Condition

Low Testosterone

Low testosterone, or hypogonadism, happens when the body makes too little of the main male sex hormone, which supports muscle, bone, energy, mood and libido. Vitamin D and zinc have the most support among supplements, with moderate evidence, and small trials in men with late-onset low testosterone found erections went up with tribulus. Most studies were small, though, and testosterone replacement remains the most effective option for true hypogonadism.

Sources: PMID 21154195; PMID 30253697

Supplements studied: 16
Graded outcomes: 14
Trials: 23
People studied: 1,460

Evidence by supplement

Strong
Moderate
Limited
Very limited

16 supplements

Tribulus Terrestris

Tribulus Terrestris: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Erections Small Increase	Improves (the measure goes up)	Small effect	4 studies	100 people
Studies that measured erections Tribulus terrestris versus placebo in the treatment of erectile dysfunction and lower urinary tract symptoms in patients with late-onset hypogonadism: A placebo-controlled studyUrologia · PMID 30253697 Pilot Study on the Effect of Botanical Medicine (Tribulus terrestris) on Serum Testosterone Level and Erectile Function in Aging Males With Partial Androgen Deficiency (PADAM)J Sex Marital Ther · PMID 25849625 Dietary Supplements for Erectile Dysfunction: Analysis of Marketed Products, Systematic Review, Meta-Analysis and Rational Use.Nutrients · PMID 37686709 and 1 more on the Tribulus Terrestris page
	Free Testosterone No effect		NoneNo effect		30 people
	Testosterone	Improves (the measure goes up)		3 studies	62 people
Studies that measured testosterone Prospective Analysis on the Effect of Botanical Medicine (Tribulus terrestris) on Serum Testosterone Level and Semen Parameters in Males with Unexplained InfertilityJ Diet Suppl · PMID 27337519 Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroidsForensic Sci Int · PMID 18282674 The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young menJ Ethnopharmacol · PMID 15994038
	Sperm Count	Improves (the measure goes up)		1 study	30 people
Studies that measured sperm count Clinical study of Tribulus terrestris Linn. in Oligozoospermia: A double blind studyAyu · PMID 23723641
	Luteinizing Hormone	Improves (the measure goes up)			60 people
	Prostate-Specific Antigen	Improves (the measure goes up)			70 people
	Sperm Quality	Improves (the measure goes up)			30 people

Coenzyme Q10

Coenzyme Q10: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Follicle-Stimulating Hormone Small Decrease	Worsens (the measure goes down)	Small effect	2 studies	212 people
Studies that measured follicle-stimulating hormone Efficacy and Safety of Coenzyme Q10 Supplementation in the Treatment of Polycystic Ovary Syndrome: a Systematic Review and Meta-analysisReprod Sci · PMID 35941510 Hormonal and Metabolic Effects of Coenzyme Q10 and/or Vitamin E in Patients With Polycystic Ovary SyndromeJ Clin Endocrinol Metab · PMID 30202998
	Seminal Motility	Improves (the measure goes up)		2 studies	212 people
Studies that measured seminal motility Efficacy of coenzyme Q10 on semen parameters, sperm function and reproductive hormones in infertile menJ Urol · PMID 19447425 Coenzyme Q(10) supplementation in infertile men with idiopathic asthenozoospermia: an open, uncontrolled pilot studyFertil Steril · PMID 14711549
	Luteinizing Hormone	Improves (the measure goes up)			212 people
	Sperm Quality	Improves (the measure goes up)			212 people
	Testosterone	Improves (the measure goes up)			212 people

Cannabis

Cortisol
Luteinizing Hormone: improves

Cannabis: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Studies	People
	Cortisol Mixed effect		1 study	40 people
Studies that measured cortisol 1 -tetrahydrocannabinol, synhexyl and marijuana extract administered orally in man: catecholamine excretion, plasma cortisol levels and platelet serotonin contentPsychopharmacologia · PMID 5523370
	Luteinizing Hormone	Improves (the measure goes up)	1 study	40 people
Studies that measured luteinizing hormone Acute effects of marihuana on luteinizing hormone in menopausal womenPharmacol Biochem Behav · PMID 3001780

Boron

Estrogen
Testosterone: improves

Boron: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Studies	People
	Estrogen Mixed effect		1 study	13 people
Studies that measured estrogen Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal womenFASEB J · PMID 3678698
	Testosterone	Improves (the measure goes up)	1 study	13 people
Studies that measured testosterone Plasma boron and the effects of boron supplementation in malesEnviron Health Perspect · PMID 7889885

