Cardiovascular safety of testosterone therapy-Insights from the TRAVERSE trial and beyond: A position statement of the European Expert Panel for Testosterone Research
Testosterone therapy has become a cornerstone treatment for men with hypogonadism, offering significant benefits such as improved sexual function, mood, muscle mass, and bone density. However, concerns about its cardiovascular safety have historically tempered its use. This position statement synthesizes the current evidence on the cardiovascular safety of testosterone therapy, drawing from key studies including the TRAVERSE trial, other trials, and recent meta-analyses.
Background and Importance
Testosterone therapy aims to restore testosterone levels in men with hypogonadism, a condition associated with increased cardiovascular and metabolic risks. Early research produced mixed results, with some studies suggesting a potential increase in cardiovascular events such as myocardial infarction and stroke, while others indicated possible cardiovascular benefits, particularly in men with coexisting conditions like metabolic syndrome and type 2 diabetes.
Findings from Recent Studies
The TRAVERSE trial, a large-scale, randomized, placebo-controlled study, provided robust evidence that testosterone therapy does not significantly increase the risk of major adverse cardiovascular events. Testosterone therapy was found to effectively mitigate anemia in hypogonadal men, highlighting a dual benefit of increasing red blood cell production while managing cardiovascular risks. The findings from the TRAVERSE trial align with those from previous meta-analyses that concluded that testosterone therapy is safe and does not increase cardiovascular risk.
Consensus and Clinical Implications
There is consensus that testosterone therapy, when prescribed to appropriately selected patients and monitored regularly, is safe from a cardiovascular standpoint, with the potential benefits outweighing the risks when the therapy is used responsibly. Current guidelines recommend individualized treatment plans with careful monitoring, especially of hematocrit levels. This position statement amalgamates previous knowledge with current data and is in agreement with recent United States Food and Drug Administration label changes for testosterone products.
Grande G et al., 2026·The Journal of clinical endocrinology and metabolism·Free to read
Male factor infertility (MFI) is frequently labelled idiopathic when evaluation relies primarily on semen analysis, potentially overlooking endocrine and pathophysiological mechanisms relevant for targeted management.
To phenotypically define MFI and develop a pathophysiology-based classification aimed at reducing idiopathic infertility following comprehensive evaluation.
Prospective monocentric cohort study conducted at a tertiary referral academic centre.
Eight hundred male partners of infertile couples evaluated between October 2024 and January 2026 after exclusion of isolated female factor infertility.
Prevalence of MFI categories, hormonal patterns across phenotypes, and proportion of idiopathic infertility after comprehensive work-up.
All patients underwent standardized clinical evaluation, hormonal assessment (total testosterone, FSH, LH), testicular ultrasound, and complete semen analysis. Microbiological testing, transrectal ultrasound, and genetic analyses were performed according to guidelines.
Primary spermatogenic failure was the most prevalent category (56.0%), followed by infection/inflammation (22.4%) and hypogonadotropic hypogonadism (8.5%). Idiopathic infertility was identified in only 5.3% of cases. Distinct endocrine profiles were observed, with high-FSH spermatogenic failure representing the dominant phenotype.
Comprehensive phenotyping markedly reduces the proportion of patients classified as having idiopathic infertility and identifies clinically relevant subgroups. This prospective study provides validation of a pathophysiology-based classification and supports a shift toward endocrine-integrated diagnostic strategies in male infertility, with potential implications for targeted management.
Rocca MS et al., 2026·Journal of translational medicine·Free to read
Standard semen analysis has little prognostic value in distinguishing fertile from infertile men. Furthermore, in men with semen parameters within the reference ranges, it cannot distinguish fertile men from infertile men, i.e. partners of couples with idiopathic infertility. Oxidative stress, mitochondrial dysfunction, sperm telomere shortening, and DNA fragmentation have been proposed as contributors to impaired male fertility. However, these biomarkers have not been evaluated as a whole in subjects with normal semen parameters, partners of fertile and infertile couples.
