Testosterone
Summary of Testosterone
Primary Information, Benefits, Effects, and Important Facts
If you are looking for an actual stack of supplements to take, we recommend you look at our increasing testosterone stack.
Tired of all the misinformation spread by supplement companies?
Learn what works, what's a waste, and how to achieve your health goals with our free supplement mini-course.
Things To Know & Note
Also Known As
test
Caution Notice
Examine.com Medical DisclaimerFrequently Asked Questions about Testosterone
Does ejaculation affect testosterone levels?
Ejaculation results in changes in prolactin (increase) and dopamine (temporary decrease), but does not result in changes in testosterone. Although prolactin and dopamine are both involved with testosterone, they do not appear to influence testosterone levels acutely.
Does creatine cause hair loss?
It’s plausible, but unlikely. One RCT linked creatine supplementation to an increase in DHT — an androgen involved in hair loss — but this RCT has never been replicated.
Do herbal aphrodisiacs work?
It depends on the product touted to be an aphrodisiac, but some of them do apparently increase sexual desire; it is a relatively under-researched topic though, and we don't know why they increase sexuality.
What is 'roid rage'?
Mostly a myth; testosterone (including injections) can increase impulsivity in some but this does not appear to be reliable (does not affect every person tested), impulsivity might lead to aggression but this is drawing at straws now with the connections
Can creatine increase your testosterone levels?
There is no convincing evidence that creatine can increase your testosterone levels.
Is semen high in protein?
Yes. Semen is 50% protein by weight and contains a variety of nutrients to protect the sperm cells from damages.
How can you increase testosterone naturally?
When it comes to increasing your testosterone, quality sleep, physical activity, and weight management come first. A few supplements can help sustain healthy testosterone levels, but most supplements marketed as testosterone boosters don’t work, though some can make you believe they do by boosting your libido.
How important is sleep?
Sleep is incredibly important, and can be considered crucial alongside diet and exercise. Proper sleep habits help sustain many biological processes, and bad sleep can cause these processes to be suboptimal or even malfunction.
Four Testosterone Boosters and Sketchy Research
Does ashwagandha increase testosterone?
There is a bit of evidence that shows Ashwagandha increases testosterone, but it is not convincing.
Human Effect Matrix
The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect testosterone
| Grade | Level of Evidence [show legend] |
|---|---|
|
Robust research conducted with repeated double-blind clinical trials |
|
Multiple studies where at least two are double-blind and placebo controlled |
|
Single double-blind study or multiple cohort studies |
|
Uncontrolled or observational studies only |
|
Level of Evidence
?
The amount of high quality evidence. The more
evidence, the more we can trust the results.
|
Outcome |
Magnitude of effect
?
The direction and size of the supplement's impact on
each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
|
Consistency of research results
?
Scientific research does not always agree. HIGH or
VERY HIGH means that most of the scientific research agrees.
|
Notes |
|---|---|---|---|---|
|
|
Notable
|
High See all 18 studies |
There appears to be an increase in testosterone following DHEA supplementation, but the vast majority of literature is in menopausal women (where testosterone contributes to libido). There is variability in the results, and DHEA is unreliable in increasing testosterone, but this unreliability extends to all demographics and subjects (with limited evidence of DHEA increasing testosterone in all studies including youthful athletes, which are less studied).
|
|
|
|
 
Minor
|
- See all 9 studies |
There appears to be a time-dependent influence on testosterone, with acute doses of alcohol increasing testosterone secondary to creating energy influx in the liver (small enough of an increase to be 'somewhat' effective but may contribute to libido) whereas abuse is known to reduce testosterone levels more notably. The acute increase in testosterone is thought to be related to spikes in libido
|
|
|
|
Minor
|
Very High See all 6 studies |
Testosterone may be increased in infertile men (who have a reduction in testosterone) and men undergoing strength training, but there is currently no evidence to suggest an inherent testosterone boosting effect in otherwise normal men.