Coleus forskohlii

Body Fat: improves
Weight: improves
Muscle Mass: improves

Coleus forskohlii: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Body Fat Small Decrease	Improves (the measure goes down)	Small effect		30 people
	Weight	Improves (the measure goes down)		3 studies	30 people
Studies that measured weight Effects of coleus forskohlii supplementation on body composition and hematological profiles in mildly overweight womenJ Int Soc Sports Nutr · PMID 18500958 Coleus forskohlii Extract Supplementation in Conjunction with a Hypocaloric Diet Reduces the Risk Factors of Metabolic Syndrome in Overweight and Obese Subjects: A Randomized Controlled TrialNutrients · PMID 26593941 Regional fat loss from the thigh in obese women after adrenergic modulationClin Ther · PMID 2894247
	Muscle Mass	Improves (the measure goes up)		1 study	30 people
Studies that measured muscle mass Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese menObes Res · PMID 16129715
	Bone Mineral Density	Improves (the measure goes up)			30 people
	Testosterone	Improves (the measure goes up)			30 people

Tongkat Ali

Body Fat: improves
Testosterone: improves
Strength: improves

Tongkat Ali: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Body Fat Small Increase	Improves (the measure goes down)	Small effect		45 people
	Testosterone	Improves (the measure goes up)		4 studies	457 people
Studies that measured testosterone Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism?Andrologia · PMID 21671978 The effect of Eurycoma Longifolia on the regulation of reproductive hormones in young males.Andrologia · PMID 33559971 Effect of Eurycoma longifolia standardised aqueous root extract-Physta ® on testosterone levels and quality of life in ageing male subjects: a randomised, double-blind, placebo-controlled multicentre studyFood Nutr Res · PMID 34262417 and 1 more on the Tongkat Ali page
	Strength	Improves (the measure goes up)		2 studies	150 people
Studies that measured strength Exercise associated or not to the intake of Eurycoma longifolia improves strength and cardiorespiratory fitness in men with androgen deficiencyComplement Ther Clin Pract · PMID 33445146 Effects of Jack Supplementation Combined with Resistance Training on Isokinetic Muscular Strength and Power, Anaerobic Power, and Urinary Testosterone: Epitestosterone Ratio in Young Males.Int J Prev Med · PMID 31367282
	Aerobic Exercise Metrics Small Detriment	Worsens (the measure goes down)	Small effect		45 people
	Cortisol	Improves (the measure goes down)			105 people
	DHEAS	Improves (the measure goes up)			105 people
	Estrogen	Changes; see studies			32 people
	Fatigue Symptoms	Improves (the measure goes down)			105 people
	Follicle-Stimulating Hormone	Improves (the measure goes up)			32 people
	Free Testosterone	Improves (the measure goes up)			137 people
	HbA1c	Improves (the measure goes down)			105 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			45 people
	IGF-1	Improves (the measure goes up)			105 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			45 people
	Luteinizing Hormone	Improves (the measure goes up)			32 people
	Sex Hormone Binding Globulin	Improves (the measure goes up)			137 people
	Thyroid-Stimulating Hormone	Improves (the measure goes up)			105 people
	Triglycerides	Improves (the measure goes down)			45 people
	Waist circumference	Improves (the measure goes down)			45 people

Nicotine

Luteinizing Hormone: improves
Prolactin: improves
Testosterone: improves

Nicotine: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Luteinizing Hormone Small Increase	Improves (the measure goes up)	Small effect		12 people
	Prolactin	Improves (the measure goes up)		1 study	12 people
Studies that measured prolactin Effects of intravenous cocaine and cigarette smoking on luteinizing hormone, testosterone, and prolactin in menJ Pharmacol Exp Ther · PMID 12893845
	Testosterone	Improves (the measure goes up)			12 people

Aspartate

Serum Testosterone (Untrained Men): improves
Serum Testosterone (Trained Athletes)

Aspartate: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Serum Testosterone (Untrained Men) 42% increase in testosterone after 12 days of 3.12g/day in untrained men; LH increased 33%	Improves (the measure goes up)	Moderate effect		23 people
	Serum Testosterone (Trained Athletes) No increase in testosterone in resistance-trained men; 6g/day actually decreased total and free testosterone		NoneNo effect		100 people

