Testosterone Undecanoate

On June 18, 2026, FDA/HHS announced requested testosterone-label revisions covering the age-related hypogonadism limitation and prostate warnings. This was a labeling-change request; older product labels still carry differing wording. It does not establish approval for performance use.^[4][5]

Jurisdiction

United States

Product

Testosterone replacement products covered by the FDA request

Indication

Testosterone replacement; requested label changes, not a performance indication

Record date

2026-09-08

• US regulatory context; a class communication does not establish the approval status of every ester or international blend.

AVEED carries a boxed warning for pulmonary oil microembolism and anaphylaxis. This warning concerns the injectable product; it should not be copied as a demonstrated adverse effect of oral testosterone undecanoate.^[2]

• Product-specific risk; the inspected label does not estimate risk for research-market products.

TRAVERSE found testosterone gel noninferior to placebo for major cardiovascular events in selected men with hypogonadism and cardiovascular risk. Atrial fibrillation, acute kidney injury and pulmonary embolism occurred more often with testosterone, but these findings had different endpoint ascertainment and statistical limits from the primary result. The study did not test injectable-AAS misuse.^[6]

• Formulation and clinical population differ from injectable or supraphysiologic nonmedical use.
• AF/AKI were investigator-reported adverse events; PE belonged to the adjudicated tertiary VTE endpoint. No multiplicity adjustment for other endpoints.

A study of male weightlifters associated long-term mixed AAS exposure with lower left-ventricular function and greater coronary plaque volume than in non-users. The observational design cannot isolate an individual steroid or prove a precise risk of heart attack.^[7]

• Class-context evidence from selected male weightlifters; residual confounding and uncertain historical exposures remain.
• This finding and the interaction file's "safety-aas-cardiovascular" note rest on the same single study, held under two source records. Seeing both is not two studies agreeing.

The HAARLEM echocardiography cohort found increased left-ventricular mass and reduced function during mixed AAS use. Left-ventricular mass and the E/A ratio returned to baseline at follow-up, when only 25 of 31 participants had recovery imaging. These group findings cannot promise that every person or repeated exposure recovers.^[8]

• Small cohort, coexposures and missing follow-up; no clinical-event or molecule-specific risk estimate.

In February 2025, FDA required testosterone-label warnings about increased blood pressure after ambulatory monitoring studies. Removal of earlier major-cardiovascular-event boxed-warning language did not mean that testosterone had no cardiovascular effects.^[9]

• Product-specific warnings and clinical context remain relevant; this communication does not establish safety of supraphysiologic use.

A cross-sectional study of male weightlifters associated long-term illicit AAS use with impaired cardiac function and more coronary plaque. The study cannot establish the risk from one particular compound, dose or combination.^[7]

• This note and the compound records' "general-anadrol-safety-86" finding rest on the same single study, held under two source records. Seeing both is not two studies agreeing.
• Observational evidence, self-reported mixed exposures and potential confounding; not a comparison of medically indicated testosterone treatment.
• This is the same underlying study cited at full-text scope elsewhere in the site (content/evidence/general.ts "general-aas-cardiovascular-full"); it is one single source, not independent corroboration.

FDA reports serious liver injury and other serious reactions involving steroid or steroid-like bodybuilding products. It advises immediately consulting a healthcare professional, including before abrupt cessation, because of dangerous withdrawal problems that can arise from quickly stopping such products.^[11]

• General product safety communication, not an incidence estimate for every listed steroid.

In the HAARLEM cohort of men using mixed anabolic-androgenic steroids, testosterone and sperm recovery differed. The final visit was one year after cycle start, not one year after cessation, and some abnormal final results were already present at baseline. The study did not measure pregnancy or live birth and does not provide a universal recovery deadline.^[1]

• Class-context evidence: mixed exposures cannot isolate any individual molecule or ester, and follow-up was too short to characterize all recovery.
• Final hormone and semen denominators differ; attrition and resumed use limit recovery inference.

Testosterone undecanoate is used in distinct intramuscular depot and oral capsule products. AVEED is an oil injection; JATENZO has meal-dependent oral absorption. One numerical half-life or active duration cannot accurately represent both.^[2][3]

• Product, route, vehicle and exposure must accompany any pharmacokinetic estimate.

The inspected Nebido label reports a depot-release half-life of 90 plus or minus 40 days. This is a formulation-specific release measure, distinct from free testosterone elimination and from the decline of intact ester measured in blood. It should not be transferred to AVEED or oral testosterone undecanoate.^[10]

• Release and elimination endpoints differ; no universal clinical duration or endocrine recovery estimate.

Long-term illicit AAS exposure was associated with myocardial dysfunction and greater coronary plaque in male weightlifters. Concern about combining AAS follows from this class evidence; the incremental risk of any two steroids was not measured, and the paper does not name or compare specific steroid combinations.^[7]

• Observational, mixed self-reported exposure; no pair-specific causal estimate.
• This is the same underlying study cited at full-text scope elsewhere in the site (general.ts "general-aas-cardiovascular-full"); it is one single source, not independent corroboration.

FDA warns that people who “stack” steroid-like bodybuilding products with other products, including stimulants, may be at greater risk for serious and life-threatening reactions. This broad warning does not establish the effect or severity of an individual compound pair.^[11]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.

A review of testosterone-treatment studies found increased hemoglobin and hematocrit. Extrapolating to combined anabolic steroids suggests a possible overlapping effect, but the review did not establish pair-specific thrombosis risk.^[12]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.

Testosterone-related hematocrit increases and tamoxifen/raloxifene thromboembolic findings come from different study populations. They motivate a possible overlapping concern, not evidence of a measured thrombosis increase from the selected pair.^[12][13]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.

A controlled study in men given goserelin, testosterone gel and anastrozole linked estrogen deficiency to increased body fat and a contribution to reduced sexual function. Only anastrozole was studied; it does not establish the outcome of combining aromatase inhibitors generally, or of adding anastrozole specifically to a particular anabolic steroid.^[14]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.
• Exemestane and letrozole were not administered in this trial and do not inherit this observation; the compound scope and the corresponding rule's applicable IDs are narrowed to anastrozole (see interactionsFileNotes).