Prolactin is suppressed by dopamine activity. Since supplementing L-DOPA suppresses prolactin (by increasing dopamine activity), supplementing L-DOPA would increase testosterone if prolactin was abnormally high. The average, healthy male does not have elevated prolactin (unless he’s on steroids), so supplementing with L-DOPA will not increase your testosterone levels.

Another effect that can limit treatment is polycythemia, which occurs due to various stimulatory effects of testosterone on erythropoiesis (Zitzmann and Nieschlag 2004). Polycythemia is known to produce increased rates of cerebral ischemia and there have been reports of stroke during testosterone induced polycythaemia (Krauss et al 1991). It is necessary to monitor hematocrit during testosterone treatment, and hematocrit greater than 50% should prompt either a reduction of dose if testosterone levels are high or high-normal, or cessation of treatment if levels are low-normal. On the other hand, late onset hypogonadism frequently results in anemia which will then normalize during physiological testosterone replacement.
Ghlissi, Z., Atheymen, R., Boujbiha, M. A., Sahnoun, Z., Makni Ayedi, F., Zeghal, K., ... Hakim, A. (2013, December). Antioxidant and androgenic effects of dietary ginger on reproductive function of male diabetic rats [Abstract]. International Journal of Food Sciences and Nutrition, 64 (8), 974–978. Retrieved from
A: Testosterone production declines naturally with age. Low testosterone, or testosterone deficiency (TD), may result from disease or damage to the hypothalamus, pituitary gland, or testicles that inhibits hormone secretion and testosterone production. Treatment involves hormone replacement therapy. The method of delivery is determined by age and duration of deficiency. Oral testosterone, Testred (methyltestosterone), is associated with liver toxicity and liver tumors and so is prescribed sparingly. Transdermal delivery with a testosterone patch is becoming the most common method of treatment for testosterone deficiency in adults. A patch is worn, either on the scrotum or elsewhere on the body, and testosterone is released through the skin at controlled intervals. Patches are typically worn for 12 or 24 hours and can be worn during exercise, bathing, and strenuous activity. Two transdermal patches that are available are Androderm (nonscrotal) and Testoderm (scrotal). The Androderm patch is applied to the abdomen, lower back, thigh, or upper arm and should be applied at the same time every evening between 8 p.m. and midnight. If the patch falls off before noon, replace it with a fresh patch until it is time to reapply a new patch that evening. If the patch falls off after noon, do not replace it until you reapply a new patch that evening. The most common side effects associated with transdermal patch therapy include itching, discomfort, and irritation at the site of application. Some men may experience fluid retention, acne, and temporary abnormal breast development (gynecosmastia). AndroGel and Testim are transdermal gels that are applied once daily to the clean dry skin of the upper arms or abdomen. When used properly, these gels deliver testosterone for 24 hours. The gel must be allowed to dry on the skin before dressing and must be applied at least 6 hours before showering or swimming. Gels cannot be applied to the genitals. AndroGel is available in a metered-dose pump, which allows physicians to adjust the dosage of the medication. Side effects of transdermal gels include adverse reactions at the site of application, acne, headache, and hair loss (alopecia). For more specific information on treatments for low testosterone, consult with your doctor or pharmacist for guidance based on current health condition. Kimberly Hotz, PharmD
The brain is also affected by this sexual differentiation;[13] the enzyme aromatase converts testosterone into estradiol that is responsible for masculinization of the brain in male mice. In humans, masculinization of the fetal brain appears, by observation of gender preference in patients with congenital diseases of androgen formation or androgen receptor function, to be associated with functional androgen receptors.[95]
The largest amounts of testosterone (>95%) are produced by the testes in men,[2] while the adrenal glands account for most of the remainder. Testosterone is also synthesized in far smaller total quantities in women by the adrenal glands, thecal cells of the ovaries, and, during pregnancy, by the placenta.[126] In the testes, testosterone is produced by the Leydig cells.[127] The male generative glands also contain Sertoli cells, which require testosterone for spermatogenesis. Like most hormones, testosterone is supplied to target tissues in the blood where much of it is transported bound to a specific plasma protein, sex hormone-binding globulin (SHBG).
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

Anabolic–androgenic steroids (AASs) are synthetic derivatives of testosterone that are commonly used among athletes aged 18–40 years, but many reports have demonstrated the presence of numerous toxic and hormonal effects as a result of long-term use of an AAS.[9] Testosterone-foods act as natural libido boosters. Due to the growing interest in herbal ingredients and other dietary supplements worldwide, the use of testosterone boosters is becoming more and more mainstream among athletes, but several side effects were documented. Hence, this study established to help in the assessment of the side effects and health risks which could occur among athletes consuming testosterone boosters.
In fact, high cortisol deals a crushing blow to testosterone in two ways. During, long-lasting stress, high amounts of cortisol release very often and have a direct negative influence on T levels. Thus, cortisol inhibits testosterone synthesis in the testes and hypothalamus. In addition, the production of cortisol is impossible without cholesterol. But testosterone synthesis also demands cholesterol. Since during stress cholesterol is first of all used for making cortisol, T levels simply plummet.
The regulation of testosterone production is tightly controlled to maintain normal levels in blood, although levels are usually highest in the morning and fall after that. The hypothalamus and the pituitary gland are important in controlling the amount of testosterone produced by the testes. In response to gonadotrophin-releasing hormone from the hypothalamus, the pituitary gland produces luteinising hormone which travels in the bloodstream to the gonads and stimulates the production and release of testosterone.
Dr. Darryn Willoughby, a professor of health, human performance and recreation and the director of the Exercise and Biochemical Nutrition Laboratory at Baylor University, told us that even in studies where there was an increase in testosterone, it was only around 15–20 percent. “In men with clinically normal testosterone levels, this modest increase will most likely not be anabolic enough to improve exercise performance,” he says. So if you have normal testosterone levels, and are simply trying to get an extra edge in gaining muscle, losing weight, or some extra time in the bedroom — you might see some results from taking a testosterone booster. But really, these will be most useful for men with low testosterone trying to get back to a healthy testosterone range.

