Testosterone Research Articles

Introduction: Testosterone replacement therapy (TRT) is linked to venous thromboembolism (VTE) and cardiovascular risks, but intracardiac thrombus formation has not been reported. This case highlights rapid left ventricular (LV) thrombus development and thromboembolic events in a patient on TRT, with no traditional hypercoagulable risk factors. Case Presentation: A 48-year-old male with tobacco use and daily alcohol intake presented with progressive dyspnea. Transthoracic echocardiography (TTE) revealed reduced ejection fraction (24%) and left ventricular dilatation (LVIDD 6 cm). There was no thrombus visualized in the left ventricle. Coronary angiography showed no obstructive disease. Guideline-directed medical therapy (GDMT) was initiated. He returned within 24 hours of discharge with dizziness and aphasia. Computed tomography angiography (CTA) identified a partially occluding embolus in the left middle cerebral artery (MCA), confirmed by MRI as an acute left frontoparietal infarct. Repeat TTE (5 days from prior TTE) demonstrated a large, mobile apical septal LV thrombus. CT imaging also revealed pulmonary embolism and splenic infarction. Hypercoagulable workup (prothrombin mutation, Factor V Leiden, cardiolipin antibodies) was negative. The patient disclosed scheduled testosterone injections for hypogonadism, with a total testosterone level of 1,081 ng/dL (reference: 300–1,000 ng/dL). Discussion: This case illustrates rapid LV thrombus formation and thromboembolism temporally linked to TRT. Despite guideline-based heart failure management, thrombus developed within 5 days of prior TTE. Prior studies associate TRT with VTE and stroke, but this is the first report of acute LV thrombus and multi-organ emboli in the absence of traditional hypercoagulable states. Proposed mechanisms include TRT-induced erythrocytosis, platelet activation, and endothelial dysfunction [1–4]. Conclusion: TRT may precipitate intracardiac thrombosis and thromboembolic events even without classical risk factors. Clinicians should consider TRT cessation and anticoagulation in similar cases, emphasizing cautious patient selection and monitoring. Further research is needed to clarify TRT’s role in hypercoagulability and cardiac remodeling.

Background Bilateral testicular tumors in infants are extremely rare. This case report describes synchronous bilateral mature teratomas complicated by torsion of an intra-abdominal undescended testis (IAT), and underscores the clinical importance of early diagnosis, timely surgical intervention, and fertility-preserving management, providing valuable reference for future cases. Case presentation A 3-month-old boy presented with an empty right hemiscrotum. Imaging revealed a right intra-abdominal mass (22.8 × 15.9 × 21.3 mm) and left testicular lesion (7.1 × 3.9 × 7.0 mm). Serum alpha-fetoprotein was within normal limits for age, suggesting benign disease. Laparoscopy confirmed a torsed necrotic right testicular mass, managed by orchiectomy. Left testis-sparing surgery excised a separate tumor. Histopathology confirmed bilateral mature teratoma. Hormonal profiles, including testosterone (0.81 ng/mL) and follicle-stimulating hormone (3.74 mIU/mL), as well as karyotype (46,XY), were normal. No additional therapy was required, as mature teratomas are benign. Postoperative alpha-fetoprotein levels normalized, with no recurrence at 6-month follow-up. Parental education regarding testicular examination is important for early detection of future abnormalities. Conclusions Tumors associated with intra-abdominal undescended testes warrant urgent intervention due to torsion risk. Surgery preserving testicular tissue is recommended for bilateral benign teratomas to maintain fertility. Serial alpha-fetoprotein monitoring and ultrasound surveillance are essential postoperatively.

Free testosterone and cognitive function: Sex-specific links in adults in the nationwide Korean frailty and aging cohort.

Mogroside V restores glycolytic function via LDHA promoter demethylation independent of alternative splicing in PCOS granulosa cells.

