Testosterone Cypionate and Cognitive Function: What the Evidence Actually Shows

What Is Testosterone Cypionate Approved For?

The Depo-Testosterone label covers testosterone cypionate injection for men with primary hypogonadism (testicular failure) or hypogonadotropic hypogonadism (pituitary or hypothalamic cause) [2]. The labeled dose is 50 to 400 mg every 2 to 4 weeks by deep gluteal intramuscular injection, after morning serum testosterone has been measured on at least two separate days and found below the normal range [2].

FDA says approved testosterone products are for men who have low testosterone together with an associated medical condition, and none are approved for low testosterone alone [4]. The Depo-Testosterone label still says safety and efficacy in age-related hypogonadism have not been established [2]. FDA requested removal of that limitation in June 2026 [4].

What Does the Main Testosterone Trial in Older Men Show?

The T-Trials enrolled 790 men aged 65 or older with a serum testosterone below 275 ng/dL and symptoms suggesting low testosterone [1]. Men received testosterone gel or placebo gel for one year, and each man joined one or more of three trials: sexual function, physical function and vitality [1].

Testosterone significantly increased sexual activity (P<0.001), as well as sexual desire and erectile function [1]. It produced no significant benefit on the vitality scale, though men who received testosterone reported slightly better mood and less severe depressive symptoms [1]. Walking distance did not differ significantly between groups in the physical function trial, but the difference was significant when men in all three trials were combined (20.5% of men on testosterone vs 12.6% on placebo, P=0.003) [1]. The authors noted that the number of participants was too few to draw conclusions about the risks of testosterone treatment [1].

What Does the Label Say to Watch For?

The Depo-Testosterone label says testosterone can increase blood pressure, which can increase cardiovascular risk over time; it says to monitor blood pressure periodically and that testosterone products are not recommended in patients with uncontrolled hypertension [2]. FDA's February 2025 class-wide labeling action states that ambulatory blood pressure studies confirmed a blood pressure increase with all testosterone products [3]. The label also says to check hemoglobin and hematocrit periodically during long-term use, and lists polycythemia, venous thromboembolism, depression, anxiety, headache and libido changes among adverse reactions [2].

The 2018 Endocrine Society guideline recommends diagnosing hypogonadism only in men with symptoms and consistently low morning testosterone, confirmed on a repeat measurement [5]. It recommends against starting testosterone in men planning fertility in the near term, and in men with breast or prostate cancer, elevated hematocrit, untreated severe sleep apnea, uncontrolled heart failure, or a heart attack or stroke within 6 months [5].