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?


Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer's type,[100][101][102][103] a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[104] where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
Many endocrinologists are sounding the alarm about the damaging effects that come with exposure to common household chemicals. Called “endocrine disruptors,” these chemicals interfere with our body’s hormone system and cause problems like weight gain and learning disabilities. One type of endocrine disruptor is particularly bad news for our testosterone levels.
This is because your body is really good at self-regulating your hormone levels. So if you have normal testosterone levels, boosting above your natural base level may at best give you a few hours while your body makes, and then immediately processes out, the excess testosterone. This means you might experience higher than your average testosterone levels, but not by much, and only for a little while.
Erectile dysfunction is a common finding in the aging male. A prevalence of over 70% was found in men older than 70 in a recent cross-sectional study (Ponholzer et al 2005). Treatment with phosphodiesterase-5 (PDE-5) inhibitors is proven to be effective for the majority of men but some do not respond (Shabsigh and Anastasiadis 2003). The condition is multi-factorial, with contributions from emotional, vascular, neurological and pharmacological factors. The concept of erectile dysfunction as a vascular disease is particularly interesting in view of the evidence presented above, linking testosterone to atherosclerosis and describing its action as a vasodilator.
If you do take DAA I recommend cycling it (i.e. 5 days on, 2 off, over 4 weeks then 4 weeks off). And taking it with an aromatase inhibitor (which ensures the aspartic acid doesn’t get converted to estrogen). Especially as more studies are coming out showing the increase in testosterone is limited to a week or two before it drops back to normal levels.
This causes your body to burn fat for the next 36 hours to replace your body’s vital energy stores. It addition to increasing your T-levels, it can help burn between 3–9 times more fat, lower your resting heart rate, lower blood pressure, keep your brain young by increasing circulation, and aids in detoxification by stimulating the lymphatic system.
Dr. Anthony’s Notes: Vitamin D has about 100 other beneficial body functions outside of it's impact on testosterone. Make sure you take the active Vitamin D3 (not D2 – from plant sources!) It’s also advisable to get 20 minutes of sunshine daily (weather permitting) – without sunscreen. Verdict: this is one of the natural testosterone supplements that work. Best Food Sources of Vitamin D3: Wild Alaskan Salmon (#1), Sardines, Eggs How To Take Vitamin D3: Using 3000-5000IU of Vitamin D3 per day is a good safe, research supported dose. Your physician can also test your blood for D3 levels for more precise monitoring.

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).

Testosterone is only one of many factors that influence aggression and the effects of previous experience and environmental stimuli have been found to correlate more strongly. A few studies indicate that the testosterone derivative estradiol (one form of estrogen) might play an important role in male aggression.[66][67][68][69] Studies have also found that testosterone facilitates aggression by modulating vasopressin receptors in the hypothalamus.[70]


Testosterone boosters are a class of herbal supplements aimed at naturally increasing your testosterone levels. Usually, they contain micronutrients that men are commonly deficient in, such as zinc, and which have been connected in research to healthy testosterone levels. They also may contain adaptogens, which are a class of supplement that are thought to help the body adapt to stress, or ingredients which have been connected to improved sleep. Sleep restriction has been shown to reduce testosterone in healthy young men, and as Chris Lockwood, Ph.D., notes, disturbed sleep is a common symptom of low T-levels.[1]
The reason I started the experiment at that point is because I know a lot of guys who live my last-August lifestyle all the time, and I wanted to see what would happen to an “average” guy who turned things around. At the same time, there was no “normal” time in my life which would have been better for me to start the experiment. My stress level and diet fluctuates throughout the year anyway, so at any point, factors in my current lifestyle would have influenced the results. I wanted to begin at “ground zero.”
To be used as hormone replacement or substitution of diminished or absent endogenous testosterone. Use in males: For management of congenital or acquired hypogonadism, hypogonadism associated with HIV infection, and male climacteric (andopause). Use in females: For palliative treatment of androgen-responsive, advanced, inoperable, metastatis (skeletal) carcinoma of the breast in women who are 1-5 years postmenopausal; testosterone esters may be used in combination with estrogens in the management of moderate to severe vasomotor symptoms associated with menopause in women who do not respond to adequately to estrogen therapy alone.
That said, magnesium is one of a few ingredients demonstrated to impact testosterone levels. Researchers at Italy’s University of Palermo found that magnesium improved participants’ anabolic hormone status — including their testosterone levels. In a follow-up study, they confirm that even adjusting for age differences in their participant group, “magnesium was positively associated with total testosterone.” They propose that magnesium supplementation might help improve muscle performance in aging men — a group particularly vulnerable to declining/low testosterone levels. Outside of Italy, researchers at Turkey’s Selçuk University found that magnesium supplementation increased testosterone levels for both athletes and more sedentary men alike.

