What does the evidence say happens over time?
Untreated low testosterone is mostly a slow problem, not an emergency, and the evidence is stronger for some effects than others. MedlinePlus lists loss of sex drive, erectile problems, infertility, osteoporosis and weakness among the effects of hypogonadism in men. Beyond that list, the research gets more uneven.
| Possible effect | Strength of evidence | What studies show |
|---|---|---|
| Low libido and sexual function | Good, small effect | Treatment brings small but real improvements |
| Lower bone density | Good for density, not fractures | Treatment raises density; fracture benefit not shown |
| Unexplained anemia | Good | Treatment corrects it in many anemic men |
| Insulin resistance and diabetes | Mixed | Some improvement in insulin sensitivity, no clear HbA1c benefit |
| Heart disease and early death | Weak, association only | Linked in observational studies, cause not proven |
| Energy, memory and thinking | Weak | Trials show little or no improvement |
| Mood | Small | Modest improvement in depressive symptoms |
The grades in the table summarize the Endocrine Society guideline, the AUA guideline and newer trial results.
Is bone loss the clearest long-term risk?
Bone is where the case is strongest, with an important catch. In the Testosterone Trials, treatment significantly increased bone density, more in the spine than the hip, according to the Endocrine Society guideline. That supports the idea that years of low testosterone leave bones thinner than they would otherwise be.
The catch is fractures. The Endocrine Society’s July 2026 statement notes that the TRAVERSE trials, with more than 5,200 men, found more bone fractures in treated men, not fewer. Denser bones on a scan have not yet translated into fewer breaks. A man with osteoporosis needs bone-specific treatment, and our page on low bone density in men explains the options.
What about anemia?
Low testosterone can leave you anemic, because testosterone helps drive red blood cell production. The Endocrine Society guideline describes a dose-dependent rise in hemoglobin with treatment, and the AUA guideline recommends testing testosterone in any man with unexplained anemia.
The trial result is clear: in the anemia study the AUA cites, 58% of men treated with testosterone were no longer anemic, compared with 22% on placebo. Anemia has many causes, so iron, B12 and other checks come first. Our page on low hemoglobin in men covers that workup.
Does untreated low testosterone lead to diabetes?
The link is real but tangled. Excess weight and sleep apnea are known contributors to low testosterone, and both also drive insulin resistance. The Endocrine Society notes that some studies show testosterone improving insulin sensitivity. A meta-analysis, however, found no improvement in HbA1c, and the guideline does not recommend testosterone for blood sugar control.
The bigger drivers of insulin resistance are the ones NIDDK lists: excess weight, low physical activity, age, family history and sleep apnea. For men with obesity and no other cause of low testosterone, the 2026 Endocrine Society statement calls weight loss the usual first treatment. Our pages on insulin resistance in men and whether TRT can reverse prediabetes go deeper.
Which claims are weaker than they sound?
Heart disease and early death top the list. Men with low testosterone do have higher rates of heart disease and death in population studies, and the AUA calls low testosterone a cardiovascular risk factor. But the Endocrine Society is explicit that these studies show association and cannot prove causation, and the AUA says it cannot be stated whether treatment raises or lowers cardiovascular risk.
Energy and thinking are next. The Endocrine Society reports that the Testosterone Trials found no improvement in vitality or cognitive function, with only small gains in mood, depressive symptoms and walking distance. If someone tells you untreated low testosterone will damage your heart or memory, ask what evidence sits behind the claim. Our article on the Testosterone Trials in men over 65 summarizes those results.
How Ultimate Male weighs the risks with you
The decision rests on your symptoms, your confirmed lab results and the specific risks in your history, not on fear of what might happen. At the San Gabriel and Downey clinics, the evaluation follows the guideline approach: low levels confirmed on more than one morning test, with reversible causes checked first.
If treatment makes sense, your provider explains which benefits are well supported and which are not, so your expectations match the evidence. If it does not, you get a plan to recheck and address the causes. Our honest look at whether TRT is worth it and our page on testosterone therapy are good next reads.