Modafinil (MOD) is a nootropic nonamphetamine medication of growing therapeutic interest. Despite the drug's rapidly expanding usage, little is known about its toxic effects on male reproduction. The present study aimed to reveal the dose-dependent MOD-induced reproductive toxicity and the potential mitigating effects of selenium (Se) in testis. Adult male rats were administered MOD300 or 600 mg/kg/day alone for 14 days or co-treated with Se either 0.1 or 0.2 mg/kg/day for 21 days. Functional, biochemical (Testosterone, Follicle-stimulating hormone, Luteinizing hormone, Nitric oxide, Malondialdehyde, Superoxide Dismutase, and Total Antioxidant Capacity), molecular, histopathological, and Transmission electron microscopy examinations were studied. Results revealed that MOD doses significantly induced deterioration of erectile function and sperm quality accompanied by a significant alteration in reproductive hormonal levels (Total and Free testosterone, LH, and FSH). MOD doses also evoked a significant increase in MDA, and NO, with a significant decrease in SOD and TAC. Furthermore, upregulation of the PI3K/Akt/NF-ҡB pathway and the increased expression of the inflammatory gene (iNOS) were demonstrated with both MOD doses. Molecular docking highlighted the virtual mechanism of binding of MOD towards the tested proteins. The observed toxicity was further confirmed by the histopathological and ultrastructural changes. The results demonstrated a significant improvement in the parameters when a Se dose of 0.2 mg/kg/day was co-administered. In conclusion, MOD interferes with male reproductive function in a dose-dependent manner, and Se may be a potentially helpful new approach for abating such toxicity.

The prevalence of liver dysfunction among men has been steadily increasing in recent decades. Among the various non-invasive assessment tools available, the Fibrosis-4 (FIB-4) Index has emerged as a particularly valuable and widely adopted scoring system for evaluating liver fibrosis. This study investigated the relationship between liver fibrosis evaluated by the FIB-4 Index and male health care parameters. Participants were assessed using standardized questionnaires, including the International Prostate Symptom Score (IPSS) for lower urinary tract symptoms (LUTS), the Sexual Health Inventory for Men (SHIM) and EHS (Erection Hardness Score) for erectile function, and the AMS (Aging Males Symptoms rating scale) for late onset hypogonadism. Endocrinological parameters, including dehydroepiandrosterone sulfate (DHEA-S), insulin-like growth factor 1 (IGF-1), total testosterone and cortisol levels, as well as metabolic factors, including hemoglobin A1c (HbA1c) and triglyceride level, were evaluated as potential confounders. The patient age was 50.62±0.24 years. The analysis revealed significant associations between higher FIB-4 Index quintiles and worsening sexual function and LUTS. Among endocrine factors, DHEA-S and IGF-1 exhibited decreasing trends with higher FIB-4 Index values, whereas cortisol showed an increasing trend. Surprisingly, no significant association was observed between FIB-4 Index and testosterone levels. HbA1c increased, but triglycerides did not correlate with FIB-4. Multiple regression confirmed IPSS and SHIM scores were independently linked to the FIB-4 Index (p<0.05). These findings highlight the importance of hepatic assessment in men with erectile dysfunction and LUTS, supporting a multidisciplinary approach to care.

Adult male testosterone concentrations in high income countries often decrease with age and adiposity, a pattern typically viewed as "normal." However, testosterone is expected to be adaptively regulated within the range of resource constrained, high pathogen, natural fertility conditions across which it evolved to function. We therefore examine associations among testosterone diurnal variation, age, and adiposity among Indigenous Shuar males of Amazonian Ecuador. Morning and evening saliva was sampled over three consecutive days to capture diurnal testosterone variation (n = 104, ages 12-67), with one-time measures of adiposity (body fat, BMI). Multilevel models tested predicted associations. Average morning and evening testosterone ratio was calculated to assess diurnal variation, and regression analyses tested the association between this ratio and age. Variation in testosterone concentrations at waking was apparent by age, with young males exhibiting the highest concentrations. Diurnal testosterone variation decreased with age (β = -0.006, p = 0.001). Significant age-by-BMI or percent body fat interactions were documented (p < 0.05). At lower adiposity levels, mean testosterone concentrations across the day were lowest at younger ages, highest in middle-aged participants, and slightly lower at older ages. At higher adiposity levels this pattern was reversed (for BMI) or attenuated (for percent body fat). "Normal" testosterone levels are largely based on studies from high-income populations that do not account for diverse ecological conditions known to influence human physiology. This study complements others highlighting the complex relationships that exist among age, adiposity, and diurnal testosterone patterns in subsistence populations, suggesting socio-ecological regulation of testosterone.

Branched chain amino acid sufficiency is necessary for proper luteinizing hormone response and testosterone synthesis.

