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]
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.

Now you know I prefer studies conducted on human participants instead of rodents, but often there is no choice.  A Japanese study on rats that you can read here: http://jn.nutrition.org/content/131/8/2150.short has demonstrated pretty convincingly that garlic supplementation significantly increases testosterone.  I wish there were more tests on humans but it turns out garlic isn’t patentable (sorry Monsanto) which means there isn’t enough financial interest to warrant human studies.  Maybe I’ll conduct one.  Any volunteers?

A large number of side-effects have been attributed to testosterone. In our clinical experience, the incidence of significant adverse effects with treatment producing physiological testosterone levels is low, and many side effects attributed to testosterone are mainly relevant to supraphysiological replacement. Some adverse effects are specific to a given mode of delivery and have already been described. Potential adverse effects concerning the prostate have also been discussed and require appropriate monitoring of symptoms, PSA and digital rectal examination. Other tumors which may be androgen responsive include cancer of the breast and primary liver tumors, and these are both contraindications to testosterone treatment


There are no studies showing its effects on healthy males, but it has been shown to drastically improve testosterone in infertile males (ref 77). It's also packed full of minerals, so is a great superfood nevertheless. I use the Sunfoods brand. Make sure you buy from a quality brand, as there are a lot of poor shilajit products out there, also some have been shown to be high in heavy metals. 


Testosterone has several positive effects on sexual function, but its most significant effect is on libido, sexual interest and arousal. Boys going through puberty develop an enhanced interest in sex (thoughts, fantasies, masturbation, intercourse) as a consequence of rising levels of testosterone. Hypogonadal men usually have a significant improvement in libido when TRT is initiated (Wang et al 2000; Morley and Perry 2003).
Cross-sectional studies conducted at the time of diagnosis of BPH have failed to show consistent differences in testosterone levels between patients and controls. A prospective study also failed to demonstrate a correlation between testosterone and the development of BPH (Gann et al 1995). Clinical trials have shown that testosterone treatment of hypogonadal men does cause growth of the prostate, but only to the size seen in normal men, and also causes a small increase in prostate specific antigen (PSA) within the normal range (Rhoden and Morgentaler 2005). Despite growth of the prostate a number of studies have failed to detect any adverse effects on symptoms of urinary obstruction or physiological measurements such as flow rates and residual volumes (Snyder et al 1999; Kenny et al 2000, 2001). Despite the lack of evidence linking symptoms of BPH to testosterone treatment, it remains important to monitor for any new or deteriorating problems when commencing patients on testosterone treatment, as the small growth of prostate tissue may adversely affect a certain subset of individuals.
The ingredients in testosterone supplements may be different. Some testosterone supplements contain zinc and magnesium. They increase testosterone levels in men who exercise. Some other testosterone supplements have hormones like DHEA (dehydroepiandrosterone) and pregnenolone. They help with making new testosterone and may help improve the ability to have an erection. But it doesn't seem to be helpful if the problem with erections is caused by diabetes or nerve disorders. Some testosterone booster supplements contain natural ingredients like herbs and botanicals. They may increase testosterone by increasing a hormone produced by the brain, which signals the testicles to produce more testosterone. In addition, others work by releasing bound testosterone, so it is in a form the body can use. Studies do not provide strong evidence that women benefit from taking these supplements. You need to talk to your doctor or pharmacist before starting a testosterone booster supplement. Discuss your medical history and current prescribed medications, over the counter medications, and any supplements that you are taking. Your doctor or pharmacist can tell you if a testosterone booster supplement is right for you. Once you know if a testosterone booster supplement is right for you, Walgreens has a variety of testosterone booster supplements to choose from and they come in different forms like tablets, capsules or gels.

Do low levels of testosterone produce symptoms in middle-aged men? Absolutely. In fact, the classic symptoms were first recognized more than 70 years ago when two American physicians, Carl Heller, MD, and Gordon Myers, MD, showed the effectiveness of testosterone treatment for symptoms of fatigue, depression, irritability, low sex drive, erectile dysfunction, night sweats, and hot flashes in men. Over the years, subsequent studies have found that some—but not all—men with low, age-adjusted testosterone levels exhibit symptoms consistent with andropause. All experience improvement with testosterone therapy.
There is a polymorphic CAG repeat sequence in the androgen receptor gene, which codes for a variable number of glutamine amino acids in the part of the receptor affecting gene transcription. A receptor with a short CAG sequence produces greater activity when androgens attach, and men with shorter CAG polymorphisms exhibit androgenic traits, such as preserved bone density (Zitzmann et al 2001) and prostate growth during testosterone treatment (Zitzmann et al 2003). Indirect evidence of the importance of androgens in the development of prostate cancer is provided by case control study findings of a shorter, more active CAG repeat sequence in the androgen receptor gene of patients with prostate cancer compared with controls (Hsing et al 2000, 2002).
That there is an association between depression and testosterone concentration seems possible because of the observation that depression may be associated with reduced testosterone concentrations, hypogonadal men may have their symptoms of depression relieved by TRT and that testosterone itself may have anti-depressant properties (Pope et al 2003). The evidence, however, is inconsistent. Seidman and colleagues (2002), for example, found that there was no relationship between testosterone and depression but there was an association of testosterone with dysthymia. McIntyre and colleagues (2006), on the other hand, found that middle-aged men with depression did have a reduction in bio-available testosterone.

