Testosterone and Erectile Function: What to Get Tested

Testosterone drives sexual desire and supports the body’s natural erection cycle, but it is not the main reason erections work or fail — that’s blood flow and nerves. This distinction matters, because men with low testosterone and men with erectile dysfunction often need completely different help, and a simple blood test tells you which conversation you should be having.

Most men have never had it done.

What testosterone actually does

It drives desire. This is the big one. Testosterone is what produces the wanting. When levels drop far enough, interest in sex fades — often not gradually, but noticeably.

It supports the nightly erection cycle. A healthy man has several erections during sleep, which is how penile tissue receives regular oxygen. That cycle is testosterone-dependent, which is why it largely stops during hormone therapy.

It affects energy, mood, muscle, and body composition. Low testosterone frequently shows up as fatigue and low mood before anyone connects it to hormones.

What it does not do is directly produce an erection. That’s arteries, veins, nerves, and smooth muscle. A man can have perfectly normal testosterone and severe erectile dysfunction, and a man with low testosterone may have no mechanical problem at all.

Signs worth testing for

• Desire has faded or disappeared
• Persistent fatigue that sleep doesn’t fix
• Loss of muscle mass, or gaining weight around the middle without changing habits
• Low mood, irritability, or difficulty concentrating
• Morning erections have become infrequent or stopped
• Reduced body hair, or breast tissue development

Any of these on its own can have other causes. Several together make a testosterone test worth asking for.

What to ask for specifically

Walk in and ask for these:

Total testosterone, drawn in the morning. Levels fluctuate through the day and peak in the morning, so an afternoon draw can look artificially low. Ideally before 10 a.m.

Free testosterone. Most testosterone in your blood is bound to proteins and unavailable to your body. Free testosterone is the portion actually doing work. A man can have acceptable total testosterone and low free testosterone, and if only total is tested he’ll be told he’s fine.

SHBG (sex hormone binding globulin). This is the protein doing the binding. It rises with age, which is one reason older men can have normal-looking totals and still be functionally low.

Two separate draws. Levels vary day to day. A single low reading should be confirmed before drawing conclusions.

PSA, if you have a prostate. Standard practice before considering any testosterone treatment.

Also reasonable to include: thyroid panel, blood sugar or A1C, and a lipid panel — because fatigue and low libido have several possible causes and it’s efficient to check them together.

Understanding the numbers

Reference ranges vary between labs, and this is where men get frustrated.

The typical range runs somewhere around 300 to 1,000 ng/dL for total testosterone, but the bottom of a lab’s range isn’t the same as optimal for you. A man at 320 is technically “normal” and may feel terrible. A man at 280 may feel fine.

Which is why the useful conversation is about numbers and symptoms together, not numbers alone. If your doctor glances at a result inside the range and says you’re fine while you’re experiencing several of the symptoms above, it’s fair to ask for free testosterone and SHBG if they weren’t run.

If you’ve had prostate cancer

This deserves its own section, and it’s the reason I’m careful with this topic.

Prostate cancer is generally testosterone-sensitive. That’s the entire principle behind androgen deprivation therapy — remove the testosterone, slow the cancer.

Which means testosterone replacement in men with a prostate cancer history is a genuinely complicated decision that belongs entirely with your oncologist and urologist. The medical thinking here has shifted over the years and continues to be debated. I’m not going to give you a position on it, because it depends on your specific cancer, your treatment, your current status, and factors only your physicians can weigh.

What I will say: testing is still worth doing. Knowing your levels is useful information regardless of whether treatment ends up being appropriate. If you’re coming off hormone therapy, tracking recovery tells you where you are in the process — and men are often surprised how long it takes.

Recovery after hormone therapy

If you’ve been on ADT, your testosterone was deliberately suppressed. After treatment ends, it typically rises again, but the timeline varies widely.

Some men recover within months. Others take a year or more. Some — particularly older men and those on longer courses — don’t return fully to their previous baseline.

Erectile function usually lags behind testosterone recovery, which surprises men who expect that once the hormone returns, everything else follows immediately. It doesn’t work that way, and what happened to the tissue during the suppressed period matters a great deal to what’s recoverable.

Ask your oncologist when to start testing after treatment ends, and then actually test rather than guessing from how you feel.

Things that support testosterone naturally

Not a replacement for medical treatment where it’s needed, but these are worth doing regardless:

Sleep. Most testosterone is produced during sleep. Chronic short sleep lowers levels measurably, and untreated sleep apnea is a common and underdiagnosed culprit.

Resistance training. Weight-bearing exercise supports testosterone. Excessive endurance training can lower it.

Body composition. Fat tissue converts testosterone to estrogen, so excess weight lowers available testosterone — and lower testosterone makes weight harder to lose. Breaking that loop helps.

Alcohol. Chronic heavy drinking suppresses testosterone production.

Stress. Sustained cortisol elevation works against testosterone.

None of this is exciting advice, and all of it is real.

Where rehabilitation fits

Here’s what I want men to take away.

If your testosterone is low, your body’s nightly erection cycle has probably slowed or stopped. That means penile tissue isn’t getting its regular oxygen supply — and tissue without regular blood flow changes over time, becoming more fibrous and less elastic.

Fixing the hormone doesn’t undo tissue changes that already happened. Which is why maintaining blood flow mechanically, while you sort out the hormonal side, protects what you’ll have to work with later.

The two work together. Address the hormones with your physician, and keep the blood flow going in the meantime.

Questions?

Call or text me at 947.224.7342. I can’t give you medical advice on hormone treatment — that’s your doctor’s call, and rightly so. But I can help you figure out what to ask for, and where rehabilitation fits alongside it. I’m a prostate cancer survivor myself, and I’ll talk with you whether or not you order anything.

Frequently Asked Questions

Does low testosterone cause erectile dysfunction? Testosterone primarily drives desire rather than the mechanics of an erection. Very low levels can contribute to erectile difficulty, but most erectile dysfunction is caused by blood flow or nerve problems rather than hormones.

What testosterone test should I ask for? Total testosterone drawn in the morning, plus free testosterone and SHBG. Free testosterone is the portion your body can actually use, and men with normal total levels can still be functionally low.

Can I take testosterone if I’ve had prostate cancer? This is a decision for your oncologist and urologist. Prostate cancer is generally testosterone-sensitive, which makes replacement a complicated question that depends on your specific situation.

How long does testosterone take to recover after hormone therapy? It varies widely — some men recover within months, others take a year or more, and some don’t fully return to their prior baseline. Erectile function typically lags behind hormone recovery.

What are the symptoms of low testosterone in men? Reduced desire, persistent fatigue, loss of muscle mass, weight gain around the middle, low mood, difficulty concentrating, and fewer or absent morning erections.