Diabetes mellitus (DM) causes male infertility through the suppression of spermatogenesis and testosterone biosynthesis. The impact of DM on male reproduction has mainly been investigated in adulthood, therefore we aimed to study the developmental effects of DM, induced in early life, on testicular cell population and fertility. Neonatal (NDM) and prepubertal DM (PDM) were induced in immature rats by streptozotocin administration on day 1 or day 10, respectively. Germ (GCs) and somatic cells (Sertoli—SCs and Leydig cells—LCs) were counted in pubertal (25 day) and post-pubertal (45 day) rats in tandem with the measurement of serum testosterone levels and the protein expression of androgen receptor. Glucose levels were higher in PDM than in NDM. Incomplete spermatogenesis and reduced GC number were found in PDM but not in NDM. LC number, testosterone, and luteinizing hormone (LH) levels were differently altered by both types of DM with a pronounced negative impact of PDM. Protein expression of androgen receptor in SCs was altered only in PDM. Reduced sperm concentration and motility was found in both groups. Thus, our results provide new insights into different mechanisms of action of PDM and NDM on developing germ cells that involved disturbances in androgen production by Leydig cells and androgen action in Sertoli cells.

Background: Data regarding the nationwide prevalence of polycystic ovary syndrome (PCOS) in Bangladeshi women is scarce. Additionally, a prevalence study using the stepwise decision-making approach, incorporating antimüllerian hormone (AMH), was also not reported. Objectives: To determine the prevalence and characteristics of PCOS and its isolated diagnostic features among Bangladeshi women aged 10-45 years, using the 2023 International Evidence-based Guidelines, including AMH. Methods: From April to September 2024, 1201 females were sampled across eight divisions of Bangladesh by history, physical examinations, and blood collection. Total testosterone (TT) and AMH levels were assessed, with specific cut-offs established from a healthy control group. Thyroid dysfunction and hyperprolactinemia were excluded. Results: Of 1201 participants, 403 were excluded. Among 798 eligible women, 38 (4.8%) had both irregular cycles and significant hirsutism, 75 (9.4%) had only significant hirsutism, 141 (17.7%) had only irregular cycles, and 544 (68.2%) had neither. After TT and AMH evaluation and excluding two hyperprolactinemia cases, a 6.9% (55/798) prevalence was found among 57 women with probable PCOS. Familial predisposition, unhealthy sleep behaviour, and higher androgenic and metabolic features were observed in women with PCOS versus controls. Metabolic syndrome frequency was higher among adult PCOS (33.3% vs. 4.0%) than adolescent PCOS. Conclusions: The prevalence of PCOS among Bangladeshi women was 6.9%, with distinctive features compared to controls. Women with isolated diagnostic criteria require further evaluation and long-term follow-up. [J Assoc Clin Endocrinol Diabetol Bangladesh, 2025;4(Suppl 1): S37]

Hyperandrogenism in women is most commonly caused by polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia (CAH), or androgen-secreting ovarian/adrenal tumors. Para-ovarian (para-tubal) cysts are generally benign and hormonally silent. A 42-year-old obese (BMI 35Kg/m2) woman presented with progressive hirsutism and amenorrhea for 5 years. Biochemistry revealed elevated total testosterone 4.66 nmol/L [normal: 0.38-1.97 nmol/L]. Adrenal imaging, 17-hydroxyprogesterone, and DHEA-S were normal. Trans vaginal USG reported polycystic ovaries along with a right adnexal cyst [9.3x6.5cm]. MRI revealed a right adnexal ovarian cyst along with bilateral ovarian hyperplasia. The patient underwent laparoscopic cystectomy. Post-operatively, serum testosterone dropped markedly to 1.13 nmol/L without any anti-androgen medication, and clinical symptoms improved, evidenced by resumption of menstruation and improvement of hirsutism. Histopathology confirmed a Müllerian cyst with no evidence of neoplasia. Although para-ovarian cysts are typically non-functional, rare reports suggest possible androgen production or paracrine ovarian stromal stimulation due to cystic lesions. In our case, normalization of testosterone following cystectomy strongly supports a causal relationship. Potential mechanisms include stromal luteinization within the cyst wall or stimulation of adjacent ovarian tissue. [J Assoc Clin Endocrinol Diabetol Bangladesh, 2025;4(Suppl 1): S58]

