Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.[77] The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.[77] Thus it is the challenge of competition among males of the species that facilitates aggression and violence.[77] Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.[77] The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males.[77]
More can be learned from a large, randomized, placebo-controlled trial of finasteride treatment in 18,800 men aged 55 or more. Finasteride is a 5α-reductase inhibitor which acts to prevent the metabolism of testosterone to dihydrotestosterone (DHT) – the most active androgen in the prostate. The trial showed a greater overall incidence of prostate cancer in the control group, but men treated with finasteride were more likely to have high grade tumors (Thompson et al 2003), suggesting that reduced androgen exposure of the prostate may delay the presentation of prostate cancer and/or promote advanced disease in some other way.
This supplier is located in north sumatra (but they ship from Amazon via the U.S). They harvest the tongkat ali from the sumatra jungle and use roots of trees >10 years of age. I know this supplier is the best because he used to purchase from Tongkatali.org, which if you search Google you will find is the most reputable stuff. But he tests every batch before sending it out and became unhappy with the quality of their product. He now purchases from a new supplier who get tongkat ali extract from the same jungle, with the same extraction process, but who performs chemical and microbiological analysis of every batch they produce, which brings me peace of mind.
There is a negative correlation of testosterone levels with plasminogen activator inhibitor-1 (PAI-1) (Glueck et al 1993; Phillips 1993), which is a major prothrombotic factor and known to be associated with progression of atherosclerosis, as well as other prothrombotic factors fibrinogen, α2-antiplasmin and factor VII (Bonithon-Kopp et al 1988; Glueck et al 1993; Phillips 1993; De Pergola et al 1997). There is a positive correlation with tissue plasminogen activator (tPA) which is one of the major fibrinolytic agents (Glueck et al 1993). Interventional trials have shown a neutral effect of physiological testosterone replacement on the major clotting factors (Smith et al 2005) but supraphysiological androgen administration can produce a temporary mild pro-coagulant effect (Anderson et al 1995).
And remember, saturated fats work best (along with monounsaturated fats – olive oil, almonds, avocados etc.). In fact higher intakes of polyunsaturated fats (canola oil, sunflower oil, soybean oil, safflower oil, margarine etc.) are linked to LOWER testosterone levels (14 & 15). I explore the dangers of PUFA's in a lot more detail in this article - PUFA's: The Worst Thing For Your Health That You Eat Everyday.
Pellets. Your doctor will place the testosterone pellets under the skin of your upper hip or buttocks. Your doctor will give a shot of local anesthesia to numb your skin, then make a small cut and place the pellets inside the fatty tissues underneath your skin. This medication dissolves slowly and is released over about 3-6 months, depending on the number of pellets. 
As crazy as it seems, it has lately been proven that there is a no relation between cholesterol intake and heart attack as doctors once thought (and many still do). This is slowly becoming common knowledge, regardless of pharmaceutical companies wishes. (Trust me, this billion dollar industry does not want you to know this. You don;t have to be a conspiracy theorist to see this.)
Ashwagandha is sometimes included in testosterone supplements because of the hypothesis that it improves fertility. However, we couldn’t find sufficient evidence to support this claim (at best, one study found that ashwagandha might improve cardiorespiratory endurance). WebMD advocates caution when taking this herb, as it may interact with immunosuppressants, sedative medications, and thyroid hormone medications.
You should also get rid of cleaning products loaded with chemicals, artificial air fresheners, dryer sheets, fabric softeners, vinyl shower curtains, chemical-laden shampoos, and personal hygiene products. Replace them all with natural, toxin-free alternatives. Adjusting your diet can also help, since many processed foods contain gender-bending toxins. Switch to organic foods, which are cultivated without chemical interventions.
That said, keep in mind that using leucine as a free form amino acid can be highly counterproductive as when free form amino acids are artificially administrated, they rapidly enter your circulation while disrupting insulin function, and impairing your body's glycemic control. Food-based leucine is really the ideal form that can benefit your muscles without side effects.
In addition to weightlifting, studies have shown that HIIT workouts can also help boost testosterone levels. For those of you who don’t know, HIIT stands for high-intensity interval training. It calls for short, intense bursts of exercise, followed by a less-intense recovery period. You repeat with the intense/less-intense cycle several times throughout the workout. In addition to increasing T, HIIT has been shown to improve athletic conditioning and fat metabolism, as well as increase muscle strength.
Studies also show a consistent negative correlation of testosterone with blood pressure (Barrett-Connor and Khaw 1988; Khaw and Barrett-Connor 1988; Svartberg, von Muhlen, Schirmer et al 2004). Data specific to the ageing male population suggests that this relationship is particularly powerful for systolic hypertension (Fogari et al 2005). Interventional trials have not found a significant effect of testosterone replacement on blood pressure (Kapoor et al 2006).

