Men, You Likely Have Half the Testosterone Your Grandfather Had

A man in his late thirties sat in my office last month, complaining of being tired all day, flat in his mood, thicker around the middle than he used to be, and losing interest in things he used to want. He assumed it was work, or age, or that he simply needed to try harder. His total testosterone came back at 310. Technically normal. Fifty years ago, that number in a man his age would have raised eyebrows across the room.

I have been having a version of that conversation more and more often, and this summer the data caught up with what the exam room has been telling me.

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The Number

In July, researchers led by Hagai Levine presented an analysis at the European reproductive medicine meeting in London pooling over 100,000 men across six long-running studies in the United States, Israel, Brazil, Finland, and Denmark. Between 1972 and 2019, average total testosterone fell 54 percent, with the drop accelerating after 2000.

Back in 2007, a Massachusetts study found that a sixty-year-old in 2002 had less testosterone than a sixty-year-old in 1987. Over almost exactly the same window, sperm concentration fell about 52 percent and total sperm count about 62 percent worldwide, with the same acceleration after 2000. Two different measures of the same system, from different laboratories and different decades, moving the same direction at the same speed. That is not a coincidence. We have a real problem.

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Why

Three things are happening at once:

The first is weight. Fat tissue runs an enzyme called aromatase that converts testosterone into estrogen, and the insulin resistance and inflammation that travel with excess weight suppress the brain's signal to the testicles to make testosterone. The relationship runs in a vicious cycle: low testosterone adds fat, and fat lowers testosterone.

The second is lifestyle: short sleep, little resistance training, alcohol, chronic stress. Testosterone is largely made during sleep. Men who sleep five hours a night for a week drop their levels by ten to fifteen percent.

The third is the one I have been writing about all year: the chemistry we live inside. The plastics in food packaging, vinyl, personal care products, and the coating on receipt paper. Plastic and its components act as endocrine disruptors, and studies of real-world chemical mixtures find some of the strongest negative signals of the whole panel between phthalate exposure and testosterone. This is the same story as the microplastics in your arteries and your brain.

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What Low Testosterone Actually Costs

This is where the conversation usually goes wrong. Testosterone gets discussed as though it were about the gym and the bedroom, so men who are struggling do not bring it up, and doctors do not check it.

It is a metabolic and structural hormone. Low levels track with visceral fat, insulin resistance and diabetes, loss of muscle mass, thinning bone and fractures, depressed mood, poor concentration, fatigue, and diminished libido and erectile function. From a longevity standpoint, muscle and bone are what keeps you out of a nursing home at eighty.

Here is what makes it worse. Testosterone is one of the hormones that almost never gets checked unless a man asks for it by name. A man can be seen every year for a decade with cholesterol drawn, blood sugar drawn, blood pressure logged, and never once have a testosterone level in his chart. When he does raise it, he often gets a single afternoon draw, which can run twenty to thirty percent below where the same man measures at nine in the morning, and a normal result closes the file.

The problem is that a hormone that has been falling across the entire population for fifty years is also one of the least frequently measured. Those two facts together are the reason I am writing this.

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What I Recommend

First, get the right number. Ask for free testosterone, not just total. Total is the cheaper test, so it is the one most men are given and usually the only number they ever hear about, but most of that total is bound up and unavailable to your tissues. Free testosterone is the fraction your body can actually use, and it is the more accurate picture of where you stand. It is what I measure. Draw it in the morning before eleven o'clock, and add LH, estradiol, estrone, and DHT.

Second, be careful with "normal." The reference range on your lab report was built from today's population, the same population that has been declining for fifty years. It tells you where you sit among your contemporaries, not whether you are well. This is a line I repeat to patients: “It is now normal to be unhealthy. You don't want to be normal.”

Third, fix what is fixable before anything else. Seven to eight hours of sleep, resistance training two or three times a week, visceral fat down, alcohol modest.

Fourth, lower the chemical load. I have written a whole series on this, and if you read one thing, read the first part. The short version: bottled water is the biggest single lever most men have. A liter of it carries something on the order of 240,000 plastic fragments, most of them small enough to cross into tissue, which adds up to tens of millions of particles a year from that habit alone. Filter your drinking water and keep it in glass. Then the rest: glass and stainless instead of plastic, never microwave food in plastic, skip the paper receipt, choose fragrance-free, and dress in natural fibers. Cotton, wool, and linen instead of polyester and fleece, which shed plastic into your air and your washing machine every day you wear them.

Fifth, if your T is low and you have symptoms, know that treatment exists and is better studied than it used to be. The TRAVERSE trial randomized 5,246 men with low testosterone and cardiovascular risk and found no excess of heart attack, stroke, or cardiovascular death compared with placebo. One old fear, though, deserves to be retired. The American Urological Association now makes it a strong recommendation that clinicians inform patients of the absence of evidence linking testosterone therapy to the development of prostate cancer. TRAVERSE found the same thing: no increase in prostate cancer or prostate-related events. If you have been told that testosterone will give you prostate cancer, that belief is a generation out of date, and your urologist is now being asked to say so out loud.

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The Bottom Line

Something in the environment has been quietly turning down a hormone that governs your muscle, your bone, your metabolism, your mood, and your desire. You cannot undo fifty years of population trend, but you can find out where you personally stand, and you can do something about it.

If you have been assuming that flat, tired, thickening version of yourself is just what your forties look like, get the number. It takes one morning and one blood draw, and it is a test where the answer leads somewhere useful.

I would like to hear from you. If you have had your level checked, leave a comment below and tell me how that conversation went.

To your good health,

The Longevity Doctor®