BackgroundObservational studies have reported associations between thyroid function, encompassing free thyroxine, thyroid-stimulating hormone, hyperthyroidism, and hypothyroidism, and female-specific cancers such as endometrial, breast, ovarian, and cervical cancers. However, the causal relationship remains unclear.ObjectiveThe researchers aimed to explore the causal relationship between thyroid function and female-specific cancers, while also investigating the role of sex hormones (total testosterone and estradiol) as potential mediators in this association.MethodsInitially, the researchers preformed bidirectional two-sample (T-S) Mendelian randomization (MR) analysis using summary-level Genome-wide association studies to investigate the causal relationship between thyroid function and female-specific cancers. Subsequently, the researchers employed mediation MR analysis to assess the potential role of sex hormones as intermediaries in this relationship. The robustness of the findings of this study was further validated through a series of sensitivity analyses. Lastly, the researchers conducted bioinformatics analyses to explore underlying mechanisms, leveraging potentially relevant genes.ResultsBidirectional T-S MR analyses indicated that hypothyroidism reduces the risk of endometrial cancer (OR: 0.33, P = 0.002) and breast cancer (OR: 0.48, P < 0.001). Mediation MR analyses further suggested that hypothyroidism may lower the risk of both endometrial and breast cancers by decreasing levels of total testosterone.ConclusionThe researchers established the causal relationship between thyroid function and female-specific cancers, offering novel perspectives for the early prevention and intervention of endometrial and breast cancer. Furthermore, the researchers investigated the mediating role of sex hormones in the association between hypothyroidism and these cancers, providing valuable insights for future mechanistic research.

Sleep is a fundamental biological process in athletes, indispensable for tissue regeneration, exercise adaptation, and injury prevention. Disruptions in sleep architecture and duration have been consistently associated with diminished physical performance and adverse health outcomes, impairing muscular strength, power output, and endurance capacity, and concurrently compromising cognitive function. On a physiological level, insufficient sleep disrupts endocrine homeostasis, elevating cortisol levels and reducing anabolic hormones such as testosterone and growth hormone. At the molecular level, sleep loss promotes the upregulation of pro-apoptotic gene expression and exacerbates pro-inflammatory signalling pathways. Optimal sleep duration and quality represent a critical “regenerative window”, essential for enhancing athletic performance and safeguarding physiological resilience. Ensuring adequate sleep among athletes can be effectively achieved through educational, behavioural, and nutritional interventions outlined in this review.

Aims: Chronic total occlusion (CTO) represents a clinically important form of coronary artery disease in which collateral circulation plays a critical role in maintaining myocardial perfusion. Although testosterone has been suggested to influence vascular function and angiogenesis, the relationship between androgenic parameters and coronary collateral development remains uncertain. Methods: This cross-sectional case-control study included 230 male patients diagnosed with CTO by coronary angiography. Coronary collateral circulation was graded using the Rentrop classified categorized as good CCF (score 2–3) or bad CCF (score 0–1). Serum levels of total testosterone, free testosterone, SHBG, dehydroepiandrosterone sulfate (DHEAS), and dihydrotestosterone (DHT) were measured, and bioavailable testosterone (BioT) and free testosterone index (FTI) were calculated. Associations between androgenic parameters and collateral circulation were analyzed using correlation analysis, logistic regression, and ROC curve analysis. Results: Of the study cohort, 142 patients had good CCF and 88 had bad CCF. Patients with good CCF had higher levels of total testosterone (p

Background: Male infertility remains a significant reproductive health challenge globally, with increasing evidence implicating hormonal and inflammatory imbalances in its pathophysiology. Objective: This study evaluated serum testosterone and selected inflammatory biomarkers in infertile men (oligospermic and azoospermic) attending fertility clinics across Imo State, Nigeria. Methodology: A total of 204 participants were recruited, comprising 68 oligospermic men, 34 azoospermic men, and 102 apparently healthy, age-matched fertile controls. Serum testosterone, C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were quantified using Enzyme linked immunosorbent assay (ELISA) methods. Data were analyzed using SPSS version 21.0 and expressed as mean ± standard deviation (SD); Group comparism were made using independent t-test and one way ANOVA. Statistical significance was set at P ≤ 0.05. Results: Results showed that total testosterone levels were significantly reduced in oligospermic and azoospermic men compared to controls (8.26 ± 1.90 ng/dL) (P &lt; 0.001). Conversely, inflammatory markers were markedly elevated among infertile subjects; CRP levels were significantly higher in azoospermic (10.59 ± 3.11 mg/L) and oligospermic (8.13 ± 2.13 mg/L) men compared to controls (2.63 ± 0.73 mg/L) (P &lt; 0.001). Similarly, IL-6 and TNF-α levels were significantly elevated in azoospermic (respectively) and oligospermic (8.70 ± 1.84 pg/mL and 9.47 ± 1.94 pg/mL, respectively) groups versus controls (P &lt; 0.001). Age and body mass index (BMI) exerted no significant influence on either testosterone or inflammatory markers (P &gt; 0.05). Pearsons Correlation analyses revealed weak and statistically non-significant associations between testosterone and inflammatory (CRP, IL-6, TNF-α) in both oligospermic and azoospermic men. Conclusion: In conclusion, the study demonstrated a clear pattern of systemic inflammation among infertile men in Imo State, who also presented with hypogonadism given their levels of testosterone. There was more pronounced inflammatory derangements in azoospermic subjects, when compared with the oligospermic subjects. These findings suggest that chronic subclinical inflammation may contribute to impaired spermatogenesis and androgen deficiency, highlighting the need for integrative therapeutic interventions targeting both endocrine and inflammatory pathways in male infertility management.

