The Science Behind Low Testosterone
28 Jan 2026 · 9 min
Dr. Charles Mok reviews an international consensus on testosterone deficiency in men. Low testosterone affects 38% of men globally and links to worse sexual health, depression, osteoporosis, and higher mortality. Testosterone therapy improves sexual function and bone density, and current evidence doesn't show increased cardiovascular or prostate-cancer risk, though the consensus calls for more research on cardiometabolic effects.
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Foreign. Something that was published in the Mayo Clinic proceedings from Harvard Medical School, also an international German medical school. But this is international consensus by several experts regarding testosterone deficiency and testosterone treatment. And this is an international consensus recommendations. So there's nine resolutions in this international consensus. I want to kind of read this. And this is specifically for men with symptoms of low test testosterone and replete replacing the testosterone. So resolution number one is testosterone deficiency is a well established significant medical condition that negatively affects male sexuality, reproduction, general health and quality of life. So this is impact number one. Low testosterone negatively impacts quality of life, is associated with all cause mortality. Increase all cause mortality, particularly cardiovascular mortality. In other words, you're more likely to die sooner if you have low testosterone contributes to decreased bone mineral density, increases the risk of developing diabetes, MA syndrome and cardiovascular disease. Number two, resolution number two. The symptoms and signs of testosterone deficiency occur as a result of low levels of testosterone and may benefit from treatment regardless of whether there is identified underlying etiology. So to recap, the consensus is regardless of the cause, if the testosterone is low and you're symptomatic, it is appropriate to treat it regardless of the cause. This lies in the face of the FDA indications. The FDA has indicated testosterone replacement. They've approved it in the 50s. Men that not only had severely low t severely low testosterone but also they had it because of either missing a testicle, having brain damage, inability to turn on the hormone that stimulates testosterone production or they have an extra female chromosome. So that's the a patients that should be treated according to the fda. Your doctor is not limited to the fda. That's actually for drug manufacturers what they can promote the use for. In this case the resolution says regardless of the cause. If you can't find one, which is most times you cannot find a cause. It's called idiopathic. Sometimes you call it primary or secondary. Just means because the brain is not asking for more testosterone or the testicles aren't producing but the actual cause is not generally known. It just seems to be an age related condition. And it is appropriate to treat low testosterone in men that have testosterone deficiency symptoms regardless of a cause is found or not. So this is a resolution saying the efficacious from 70 years ago. This is what we believe now. Number three resolution number three. Testosterone deficiency is a global public health concern. The incidence of low testosterone is thought to be as high as 38% throughout the world and is expected that costs billions and billions of dollars of health care. Costs are wasted regarding not treating low testosterone. Low testosterone has increased Incidence of diabetes, heart disease, metabolic syndrome, fractures, osteoporosis, sarcopenia, depression, increased mortality from heart failure does not treating testosterone routinely. It's expected that this is wasting billions of dollars treating things with medications that potentially could be averted with replacing a crucial hormone that has declined. Number four resolution. Number four. Testosterone therapy with for men with testosterone deficiency is an effective, rational and evidence based. The evidence shows that testosterone effectively increases sexual desire, erectile function, orgasmic function, increases lean body mass, which is a predictor of longevity, decreases fat mass, which is a predictor of longevity, improves bone mineral density, which is a predictor of longevity and improves mood and energy. So quality of life plus us improve our health span lifespan. No testosterone concentration threshold that reliably distinguishes those who respond to treatment than those who will not. Now what does that mean? It means that there's not a blood test determining who will respond to testosterone replacement in men with low testosterone symptoms. And if we look at the range of testosterone levels in men, there's a pretty big range. Most men fall in the range of say 200 to, you know, 1100. But you know, somebody with a level 400 may have symptoms low testosterone because they 800 when they were younger. And this resolution says we should not be relying on the blood test level to determine who may respond to testosterone replacement therapy. The way you determine that if somebody has symptoms of low testosterone, you replace it and see those symptoms go away. So let's use an example of somebody with high blood pressure. We measure the blood pressure, it's high and we put them on say lisinopril and we retest and their blood pressure comes down. We don't measure a lisinopril level, the pathway of the kidney, we measure the blood pressure. In this position, they're stating that you can check testosterone level, but that should not be the guiding factor or whether or not somebody will benefit from testosterone replacement therapy. Next resolution. There's no scientific basis for any age specific recommendations against use of testosterone therapy in men. Let me restate that. There's no scientific basis for any age specific recommendations against use of testosterone therapy in men. This mostly refers to the fact that as men get older, their doctors are less likely to replace testosterone. But numerous studies have shown they benefit just as much, if not more than younger men with low testosterone and saying, well, you're 75 years old, you're too old to have energy and libido and mood. We also have things like cardiovascular protection, mass protection. And there is no, and there is no evidence that we should be avoiding testosterone Placement in men with low testosterone symptoms in older men. Number seven, the evidence does not support the increased risk of cardiovascular events in testosterone therapy. Now they they have this as a resolution because the FDA has made a claim that testosterone increases the risk of cardiovascular events. And this is nothing's further than the from the truth. This has never been demonstrated in any way, shape or form. There was one faulted retracted paper that suggested that and that's what they based it on. Their study was in 2016 with about 83,000 men that had low testosterone and they followed them over six years. So 80,000 men over six years as 480,000 person years. We refer to as one of the massive study done through the VA and they found the men that had testosterone place were half as likely to be dead as the men who did not have testosterone replacement therapy. And is mostly cardiovascular events but it actually decreases all cause mortality testosterone replacement. Number eight, the evidence does not support increased risk of prostate cancer with testosterone therapy. So this is a common myth that some doctors believe the person that has testosterone or has prostate cancer may be put on testosterone suppressive therapy during treatment, but then they can resume testosterone after they're in remission. And if they in this also, there's no studies supporting increased risk of prostate cancer in men with low T that have replacement of testosterone. Now, men who are untreated have higher incidence of more aggressive cancers, but when they're treated, they have the same incidence of prostate cancer as other Recommend it. Number 9, the evidence supports a major research initiative to explore the possible benefits of testosterone therapy for cardiometabolic disease, including diabetes. Now, this last resolution is just stating that even though we've shown that men with low T have more diabetes, more cardiovascular disease, and that testosterone replacement observationally leads to less diabetes, less cardiovascular disease, there's no evidence to say, well if a man has diabetes, just go ahead and put him on testosterone really should be based on having symptoms of testosterone replacement therapy. But in this resolution they're calling for the research to see if you can consider testosterone as a direct treatment for diabetes or cardiovascular disease, along with beta blockers and glycemic control medications. So these are the nine resolutions by the international consensus. Kind of flies in the face of the FDA indications for low testosterone. Also flies in the face of the insurance regulations for replacing testosterone for insurance companies. Typically the idea is you'd have somebody with severely low testosterone. They give you a number. It's got to be checked twice in a row before 10:30 in the morning. If it's really severely low, they'll pay to get it just above low. Really not what we're calling for in these expert recommendations is more replacing it to a more physiologic level, something that you would have had when you were younger. There is no specific level of testosterone when you draw your blood. That tells who will respond and who will not respond. So this is something you can have this conversation with your physician. You can bring this article with you. The Mayo Clinic proceedings expert consensus opinion on treatment of testosterone and men with testosterone deficiency. So thank you very much. It.