To characterise a multidimensional panel of sperm biomarkers-including sperm telomere length (STL), mitochondrial DNA copy number (mtDNAcn), reactive oxygen species (ROS), lipid peroxidation (LP), sperm chromatin dispersion (SCD), and respiratory control ratio (RCR)-and to identify whether these parameters might discriminate, in men with normal semen parameters, infertile men from fertile controls.
A total of 150 men with semen parameters within the normal ranges were enrolled: 47 male partners of couples with idiopathic infertility and 103 fertile controls. STL and mtDNAcn were quantified by qPCR; ROS were assessed using OxiSperm®II with semiquantitative imaging; LP was measured spectrophotometrically in seminal plasma; SCD was used to determine DNA fragmentation; and mitochondrial function was evaluated by oxygen consumption and RCR. Correlations between biomarkers and semen parameters were analysed using Pearson or Spearman coefficients, and intergroup comparisons were adjusted for age.
Semen parameters did not differ significantly between male partners of fertile and infertile couples. compared to men of fertile couples, men of infertile couples exhibited significantly shorter STL (0.57 ± 0.59 vs 1.21 ± 1.13, p_adj = 0.001) and higher oxidative stress, with both ROS (8300.9 ± 4214.8 vs 6555.3 ± 3394.3, p_adj = 0.027) and LP (88.33 ± 55.50 vs 40.29 ± 46.98, p_adj < 0.001) markedly elevated. mtDNAcn, SCD, and RCR showed no difference between the groups. Across the entire cohort, STL correlated negatively with ROS and LP and positively with RCR. ROS correlated negatively with total sperm count, motility and RCR, and positively with LP. LP displayed the strongest pattern of associations, correlating negatively with concentration, total count, motility, STL and RCR, and positively with age and volume.
Among men with normal semen analysis, partners of couples with idiopathic infertility exhibit a distinct sperm molecular profile characterised by telomere shortening and oxidative imbalance. STL, ROS and LP emerged as age-independent biomarkers associated with infertility status and showed promising discriminatory ability in this cohort, supporting their integration as second-level tests to complement routine semen analysis in cases of normozoospermia.
Ponce MR et al., 2026·Andrology·Free full text on PubMed Central
Transgender individuals assigned male at birth (AMAB) may choose to preserve their fertility prior to starting gender-affirming hormone therapy (GAHT). However, limited data exist regarding the baseline reproductive and hormonal characteristics of this population before and after GAHT.
To characterize semen quality and hormonal profiles in transgender AMAB individuals prior to GAHT and compare findings with cisgender men and with transgender individuals who discontinued GAHT for at least 3 months.
This retrospective study included transgender AMAB individuals from two tertiary andrology centers who underwent sperm cryopreservation before GAHT initiation (treatment-naïve group). Clinical evaluation included anthropometric measures, testicular volume assessment, varicocele detection, and sex hormone measures. Semen parameters were analyzed according to WHO criteria and compared with those of cisgender men and previously treated transgender individuals.
Thirty-two treatment-naïve transgender AMAB individuals were included. Hormonal parameters were generally within reference ranges. Only 46.9% of treatment-naïve individuals met WHO criteria for normozoospermia, compared with 75.5% of cisgender controls. Compared with nine previously treated individuals, estradiol levels were higher and seminal volume lower. A higher frequency of seminal abnormalities was observed, although not statistically significant.
A substantial proportion of treatment-naïve transgender AMAB individuals exhibited impaired semen parameters prior to GAHT initiation. Prior GAHT exposure showed a trend toward poorer semen quality. These findings support early fertility counseling and preservation in transgender individuals prior to GAHT initiation.