Uncovering novel protein pathways regulating bioavailable testosterone through sex hormone-binding globulin.

Objective: Antisocial personality disorder (ASPD) is associated with a heightened risk of suicide, particularlyamong male patients, where chosen suicide methods tend to be more lethal. The link between suicidalbehavior and plasma testosterone levels remains a key area of investigation. This study investigateswhether plasma testosterone levels differ between ASPD patients with a history of suicide attempts,aiming to explore the hormone’s potential role as a biomarker for suicide risk. This study aimed to explorethe association between plasma testosterone levels and suicidal behavior in individuals with ASPD whoattempted suicide.Methods: A total of 44 patients with ASPD and 24 healthy controls were enrolled, matched by age,education, and gender. Biochemical evaluations included total and free testosterone, thyroid functiontests, blood lipids, folate, ferritin, and vitamin B12 levels. Psychopathological assessments were conductedusing the Hamilton Depression (HAM-D) and Anxiety (HAM-A) Scales.Results: The mean ages of the patient and control groups were 22.26 (±3.04) and 24.36 (±2.5) years,respectively. Free testosterone levels were significantly elevated in the patient group compared to controls(P=.02). Hamilton Anxiety (HAM-A) and HAM-D scores were also notably higher in the patient group. Apositive correlation was identified between free testosterone levels and high-density lipoprotein inpatients with ASPD (R=0.520; P &lt; .05).Conclusion: These preliminary findings suggest that elevated free testosterone may contribute toincreased suicide risk in men with ASPD, potentially through its impact on impulsivity and aggression.While the effect size was modest, identifying hormonal patterns associated with suicidal behavior mayhelp guide future risk assessment strategies. Further research with larger and more diverse samples is warranted.Cite this article as: Garip B, İnanç Ö. Relationship between plasma testosterone and suicidal behavior in patients withantisocial personality disorder. Neuropsychiatr Invest. 2025, 63, 0017, doi:10.5152/NeuropsychiatricInvest.2025.25017.

Male volleyball athletes may be at risk of inadequate energy and carbohydrate intake. This may increase their risk of relative energy deficiency in sport (REDs) and impair a variety of physiological and psychological systems involved with performance and health. This study explored the eating behaviours and diet quality of international elite volleyball male athletes and their association on hormones associated with acute energy deficit and primary serum REDs indicators outlined in the International Olympic Committee REDs Clinical Assessment Tool 2. Methods: Using a retrospective design, 30 male athletes from a national indoor volleyball programme were assessed using DXA bone mineral density, hematological analysis, anthropometry, restrained eating behaviour via the Three-Factor Eating Questionnaire-R18 and the Athlete Diet Index (ADI) questionnaire. Results: All participants met or exceeded dietary recommendations for health and sport with ADI mean score of 95.2/125 ± 10.5. Restraint eating was inversely associated with insulin (r = − 0.37; p < 0.05). Both the ADI total and core nutrition sub-scores were inversely associated with free-triiodothyronine (r = − 0.58; p < 0.01) but not with total testosterone, insulin or leptin. Conclusion: Male volleyball athletes at risk of inadequate energy intake may not necessarily demonstrate signs of poor diet quality.

