Fatherhood decreases testosterone levels in men, suggesting that the emotions and behavior tied to decreased testosterone promote paternal care. In humans and other species that utilize allomaternal care, paternal investment in offspring is beneficial to said offspring's survival because it allows the parental dyad to raise multiple children simultaneously. This increases the reproductive fitness of the parents, because their offspring are more likely to survive and reproduce. Paternal care increases offspring survival due to increased access to higher quality food and reduced physical and immunological threats.[60] This is particularly beneficial for humans since offspring are dependent on parents for extended periods of time and mothers have relatively short inter-birth intervals.[61] While extent of paternal care varies between cultures, higher investment in direct child care has been seen to be correlated with lower average testosterone levels as well as temporary fluctuations.[62] For instance, fluctuation in testosterone levels when a child is in distress has been found to be indicative of fathering styles. If a father's testosterone levels decrease in response to hearing their baby cry, it is an indication of empathizing with the baby. This is associated with increased nurturing behavior and better outcomes for the infant.[63]


Christopher Walker is a co-founder of UMZU and creator of the Thermo Diet. He is the first person to get a Duke Neuroscience degree in 3 years. After naturally solving his own health complications with a brain tumor as a teenager, he has devoted his life to creating all-natural products and education to help men, women, children and pets to improve their own health naturally using science-backed research.
Testosterone is a hormone with multifaceted physiological functions and multiple associations with pathophysiological states. It is an important hormone in male reproductive and metabolic function from intrauterine life to old age. In severe or classical hypogonadal states there is little controversy about the need to administer testosterone by an intramuscular, oral or transdermal formulation. There is controversy about making the diagnosis in the less severe cases of hypogonadism associated with the aging male but the current evidence suggests that this is efficacious in appropriately selected men and that there is little if any risk in giving aging symptomatic hypogonadal men a 6 month trial of therapy to determine whether symptoms will improve.
Vitamin D supplementation may potentially boost testosterone levels, but further research is needed to determine if it really has an effect on the testosterone levels of young people and athletes. The truth is likely similar to zinc and magnesium — being in a deficient state causes your testosterone levels to drop below baseline, and supplementing it just takes you right back to baseline (but not any higher).
Testosterone is used as a medication for the treatment of males with too little or no natural testosterone production, certain forms of breast cancer,[10] and gender dysphoria in transgender men. This is known as hormone replacement therapy (HRT) or testosterone replacement therapy (TRT), which maintains serum testosterone levels in the normal range. Decline of testosterone production with age has led to interest in androgen replacement therapy.[105] It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful.[106]

Finally, we looked at the proprietary blends of our remaining boosters, and dug into their ingredient lists. Supplements frequently include ingredients known for their “folk-lore” value; they’re believed to work, even when there isn’t any scientific background to prove it. Though we didn’t ding points if an ingredient wasn’t proven to be good (just so long as it wasn’t proven to be bad), we didn’t want to include any ingredient with evidence of causing harm.


Total levels of testosterone in the body are 264 to 916 ng/dL in men age 19 to 39 years,[165] while mean testosterone levels in adult men have been reported as 630 ng/dL.[166] Levels of testosterone in men decline with age.[165] In women, mean levels of total testosterone have been reported to be 32.6 ng/dL.[167][168] In women with hyperandrogenism, mean levels of total testosterone have been reported to be 62.1 ng/dL.[167][168]


