Testosterone side effects: what 23,227 FDA adverse event reports show
Who reports
23,227 reports · 61% serious · 1,151 with death outcome · 16% female
Used for
Testosterone gel, 1.62% is indicated for replacement therapy in adult males for conditions associated with a deficiency or absence of endogenous testosterone: Primary hypogonadism (congenital or acquired): testicular failure due to conditions such as cryptorchidism, bilateral torsion, orchitis, vanishing testis syndrome, orchiectomy, Klinefelter's syndrome, chemotherapy, or toxic damage from alcohol or heavy metals.
What it is
Testosterone gel, 1.62% for topical use is a clear, colorless gel containing testosterone. Testosterone is an androgen. Testosterone gel 1.62% is available in a metered-dose pump. The active pharmacologic ingredient in testosterone gel, 1.62% is testosterone.
Boxed warning
SECONDARY EXPOSURE TO TESTOSTERONE Virilization has been reported in children who were secondarily exposed to testosterone gel [see Warnings and Precautions ( 5.2 ) and Adverse Reactions ( 6.2 )]. Children should avo.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,147 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Performance enhancing product use | 24 | 309.3 194.4–492.1ROR 309.7 · χ² 5,246 / p <1e-300 | 194.4 EB05 137.5 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=24 · 100% clinician | not reported in cached trials |
| Sexual relationship change | 18 | 250.1 148.3–421.9ROR 250.3 · χ² 3,294 / p <1e-300 | 162.1 EB05 108.5 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Virilism | 22 | 227.5 142.5–363.3ROR 227.7 · χ² 3,772 / p <1e-300 | 156.9 EB05 109.2 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=19 | not reported in cached trials |
| Polycythaemia | 296 | 153.2 135.5–173.2ROR 155.2 · χ² 38,060 / p <1e-300 | 129.8 EB05 117.8 · IC025 +6.6 3/3 methods agree | Labeled adverse reaction exact term | serious n=272 · 93% clinician | not reported in cached trials |
| Cervix carcinoma stage iv | 20 | 142.3 88.8–228.1ROR 142.4 · χ² 2,299 / p <1e-300 | 110.2 EB05 75.3 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=20 · 100% clinician | not reported in cached trials |
| Toxic cardiomyopathy | 28 | 133.9 90.0–199.1ROR 134.0 · χ² 3,095 / p <1e-300 | 108.1 EB05 78.5 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=28 · 100% clinician | not reported in cached trials |
| Secondary hypogonadism | 42 | 132.5 95.8–183.1ROR 132.7 · χ² 4,655 / p <1e-300 | 109.8 EB05 84.6 · IC025 +5.1 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=41 · 100% clinician | not reported in cached trials |
| Expulsion of medication | 57 | 116.5 88.4–153.5ROR 116.8 · χ² 5,671 / p <1e-300 | 99.8 EB05 79.9 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Blood testosterone increased | 238 | 111.9 97.9–128.0ROR 113.1 · χ² 23,145 / p <1e-300 | 98.8 EB05 88.7 · IC025 +6.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=120 | not reported in cached trials |
| Acne fulminans | 20 | 101.6 64.0–161.4ROR 101.7 · χ² 1,699 / p <1e-300 | 84.2 EB05 57.6 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=20 | not reported in cached trials |
| Product deposit | 147 | 95.5 80.6–113.2ROR 96.1 · χ² 12,328 / p <1e-300 | 85.4 EB05 74.4 · IC025 +5.8 3/3 methods agree | Reporting / coding artifact | – | not reported in cached trials |
| Blood luteinising hormone decreased | 16 | 91.2 54.5–152.6ROR 91.3 · χ² 1,214 / p 2e-266 | 75.6 EB05 49.4 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=14 | not reported in cached trials |