Saw Palmetto

DHT
Testosterone: improves

Saw Palmetto: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	DHT No effect		NoneNo effect	1 study	32 people
Studies that measured dht Comparison of finasteride (Proscar) and Serenoa repens (Permixon) in the inhibition of 5-alpha reductase in healthy male volunteersEur Urol · PMID 7805711
	Testosterone	Improves (the measure goes up)			32 people

Chrysin

Testosterone

Chrysin: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Testosterone No effect		NoneNo effect	1 study	20 people
Studies that measured testosterone Effects of chrysin on urinary testosterone levels in human malesJ Med Food · PMID 14977449

DHEA

Body Fat
Estrogen: changes; see studies
Testosterone: improves

DHEA: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Body Fat No effect		NoneNo effect	1 study
Studies that measured body fat DHEA in elderly women and DHEA or testosterone in elderly men.N Engl J Med · 2006 · PMID 17050889
	Estrogen	Changes; see studies		8 studies	19 people
Studies that measured estrogen Dehydroepiandrosterone combined with exercise improves muscle strength and physical function in frail older womenJ Am Geriatr Soc · PMID 20863330 Dehydroepiandrosterone replacement in healthy men with age-related decline of DHEA-S: effects on fat distribution, insulin sensitivity and lipid metabolismAging Male · PMID 14628495 Short-term dehydroepiandrosterone treatment increases platelet cGMP production in elderly male subjectsClin Endocrinol · PMID 16487434 and 5 more on the DHEA page
	Testosterone	Improves (the measure goes up)		3 studies	98 people
Studies that measured testosterone Effects of dehydroepiandrosterone supplementation on cognitive function and activities of daily living in older women with mild to moderate cognitive impairmentGeriatr Gerontol Int · PMID 20497239 Androgens and sexual function: a placebo-controlled, randomized, double-blind study of testosterone vs. dehydroepiandrosterone in men with sexual dysfunction and androgen deficiencyAging Male · PMID 19883295 A dose-response and meta-analysis of dehydroepiandrosterone (DHEA) supplementation on testosterone levels: perinatal prediction of randomized clinical trials.Exp Gerontol · PMID 33045358
	Serum DHEA	Improves (the measure goes up)		2 studies	98 people
Studies that measured serum dhea Effects of dehydroepiandrosterone vs androstenedione supplementation in menMed Sci Sports Exerc · PMID 10613429 Effect of acute DHEA administration on free testosterone in middle-aged and young men following high-intensity interval trainingEur J Appl Physiol · PMID 23417481
	Erections	Improves (the measure goes up)			79 people
	Follicle-Stimulating Hormone	Improves (the measure goes up)			19 people
	Libido
	Luteinizing Hormone	Improves (the measure goes up)			19 people
	Muscle Mass
	Power Output
	Prostate-Specific Antigen	Improves (the measure goes up)			79 people

Garcinia

Estrogen
Testosterone: improves

Garcinia: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People
	Estrogen No effect		NoneNo effect		44 people
	Testosterone	Improves (the measure goes up)		1 study	44 people
Studies that measured testosterone Effects of Garcinia cambogia extract on serum sex hormones in overweight subjectsFitoterapia · PMID 18316163

Ashwagandha

Testosterone: improves
Cortisol: improves
Sperm Quality: improves

Ashwagandha: outcomes studied for Low Testosterone
Outcome	Effect	Studies	People
Testosterone	Improves (the measure goes up)	5 studies	135 people
Cortisol	Improves (the measure goes down)	1 study	60 people
Sperm Quality	Improves (the measure goes up)	1 study	75 people
Anxiety Symptoms
Follicle-Stimulating Hormone	Improves (the measure goes up)		75 people
Luteinizing Hormone	Improves (the measure goes up)		75 people

Licorice

Testosterone: improves
Cortisol: improves
Blood Pressure: worsens

Licorice: outcomes studied for Low Testosterone
Outcome	Effect	Size	Studies	People
Testosterone	Improves (the measure goes up)		4 studies	9 people
Cortisol	Improves (the measure goes down)		2 studies	9 people
Blood Pressure Moderate Detriment	Worsens (the measure goes up)	Moderate effect	1 study	9 people
Luteinizing Hormone	Improves (the measure goes up)		1 study	9 people

Caffeine

Power Output: improves
Cortisol
Testosterone: improves

Caffeine: outcomes studied for Low Testosterone
Outcome	Effect	Studies	People
Power Output	Improves (the measure goes up)	3 studies	16 people
Cortisol
Testosterone	Improves (the measure goes up)		16 people