Testosterone boosters are used by many athletes worldwide to achieve a significant muscle mass increase within a short period of time.[1] However; one cannot be completely confident in terms of the quality and efficacy of such products because of several reasons, such as the possibility of bad storage conditions and originating from an unreliable source. Over the years, some consumers of testosterone boosters have complained of kidney and liver abnormalities that could be linked to their use of boosters.[10] Cases of erroneous product administration have occurred in the past as athletes may not follow the instructions on the label fully, which can lead to many side effects.[11] In the present case, a man was admitted to a hospital because of a severe abdominal pain. The pain was later found to be caused by liver injury. The diagnosis confirmed that the levels of the key hepatic enzymes were markedly elevated. The medical complications observed were found to have occurred following the consumption of two courses of a commercial testosterone booster. According to researchers based in the US, about 13% of the annual cases of acute liver failure are attributable to idiosyncratic drug- and/or supplement-induced liver injury.[12] Marked increase in the levels of ALT, AST, and gamma-glutamyl transferase was observed after consuming the first course of the commercial testosterone booster, and they started to decline after the 2nd and 3rd course. This abruptly increases the levels of liver enzymes after the first course may be attributed to the interruption effect of commercial testosterone booster on liver function as a result of the effects of its ingredients.
Dr. Anthony’s Notes: Here's a funny little effect – fenugreek can make you sweet and your urine smell sweet like Maple Syrup. Hell, this could be a good thing for you! This supplement is commonly used for good reasons – it's quite effective for enhancing libido when stacked with the other herbs on this list. Medical Note: Fenugreek may interact with blood thinning medications (Warfarin, Coumadin, Xarleto). Check with your doctor before taking any of these supplements. How To Take Fenugreek: Take 400-600mg (capsule) with food; it's best to take a product standardized for fenuside.
In many of the studies we found, those who saw the most improvement in health, testosterone, or muscle gain were those with existing nutrient or vitamin deficiencies. This means that some gains may be due more to dietary changes and generally restoring nutrient and vitamin levels than any one magic ingredient, but also that making sure your diet includes healthy amounts of nutrients should be your first step.
When you’re under stress (be it from lack of sleep, workplace stress, emotional stress, stress from a bad diet, overtraining etc.), your body releases cortisol. Cortisol blunts the effects of testosterone (47), which makes sense from an evolutionary point of view – if we were stressed as cavemen chances are it was a life or death situation – not running late to a meeting - in this state (i.e. running from a lion) the body wouldn’t care if you couldn’t get it up, there was more to worry about!
There are studies that show Soy consumption in humans leads to lower sperm count, but unfortunately they did not look at testosterone levels in the study (40). This (41) particular study compared the estrogen production of men drinking soy protein to those drinking whey. After two weeks they found the estradiol levels were equal, however soy drinkers had LOWER Testosterone levels and HIGHER cortisol levels (both bad).
Transdermal preparations of testosterone utilize the fact that the skin readily absorbs steroid hormones. Initial transdermal preparations took the form of scrotal patches with testosterone loaded on to a membranous patch. Absorption from the scrotal skin was particularly good and physiological levels of testosterone with diurnal variation were reliably attained. The scrotal patches are now rarely used because they require regular shaving or clipping of scrotal hair and because they produce rather high levels of dihydrotestosterone compared to testosterone (Behre et al 1999). Subsequently, non-scrotal patches were developed but the absorptive capacity of non-scrotal skin is much lower, so these patches contain additional chemicals which enhance absorption. The non-scrotal skin patches produce physiological testosterone levels without supraphysiological dihydrotestosterone levels. Unfortunately, the patches produce a high rate of local skin reactions often leading to discontinuation (Parker and Armitage 1999). In the last few years, transdermal testosterone gel preparations have become available. These require daily application by patients and produce steady state physiological testosterone levels within a few days in most patients (Swerdloff et al 2000; Steidle et al 2003). The advantages compared with testosterone patches include invisibility, reduced skin irritation and the ability to adjust dosage, but concerns about transfer to women and children on close skin contact necessitate showering after application or coverage with clothes.
Testosterone retains nitrogen and is an essential ingredient in the development and maintenance of muscle mass (Sinha-Hikim et al 2006). With a diminution in testosterone, muscle mass diminishes as does strength. Weakness and fatigue result. A number of studies have demonstrated the ability of testosterone to restore lean body mass (muscle) in hypogonadal men, while at the same time causing a reduction in fat mass (Wang et al 2004). Treatment of hypogonadal men with testosterone results in improvement in overall physical performance as well as strength as assessed by, eg, hand grip power (Page 2005). Because of decreased muscle strength and impaired balance, older hypogonadal men are susceptible to falling and since they may already be osteopenic or osteoporotic as a consequence of hypogonadism, they are at increased risk for fracture as a result of the fall (Szulc et al 2003). Men with low levels of testosterone as in androgen deprivation therapy for prostate cancer, have a significant decrease in lean body mass and hemoglobin, while at the same time they experience an increase in weight, body fat and body mass index (Smith et al 2002). Treatment of frail hypogonadal men with testosterone, therefore, can result in changes in muscle gene expression, increased muscle mass, improvements in strength, power and endurance and improved physical function.
In fact, testosterone supplements might cause more problems than they solve. Studies have suggested a connection between supplements and heart problems. A 2010 study reported in The New England Journal of Medicine showed that some men over age 65 had an increase in heart problems when they used testosterone gel. A later of men younger than 65 at risk for heart problems and heart-healthy older men showed that both groups had a greater risk of heart attack when taking testosterone supplements.
The hormone also plays a role in sex drive, sperm production, fat distribution, red cell production, and maintenance of muscle strength and mass, according to the Mayo Clinic. For these reasons, testosterone is associated with overall health and well-being in men. One 2008 study published in the journal Frontiers of Hormone Research even linked testosterone to the prevention of osteoporosis in men.
Male hypogonadism becomes more common with increasing age and is currently an under-treated condition. The diagnosis of hypogonadism in the aging male requires a combination of symptoms and low serum testosterone levels. The currently available testosterone preparations can produce consistent physiological testosterone levels and provide for patient preference.
Epidemiological evidence supports a link between testosterone and glucose metabolism. Studies in non-diabetic men have found an inverse correlation of total or free testosterone with glucose and insulin levels (Simon et al 1992; Haffner et al 1994) and studies show lower testosterone levels in patients with the metabolic syndrome (Laaksonen et al 2003; Muller et al 2005; Kupelian et al 2006) or diabetes (Barrett-Connor 1992; Andersson et al 1994; Rhoden et al 2005). A study of patients with type 2 diabetes using measurement of serum free testosterone by the gold standard method of equilibrium dialysis, found a 33% prevalence of biochemical hypogonadism (Dhindsa et al 2004). The Barnsley study demonstrated a high prevalence of clinical and biochemical hypogonadism with 19% having total testosterone levels below 8 nmol/l and a further 25% between 8–12 nmol/l (Kapoor, Aldred et al 2007). There are also a number longitudinal studies linking low serum testosterone levels to the future development of the metabolic syndrome (Laaksonen et al 2004) or type 2 diabetes (Haffner et al 1996; Tibblin et al 1996; Stellato et al 2000; Oh et al 2002; Laaksonen et al 2004), indicating a possible role of hypogonadism in the pathogenesis of type 2 diabetes in men. Alternatively, it has been postulated that obesity may be the common link between low testosterone levels and insulin resistance, diabetes and cardiovascular disease (Phillips et al 2003; Kapoor et al 2005). With regard to this hypothesis, study findings vary as to whether the association of testosterone with diabetes occurs independently of obesity (Haffner et al 1996; Laaksonen et al 2003; Rhoden et al 2005).
The rise in testosterone levels during competition predicted aggression in males but not in females.[86] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[87] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[88] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[89] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[90] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[91]
Hoffman, J., Ratamess, N., Kang, J., Magine, G., Faigenbaum, A. & Stout, J. (2006, August). Effect of creatine and beta-alanine supplementation on performance and endocrine responses in strength/power athletes [Abstract]. International Journal of Sport Nutrition and Exercise Metabolism, 16(4), 430–46. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/17136944