|
|
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
|
|
||||
References
- Exton MS, et al. Endocrine response to masturbation-induced orgasm in healthy men following a 3-week sexual abstinence. World J Urol. (2001)
- Jiang M, et al. A research on the relationship between ejaculation and serum testosterone level in men. J Zhejiang Univ Sci. (2003)
- Krüger T, et al. Neuroendocrine and cardiovascular response to sexual arousal and orgasm in men. Psychoneuroendocrinology. (1998)
- Krüger TH, et al. Specificity of the neuroendocrine response to orgasm during sexual arousal in men. J Endocrinol. (2003)
- Krüger TH, et al. Effects of acute prolactin manipulation on sexual drive and function in males. J Endocrinol. (2003)
- Krüger TH, et al. Orgasm-induced prolactin secretion: feedback control of sexual drive. Neurosci Biobehav Rev. (2002)
- Stahl SM. The psychopharmacology of sex, Part 1: Neurotransmitters and the 3 phases of the human sexual response. J Clin Psychiatry. (2001)
- Motofei IG, Rowland DL. Neurophysiology of the ejaculatory process: developing perspectives. BJU Int. (2005)
- Pharmacotherapy for Premature Ejaculation.
- Assessment of erectogenic properties of apomorphine and yohimbine in man.
- McMahon CG. Treatment of premature ejaculation with sertraline hydrochloride: a single-blind placebo controlled crossover study. J Urol. (1998)
- McMahon CG, Samali R. Pharmacological treatment of premature ejaculation. Curr Opin Urol. (1999)
- Krüger TH, Hartmann U, Schedlowski M. Prolactinergic and dopaminergic mechanisms underlying sexual arousal and orgasm in humans. World J Urol. (2005)
- Passie T, et al. Ecstasy (MDMA) mimics the post-orgasmic state: impairment of sexual drive and function during acute MDMA-effects may be due to increased prolactin secretion. Med Hypotheses. (2005)
- van der Merwe J, Brooks NE, Myburgh KH. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clin J Sport Med. (2009)
- Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. (2017)
- Kaufman KD. Androgens and alopecia. Mol Cell Endocrinol. (2002)
- Bang HJ, et al. Comparative studies on level of androgens in hair and plasma with premature male-pattern baldness. J Dermatol Sci. (2004)
- Nyholt DR, et al. Genetic basis of male pattern baldness. J Invest Dermatol. (2003)
- Rathnayake D, Sinclair R. Male androgenetic alopecia. Expert Opin Pharmacother. (2010)
- Bartsch G, Rittmaster RS, Klocker H. Dihydrotestosterone and the concept of 5alpha-reductase inhibition in human benign prostatic hyperplasia. World J Urol. (2002)
- Hamada K, Randall VA. Inhibitory autocrine factors produced by the mesenchyme-derived hair follicle dermal papilla may be a key to male pattern baldness. Br J Dermatol. (2006)
- Trüeb RM. Molecular mechanisms of androgenetic alopecia. Exp Gerontol. (2002)
- Adil A, Godwin M. The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis. J Am Acad Dermatol. (2017)
- Redler S, Messenger AG, Betz RC. Genetics and other factors in the aetiology of female pattern hair loss. Exp Dermatol. (2017)
- Price VH. Androgenetic alopecia in women. J Investig Dermatol Symp Proc. (2003)
- Yip L, Rufaut N, Sinclair R. Role of genetics and sex steroid hormones in male androgenetic alopecia and female pattern hair loss: an update of what we now know. Australas J Dermatol. (2011)
- Green G. Creatine supplementation and DHT:T ratio in male rugby players. Clin J Sport Med. (2010)
- Vatani DS, et al. The Effects of Creatine Supplementation on Performance and Hormonal Response in Amateur Swimmers. Science and Sports. (2011)
- Arazi H, et al. Effects of short term creatine supplementation and resistance exercises on resting hormonal and cardiovascular responses. Science and Sports. (2015)
- Cooke MB, et al. Creatine supplementation post-exercise does not enhance training-induced adaptations in middle to older aged males. Eur J Appl Physiol. (2014)
- Cook CJ, et al. Skill execution and sleep deprivation: effects of acute caffeine or creatine supplementation - a randomized placebo-controlled trial. J Int Soc Sports Nutr. (2011)
