Does testosterone make you harder? What to do about ED

Testosterone often gets blamed for weak erections, but does testosterone make you harder?

The short answer is that testosterone is part of the biology behind an erection, but raising it doesn't automatically make things harder. Whether it actually helps depends on why erections are struggling in the first place.

Here's a closer look at who benefits from raising testosterone, when it doesn't help, and what to do if you think low T is the cause of your weak erections.

We recognize that not everyone with a penis identifies as a man. Gender identity is personal, and bodies don't determine gender. This information applies to anyone with the relevant anatomy, regardless of gender identity.

Raising testosterone can make erections firmer, usually only if your levels were low to begin with.

Testosterone plays a key role throughout every man’s life. Having too little of it can affect everything from sexual function to heart and metabolic health.

Trouble tends to show up once levels drop below roughly 300 nanograms per deciliter (ng/dL). Bring them back up from there, and erections tend to get stronger for many men.

If your testosterone is already in a normal range, though, extra won't sweeten the deal — it's more of a switch than a volume knob, so flipping it back on helps, but turning it up further once it's already on doesn't.

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Testosterone supports erections in part by keeping the blood vessels in the penis working the way they should.

Part of what makes an erection start is when nerve signals release nitric oxide, a chemical messenger thatopens those blood vessels and lets blood rush in. Testosterone is what keeps the messenger doing its job.

Take testosterone away, and the system breaks down quickly. In castrated rats, losing testosterone weakened erections, and restoring testosterone to their bodies brought erections back.

That same effect shows up in human tissue, too. Testosterone directly improves how well penile tissue responds to nitric oxide, the same pathway that many erectile dysfunction (ED) drugs like sildenafil (Viagra) act on.

So on a biological level, testosterone plays a bigger role than sex drive alone. It's woven into the actual plumbing behind an erection.

Testosterone is clearly tied to the mechanics of an erection, but increasing it doesn't always translate into a harder erection. The research on raising testosterone levels is more layered than it might first appear, though.

In one trial, men with ED and low testosterone (under 330 ng/dL) took sildenafil, then either testosterone gel or a placebo gel on top of it. The result: Adding testosterone didn't improve erectile function any more than the placebo did.

A different trial dug deeper into who might benefit from added testosterone. Men only received testosterone after they'd already failed to respond to tadalafil alone, and the benefit only showed up in those whose baseline testosterone was 300 ng/dL or lower. Above that threshold, adding testosterone made no measurable difference to erectile function.

Two large trials in older men tell a similar, split story. In the Testosterone Trials, men 65 and older with clearly low testosterone saw significant improvement in erectile function on testosterone therapy. Of note, all of these men had a low testosterone level (less than 275 ng/dL)

But in the TRAVERSE trial, which studied middle-aged and older men with two testosterone concentrations less than 300 ng/dL, heart disease or risk factors for heart disease, testosterone therapy boosted sexual desire and activity. But it didn’t significantly improve erectile function.

We don’t have a clear understanding of the differences between the effects on erectile function. One possibility is that heart disease itself affects blood flow to the penis, which could help explain why testosterone's benefit was more limited in this specific group and may have contributed to the difference in findings between the two studies. 

Whether raising your testosterone with prescription medication would help your erectile function comes down to one thing: how low your levels are, not just where you land within a normal range.

That's why testing for low testosterone can sometimes be an important part of evaluating ED, depending on your symptoms.

Testosterone levels are generally considered low once they'reconsistently below 300 ng/dL on two separate morning blood tests, along with symptoms like low sex drive or constant fatigue. Of course, different laboratory centers and health systems may have varying cutoffs (though they all tend to be in a similar range).

If your testosterone falls in a low range, prescription testosterone may improve your symptoms and could potentially help your erectile function, though how much it helps varies from person to person. If your testosterone is within a normal range already, boosting it further is unlikely to fix the problem.

In cases where your testosterone levels are normal, weak erections or erections that don’t last are more often tied to blood flow issues, stress, certain medications, or performance anxiety. In fact, even if you do have low testosterone levels, some of these other factors could also apply. 

Age-related testosterone decline can contribute to weaker erections, but it's rarely the only cause.

Levels drop slowly with age, and by later decades, many men fall into a low range. Lab-defined low testosterone affects roughly 1 in 5 men over 60, and about half of men over 80.

Age-related hormone changes are only one part of the picture, alongside things like blood vessel health and overall fitness. Erectile changes with age are common but not universal, and often respond to treatment.

There's no fixed age when erections stop working altogether, so a noticeable change is something to check into, not something to simply accept as inevitable.

If you’re concerned about your testosterone levels, start with a blood test rather than guessing.

A morning testosterone test, ideally repeated to confirm the result, is the only way to know whether your levels fall into the low range where treatment tends to help. You can ask your healthcare provider to order one for you if you are curious about your levels. 

If your morning testosterone comes back low and your symptoms line up, a healthcare provider can walk you through your options, including prescription testosterone therapy if it's the right fit. Remember that testosterone therapy comes with risks such as acne, mood changes, and even potentially blood clots. So, you should always discuss the risks and benefits with your healthcare provider before considering treatment.

If you are having erectile difficulties, many healthcare providers may recommend treating your erectile symptoms either alongside testosterone treatment or as a stand-alone treatment to start.  For example, Ro offers Cialis (tadalafil), Ro Sparks*, and Daily Rise Gummies.*

No matter what your testosterone levels are, everyday habits behind building stronger erections, like cardiovascular health, sleep, stress, and daily routines, can be a good place to start. 

You may have heard of testosterone boosters online, but the evidence behind them is limited, and some of them could contain undisclosed ingredients and may be associated with side effects. So, it's worth researching carefully and talking to a provider before trying one. There are many better options if your goal is to improve your erections. *Though this particular formulation is not approved by the US Food and Drug Administration (FDA), it is composed of active ingredients that have been FDA-approved for erectile dysfunction.

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So, does testosterone make you harder? It’s tied to erection strength, but raising it only helps when levels are actually low to begin with. Here's what the research shows:

• Nitric oxide, not testosterone alone, helps trigger an erection. Part of testosterone's job is to keep that chemical signal working properly.

• Treatment tends to help if your testosterone levels are under 300 ng/dL. Anything below this, combined with symptoms, may warrant diagnosis and treatment — still, the evidence for improvement in your erections is inconclusive.

• Testosterone declines gradually with age. By their 80s, roughly half of men fall into a low range.

• Heart disease or its risk factors can limit the benefit: Testosterone therapy made less of a difference in one research study that included people with heart disease.

If your erections still aren't cooperating after ruling out low testosterone, the answer might lie somewhere else in the body, and Ro can connect you with a provider to help.