In addition to weight training, combining this with interval training like burst training is the best overall combo to increase HGH. In fact, Burst training has been proven to not only boost T-levels, it helps keeps your testosterone elevated and can prevent its decline. Burst training involves exercising at 90–100 percent of your maximum effort for a short interval in order to burn your body’s stored sugar (glycogen), followed by a period of low impact for recovery.

If in a 46 XY individual testosterone is either not produced in adequate concentrations as in gonadal dysgenesis (MacLaughlin and Donahue 2004), or in the absence of the enzyme 17 alpha-hydroxylase so that testosterone is not produced (Ergun-Longmire et al 2006), or testosterone androgen receptors are absent as in the androgen insensitivity syndrome (Hughes and Deeb 2006), phenotypic females will result.
At the present time, it is suggested that androgen replacement should take the form of natural testosterone. Some of the effects of testosterone are mediated after conversion to estrogen or dihydrotestosterone by the enzymes aromatase and 5a-reductase enzymes respectively. Other effects occur independently of the traditional action of testosterone via the classical androgen receptor- for example, its action as a vasodilator via a cell membrane action as described previously. It is therefore important that the androgen used to treat hypogonadism is amenable to the action of these metabolizing enzymes and can also mediate the non-androgen receptor actions of testosterone. Use of natural testosterone ensures this and reduces the chance of non-testosterone mediated adverse effects. There are now a number of testosterone preparations which can meet these recommendations and the main factor in deciding between them is patient choice.
Testosterone is necessary for normal sperm development. It activates genes in Sertoli cells, which promote differentiation of spermatogonia. It regulates acute HPA (hypothalamic–pituitary–adrenal axis) response under dominance challenge.[22] Androgen including testosterone enhances muscle growth. Testosterone also regulates the population of thromboxane A2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans.[23][24]
Intramuscular testosterone injections were first used around fifty years ago. Commercially available preparations contain testosterone esters in an oily vehicle. Esterification is designed to retard the release of testosterone from the depot site into the blood because the half life of unmodified testosterone would be very short. For many years intramuscular preparations were the most commonly used testosterone therapy and this is still the case in some centers. Pain can occur at injection sites, but the injections are generally well tolerated and free of major side effects. Until recently, the available intramuscular injections were designed for use at a frequency of between weekly and once every four weeks. These preparations are the cheapest mode of testosterone treatment available, but often cause supraphysiological testosterone levels in the days immediately following injection and/or low trough levels prior to the next injection during which time the symptoms of hypogonadism may return (Nieschlag et al 1976). More recently, a commercial preparation of testosterone undecanoate for intramuscular injection has become available. This has a much longer half life and produces testosterone levels in the physiological range throughout each treatment cycle (Schubert et al 2004). The usual dose frequency is once every three months. This is much more convenient for patients but does not allow prompt cessation of treatment if a contraindication to testosterone develops. The most common example of this would be prostate cancer and it has therefore been suggested that shorter acting testosterone preparations should preferably used for treating older patients (Nieschlag et al 2005). Similar considerations apply to the use of subcutaneous implants which take the form of cylindrical pellets injected under the skin of the abdominal wall and steadily release testosterone to provide physiological testosterone levels for up to six months. Problems also include pellet extrusion and infection (Handelsman et al 1997).
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]
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.
The sex hormone testosterone is far more than just the stuff of the alpha male's swagger. Though it plays a more significant role in the life of the biological male, it is actually present in both sexes to some degree. Despite popular perceptions that testosterone primarily controls aggression and sex drive—although it does play a role in both of those things—research has shown that individual levels of testosterone are also correlated with our language skills and cognitive abilities. Testosterone occurs in the body naturally, but can be administered as a medication, too: its most common uses are in the treatment of hypogonadism and breast cancer, as well as in hormone therapy for transgender men.
Testosterone is considered to be the "male hormone" that's produced in men by the testes. Although women's ovaries produce some testosterone, the hormone is produced in much higher concentrations in men and it is responsible for many of the secondary sex characteristics seen in men such as a deeper voice and hair on the chest, in addition to contributing to a healthy libido, building muscle mass, and maintaining energy levels.

Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than testosterone, so that its androgenic potency is about 5 times that of T.[114] The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects.
However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
^ Butenandt A, Hanisch G (1935). "Uber die Umwandlung des Dehydroandrosterons in Androstenol-(17)-one-(3) (Testosterone); um Weg zur Darstellung des Testosterons auf Cholesterin (Vorlauf Mitteilung). [The conversion of dehydroandrosterone into androstenol-(17)-one-3 (testosterone); a method for the production of testosterone from cholesterol (preliminary communication)]". Chemische Berichte (in German). 68 (9): 1859–62. doi:10.1002/cber.19350680937.

Millions of American men use a prescription testosterone gel or injection to restore normal levels of the manly hormone. The ongoing pharmaceutical marketing blitz promises that treating "low T" this way can make men feel more alert, energetic, mentally sharp, and sexually functional. However, legitimate safety concerns linger. For example, some older men on testosterone could face higher cardiac risks.