The use of anabolic steroids (manufactured androgenic hormones) shuts down the release of luteinising hormone and follicle stimulating hormone secretion from the pituitary gland, which in turn decreases the amount of testosterone and sperm produced within the testes. In men, prolonged exposure to anabolic steroids results in infertility, a decreased sex drive, shrinking of the testes and breast development. Liver damage may result from its prolonged attempts to detoxify the anabolic steroids. Behavioural changes (such as increased irritability) may also be observed. Undesirable reactions also occur in women who take anabolic steroids regularly, as a high concentration of testosterone, either natural or manufactured, can cause masculinisation (virilisation) of women.

A: If a health insurance company is providing coverage for a medication, including testosterone replacement therapy, they determine the final cost of the product. Costs will vary from one health insurance plan to another. To determine the costs of the testosterone replacement options, the health insurance plan should be contacted. There are various options for testosterone replacement therapy including gels, injections, patches, and tablets that dissolve under the lip. All of the formulations can be effective and each has advantages and disadvantages. The most appropriate testosterone replacement therapy depends on a variety of factors, including cost, patient preference, and tolerability. Testosterone replacement gels, such as AndroGel and Testim, are very effective and easy to administer. AndroGel and Testim can be easily applied to the skin once daily. However, the gels can be irritating to the skin and AndroGel and Testim are typically quite expensive. Testosterone replacement injections, such as Depo-Testosterone (testosterone cypionate) and Delatestryl (testosterone enanthate), are usually inexpensive. The injections are given only once every one to two weeks. The major disadvantage with injectable testosterone is that testosterone levels may be difficult to control. Levels may be too high after an injection and too low before the following injection. A testosterone replacement patch, such as Androderm, is applied every night and left on for 24 hours. Androderm can be applied to the arm, back or stomach, in an area without too much hair. Androderm can cause irritation of the skin. A testosterone tablet, Striant, is placed under the upper lip against the gums and replaced every 12 hours. Striant molds to the upper gum so that eating and drinking can occur normally. The testosterone tablet can irritate the gums and cause a bitter taste and toothache. People with low testosterone should work with their doctor or healthcare provider to find a safe, effective, and affordable testosterone replacement option for them. For more specific information, consult with your doctor or pharmacist for guidance based on your health status and current medications, particularly before taking any action. Derek Dore, PharmD
Testing is the only way you can validate a low-T diagnosis and measure treatment progress. I always say, "Test, don’t guess!" Your doctor may "suspect" you have hormone imbalances by your symptoms, but you should ask that they do testing to confirm unhealthy levels. Testing also ensures your doctor rules out other issues that may simply have similar symptoms. With your test results in hand, your physician can best determine what the optimal levels are for you and determine the best course of treatment.

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:

The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".[78][79] Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.[78] The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.[80] Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.[81][82][83][84][85]
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]

Here’s a scary thought: You may be less of a man than your father was—at least hormonally. A study in the Journal of Clinical Endocrinology and Metabolism found that, on average, testosterone levels were higher in men of the same age in the ’80s than they were in the 2000s (due, researchers speculate, to higher rates of obesity and the wider use of medication these days).  
If you want to naturally boost testosterone and HGH then combining weight training with HIIT workouts (high intensity interval training). Go to the gym at least three days a week, ideally at least three days a week, and lift heavy weights. Lifting heavy weights 6–12 reps with larger muscle groups like your quadriceps, hamstrings, back, shoulders and chest will help your body pack on the maximum amount of muscle. Specifically, lifting at least 30 minutes up to as long as an hour or so can be very, very beneficial boost low testosterone levels.
Ten healthy men aged around 24 years old spent 1 week sleeping for 8 hours per night at home, they then spent the next 11 nights in a lab. They slept for 10 hours per night for 3 nights, followed by 8 nights of restricted sleep, when they slept for only 5 hours. Doctors checked their blood every 15 to 30 minutes during the last night that they slept 10 hours, as well as on the sleep-restricted session.
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]

Both men and women with Alzheimer’s Disease were found to have an increased concentration of SHBG and decreased free androgen index when compared with controls (Paoletti et al 2004). In a prospective study of 574 men whose baseline age span was 32–87 years and who were followed for a mean of 19.1 years (range, 4–37), the risk of developing Alzheimers’ Disease decreased 26 percent for each 10 unit increase in free testosterone index. The authors concluded that testosterone may be important for the prevention and treatment of AD (Moffat et al 2004).

As blood levels of testosterone increase, this feeds back to suppress the production of gonadotrophin-releasing hormone from the hypothalamus which, in turn, suppresses production of luteinising hormone by the pituitary gland. Levels of testosterone begin to fall as a result, so negative feedback decreases and the hypothalamus resumes secretion of gonadotrophin-releasing hormone.