| Precocious puberty | 50 | 86.7 64.9–115.9ROR 86.9 · χ² 3,781 / p <1e-300 | 76.8 EB05 60.6 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=37 · ♀ 38% (drug 16%) · 100% clinician | not reported in cached trials |
| Blood follicle stimulating hormone decreased | 15 | 84.4 49.7–143.4ROR 84.5 · χ² 1,054 / p 1e-231 | 70.6 EB05 45.4 · IC025 +3.6 3/3 methods agree | Likely indication confounding term in indications | serious n=13 | not reported in cached trials |
| Hepatic adenoma | 42 | 79.6 58.1–109.2ROR 79.8 · χ² 2,922 / p <1e-300 | 70.9 EB05 54.7 · IC025 +4.8 3/3 methods agree | Labeled adverse reaction exact term | serious n=42 · 100% clinician | not reported in cached trials |
| Clear cell renal cell carcinoma | 50 | 71.0 53.3–94.7ROR 71.2 · χ² 3,133 / p <1e-300 | 64.3 EB05 50.7 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=50 | not reported in cached trials |
| Central serous chorioretinopathy | 45 | 70.8 52.3–95.9ROR 71.0 · χ² 2,805 / p <1e-300 | 64.0 EB05 49.8 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious n=45 · 100% clinician | not reported in cached trials |
| Renal artery thrombosis | 22 | 70.6 45.8–109.0ROR 70.7 · χ² 1,335 / p 1e-292 | 62.1 EB05 43.3 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=22 | not reported in cached trials |
| Pilonidal disease | 17 | 69.4 42.3–113.6ROR 69.4 · χ² 1,000 / p 1e-219 | 60.3 EB05 39.9 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Breast hyperplasia | 25 | 68.6 45.7–103.1ROR 68.7 · χ² 1,484 / p <1e-300 | 61.0 EB05 43.4 · IC025 +4.2 3/3 methods agree | Labeled (related wording) related wording | serious n=23 · 100% clinician | not reported in cached trials |
| Oestradiol increased | 20 | 64.7 41.1–101.8ROR 64.7 · χ² 1,110 / p 1e-243 | 57.2 EB05 39.1 · IC025 +3.9 3/3 methods agree | Lab value / disease marker | serious n=16 | not reported in cached trials |
| Blood testosterone decreased | 442 | 61.7 56.1–67.9ROR 62.8 · χ² 24,622 / p <1e-300 | 57.6 EB05 53.2 · IC025 +5.6 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=118 · 73% consumer | not reported in cached trials |
| Breathing-related sleep disorder | 15 | 60.1 35.6–101.4ROR 60.1 · χ² 762 / p 5e-168 | 52.8 EB05 34.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Craniopharyngioma | 21 | 59.9 38.5–93.1ROR 59.9 · χ² 1,084 / p 4e-238 | 53.6 EB05 37.0 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=21 | not reported in cached trials |
| Idiopathic intracranial hypertension | 117 | 49.5 41.1–59.6ROR 49.8 · χ² 5,224 / p <1e-300 | 46.6 EB05 40.0 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=117 · ♀ 76% (drug 16%) · 100% clinician | not reported in cached trials |
| Muscle mass | 22 | 47.3 30.8–72.6ROR 47.3 · χ² 902 / p 1e-198 | 43.4 EB05 30.2 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=20 | not reported in cached trials |
| Blood growth hormone increased | 28 | 47.0 32.1–68.7ROR 47.0 · χ² 1,154 / p 4e-253 | 43.5 EB05 31.6 · IC025 +4.0 3/3 methods agree | Lab value / disease marker | serious n=24 | not reported in cached trials |
| Testicular atrophy | 43 | 46.9 34.5–63.7ROR 47.0 · χ² 1,790 / p <1e-300 | 43.8 EB05 33.8 · IC025 +4.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=34 | not reported in cached trials |
| Metaplasia | 23 | 46.0 30.2–69.9ROR 46.0 · χ² 920 / p 3e-202 | 42.3 EB05 29.7 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=23 · 100% clinician | not reported in cached trials |