Reproduction in chondrichthyan fishes (sharks, rays, skates, and chimaeras) is generally assumed to be a long-term, energetically costly process, given their slow generation times. However, metabolic costs of reproduction remain poorly understood due to a lack of direct, non-lethal measurements. To address this, we investigated metabolic and physiological changes during oviparous reproduction in five female epaulette sharks (Hemiscyllium ocellatum). We tracked oxygen uptake rates - a proxy for metabolic rate - across a three-week cycle, capturing data before, during, and after egg case encapsulation and oviposition. We also measured reproductive hormones (testosterone, 17β-estradiol, progesterone) and hematological parameters (hematocrit, hemoglobin concentration). Results revealed a positive but non-significant relationship between metabolic rate and body mass, and contrary to expectations, metabolic rate did not significantly change throughout the 19-day cycle. Hormone levels remained stable, except for a transient testosterone peak early in the cycle, and hematological parameters showed no significant variation. These findings tentatively suggest epaulette sharks maintain reproductive effort without marked increases in metabolic or physiological costs. Continued research under seasonal environmental variation could clarify reproductive energetics in chondrichthyans further. This study provides the first direct measurement of metabolic effects of oviparous reproduction in chondrichthyans, challenging assumptions about energetic demands in this taxon.

Abstract Disclosure: J. Walravens: None. N. Narinx: None. T. Reyns: None. D.M. Vanderschueren: None. F.C. Wu: None. T. Fiers: None. L. Antonio: None. J. Kaufman: None. B. Lapauw: None. Introduction: Guidelines suggest determination of serum free testosterone (FT) for diagnosis of male hypogonadism, especially in men with borderline low total T or with altered sex hormone-binding globulin. While mathematical approximations of FT (cFT) are most used, direct measurement of FT (mFT) using equilibrium dialysis followed by mass spectrometry (ED LC-MS/MS) is considered the gold standard. It is unclear if mFT can provide additional value over cFT in confirming androgen deficiency. Objective: To evaluate whether low mFT and cFT are differentially associated with sexual symptoms of androgen deficiency. Methods: Total T and SHBG levels were determined using LC-MS/MS and immunoassay, respectively, on serum samples of 525 community-dwelling men aged 55 to 85 years participating in the EMAS study1. FT levels were calculated using the Vermeulen formula and measured directly using ED LC-MS/MS. Sexual symptoms of hypogonadism were assessed using the EMAS Sexual Function Questionnaire. Participants were grouped by low or normal mFT and cFT levels. The cFT threshold was 220 pmol/L2. The mFT threshold was 190 pmol/L, the lower reference limit for mFT in healthy men aged 18-39 years in the SIBLOS study3. Logistic regression was used to determine if men with low FT had increased risk of sexual symptoms compared to those with normal FT. Results: Participants were divided in four groups: normal mFT/normal cFT (n = 258; mean age: 67.4 ± 7.6; mean BMI: 26.8 ± 3.2), normal mFT/low cFT (n = 15; mean age: 63.4 ± 8.6; mean BMI: 27.6 ± 2.5), low mFT/normal cFT (n = 112; mean age: 73.3 ± 8.03; mean BMI 27.2 ± 3.6) and low mFT/low cFT (n = 140; mean age: 74.6 ± 7.8; mean BMI: 28.3 ± 3.2). The low mFT/normal cFT and low mFT/low cFT groups had an increased risk of insufficient spontaneous erections (OR: 2.4 (CI: 1.5-4.0) and 2.8 (1.8-4.6)), less frequent sexual thoughts (OR: 1.9 (1.2-3.1) and 2.5 (1.6-4.0)) and lower sexual desire (OR: 1.8 (1.1-3.0) and 2.0 (1.3-3.1)). The normal mFT/low cFT group had no significantly increased risks of sexual symptoms. Conclusion: Men with low mFT had higher risks of lower sexual function, even with normal cFT. As such, mFT may be more accurate to assess androgen deficiency than cFT. However, given challenges in measuring FT, it is now not easily available for clinicians. Future efforts of academy and industry should focus on harmonizing methods and developing validated diagnostic thresholds for mFT. 1.Lee, D. M. et al. The European Male Ageing Study (EMAS): design, methods and recruitment. Int J Androl32, 11-24 (2009). 2.Wu, F. C. W. et al. Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men. New England Journal of Medicine363, 123-135 (2010). 3.Lapauw, B. M. et al. Serum Estradiol Is Associated With Volumetric BMD and Modulates the Impact of Physical Activity on Bone Size at the Age of Peak Bone Mass: A Study in Healthy Male Siblings. Journal of Bone and Mineral Research24, (2009). Presentation: Saturday, July 12, 2025