The double-edged sword of dominance
Research finds that dominant animals in primate societies have higher parasite loads due to suppressed immune systems. Frequent aggression and contact with other animals may contribute to the risk of infection.
Testosterone
Articles tagged with Testosterone
New ground broken on aggression research
A study by U of A Psychology researcher Peter Hurd found that less sensitive genes were associated with more aggressive behaviour, suggesting a possible link between fetal testosterone exposure and adult social behavior. The researchers also discovered subtle forms of aggression, such as indirect aggression through gossip-like behaviors.
Male reproductive problems may add to falling fertility rates
Declining sperm counts and testosterone levels are contributing to reduced fertility rates worldwide. At least one in five young men in Europe have subfertile semen quality, while testicular cancer and developmental abnormalities also rise. Poor sperm quality is linked to poorer IVF success rates.
Alpha males take greater risks: Study links finger length to behavior
Researchers at Concordia University discovered a link between the length of the second and fourth fingers and risk-taking behavior in men. The study found that alpha males with shorter ratios were more likely to engage in recreational, social, and financial risk-taking.
Study shows a single shot of morphine has long lasting effects on testosterone levels
A new study published in Molecular Pain found that a single injection of morphine can strongly reduce testosterone levels in the brain and plasma of male rats. The study's findings are particularly important as testosterone is essential for various bodily functions, including cognitive functions and bone structure remodeling.
Beneficial effects of testosterone for frailty in older men are short-lived
A study found that testosterone treatment improved muscle mass, strength, and quality of life in frail elderly men, but these effects were not maintained six months after treatment. Researchers suggest a multi-disciplinary approach, including resistance exercise and lifestyle options, to interrupt the downward spiral into frailty.
Study reveals how sex hormones influence right heart function
Researchers found that higher estrogen levels are associated with improved blood-pumping efficiency in women on hormone therapy, while testosterone and DHEA increase RV mass in men. These findings may help explain the paradox of better survival in women with PAH.
Low testosterone linked to heightened risk of early death
Research published in Heart found that men with low testosterone levels were more likely to die prematurely from heart disease and all causes. The study of 930 men with coronary artery heart disease showed that those with low testosterone had nearly twice the risk of death compared to those with normal levels.
Frequent inaccuracies in testosterone testing lead to call for standardization
A consensus statement from The Endocrine Society and the US Centers for Disease Control and Prevention calls for improved testosterone testing standards. The recommendations aim to increase accuracy, reliability, and comparability of measurements over time.
Low testosterone linked to Alzheimer's disease
A study by Saint Louis University scientist John E. Morley found that low testosterone levels are associated with an increased risk of developing Alzheimer's disease in older Chinese men. The study, which analyzed data from 153 participants, also revealed elevated ApoE 4 protein levels and high blood pressure as additional risk factors.
Male maturity shaped by early nutrition
A new Northwestern University study found that rapid weight gain in the first six months of life predicts earlier puberty for boys and has long-term effects on their physical characteristics and reproductive strategy. The researchers suggest that testosterone plays a key role in shaping these differences.
Young, male, testosterone-fueled CEOs more likely to start or drop deals: UBC study
A recent study published in the INFORMS journal Management Science found that young, male CEOs with higher levels of testosterone are more likely to initiate, scrap, or resist mergers and acquisitions. This is due to testosterone's association with male dominance-seeking in competitive situations.
Having a male co-twin improves mental rotation performance in females
A recent study published in Psychological Science found that females with a male co-twin score higher on mental rotation tasks than those with a female co-twin. The study suggests that prenatal masculinization may play a role in this skill, which is often associated with testosterone levels.
BPA and testosterone levels
A large population study found a statistically significant association between BPA exposure and increased testosterone levels in men. The study, which analyzed data from over 700 adults aged 20-74 years, suggests that even low-level exposure to BPA may have endocrine-disrupting effects on human health.
Higher testosterone may raise risk of heart disease in elderly men
A large US multicenter study suggests that older men with higher testosterone levels are more likely to have a heart attack or other cardiovascular disease. Higher total testosterone levels relate to an increased risk of coronary disease, particularly in those above 495 ng/dL.