- Crowe MJ, O'Connor DM, Lukins JE. The effects of beta-hydroxy-beta-methylbutyrate (HMB) and HMB/creatine supplementation on indices of health in highly trained athletes. Int J Sport Nutr Exerc Metab. (2003)
- Hoffman J, et al. Effect of creatine and beta-alanine supplementation on performance and endocrine responses in strength/power athletes. Int J Sport Nutr Exerc Metab. (2006)
- Eijnde BO, Hespel P. Short-term creatine supplementation does not alter the hormonal response to resistance training. Med Sci Sports Exerc. (2001)
- Volek JS, et al. The effects of creatine supplementation on muscular performance and body composition responses to short-term resistance training overreaching. Eur J Appl Physiol. (2004)
- Faraji H, et al. The effects of creatine supplementation on sprint running performance and selected hormonal responses. SAJRSPER. (2010)
- Rahimi R, et al. Creatine supplementation alters the hormonal response to resistance exercise. Kinesiology. (2010)
- Volek JS, et al. Response of Testosterone and Cortisol Concentrations to High-Intensity Resistance Exercise Following Creatine Supplementation. JSCR. (1997)
- Tyka AK, et al. Effect of creatine malate supplementation on physical performance, body composition and selected hormone levels in spinters and long-distance runners. Acta Physiol Hung. (2015)
- Bagatell CJ, et al. Metabolic and behavioral effects of high-dose, exogenous testosterone in healthy men. J Clin Endocrinol Metab. (1994)
- Anderson RA, Bancroft J, Wu FC. The effects of exogenous testosterone on sexuality and mood of normal men. J Clin Endocrinol Metab. (1992)
- Alexander GM, et al. Androgen-behavior correlations in hypogonadal men and eugonadal men. I. Mood and response to auditory sexual stimuli. Horm Behav. (1997)
- O'Connor DB, et al. Exogenous testosterone, aggression, and mood in eugonadal and hypogonadal men. Physiol Behav. (2002)
- Tricker R, et al. The effects of supraphysiological doses of testosterone on angry behavior in healthy eugonadal men--a clinical research center study. J Clin Endocrinol Metab. (1996)
- Giorgi A, Weatherby RP, Murphy PW. Muscular strength, body composition and health responses to the use of testosterone enanthate: a double blind study. J Sci Med Sport. (1999)
- O'Connor DB, et al. Activational effects of testosterone on cognitive function in men. Neuropsychologia. (2001)
- Alexander GM, et al. Androgen-behavior correlations in hypogonadal men and eugonadal men. II. Cognitive abilities. Horm Behav. (1998)
- Wolf OT, et al. Testosterone and cognition in elderly men: a single testosterone injection blocks the practice effect in verbal fluency, but has no effect on spatial or verbal memory. Biol Psychiatry. (2000)
- O'Leary CB, Hackney AC. Acute and chronic effects of resistance exercise on the testosterone and cortisol responses in obese males: a systematic review. Physiol Res. (2014)
- Kraemer WJ, Ratamess NA. Hormonal responses and adaptations to resistance exercise and training. Sports Med. (2005)
- Wilson JM, et al. β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men. Br J Nutr. (2013)
- Hoffman JR, et al. Effects of beta-hydroxy beta-methylbutyrate on power performance and indices of muscle damage and stress during high-intensity training. J Strength Cond Res. (2004)
- Portal S, et al. The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: a prospective randomized, double-blind, placebo-controlled study. Eur J Appl Physiol. (2011)
- Slater GJ, et al. Beta-hydroxy beta-methylbutyrate (HMB) supplementation does not influence the urinary testosterone: epitestosterone ratio in healthy males. J Sci Med Sport. (2000)
- A Review of the Physical and Chemical Properties of Human Semen and the Formulation of a Semen Simulant.
- The density of human semen and the validation of weight as an indicator of volume: a multicentre study.
- Rehan N, Sobrero AJ, Fertig JW. The semen of fertile men: statistical analysis of 1300 men. Fertil Steril. (1975)
- HARVEY C. Relation between the volume and fructose content of human semen. Nature. (1948)
- Relation Between Fructose Content of Semen and Fertility in Man.