Delbarba A et al., 2026·Reviews in endocrine & metabolic disorders·Free full text on PubMed Central
Male hypogonadism is associated with significant alterations in body composition, including reduced lean body mass (LBM), increased fat body mass (FBM), particularly visceral adiposity, and impaired muscle function, contributing to frailty and cardiometabolic risk. These changes reflect the disruption of a complex endocrine crosstalk among bone, muscle, and adipose tissue, mediated by cytokines such as osteokines, myokines, and adipokines. This dysregulation promotes the development of osteosarcopenic obesity, a condition characterized by the coexistence of low bone mass, sarcopenia, and excess adiposity. Testosterone (T) plays a central role in maintaining body composition by stimulating muscle protein synthesis, inhibiting adipogenesis, and preserving bone health. Its deficiency, irrespective of etiology, leads to rapid impairment of anabolic pathways, resulting in decreased lean mass and increased fat accumulation. Evidence from clinical and experimental models demonstrates that these alterations are partially reversible with T replacement therapy (TRT), although variability exists depending on the underlying cause of hypogonadism. Dual-energy X-ray absorptiometry (DXA) represents the gold standard for assessing bone mineral density (BMD) and a key tool for evaluating body composition through a three-compartment model. It allows precise quantification of fat and lean mass, as well as their regional distribution, with minimal radiation exposure. In this review, we provide a comprehensive and clinically oriented overview of body composition alterations in male hypogonadism, focusing on underlying pathophysiological mechanisms and the practical application of DXA across different clinical scenarios. We discuss evidence from conditions such as Klinefelter syndrome, Kallmann syndrome, androgen deprivation therapy, HIV infection, and transgender care, aiming to offer a pragmatic framework for integrating body composition assessment into routine practice and improving patient management.
Lincoff AM et al., 2023·The New England journal of medicine
The cardiovascular safety of testosterone-replacement therapy in middle-aged and older men with hypogonadism has not been determined. In a multicenter, randomized, double-blind, placebo-controlled, noninferiority trial, we enrolled 5246 men 45 to 80 years of age who had preexisting or a high risk of cardiovascular disease and who reported symptoms of hypogonadism and had two fasting testosterone levels of less than 300 ng per deciliter. Patients were randomly assigned to receive daily transdermal 1.62% testosterone gel (dose adjusted to maintain testosterone levels between 350 and 750 ng per deciliter) or placebo gel. The primary cardiovascular safety end point was the first occurrence of any component of a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke, assessed in a time-to-event analysis. A secondary cardiovascular end point was the first occurrence of any component of the composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or coronary revascularization, assessed in a time-to-event analysis. Noninferiority required an upper limit of less than 1.5 for the 95% confidence interval of the hazard ratio among patients receiving at least one dose of testosterone or placebo. The mean (±SD) duration of treatment was 21.7±14.1 months, and the mean follow-up was 33.0±12.1 months. A primary cardiovascular end-point event occurred in 182 patients (7.0%) in the testosterone group and in 190 patients (7.3%) in the placebo group (hazard ratio, 0.96; 95% confidence interval, 0.78 to 1.17; P<0.001 for noninferiority). Similar findings were observed in sensitivity analyses in which data on events were censored at various times after discontinuation of testosterone or placebo. The incidence of secondary end-point events or of each of the events of the composite primary cardiovascular end point appeared to be similar in the two groups. A higher incidence of atrial fibrillation, of acute kidney injury, and of pulmonary embolism was observed in the testosterone group. In men with hypogonadism and preexisting or a high risk of cardiovascular disease, testosterone-replacement therapy was noninferior to placebo with respect to the incidence of major adverse cardiac events. (Funded by AbbVie and others; TRAVERSE ClinicalTrials.gov number, NCT03518034.).
Scala A et al., 2024·Minerva endocrinology·Free to read
In transgender individuals assigned female at birth, testosterone therapy is employed for body masculinization. Guidelines recommend close monitoring for potential side effects of hormonal therapy, especially during the first year. Erythrocytosis is a common finding during testosterone therapy and has been associated with a potential risk of thrombotic and cardiovascular events. Currently, the hematologic effects of testosterone therapy are understudied, with existing data primarily derived from the cisgender male population. The aim of this study was to comprehensively examine the hematological changes induced by testosterone therapy in the transgender population.
A systematic search was conducted using the electronic database PubMed.
Thirty-six manuscripts were retrieved. After screening for original studies, 19 articles were included. Selected articles were published between 2005 and 2023.
In our systematic review, the prevalence of erythrocytosis varied from 0% to 29.3%, with severe erythrocytosis ranging from 0.5% to 2.3%. Testosterone therapy was associated with an increase in hemoglobin and hematocrit, particularly within the first year of therapy. Factors such as serum testosterone levels, along with the duration, doses, and formulation of testosterone therapy, were found to be associated with the development of erythrocytosis. Further research is crucial to provide specific recommendations for clinical practice.