Some males react to competition like bonobos, others like chimpanzees
A new study reveals differing hormone levels in humans, bonobos, and chimpanzees before competition. Males who are intolerant of sharing food showed hormonal changes similar to chimpanzees, while those who tolerated cooperation showed cortisol increases like bonobos.
Early life exposure to BPA may affect testis function in adulthood
A new study conducted in animals found that early life exposure to BPA may cause long-lasting harm to testicular function. The study showed that even low levels of BPA exposure during critical developmental periods can lead to decreased testosterone secretion in male offspring.
Researchers unzip symptoms of the 'male menopause'
A study identified nine key symptoms associated with late-onset hypogonadism, including decreased sexual function and energy levels. The researchers found that testosterone treatment may only be useful in a small number of cases, highlighting the need for clear diagnosis criteria.
Status symbols of house sparrows
A study by Max-Planck-Gesellschaft researchers found that House sparrow males' bill color is correlated with their testosterone levels, while the size of their badge has no such correlation. This suggests that the badge may be an honest signal of a male's quality rather than his dominance status.
What happens when we get angry?
A new investigation reveals that anger provokes profound changes in the state of mind of individuals, as well as psychobiological parameters. Heart rate, arterial tension, and testosterone increase, but cortisol levels decrease. The study also highlights the complexity of emotions, with anger exhibiting unique patterns.
The deep voice of alpha male
A new study published in Springer's journal Behavioral Ecology and Sociobiology found that men perceive vocal masculinity as a strong indicator of dominance, but it does not influence their attentiveness to rivals' voices. The researchers also discovered that testosterone levels are linked to dominance ratings.
Natural selection for moderate testosterone surprises scientists
A field study found that intermediate testosterone production is associated with increased survival and reproductive success in male dark-eyed juncos. The researchers also discovered that high and low testosterone levels lead to decreased survival rates, contradicting previous expectations.
Male obesity linked to low testosterone levels, study shows
A study published in Diabetes Care reveals that 40% of obese participants had lower-than-normal testosterone readings, with a significant decrease in testosterone levels as BMI increased. Obesity and diabetes may exert independent influences on testosterone concentrations.
Safety and influence on hormones and PSA examined in men taking novel soy germ-based dietary supplement, SE5-OH containing Natural S-equol
A new study examines the safety and tolerance of SE5-OH containing Natural S-equol in healthy adult Japanese men, with results showing normal hormone levels and PSA levels. The supplement appears to be well-tolerated, but further studies are needed to confirm its effects on prostate health.
Women do make men throw caution to the wind, research confirms
A study in Social Psychological and Personality Science found that young men took greater physical risks and had higher testosterone levels when attempting tricks in front of an attractive female. This suggests that the presence of a beautiful woman can lead to increased risk-taking behavior and elevated testosterone levels in men.
Pesticide atrazine can turn male frogs into females
A new study by University of California, Berkeley biologists found that pesticide atrazine can turn three-quarters of adult male frogs into females, leading to a significant decline in reproduction. The study also showed that the altered sex ratios can have devastating effects on frog populations.
Testosterone deficiency affects male cancer survivors' quality of life
A new study found that testosterone deficiency after chemotherapy or radiation therapy affects male cancer survivors' quality of life and energy levels. Young male cancer survivors with low testosterone may benefit from replacement therapy.
Scent of a woman: Men's testosterone responses to olfactory ovulation cues
A new study published in Psychological Science found that men's testosterone levels increase when exposed to scents from women who are ovulating. The research suggests that this response may promote mating-related behavior in males. This study provides direct evidence of the influence of olfactory cues on male biological responses.
Testosterone does not induce aggression
A study published in Nature found that testosterone actually encourages fair behaviors if it serves to ensure one's own status. The hormone increases sensitivity for status, leading to pro-social behavior in humans, rather than aggression. This challenges the long-held assumption that testosterone causes aggressive behavior.
Biology, training and profit sharing make best traders
A study by John Coates and Lionel Page found that experienced traders outperform the market with a high Sharpe Ratio, indicating prudent risk-taking. The researchers also discovered that profit-sharing incentives encourage traders to lower risk variance.