- Haendler Y. A rare case of secondary infertility in a man of 27 years due to lack of fructose in the semen. Minerva Ginecol. (1965)
- Fructolysis in Human Spermatozoa under normal and pathological conditions.
- The Biochemistry of Semen {E-book}.
- Chang A, Shin SH. Dopamine agonists both stimulate and inhibit prolactin release in GH4ZR7 cells. Eur J Endocrinol. (1999)
- Ben-Jonathan N, Hnasko R. Dopamine as a prolactin (PRL) inhibitor. Endocr Rev. (2001)
- D'Aniello G, et al. Occurrence of D-aspartic acid in human seminal plasma and spermatozoa: possible role in reproduction. Fertil Steril. (2005)
- Haldar S, et al. Influence of habitual diet on antioxidant status: a study in a population of vegetarians and omnivores. Eur J Clin Nutr. (2007)
- Szeto YT, Kwok TC, Benzie IF. Effects of a long-term vegetarian diet on biomarkers of antioxidant status and cardiovascular disease risk. Nutrition. (2004)
- Kanďár R, Drábková P, Hampl R. The determination of ascorbic acid and uric acid in human seminal plasma using an HPLC with UV detection. J Chromatogr B Analyt Technol Biomed Life Sci. (2011)
- Gavella M, et al. Evaluation of ascorbate and urate antioxidant capacity in human semen. Andrologia. (1997)
- Rosecrans RR, et al. Comparison of biochemical parameters of human blood serum and seminal plasma. Andrologia. (1987)
- Persson BE, et al. Uridine, xanthine and urate concentrations in prostatic fluid and seminal plasma of patients with prostatitis. Eur Urol. (1991)
- Tepper BJ, et al. Genetic variation in bitter taste and plasma markers of anti-oxidant status in college women. Int J Food Sci Nutr. (2009)
- Dsamou M, et al. Salivary protein profiles and sensitivity to the bitter taste of caffeine. Chem Senses. (2012)
- Travison TG, et al. The relationship between libido and testosterone levels in aging men. J Clin Endocrinol Metab. (2006)
- Chrysohoou C, et al. Low total testosterone levels are associated with the metabolic syndrome in elderly men: the role of body weight, lipids, insulin resistance, and inflammation; the Ikaria study. Rev Diabet Stud. (2013)
- Westley CJ, Amdur RL, Irwig MS. High Rates of Depression and Depressive Symptoms among Men Referred for Borderline Testosterone Levels. J Sex Med. (2015)
- Giltay EJ, et al. Salivary testosterone: associations with depression, anxiety disorders, and antidepressant use in a large cohort study. J Psychosom Res. (2012)
- Feldman HA, et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. J Clin Endocrinol Metab. (2002)
- Wu FC, et al. Hypothalamic-pituitary-testicular axis disruptions in older men are differentially linked to age and modifiable risk factors: the European Male Aging Study. J Clin Endocrinol Metab. (2008)
- Handelsman DJ, et al. Age-specific population centiles for androgen status in men. Eur J Endocrinol. (2015)
- Cote KA, et al. Sleep deprivation lowers reactive aggression and testosterone in men. Biol Psychol. (2013)
- Leproult R, Van Cauter E. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA. (2011)
- Penev PD. Association between sleep and morning testosterone levels in older men. Sleep. (2007)
- González-Santos MR, et al. Sleep deprivation and adaptive hormonal responses of healthy men. Arch Androl. (1989)
- Cortés-Gallegos V, et al. Sleep deprivation reduces circulating androgens in healthy men. Arch Androl. (1983)
- Nedeltcheva AV, et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. (2010)
- Daly W, et al. Relationship between stress hormones and testosterone with prolonged endurance exercise. Eur J Appl Physiol. (2005)
- Hackney AC, Aggon E. Chronic Low Testosterone Levels in Endurance Trained Men: The Exercise- Hypogonadal Male Condition. J Biochem Physiol. (2018)
- Grossmann M. Low testosterone in men with type 2 diabetes: significance and treatment. J Clin Endocrinol Metab. (2011)