Before assessing the evidence of testosterone’s action in the aging male it is important to note certain methodological considerations which are common to the interpretation of any clinical trial of testosterone replacement. Many interventional trials of the effects of testosterone on human health and disease have been conducted. There is considerable heterogenicity in terms of study design and these differences have a potential to significantly affect the results seen in various studies. Gonadal status at baseline and the testosterone level produced by testosterone treatment in the study are of particular importance because the effects of altering testosterone from subphysiological to physiological levels may be different from those of altering physiological levels to supraphysiological. Another important factor is the length of treatment. Randomised controlled trials of testosterone have ranged from one to thirty-six months in duration (Isidori et al 2005) although some uncontrolled studies have lasted up to 42 months. Many effects of testosterone are thought to fully develop in the first few months of treatment but effects on bone, for example, have been shown to continue over two years or more (Snyder et al 2000; Wang, Cunningham et al 2004).
Epidemiological data has associated low testosterone levels with atherogenic lipid parameters, including lower HDL cholesterol (Lichtenstein et al 1987; Haffner et al 1993; Van Pottelbergh et al 2003) and higher total cholesterol (Haffner et al 1993; Van Pottelbergh et al 2003), LDL cholesterol (Haffner et al 1993) and triglyceride levels (Lichtenstein et al 1987; Haffner et al 1993). Furthermore, these relationships are independent of other factors such as age, obesity and glucose levels (Haffner et al 1993; Van Pottelbergh et al 2003). Interventional trails of testosterone replacement have shown that treatment causes a decrease in total cholesterol. A recent meta-analysis of 17 randomized controlled trials confirmed this and found that the magnitude of changes was larger in trials of patients with lower baseline testosterone levels (Isidori et al 2005). The same meta-analysis found no significant overall change in LDL or HDL cholesterol levels but in trials with baseline testosterone levels greater than 10 nmol/l, there was a small reduction in HDL cholesterol with testosterone treatment.
The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of aromatization to estradiol. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting LH secretion).[115] In many mammals, prenatal or perinatal "masculinization" of the sexually dimorphic areas of the brain by estradiol derived from testosterone programs later male sexual behavior.[116]