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Testosterone is a vital hormone for men, but just like estrogen in women, it goes down as you age. This is a natural process that has many drawbacks. In men, testosterone is responsible for hair growth, bone density, proper weight distribution, sex drive, muscle mass, red cell production, and so much more. But did you know that you can actually increase your testosterone levels as opposed to letting them dwindle?
Two of the immediate metabolites of testosterone, 5α-DHT and estradiol, are biologically important and can be formed both in the liver and in extrahepatic tissues.[151] Approximately 5 to 7% of testosterone is converted by 5α-reductase into 5α-DHT, with circulating levels of 5α-DHT about 10% of those of testosterone, and approximately 0.3% of testosterone is converted into estradiol by aromatase.[2][151][157][158] 5α-Reductase is highly expressed in the male reproductive organs (including the prostate gland, seminal vesicles, and epididymides),[159] skin, hair follicles, and brain[160] and aromatase is highly expressed in adipose tissue, bone, and the brain.[161][162] As much as 90% of testosterone is converted into 5α-DHT in so-called androgenic tissues with high 5α-reductase expression,[152] and due to the several-fold greater potency of 5α-DHT as an AR agonist relative to testosterone,[163] it has been estimated that the effects of testosterone are potentiated 2- to 3-fold in such tissues.[164]
Testosterone may prove to be an effective treatment in female sexual arousal disorders,[52] and is available as a dermal patch. There is no FDA approved androgen preparation for the treatment of androgen insufficiency; however, it has been used off-label to treat low libido and sexual dysfunction in older women. Testosterone may be a treatment for postmenopausal women as long as they are effectively estrogenized.[52]

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.
I have been using HerbalT for almost two months. I noticed improvement in my sleep, energy and mood within 3-4 days. Prior to use, I had a sleeping disorder and would wake up tired in the morning. My energy level was low and the sexual desire needed a trigger. After using this product, my energy level has improved. I wake up in the mornings and feel that my system is default. My mood has also improved. I don’t think to feel/think negative and hardly stress over anything.
In the hepatic 17-ketosteroid pathway of testosterone metabolism, testosterone is converted in the liver by 5α-reductase and 5β-reductase into 5α-DHT and the inactive 5β-DHT, respectively.[1][151] Then, 5α-DHT and 5β-DHT are converted by 3α-HSD into 3α-androstanediol and 3α-etiocholanediol, respectively.[1][151] Subsequently, 3α-androstanediol and 3α-etiocholanediol are converted by 17β-HSD into androsterone and etiocholanolone, which is followed by their conjugation and excretion.[1][151] 3β-Androstanediol and 3β-etiocholanediol can also be formed in this pathway when 5α-DHT and 5β-DHT are acted upon by 3β-HSD instead of 3α-HSD, respectively, and they can then be transformed into epiandrosterone and epietiocholanolone, respectively.[153][154] A small portion of approximately 3% of testosterone is reversibly converted in the liver into androstenedione by 17β-HSD.[152]

Hypogonadism is a disease in which the body is unable to produce normal amounts of testosterone due to a problem with the testicles or with the pituitary gland that controls the testicles. Testosterone replacement therapy can improve the signs and symptoms of low testosterone in these men. Doctors may prescribe testosterone as injections, pellets, patches or gels.
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