- Tajar A, et al. Characteristics of secondary, primary, and compensated hypogonadism in aging men: evidence from the European Male Ageing Study. J Clin Endocrinol Metab. (2010)
- Hall SA, et al. Correlates of low testosterone and symptomatic androgen deficiency in a population-based sample. J Clin Endocrinol Metab. (2008)
- Grossmann M, Matsumoto AM. A Perspective on Middle-Aged and Older Men With Functional Hypogonadism: Focus on Holistic Management. J Clin Endocrinol Metab. (2017)
- Corona G, et al. Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis. Eur J Endocrinol. (2013)
- Camacho EM, et al. Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study. Eur J Endocrinol. (2013)
- Pilz S, et al. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. (2011)
- Wehr E, et al. Association of vitamin D status with serum androgen levels in men. Clin Endocrinol (Oxf). (2010)
- . Dietary Reference Intakes for Calcium and Vitamin D. . ()
- Heaney R, et al. Letter to Veugelers, P.J. and Ekwaru, J.P., A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients 2014, 6, 4472-4475; doi:10.3390/nu6104472. Nutrients. (2015)
- Veugelers PJ, Ekwaru JP. A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients. (2014)
- Netter A, Hartoma R, Nahoul K. Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count. Arch Androl. (1981)
- Chang CS, et al. Correlation between serum testosterone level and concentrations of copper and zinc in hair tissue. Biol Trace Elem Res. (2011)
- Tang YM, et al. Relationships between micronutrient losses in sweat and blood pressure among heat-exposed steelworkers. Ind Health. (2016)
- . Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. . ()
- Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. (2011)
- Valentiner-Branth P, et al. A randomized controlled trial of the effect of zinc as adjuvant therapy in children 2-35 mo of age with severe or nonsevere pneumonia in Bhaktapur, Nepal. Am J Clin Nutr. (2010)
- Willis MS, et al. Zinc-induced copper deficiency: a report of three cases initially recognized on bone marrow examination. Am J Clin Pathol. (2005)
- Afrin LB. Fatal copper deficiency from excessive use of zinc-based denture adhesive. Am J Med Sci. (2010)
- Maggio M, et al. The Interplay between Magnesium and Testosterone in Modulating Physical Function in Men. Int J Endocrinol. (2014)
- Uwitonze AM, Razzaque MS. Role of Magnesium in Vitamin D Activation and Function. J Am Osteopath Assoc. (2018)
- Costello RB, Moser-Veillon PB. A review of magnesium intake in the elderly. A cause for concern?. Magnes Res. (1992)
- Nielsen FH, Lukaski HC. Update on the relationship between magnesium and exercise. Magnes Res. (2006)
- Institute of Medicine (US) Committee on Military Nutrition Research; Marriott BM, editor. Washington (DC). Nutritional Needs in Hot Environments, “Influence of Exercise and Heat on Magnesium Metabolism”. National Academies Press (US). (1993)
- Consolazio CF, et al. Excretion of sodium, potassium, magnesium and iron in human sweat and the relation of each to balance and requirements. J Nutr. (1963)
- Yoshimura Y, et al. Pharmacokinetic Studies of Orally Administered Magnesium Oxide in Rats. Yakugaku Zasshi. (2017)
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. (2001)
- Gonzales-Arimborgo C, et al. Acceptability, Safety, and Efficacy of Oral Administration of Extracts of Black or Red Maca (Lepidium meyenii) in Adult Human Subjects: A Randomized, Double-Blind, Placebo-Controlled Study. Pharmaceuticals (Basel). (2016)
- Zenico T, et al. Subjective effects of Lepidium meyenii (Maca) extract on well-being and sexual performances in patients with mild erectile dysfunction: a randomised, double-blind clinical trial. Andrologia. (2009)
- Gonzales GF, et al. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia. (2002)