LA BioMed to launch study of testosterone in older men
A large national study on testosterone's effectiveness will be conducted at LA BioMed, focusing on its impact on anemia, cardiovascular disease, and other health conditions in older men with low testosterone levels. The Testosterone Trial will involve 800 men across 12 sites, including LA BioMed, to evaluate the treatment's benefits.
Postmenopausal women with higher testosterone levels
A new study found that postmenopausal women with higher testosterone levels are three times as likely to have coronary heart disease and the metabolic syndrome compared to those with lower testosterone levels. Insulin resistance is also more common in these women.
Presidential election outcome changed voters' testosterone
A study by researchers at Duke University and the University of Michigan found that men who voted for McCain or Barr experienced a significant drop in testosterone levels after the election results were announced. In contrast, Obama voters showed stable testosterone levels. The study suggests that vicarious participation in elections c...
The making of the male brain (estrogen required)
A new study in mice reveals that early estrogen exposure 'masculinizes' the brain circuitry, leading to aggressive and territorial behaviors typically observed in males. The researchers found that female mice exposed to estrogen as pups exhibit similar behaviors, suggesting a critical role for estrogen in shaping masculine behavior.
Studies examine how living conditions impact reproductive health
Recent studies by Indiana University researcher Virginia J. Vitzthum found that living conditions, particularly economic activities and food supply, can more than double early pregnancy loss rates in rural Bolivian women. Environmental factors also play a major role in reproductive fitness for men.
Higher level of testosterone in women linked to choice of risky careers
Research finds that higher levels of testosterone in women are associated with a greater appetite for risk, leading to more risk-prone career choices. In contrast, men with similar testosterone levels exhibit lower risk aversion.
Increase in visceral fat during menopause linked with testosterone
Visceral fat accumulation during menopause is strongly linked to increasing testosterone levels, according to a study published in Obesity. The research found that bioavailable testosterone was the strongest predictor of visceral fat, with estradiol levels bearing little relationship to the amount of visceral fat.
Couples' treatment for sexual problems on the agenda for sexual medicine experts
Sexual medicine experts focus on treating causes of sexual dysfunction beyond physical issues, exploring relationship dynamics and hormonal imbalance. New treatments and options for women and men are being developed to address complex sexual health needs.
Injectable testosterone may provide effective male contraception
A new study published in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism found that injecting testosterone undecanoate monthly can effectively prevent pregnancy. After thirty months, the cumulative contraceptive failure rate was 1.1 per 100 men.
Steroid doping tests ignore vital ethnic differences in hormone activity
Current testosterone doping tests may fail to detect steroid abuse in athletes of different ethnicities due to varying hormone metabolism. Researchers suggest recalibrating thresholds for each ethnic group to address this issue.
Thumbs down for new testosterone patch to boost women's sex drive
A new testosterone patch designed to boost female sex drive after menopause has been found ineffective, with small improvements and large placebo responses reported in clinical trials. The treatment's long-term safety is also unknown due to short trial duration and high side effect rates.
Prostate cancer drug reduces testosterone levels in as little as 3 days
A new prostate cancer drug, degarelix, has been shown to dramatically reduce testosterone levels in patients as early as three days after treatment. Compared to other treatments, degarelix also resulted in faster declines in prostate-specific antigen (PSA) levels and fewer side effects such as urinary tract infections and joint pains.
Hormones and brain activity: Kinsey Institute study sheds light on facial preferences
A new study from Indiana University's Kinsey Institute explores the link between hormone levels and brain responses to masculinized versus feminized male faces. The research found that neural activation in response to face stimuli is sensitive to facial masculinization, with differences appearing strongest during the follicular phase c...
Study shows testosterone improves sexual well-being in post-menopausal women
A study published in the New England Journal of Medicine found that testosterone administered by a skin patch improves sexual well-being in post-menopausal women. The research involved over 800 participants from across the globe and suggests testosterone as a potential treatment for low libido in this demographic.
Genetic link to gender identity
Researchers discovered a significant genetic link between male to female transsexuals and a longer version of the androgen receptor (AR) gene, which modifies testosterone action. This study provides evidence for a biological basis of how gender identity develops.