Pizzocaro A et al., 2020·Journal of endocrinological investigation
Low testosterone (T) in Klinefelter's syndrome (KS) can contribute to typical features of the syndrome such as reduced bone mineral density, obesity, metabolic disturbances and increased cardiovascular risk. The aim of the present study is to review and meta-analyze all available information regarding possible differences in metabolic and bone homeostasis profile between T treated (TRT) or untreated KS and age-matched controls.
We conducted a random effect meta-analysis considering all the available data from observational or randomized controlled studies comparing TRT-treated and untreated KS and age-matched controls. Data were derived from an extensive MEDLINE, Embase, and Cochrane search.
Out of 799 retrieved articles, 21 observational and 22 interventional studies were included in the study. Retrieved trials included 1144 KS subjects and 1284 healthy controls. Not-treated KS patients showed worse metabolic profiles (including higher fasting glycemia and HOMA index as well as reduced HDL-cholesterol and higher LDL-cholesterol) and body composition (higher body mass index and waist circumference) and reduced bone mineral density (BMD) when compared to age-matched controls. TRT in hypogonadal KS subjects was able to improve body composition and BMD at spinal levels but it was ineffective in ameliorating lipid and glycemic profile. Accordingly, TRT-treated KS subjects still present worse metabolic parameters when compared to age-matched controls.
TRT outcomes observed in KS regarding BMD, body composition and glyco-metabolic control, are similar to those observed in male with hypogonadism not related to KS. Moreover, body composition and BMD are better in treated than untreated hypogonadal KS. Larger and longer randomized placebo-controlled trials are advisable to better confirm the present data, mainly derived from observational studies.
Di Lodovico E et al., 2022·Circulation. Heart failure
Male hypogonadism is defined as low circulating testosterone level associated with signs and symptoms of testosterone deficiency. Although the bidirectional link between hypogonadism and cardiovascular disease has been clarified, the association between testosterone and chronic heart failure (HF) is more controversial. Herein, we critically review published studies relating to testosterone, hypogonadism, and HF and provide practical clinical information on proper diagnosis and treatment of male hypogonadism in patients with HF. In general, published studies are extremely heterogeneous, frequently have not adhered to hypogonadism guidelines, and suffer from many intrinsic methodological inaccuracies; therefore, data provide only low-quality evidence. Nevertheless, by selecting the few methodologically robust studies, we show the prevalence of testosterone deficiency (30%-50%) and symptomatic hypogonadism (15%) in men with HF is significant. Low testosterone correlates with HF severity, New York Heart Association class, exercise functional capacity, and a worse clinical prognosis and mortality. Interventional studies on testosterone treatment in men with HF are inconclusive but do suggest beneficial effects on exercise capacity, New York Heart Association class, metabolic health, and cardiac prognosis. We suggest that clinicians should measure testosterone levels in men with HF who have symptoms of a testosterone deficiency and conditions that predispose to hypogonadism, such as obesity and diabetes. These patients-if diagnosed as hypogonadal-may benefit from the short- and long-term effects of testosterone replacement therapy, which include improvements in both cardiac prognosis and systemic outcomes. Further collaborative studies involving both cardiologists and endocrinologists are warranted.
Therapeutics › Hormonal Agents › Androgens and DHEA
Michael Zitzmann, Robert D Murray, David Edwards, Yacov Reisman, Preethi Mohan Rao, Alexander Sahi, Thomas Hugh Jones, Eleni Armeni, Emiliano Corpas, Jann-Frederik Cremers, Janine David, Leen Antonio
Mike Zitzmann, M Zitzmann, Bob Murray, Rob Murray, Bobby Murray, R Murray, Dave Edwards, D Edwards, Y Reisman, P Rao, Alex Sahi, A Sahi, Tom Jones, T Jones, E Armeni, E Corpas, J Cremers, J David, L Antonio
PMID 40372318 40372318 DOI 10.1111/andr.70062 10.1111/andr.70062 Zitzmann et al. 2026, Zitzmann 2026
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