- Dording CM, et al. A double-blind placebo-controlled trial of maca root as treatment for antidepressant-induced sexual dysfunction in women. Evid Based Complement Alternat Med. (2015)
- G. D’Aniello, et al. D-asparate, a key element for the improvement of sperm quality. Advances in Sexual Medicine. (2012)
- Topo E, et al. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reprod Biol Endocrinol. (2009)
- Melville GW, Siegler JC, Marshall PW. Three and six grams supplementation of d-aspartic acid in resistance trained men. J Int Soc Sports Nutr. (2015)
- Willoughby DS, Leutholtz B. D-aspartic acid supplementation combined with 28 days of heavy resistance training has no effect on body composition, muscle strength, and serum hormones associated with the hypothalamo-pituitary-gonadal axis in resistance-trained men. Nutr Res. (2013)
- Yi S, et al. Short sleep duration in association with CT-scanned abdominal fat areas: the Hitachi Health Study. Int J Obes (Lond). (2012)
- Park SE, et al. The association between sleep duration and general and abdominal obesity in Koreans: data from the Korean National Health and Nutrition Examination Survey, 2001 and 2005. Obesity (Silver Spring). (2009)
- Hairston KG, et al. Sleep duration and five-year abdominal fat accumulation in a minority cohort: the IRAS family study. Sleep. (2010)
- Watson NF, et al. Sleep duration and body mass index in twins: a gene-environment interaction. Sleep. (2012)
- Di Milia L, Vandelanotte C, Duncan MJ. The association between short sleep and obesity after controlling for demographic, lifestyle, work and health related factors. Sleep Med. (2013)
- Benedict C, et al. Acute Sleep Deprivation Enhances the Brain's Response to Hedonic Food Stimuli: An fMRI Study. J Clin Endocrinol Metab. (2012)
- St-Onge MP, et al. Sleep restriction leads to increased activation of brain regions sensitive to food stimuli. Am J Clin Nutr. (2012)
- Bosy-Westphal A, et al. Influence of partial sleep deprivation on energy balance and insulin sensitivity in healthy women. Obes Facts. (2008)
- Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on physiological rhythms. Rev Neurol (Paris). (2003)
- Lemola S, et al. Optimism and Self-Esteem Are Related to Sleep. Results from a Large Community-Based Sample. Int J Behav Med. (2012)
- Sio UN, Monaghan P, Ormerod T. Sleep on it, but only if it is difficult: Effects of sleep on problem solving. Mem Cognit. (2012)
- Knutson KL. Sleep duration and cardiometabolic risk: a review of the epidemiologic evidence. Best Pract Res Clin Endocrinol Metab. (2010)
- Choi JK, et al. Association between short sleep duration and high incidence of metabolic syndrome in midlife women. Tohoku J Exp Med. (2011)
- Najafian J, et al. Association between sleep duration and metabolic syndrome in a population-based study: Isfahan Healthy Heart Program. J Res Med Sci. (2011)
- Cappuccio FP, et al. Quantity and quality of sleep and incidence of type 2 diabetes: a systematic review and meta-analysis. Diabetes Care. (2010)
- Beihl DA, Liese AD, Haffner SM. Sleep duration as a risk factor for incident type 2 diabetes in a multiethnic cohort. Ann Epidemiol. (2009)
- Chaput JP, et al. Sleep duration as a risk factor for the development of type 2 diabetes or impaired glucose tolerance: analyses of the Quebec Family Study. Sleep Med. (2009)
- Chao CY, et al. Sleep duration is a potential risk factor for newly diagnosed type 2 diabetes mellitus. Metabolism. (2011)
- Broussard JL, et al. Impaired insulin signaling in human adipocytes after experimental sleep restriction: a randomized, crossover study. Ann Intern Med. (2012)
- Robertson MD, et al. Effects of three weeks of mild sleep restriction implemented in the home environment on multiple metabolic and endocrine markers in healthy young men. Metabolism. (2013)
- Impact of Five Nights of Sleep Restriction on Glucose Metabolism, Leptin and Testosterone in Young Adult Men.