| Blood testosterone abnormal | 53 | 44.9 34.1–59.1ROR 45.0 · χ² 2,124 / p <1e-300 | 42.2 EB05 33.5 · IC025 +4.5 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=14 · 82% consumer | not reported in cached trials |
| Mesenteric vein thrombosis | 45 | 42.4 31.5–57.2ROR 42.5 · χ² 1,699 / p <1e-300 | 39.9 EB05 31.1 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=45 · 100% clinician | not reported in cached trials |
| Endometrial adenocarcinoma | 28 | 41.7 28.6–60.9ROR 41.8 · χ² 1,024 / p 5e-225 | 38.9 EB05 28.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=28 · 100% clinician | not reported in cached trials |
| Blood oestrogen increased | 24 | 38.9 25.9–58.6ROR 39.0 · χ² 814 / p 2e-179 | 36.4 EB05 25.7 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=11 | not reported in cached trials |
| Infertility male | 18 | 36.9 23.0–59.1ROR 36.9 · χ² 569 / p 4e-126 | 34.3 EB05 22.9 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Hypogonadism | 39 | 35.9 26.1–49.4ROR 36.0 · χ² 1,239 / p 1e-271 | 34.0 EB05 26.0 · IC025 +4.1 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=36 | not reported in cached trials |
| Renal infarct | 55 | 35.4 27.0–46.3ROR 35.4 · χ² 1,734 / p <1e-300 | 33.7 EB05 26.9 · IC025 +4.3 3/3 methods agree | Labeled (related wording) related wording | serious n=55 · 100% clinician | not reported in cached trials |
| Blood oestrogen decreased | 25 | 34.4 23.1–51.2ROR 34.4 · χ² 748 / p 6e-165 | 32.4 EB05 23.1 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=11 · ♀ 100% (drug 16%) · 100% consumer | not reported in cached trials |
| Palmoplantar pustulosis | 17 | 31.0 19.1–50.3ROR 31.1 · χ² 449 / p 6e-100 | 29.2 EB05 19.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=16 | not reported in cached trials |
| Product delivery mechanism issue | 153 | 29.3 24.9–34.4ROR 29.5 · χ² 4,020 / p <1e-300 | 28.3 EB05 24.7 · IC025 +4.4 3/3 methods agree | Reporting / coding artifact | – | not reported in cached trials |
| Polycythaemia vera | 25 | 28.6 19.2–42.6ROR 28.6 · χ² 619 / p 6e-137 | 27.2 EB05 19.4 · IC025 +3.5 3/3 methods agree | Labeled (related wording) related wording | serious n=24 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Testosterone as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT00467259 — Endometrial Safety Study of Transdermal Testosterone (300 Mcg/Day) in Naturally Postmenopausal Women (N=1271, PHASE3; 65 AE terms posted; arms: Placebo; Testosterone)
- NCT01143818 — ESPRIT Study in Hypogonadal Men (N=1053, phase n/a; 4 AE terms posted; arms: AndroGel (Testosterone Gel) 1%)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 1,608 | 1.1 1.1–1.2ROR 1.1 · χ² 16 / p 3e-5 | 1.1 EB05 1.1 · IC025 +0.1 | Reporting / coding artifact | serious PRR 0.9 | not reported in cached trials |
| Off label use (used outside approved label) | 1,317 | 1.4 1.3–1.4ROR 1.4 · χ² 137 / p 8e-32 | 1.4 EB05 1.3 · IC025 +0.4 | Reporting / coding artifact | serious PRR 1.4 · ♀ 36% (drug 16%) | not reported in cached trials |
| Fatigue (tiredness) | 1,270 | 1.5 1.4–1.6ROR 1.5 · χ² 202 / p 5e-46 | 1.5 EB05 1.4 · IC025 +0.5 | Labeled adverse reaction exact term | serious PRR 1.5 | not reported in cached trials |
| Pain | 1,262 | 1.9 1.8–2.0ROR 1.9 · χ² 508 / p 8e-113 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 2.2 | NCT00467259: 1/251 (0.4%) control (serious AE) |
| Myocardial infarction (heart attack) | 1,019 | 5.3 4.9–5.6ROR 5.4 · χ² 3,514 / p <1e-300 | 5.2 EB05 5.0 · IC025 +2.3 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 5.0 | not reported in cached trials |