Testosterone fluctuates according to age and life circumstance, often plummeting at the onset of parenthood, and spiking (for some) during moments of triumph. Romantic relationships, too, can impact a person’s testosterone production; though the reasons are still not fully understood, entering a relationship tends to increase women’s testosterone levels, while decreasing men’s. Since males produce significantly more testosterone than females—about 20 times more each day—females can be more sensitive to these fluctuations. High levels of testosterone, particularly in men, have been correlated with a greater likelihood of getting divorced or engaging in extramarital affairs, though a causal link has not been established.
The reliable measurement of serum free testosterone requires equilibrium dialysis. This is not appropriate for clinical use as it is very time consuming and therefore expensive. The amount of bioavailable testosterone can be measured as a percentage of the total testosterone after precipitation of the SHBG bound fraction using ammonium sulphate. The bioavailable testosterone is then calculated from the total testosterone level. This method has an excellent correlation with free testosterone (Tremblay and Dube 1974) but is not widely available for clinical use. In most clinical situations the available tests are total testosterone and SHBG which are both easily and reliably measured. Total testosterone is appropriate for the diagnosis of overt male hypogonadism where testosterone levels are very low and also in excluding hypogonadism in patients with normal/high-normal testosterone levels. With increasing age, a greater number of men have total testosterone levels just below the normal range or in the low-normal range. In these patients total testosterone can be an unreliable indicator of hypogonadal status. There are a number of formulae that calculate an estimated bioavailable or free testosterone level using the SHBG and total testosterone levels. Some of these have been shown to correlate well with laboratory measures and there is evidence that they more reliably indicate hypogonadism than total testosterone in cases of borderline biochemical hypogonadism (Vermeulen et al 1971; Morris et al 2004). It is important that such tests are validated for use in patient populations relevant to the patient under consideration.
There is increasing interest in the group of patients who fail to respond to treatment with PDE-5 inhibitors and have low serum testosterone levels. Evidence from placebo-controlled trials in this group of men shows that testosterone treatment added to PDE-5 inhibitors improves erectile function compared to PDE-5 inhibitors alone (Aversa et al 2003; Shabsigh et al 2004).
We kept it simple, and followed the premise of testosterone boosters: testosterone affects muscle gain, weight loss, and libido, so by increasing the amount of testosterone in the body, we can improve on each of those goals. This meant that we looked for ingredients proven to increase testosterone levels, not ingredients that might increase libido or help build muscle mass independently of testosterone (like having a healthy diet and feeling good about yourself). In addition, we dove deep into the specific ingredient lists of our finalists and cross-checked them against WebMD and the National Institutes of Health (NIH) database to make sure that they did not contain ingredients known to be harmful.

Stored food in glassware and never, ever, ever heated food in plastic containers. Most modern plastics contain phthalates. Phthalates are what give plastic their flexibility, durability, and longevity. But they also screw with hormones by imitating estrogen. Because I didn’t want any of those T-draining molecules in my food, I kept all my food in glassware. I also made sure to never heat food in plastic containers, as heat increases the transfer of phthalates into food.


