system? No, not in the way the question is usually meant. It modulates it, mostly by dialing down inflammation, and that can cut either way depending on the threat. That's a less exciting answer than the myth, but it's the accurate one, and accurate is what I owe you. If you're curious where your own levels actually sit and whether they're helping or hurting your bigger health picture, that's a real conversation worth having with a physician who'll give you the honest version. That's the medicine we practice every day at Magnolia Functional Wellness here in Southlake, one straight answer at a time.