Financial risk-taking behavior is associated with higher testosterone levels
A new study led by Anna Dreber and Coren Apicella found that men with higher testosterone levels invest more in risky investments. The researchers discovered a correlation between testosterone levels and financial risk-taking behavior, which may be linked to evolutionary factors.
Low sperm count may be associated with prenatal testosterone excess
A study by the Endocrine Society suggests prenatal testosterone excess may contribute to low sperm counts and reduced fertility in males. Researchers found that exposure to high levels of testosterone during fetal development can negatively impact male reproductive health.
Young type-2 diabetic men suffer low testosterone levels, study shows
A study published in Diabetes Care found that young men with type-2 diabetes have significantly lower levels of testosterone, which can impact fertility, muscle development, and increase the risk of heart disease. The study also highlights the potential clinical implications of low testosterone in these individuals.
Testosterone key to disease transmission
Research suggests that increased testosterone in male mice increases their ability to transmit diseases, driving transmission through close social contact. The study found that treated mice made significantly more contacts with both males and females than untreated mice, leading to a higher risk of disease spread.
Testosterone predominance increases prevalence of metabolic syndrome during menopause
A new study found that testosterone predominance during menopause is associated with a higher prevalence of metabolic syndrome, which increases the risk of cardiovascular disease. The study suggests that testosterone may play a more significant role in cardiovascular risk than previously thought.
New test makes cheating with drugs in sports easier to detect
A new mass spectrometry test can detect naturally occurring steroid levels in athletes more accurately than previous tests. The test is faster to perform and can be run on standard laboratory equipment, making it easier to detect doping violations.
Low testosterone appears to increase long-term risk of death
A new study from Germany suggests that men with low testosterone levels are at a higher risk of dying from all causes over time. The study found that men with low testosterone had more than 2.5 times greater risk of dying in the next 10 years compared to those with normal testosterone levels, regardless of age or lifestyle factors.
Testosterone replacement benefits older men with low testosterone
Restoring normal testosterone levels in hypogonadal men leads to major improvements in metabolic syndrome features. Older men (63+) benefit equally as younger men from testosterone treatment, according to studies presented at The Endocrine Society's 90th Annual Meeting.
Low testosterone may cause health problems that lead to erectile dysfunction
A new study by The Endocrine Society reveals that low testosterone may cause health problems leading to erectile dysfunction, metabolic syndrome, and cardiovascular disease. Researchers found that 18.3% of men with erectile dysfunction had undetected testosterone deficiency.
Overweight does not decrease sperm production
A new study by The Endocrine Society found that overweight men are not more likely to be infertile, contradicting previous research on obese women. Greater body weight was linked to lower testosterone levels in some participants, but impaired sperm production remains the primary cause of infertility in men.
Study is key for approval of first drug for female sexual dysfunction
A new multicenter study is being conducted to assess the safety of testosterone gel (LibiGel) for postmenopausal women with low sexual desire. The study aims to enroll 2,400 to 3,100 women aged 50-80 with hypoactive sexual desire disorder and follow them for at least a year.
New barn swallow study reveals image makes the bird
A new study by Arizona State University researchers found that artificially coloring the breast feathers of male barn swallows increased their testosterone levels, challenging the traditional view that internal processes determine external features. The study suggests a dynamic system where physical appearance affects physiology.
Many men with low testosterone levels do not receive treatment
Low testosterone levels in men are often untreated, even among those with sufficient healthcare access, according to a study of Boston-area men. Despite this, treated and untreated men report similar healthcare visits, suggesting barriers may lie in diagnosis or prescription issues.
Biology of Reproduction highlights
Recent studies in Biology of Reproduction suggest that maternal follicular testosterone influences the sex of bovine embryos, while research on maternal cell microchimerism reveals its presence in major organs of healthy newborn mice. These findings highlight the importance of understanding the mechanisms behind these phenomena.
Testosterone levels predict city traders' profitability
Research at University of Cambridge reveals high morning testosterone levels increase City traders' profits for the rest of the day. Testosterone is found to boost confidence and appetite for risk, leading to a positive-feedback loop that can be detrimental if excessive.