Vitamin D

Testosterone: improves

Vitamin D: outcomes studied for Low Testosterone
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Testosterone	Improves (the measure goes up)		1 study	165 people

Key findings

ErectionsTribulus TerrestrisImproves (the measure goes up)
Follicle-Stimulating HormoneCoenzyme Q10Worsens (the measure goes down)
CortisolCannabis

The Low Testosterone (Male Hypogonadism) protocol

2 primary supplements · 6 supporting supplements

Vitamin D3,000–5,000 IU daily (based on blood levels)
Zinc25–45 mg daily (if deficient)

See the full protocol

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Studies cited

100 studies from PubMed

Effects of Coenzyme Q10 Supplementation on Depressive Symptoms and Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.J Clin Psychopharmacol, 2026 · PMID 41294251
Evaluation of in vivo supplementation of 2660 mg D-aspartic acid and 200 mg ubiquinol and 10 mg zinc on different semen parameters in idiopathic male infertility: a randomized double blind placebo controlled studyJ Assist Reprod Genet, 2025 · PMID 40248985
Effect of vitamin D supplementation for major adverse cardiovascular events: a meta-analysis based on randomised controlled trials.Br J Nutr, 2025 · PMID 40685646
Effects of oral d-aspartate on sperm quality in B6N miceTheriogenology, 2018 · PMID 30125828
The effects of d-aspartic acid supplementation in resistance-trained men over a three month training period: A randomised controlled trialPLoS One, 2017 · PMID 28841667
In vitro effects of zinc, D-aspartic acid, and coenzyme-Q10 on sperm functionReproduction, 2016 · PMID 27422792
Vitamin D3 supplementation does not modify cardiovascular risk profile of adults with inadequate vitamin D statusEur J Nutr, 2015 · PMID 26621634
Evaluation of antioxidant potential of Rasayana drugs in healthy human volunteersAyu, 2014 · PMID 25364199
D-aspartate affects NMDA receptor-extracellular signal-regulated kinase pathway and upregulates androgen receptor expression in the rat testisTheriogenology, 2014 · PMID 24439162
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 menNutr Res, 2013 · PMID 24074738
Association of A1C levels with vitamin D status in U.S. adults: data from the National Health and Nutrition Examination SurveyDiabetes Care, 2010 · PMID 20215453
D-Aspartic acid: an endogenous amino acid with an important neuroendocrine roleBrain Res Rev, 2007 · PMID 17118457
Serum 25-hydroxyvitamin D, ethnicity, and blood pressure in the Third National Health and Nutrition Examination SurveyAm J Hypertens, 2007 · PMID 17586404
Occurrence of D-aspartic acid in human seminal plasma and spermatozoa: possible role in reproductionFertil Steril, 2005 · PMID 16275242
Occurrence of D-aspartic acid and N-methyl-D-aspartic acid in rat neuroendocrine tissues and their role in the modulation of luteinizing hormone and growth hormone releaseFASEB J, 2000 · PMID 10744627
Effects of Withania somnifera in patients of schizophrenia: A randomized, double blind, placebo controlled pilot trial studyIndian J Pharmacol · PMID 24014929
Adjunctive Use of a Standardized Extract of Withania somnifera (Ashwagandha) to Treat Symptom Exacerbation in Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled StudyJ Clin Psychiatry · PMID 29995356
Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trialJ Int Soc Sports Nutr · PMID 26609282
Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteersJ Ayurveda Integr Med · PMID 23125505
Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR TrialNutrients · PMID 30463324
Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclistsJ Ayurveda Integr Med · PMID 23326093
Effects of Ashwagandha ( Withania somnifera) on Physical Performance: Systematic Review and Bayesian Meta-AnalysisJ Funct Morphol Kinesiol · PMID 33670194
Body Weight Management in Adults Under Chronic Stress Through Treatment With Ashwagandha Root Extract: A Double-Blind, Randomized, Placebo-Controlled TrialJ Evid Based Complementary Altern Med · PMID 27055824
Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trialsPhytother Res · PMID 36017529
A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adultsIndian J Psychol Med · PMID 23439798
Adaptogenic and Anxiolytic Effects of Ashwagandha Root Extract in Healthy Adults: A Double-blind, Randomized, Placebo-controlled Clinical StudyCureus · PMID 32021735
Efficacy of Withania somnifera on seminal plasma metabolites of infertile males: a proton NMR study at 800 MHzJ Ethnopharmacol · PMID 23796876
Withania somnifera Improves Semen Quality in Stress-Related Male FertilityEvid Based Complement Alternat Med · PMID 19789214
Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile malesFertil Steril · PMID 19501822
Clinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males: A Pilot StudyEvid Based Complement Alternat Med · PMID 24371462
Comparative evaluation of the effects of Withania somnifera with pentoxifylline on the sperm parameters in idiopathic male infertility: A triple-blind randomised clinical trialAndrologia · PMID 29770466
A double-blind, placebo-controlled evaluation of the anxiolytic efficacy ff an ethanolic extract of withania somniferaIndian J Psychiatry · PMID 21407960
Naturopathic care for anxiety: a randomized controlled trial ISRCTN78958974PLoS One · PMID 19718255
Safety and efficacy of Withania somnifera for anxiety and insomnia: Systematic review and meta-analysis.Hum Psychopharmacol · PMID 39083548
Randomized placebo-controlled adjunctive study of an extract of withania somnifera for cognitive dysfunction in bipolar disorderJ Clin Psychiatry · PMID 24330893
Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive FunctionsJ Diet Suppl · PMID 28471731
Effect of standardized aqueous extract of Withania somnifera on tests of cognitive and psychomotor performance in healthy human participantsPharmacognosy Res · PMID 24497737
A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha ( Withania somnifera) in Aging, Overweight MalesAm J Mens Health · PMID 30854916
Efficacy of Ashwagandha (Withania somnifera Dunal. Linn.) in the management of psychogenic erectile dysfunctionAyu · PMID 22529644
Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled TrialJ Altern Complement Med · PMID 28829155
An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled studyMedicine · PMID 31517876
In vivo effects of Ashwagandha (Withania somnifera) extract on the activation of lymphocytesJ Altern Complement Med · PMID 19388865
Evaluation of the efficacy of Withania somnifera (Ashwagandha) root extract in patients with obsessive-compulsive disorder: A randomized double-blind placebo-controlled trialComplement Ther Med · PMID 27515872
Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysisPLoS One · PMID 34559859
Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-blind, Randomized, Placebo-controlled StudyCureus · PMID 31728244
Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Improving Sexual Function in Women: A Pilot StudyBiomed Res Int · PMID 26504795
A randomized, double blind placebo controlled study of efficacy and tolerability of Withaina somnifera extracts in knee joint painJ Ayurveda Integr Med · PMID 27647541
Hypoglycemic, diuretic and hypocholesterolemic effect of winter cherry (Withania somnifera, Dunal) rootIndian J Exp Biol · PMID 11116534
Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adultsAyu · PMID 26730141
Effect of Withania somnifera (Ashwagandha) on the development of chemotherapy-induced fatigue and quality of life in breast cancer patientsIntegr Cancer Ther · PMID 23142798
The adjuvant use of calcium fructoborate and borax with etanercept in patients with rheumatoid arthritis: Pilot studyJ Intercult Ethnopharmacol · PMID 28163961
Effects of Calcium Fructoborate on Levels of C-Reactive Protein, Total Cholesterol, Low-Density Lipoprotein, Triglycerides, IL-1β, IL-6, and MCP-1: a Double-blind, Placebo-controlled Clinical StudyBiol Trace Elem Res · PMID 25433580
Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokinesJ Trace Elem Med Biol · PMID 21129941
Effects of boron supplementation on the severity and duration of pain in primary dysmenorrheaComplement Ther Clin Pract · PMID 25906949
Plasma boron and the effects of boron supplementation in malesEnviron Health Perspect · PMID 7889885
Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal womenFASEB J · PMID 3678698
Preliminary evidence hints at a protective role for boron in urolithiasisJ Altern Complement Med · PMID 22385047
A double-blind, placebo-controlled pilot study to evaluate the effect of calcium fructoborate on systemic inflammation and dyslipidemia markers for middle-aged people with primary osteoarthritisBiol Trace Elem Res · PMID 21607703
Effect of boron supplementation on blood and urinary calcium, magnesium, and phosphorus, and urinary boron in athletic and sedentary womenAm J Clin Nutr · PMID 7840072
Oral resveratrol and calcium fructoborate supplementation in subjects with stable angina pectoris: effects on lipid profiles, inflammation markers, and quality of lifeNutrition · PMID 23153742
Short-term efficacy of calcium fructoborate on subjects with knee discomfort: a comparative, double-blind, placebo-controlled clinical studyClin Interv Aging · PMID 24940052