| Anxiety | 955 | 3.0 2.8–3.2ROR 3.1 · χ² 1,308 / p 1e-286 | 3.0 EB05 2.9 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.6 | not reported in cached trials |
| Nausea | 913 | 1.0 1.0–1.1ROR 1.0 · χ² 2 / p 0.094 | 1.0 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 1.1 | NCT00467259: 10/1,019 (1.0%) on Testosterone; 5/251 (2.0%) control |
| Deep vein thrombosis (leg blood clot) | 875 | 12.2 11.5–13.1ROR 12.7 · χ² 8,925 / p <1e-300 | 12.1 EB05 11.4 · IC025 +3.5 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 11.4 | NCT00467259: 2/1,019 (0.2%) on Testosterone (serious AE) |
| Headache | 860 | 1.2 1.2–1.3ROR 1.2 · χ² 41 / p 9e-11 | 1.2 EB05 1.2 · IC025 +0.2 | Labeled adverse reaction exact term | serious PRR 1.2 | NCT00467259: 22/1,019 (2.2%) on Testosterone; 8/251 (3.2%) control |
| Pulmonary embolism (lung blood clot) | 843 | 8.0 7.5–8.6ROR 8.3 · χ² 5,158 / p <1e-300 | 7.9 EB05 7.5 · IC025 +2.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.5 | not reported in cached trials |
| Cerebrovascular accident (stroke) | 834 | 4.4 4.2–4.7ROR 4.6 · χ² 2,228 / p <1e-300 | 4.4 EB05 4.2 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.2 | NCT00467259: 1/1,019 (0.1%) on Testosterone (serious AE) |
| Asthenia (weakness) | 690 | 1.7 1.5–1.8ROR 1.7 · χ² 182 / p 9e-42 | 1.7 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.4 | not reported in cached trials |
| Dizziness | 640 | 1.2 1.1–1.3ROR 1.2 · χ² 14 / p 8e-5 | 1.2 EB05 1.1 · IC025 +0.1 | Labeled adverse reaction exact term | serious PRR 1.3 | not reported in cached trials |
| Diarrhoea (diarrhea) | 636 | 0.9 0.8–1.0ROR 0.9 · χ² 8 / p 0.002 | 0.9 EB05 0.8 · IC025 -0.3 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 0.9 | NCT00467259: 8/1,019 (0.8%) on Testosterone; 6/251 (2.4%) control |
| Dyspnoea (shortness of breath) | 623 | 1.0 0.9–1.1ROR 1.0 · χ² 0 / p 0.446 | 1.0 EB05 0.9 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 1.0 | not reported in cached trials |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Performance enhancing product use — n=24, PRR 309.3
- Virilism — n=22, PRR 227.5
- Cervix carcinoma stage iv — n=20, PRR 142.3
- Toxic cardiomyopathy — n=28, PRR 133.9
- Expulsion of medication — n=57, PRR 116.5
- Acne fulminans — n=20, PRR 101.6
- Precocious puberty — n=50, PRR 86.7
- Clear cell renal cell carcinoma — n=50, PRR 71.0
- Central serous chorioretinopathy — n=45, PRR 70.8
- Renal artery thrombosis — n=22, PRR 70.6
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Testosterone?
In FDA FAERS, the most frequently co-reported reaction terms for Testosterone are fatigue, pain, myocardial infarction, anxiety, nausea, deep vein thrombosis. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Testosterone have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: SECONDARY EXPOSURE TO TESTOSTERONE Virilization has been reported in children who were secondarily exposed to testosterone gel [see Warnings and Precautions ( 5.2 ) and Adverse Reactions ( 6.2 )]. Children should avo.
Do FAERS signals prove that Testosterone causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 21705fce-bc6c-41f6-aa92-fa6fc1c22fb6, effective 20231208; matched on
openfda.generic_name.exact:"TESTOSTERONE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 1,187 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath - ClinicalTrials.gov API v2 (query
TESTOSTERONE, results-bearing studies sorted by enrollment)
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.