There is increasing interest in the group of patients who fail to respond to treatment with PDE-5 inhibitors and have low serum testosterone levels. Evidence from placebo-controlled trials in this group of men shows that testosterone treatment added to PDE-5 inhibitors improves erectile function compared to PDE-5 inhibitors alone (Aversa et al 2003; Shabsigh et al 2004).
Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.
‘Testosterone boosting’ products  - found online, or in health food or body-building shops, these products claim to boost testosterone levels if you buy them. The majority of these products will not have the effect you want and are not worth spending money on. Any of these products that do have a real effect may have a form of prescription medication in which is both dangerous and illegal.

Studies conducted in rats have indicated that their degree of sexual arousal is sensitive to reductions in testosterone. When testosterone-deprived rats were given medium levels of testosterone, their sexual behaviors (copulation, partner preference, etc.) resumed, but not when given low amounts of the same hormone. Therefore, these mammals may provide a model for studying clinical populations among humans suffering from sexual arousal deficits such as hypoactive sexual desire disorder.[37]
Testosterone belongs to a class of male hormones called androgens, which are sometimes called steroids or anabolic steroids. In men, testosterone is produced mainly in the testes, with a small amount made in the adrenal glands. The brain's hypothalamus and pituitary gland control testosterone production. The hypothalamus instructs the pituitary gland on how much testosterone to produce, and the pituitary gland passes the message on to the testes. These communications happen through chemicals and hormones in the bloodstream.
You should also know that a lot of people are deficient in Vitamin D. In the USA & many other western regions in the world, vitamin D deficiency is at epidemic proportions. The best way to increase your D levels is sun exposure. You only need 20-30 minutes of exposure to a large amount of skin (i.e., take your shirt off and go for a walk during the day).
Cross-sectional studies have found a positive association between serum testosterone and some measures of cognitive ability in men (Barrett-Connor, Goodman-Gruen et al 1999; Yaffe et al 2002). Longitudinal studies have found that free testosterone levels correlate positively with future cognitive abilities and reduced rate of cognitive decline (Moffat et al 2002) and that, compared with controls, testosterone levels are reduced in men with Alzheimer’s disease at least 10 years prior to diagnosis (Moffat et al 2004). Studies of the effects of induced androgen deficiency in patients with prostate cancer have shown that profoundly lowering testosterone leads to worsening cognitive functions (Almeida et al 2004; Salminen et al 2004) and increased levels of serum amyloid (Gandy et al 2001; Almeida et al 2004), which is central to the pathogenesis of Alzheimer’s disease (Parihar and Hemnani 2004). Furthermore, testosterone reduces amyloid-induced hippocampal neurotoxity in vitro (Pike 2001) as well as exhibiting other neuroprotective effects (Pouliot et al 1996). The epidemiological and experimental data propose a potential role of testosterone in protecting cognitive function and preventing Alzheimer’s disease.
In many of the studies we found, those who saw the most improvement in health, testosterone, or muscle gain were those with existing nutrient or vitamin deficiencies. This means that some gains may be due more to dietary changes and generally restoring nutrient and vitamin levels than any one magic ingredient, but also that making sure your diet includes healthy amounts of nutrients should be your first step.
February 22, 2018 - Since our last review, the manufacturers of two of our top picks have gone out of business, and some new testosterone boosters have entered the arena. We’ve updated this review to evaluate the current field of testosterone supplements, as well as beef up analysis on what kind of results you can expect from t-boosters. Our only current top pick, Beast Sports Nutrition, is a new player in the industry that contains all four of the ingredients with studies showing a positive effect on testosterone.
The converse is also true; there is an increased incidence of rheumatic/autoimmune disease in men with hypogonadism. Jimenez-Balderas et al (2001) carried out neuroendocrine, genetic and rheumatologic investigations in hypogonadal men. Of the 13 hypogonadal patients, 8 (61%) had rheumatic autoimmune disease (ankylosing spondylitis, systemic lupus erythemetosus, rheumatoid arthritis, dermatomyositis). There is a low frequency of those diseases (0.83%) in the general population.
“This study establishes testosterone levels at which various physiological functions start to become impaired, which may help provide a rationale for determining which men should be treated with testosterone supplements,” Finkelstein says. “But the biggest surprise was that some of the symptoms routinely attributed to testosterone deficiency are actually partially or almost exclusively caused by the decline in estrogens that is an inseparable result of lower testosterone levels.”
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