Effects of 1,3-dimethylamylamine and caffeine alone or in combination on heart rate and blood pressure in healthy men and womenPhys Sportsmed · PMID 22030947
Ergogenic effect of varied doses of coffee-caffeine on maximal aerobic power of young African subjectsAfr Health Sci · PMID 21503180
The effect of caffeine ingestion on mood state and bench press performance to failureJ Strength Cond Res · PMID 21157384
Effect of Caffeine on LT, VT and HRVTInt J Sports Med · PMID 22499570
Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over studyClin Endocrinol · PMID 16886964
Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures designJ Int Soc Sports Nutr · PMID 22569090
Acute caffeine ingestion increases voluntarily chosen resistance training load following limited sleepInt J Sport Nutr Exerc Metab · PMID 22349085
Effects of caffeine on the metabolic and catecholamine responses to exercise in 5 and 28 degrees CMed Sci Sports Exerc · PMID 8201901
Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained menPLoS One · PMID 22496767
Effect of two doses of caffeine on muscular function during isokinetic exerciseMed Sci Sports Exerc · PMID 20421833
Dose effect of caffeine on testosterone and cortisol responses to resistance exerciseInt J Sport Nutr Exerc Metab · PMID 18458357
The effects of low-dose caffeine on perceived pain during a grip to exhaustion taskJ Strength Cond Res · PMID 21522070
Caffeine increases sweating sensitivity via changes in sudomotor activity during physical loadingJ Med Food · PMID 21883004
Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trialNutr J · PMID 21914162
Caffeine and sprinting performance: dose responses and efficacyJ Strength Cond Res · PMID 22388491
Effects of caffeine on prolonged intermittent-sprint ability in team-sport athletesMed Sci Sports Exerc · PMID 16540848
Caffeinated chewing gum increases repeated sprint performance and augments increases in testosterone in competitive cyclistsEur J Appl Physiol · PMID 20737165
The effects of different doses of caffeine on endurance cycling time trial performanceJ Sports Sci · PMID 22142020
Effect of caffeine ingestion on time trial performance in cyclists: a systematic review and meta-analysis.J Int Soc Sports Nutr · PMID 38836626
Effect of ambient temperature on caffeine ergogenicity during endurance exerciseEur J Appl Physiol · PMID 21120518
The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeineJ Int Soc Sports Nutr · PMID 22420682
Caffeine ingestion, affect and perceived exertion during prolonged cyclingAppetite · PMID 21605608
Effect of caffeine intake on pain perception during high-intensity exerciseInt J Sport Nutr Exerc Metab · PMID 21411832
Caffeine as an analgesic adjuvant for acute pain in adultsCochrane Database Syst Rev · PMID 25502052
Caffeine for the prevention of injuries and errors in shift workers.Cochrane Database Syst Rev · PMID 20464765
Caffeine enhances working memory for extravertsBiol Psychol · PMID 20816912
Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memoryBehav Brain Res · PMID 18554731
Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine usersPsychopharmacology · PMID 16541243
Effects of caffeine and glucose, alone and combined, on cognitive performanceHum Psychopharmacol · PMID 20521321
Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis.Neurosci Biobehav Rev · PMID 31837359
Effect of caffeine on reactive agility time when fresh and fatiguedMed Sci Sports Exerc · PMID 21266929
Effects of Nutritional Interventions on Accuracy and Reaction Time with Relevance to Mental Fatigue in Sporting, Military, and Aerospace Populations: A Systematic Review and Meta-Analysis.Int J Environ Res Public Health · PMID 35010566
Effect of caffeine on target detection and rifle marksmanshipErgonomics · PMID 14668172
Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumptionNeuropsychopharmacology · PMID 20520601
Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteersAm J Clin Nutr · PMID 2333832
Caffeine can decrease insulin sensitivity in humansDiabetes Care · PMID 11815511
Effects of caffeine on glucose tolerance: a placebo-controlled studyEur J Clin Nutr · PMID 9846599
Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humansDiabetes · PMID 11574419
Caffeinated coffee does not acutely affect energy intake, appetite, or inflammation but prevents serum cortisol concentrations from falling in healthy menJ Nutr · PMID 21346100

Evidence by supplement

Key findings

The Low Testosterone (Male Hypogonadism) protocol

Shop the evidence-backed picks

Studies cited

Related conditions

Supplement stack for Low Testosterone