What psychological side effects can occur in a 59-year-old man receiving testosterone injections with serum testosterone around 850 ng/dL (started at 450 ng/dL)?

Psychological Side Effects of Testosterone Therapy at Supraphysiologic Levels

Your testosterone level of 850 ng/dL is well within the normal physiologic range and is unlikely to cause significant psychological side effects. In fact, testosterone therapy at this level produces minimal to no meaningful psychological benefit or harm in most men.

Expected Psychological Effects at Your Current Level

Mood and Depression

• Testosterone therapy produces less-than-small improvements in depressive symptoms (standardized mean difference ≈ -0.19), which is clinically insignificant even in men with confirmed hypogonadism 1.
• At your current level of 850 ng/dL—which falls in the mid-to-upper normal range—you should not expect meaningful mood changes, either positive or negative 1, 2.
• Studies show that fatigue, low energy, depressed mood, poor concentration, and reduced physical strength have minimal correlation with serum testosterone levels and do not improve reliably with testosterone therapy 1.

Cognitive Function

• Testosterone therapy has little to no effect on cognition, memory, or overall thinking ability, even in men with confirmed hypogonadism 1, 2.
• Your level of 850 ng/dL is not associated with cognitive impairment or enhancement 1.

Anxiety and Behavioral Changes

• The FDA label for injectable testosterone lists anxiety as a potential adverse reaction, though this is not commonly reported in clinical practice 3.
• Increased or decreased libido can occur with testosterone therapy, but at physiologic levels like yours (850 ng/dL), dramatic changes are uncommon 3.
• Headache and generalized paresthesia are listed as nervous system adverse reactions but are not specifically psychological 3.

What the Evidence Shows About "Normal-High" Testosterone

Safety of Elevated Endogenous Levels

• A 2022 study examining men with naturally elevated testosterone (>800 ng/dL) found no association between higher endogenous testosterone levels and adverse psychological events 4.
• Men with testosterone >800 ng/dL had similar rates of sleep disorders, urinary symptoms, and depression compared to men with normal testosterone (300-800 ng/dL) 4.
• Your level of 850 ng/dL is only slightly above this threshold and falls well within the range studied 4.

Target Range for Therapy

• Current guidelines recommend targeting mid-normal testosterone levels of 450-600 ng/dL during testosterone replacement therapy 2, 5, 6.
• Your level of 850 ng/dL is above this target but still within the normal physiologic range (upper limit typically 916-1,000 ng/dL depending on the laboratory) 7, 8.
• Supraphysiologic levels (>1,000 ng/dL) are associated with increased risk of adverse effects, particularly erythrocytosis, but psychological side effects remain poorly documented even at these higher levels 5, 4.

What You Should Actually Monitor

Physical Side Effects (More Relevant Than Psychological)

• Erythrocytosis (elevated hematocrit) is the most common dose-dependent side effect of testosterone therapy, occurring in up to 44% of men on injectable testosterone 2, 5.
• At your level of 850 ng/dL, you should have your hematocrit checked regularly; therapy should be withheld if it exceeds 54% 2, 8.
• Gynecomastia, fluid retention, and acne are other physical side effects listed in the FDA label but are not psychological 3.

Realistic Expectations for Psychological Benefits

• The primary proven benefit of testosterone therapy is improvement in sexual function and libido (standardized mean difference ≈ 0.35), not mood or cognition 1, 2.
• Energy, vitality, physical functioning, and mood show minimal to no improvement even in men with confirmed hypogonadism 1, 2.
• At your starting level of 450 ng/dL (which is mid-normal), you were not hypogonadal, so the psychological benefits of therapy are likely negligible 1, 2.

Common Pitfalls to Avoid

• Do not attribute nonspecific symptoms like fatigue, low energy, or mood changes to testosterone levels, as these symptoms show minimal correlation with serum testosterone and do not improve reliably with therapy 1.
• Do not assume that higher testosterone levels will improve mood, cognition, or energy, as the evidence does not support this even in hypogonadal men 1, 2.
• Do not ignore physical side effects like erythrocytosis, which are far more common and clinically significant than psychological side effects at your current level 2, 5, 4.

Bottom Line

At 850 ng/dL, you are in the normal physiologic range and should not experience significant psychological side effects. The evidence shows that testosterone therapy produces minimal to no meaningful psychological changes—either positive or negative—even in men with confirmed hypogonadism. Your primary concern should be monitoring for physical side effects like erythrocytosis, not psychological changes 1, 2, 4.