- Buxton OM, et al. Sleep restriction for 1 week reduces insulin sensitivity in healthy men. Diabetes. (2010)
- Donga E, et al. A single night of partial sleep deprivation induces insulin resistance in multiple metabolic pathways in healthy subjects. J Clin Endocrinol Metab. (2010)
- Luboshitzky R, Shen-Orr Z, Herer P. Middle-aged men secrete less testosterone at night than young healthy men. J Clin Endocrinol Metab. (2003)
- Randler C, et al. Chronotype but not sleep length is related to salivary testosterone in young adult men. Psychoneuroendocrinology. (2012)
- Validation of the full and reduced Composite Scale of Morningness.
- An actigraphic validation study of seven morningness-eveningness inventories.
- Roenneberg T, et al. A marker for the end of adolescence. Curr Biol. (2004)
- Leproult R, et al. Sleep loss results in an elevation of cortisol levels the next evening. Sleep. (1997)
- Backhaus J, Junghanns K, Hohagen F. Sleep disturbances are correlated with decreased morning awakening salivary cortisol. Psychoneuroendocrinology. (2004)
- Wu H, et al. Effects of sleep restriction periods on serum cortisol levels in healthy men. Brain Res Bull. (2008)
- Vgontzas AN, et al. Sleep deprivation effects on the activity of the hypothalamic-pituitary-adrenal and growth axes: potential clinical implications. Clin Endocrinol (Oxf). (1999)
- Caine-Bish N, et al. The effect of cold exposure on the hormonal and metabolic responses to sleep deprivation. Wilderness Environ Med. (2005)
- Opstad PK, et al. The thyroid function in young men during prolonged exercise and the effect of energy and sleep deprivation. Clin Endocrinol (Oxf). (1984)
- Sadamatsu M, et al. The 24-hour rhythms in plasma growth hormone, prolactin and thyroid stimulating hormone: effect of sleep deprivation. J Neuroendocrinol. (1995)
- Klingenberg L, et al. Sleep restriction is not associated with a positive energy balance in adolescent boys. Am J Clin Nutr. (2012)
- Koban M, Swinson KL. Chronic REM-sleep deprivation of rats elevates metabolic rate and increases UCP1 gene expression in brown adipose tissue. Am J Physiol Endocrinol Metab. (2005)
- Rechtschaffen A, Bergmann BM. Sleep deprivation in the rat: an update of the 1989 paper. Sleep. (2002)
- Takahashi Y, Kipnis DM, Daughaday WH. Growth hormone secretion during sleep. J Clin Invest. (1968)
- Sassin JF, et al. Human growth hormone release: relation to slow-wave sleep and sleep-walking cycles. Science. (1969)
- Gronfier C, et al. A quantitative evaluation of the relationships between growth hormone secretion and delta wave electroencephalographic activity during normal sleep and after enrichment in delta waves. Sleep. (1996)
- Van Cauter E, et al. A quantitative estimation of growth hormone secretion in normal man: reproducibility and relation to sleep and time of day. J Clin Endocrinol Metab. (1992)
- Obál F Jr, Krueger JM. The somatotropic axis and sleep. Rev Neurol (Paris). (2001)
- Saini J, et al. Continuous positive airway pressure treatment. Effects on growth hormone, insulin and glucose profiles in obstructive sleep apnea patients. Horm Metab Res. (1993)
- Brandenberger G, Weibel L. The 24-h growth hormone rhythm in men: sleep and circadian influences questioned. J Sleep Res. (2004)
- Ho KY, et al. Effects of sex and age on the 24-hour profile of growth hormone secretion in man: importance of endogenous estradiol concentrations. J Clin Endocrinol Metab. (1987)
- Brandenberger G, et al. Effect of sleep deprivation on overall 24 h growth-hormone secretion. Lancet. (2000)
- Spiegel K, et al. Adaptation of the 24-h growth hormone profile to a state of sleep debt. Am J Physiol Regul Integr Comp Physiol. (2000)
- Zahra Kiasalari, Mohsen Khalili, Mahbobeh Aghaei. Effect of withania somnifera on levels of sex hormones in the diabetic male rats. International Journal of Reproductive Biomed. (2009)
- Ahmad MK, et al. Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males. Fertil Steril. (2010)
- Mahdi AA, et al. Withania somnifera Improves Semen Quality in Stress-Related Male Fertility. Evid Based Complement Alternat Med. (2009)
- Wankhede S, et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. (2015)