The participants were seen every 4 weeks. Blood was taken to measure hormone levels, and questionnaires were given to assess physical function, health status, vitality, and sexual function. Body fat and muscle measurements were also taken at the beginning and end of the 16 weeks. The study was funded in part by NIH’s National Institute on Aging (NIA) and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Results appeared in the September 12, 2013, issue of the New England Journal of Medicine.
A: There are no over-the-counter products approved by the U.S. Food and Drug Administration (FDA) to increase testosterone levels. There are several prescription medication options available. Please consult with your health care provider in regards to your testosterone levels and to determine which treatment option best meets your individual needs. 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. Kristen Dore, PharmD
Every vitamin, mineral, and ingredient that affects the human body can be taken in enough quantities that they are harmful, or toxic, even the ones that — at lower levels — are beneficial or necessary. Unfortunately, testosterone boosters contain a lot of ingredients that are not well understood. This means in addition to not being able to confirm whether certain ingredients increase testosterone, the scientific and medical communities also don’t know at what levels many ingredients become toxic. On the up side, you might need to eat several pounds of a particular leafy plant before it becomes harmful. On the down side, it could be significantly less that pushes you over your body’s limit. We simply don’t know how little or how much the human body can tolerate. We recommend keeping your doctor in the loop when you add any supplement with unproven ingredients into your diet — they’ll be able to help you find and track any undesired side-effects that these ingredients might cause.
As we age, the body undergoes multiple degenerative changes at multiple sites and in multiple systems. The changes of aging are inevitable and inexorable and represent the march toward ultimate death. We are mortal beings whose destiny it is to die. As we come to learn about the processes of life we can better prepare ourselves for the finality of death and on the way perhaps retard the degenerative process, or repair it (for however long we may enjoy this repair), or substitute chemical compounds that our bodies once produced in abundance, an abundance which fades with the advance of age.
That said, a group of researchers at the National University of Malaysia did a systemic literature review of longjack, looking for clinical research that demonstrated a relationship between the shrub and testosterone levels. Of 150 articles, only 11 met their inclusion criteria — involving humans and scientifically rigorous. However, of those 11 studies, seven “revealed remarkable association” between using longjack and improving male sexual health, while the remaining four “failed to demonstrate sufficient effects.” The team concluded that longjack looks “promising” when it comes to raising low testosterone, and that there is convincing evidence that it works.
One study found that men who took 3,332 international units (IU) of vitamin D daily for one year significantly increased their testosterone levels. But vitamin D supplements may only work for men who are severely deficient in this specific vitamin. Another study found that men without a vitamin D deficiency had no increase in testosterone levels after taking vitamin D.
A study out of the University of Mary Hardin-Baylor in Belton, Texas, examined the effects of fenugreek supplementation on strength and body composition in resistance-trained men. Researchers found that while both the placebo and fenugreek groups significantly increased their strength during the first four weeks, only the fenugreek group saw significant increases in strength after eight weeks of training and supplementation.[5]
Any day that you don’t get 20 minutes of direct sunlight on your skin, you want to supplement with 5,000 IUs of vitamin D3. If you get your blood levels tested and you’re extremely low — below 50 IUs — you typically want to do 5,000 IUs twice a day for three months until you get those numbers up. You can do everything in the world, but if your vitamin D levels aren’t right, your testosterone levels will stay low.
It seems that adequate testosterone levels are an important influence on sexual symptoms in the aging male and also influence the response of men to PDE-5 inhibitors, the first line treatment for erectile dysfunction in men. Many would now suggest screening for testosterone deficiency in all men presenting with erectile dysfunction (Gore and Rajfer 2004; Shabsigh 2005). This would seem appropriate because, in addition to benefits on sexual function, identification and treatment of hypogonadal men with testosterone could improve other symptoms of hypogonadism and protect against other conditions such as osteoporosis.
The biggest change I made to my diet was increasing my fat and cholesterol intake. There’s a reason why old school strong men would drink raw eggs — studies have suggested that higher fat and cholesterol consumption results in increased levels of total T; men eating low-fat diets typically have decreased testosterone levels. The emphasis on increasing fat and cholesterol consumption meant I got to eat like Ron Swanson for three months — bacon and eggs and steak was pretty much the staple of my diet.
If testosterone deficiency occurs during fetal development, then male characteristics may not completely develop. If testosterone deficiency occurs during puberty, a boy’s growth may slow and no growth spurt will be seen. The child may have reduced development of pubic hair, growth of the penis and testes, and deepening of the voice. Around the time of puberty, boys with too little testosterone may also have less than normal strength and endurance, and their arms and legs may continue to grow out of proportion with the rest of their body.
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