Andy – If you take testosterone, your hypothalamus will notice an abundance of testosterone in your system and will instruct your pituitary gland not to send LH and FSH to your testicles. If you’re testicles are not receiving these two hormones, they will stop making testosterone. If you quit testosterone call turkey, you will likely fall back to your baseline level fairly quickly. There is a protocol however to get back to your normal production much quicker should you choose to quit therapy.
According to a study in the International Journal of Reproductive BioMedicine, D-Aspartic acid increases testosterone levels in some animals. However, studies that have looked at its effects on humans are inconclusive and mainly of poor quality. The paper says there is an urgent need for more research on this chemical, which occurs naturally in some human tissues.
Men who start using the gels have to come back in to have their testosterone levels measured again to make sure they’re absorbing the right amount. Our target is the mid to upper range of normal, which usually means around 500 to 600 ng/dl. The concentration of testosterone in the blood actually goes up quite quickly, within a few doses. I usually measure it after two weeks, though symptoms may not change for a month or two.
Studies have demonstrated reduced testosterone levels in men with heart failure as well as other endocrine changes (Tappler and Katz 1979; Kontoleon et al 2003). Treatment of cardiac failure with chronic mechanical circulatory support normalizes many of these changes, including testosterone levels (Noirhomme et al 1999). More recently, two double-blind randomized controlled trials of testosterone treatment for men with low or low-normal serum testosterone levels and heart failure have shown improvements in exercise capacity and symptoms (Pugh et al 2004; Malkin et al 2006). The mechanism of these benefits is currently unclear, although a study of the acute effects of buccal testosterone given to men with chronic cardiac failure under invasive monitoring showed that testosterone increased cardiac index and reduced systemic vascular resistance (Pugh et al 2003). Testosterone may prove useful in the management of cardiac failure but further research is needed.
In 2003, an Institute of Medicine panel concluded that there was insufficient evidence supporting the benefits of testosterone in older men and recommended further research. Consequently, in 2010, the National Institute of Aging, which is part of the NIH, launched the Testosterone Trials (T Trials) to figure out whether testosterone can help with symptoms associated with low levels of testosterone secondary to older age (i.e., symptomatic hypogonadism).
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. 
The most popular way is to combine with a good tasting protein powder. Advanced BCAA’s taste very bitter due to the high amount of peptides. Peptides taste very bitter. You want to use 1 tsp of Advanced BCAA’s with every serving of protein powder. This will really upgrade the quality of the protein powder by adding BCAA, AND in peptides form. If you are using a whey protein you’ll increase the overall BCAA content by over 20%
Both Beast Sports’ Super Test and iSatori’s ISA-Test contain a proprietary blend, which means they don’t disclose the amount of each and every ingredient in the mix. This is only a problem if there is an ingredient tucked into a proprietary blend for which we need to know an amount, like magnesium and zinc. While none of the ingredients in Beast Sports’s proprietary blend raised any red flags, iSatori’s blend contains melatonin, a hormone that helps regulate sleep. Melatonin is an ingredient that has a hard upper limit — Healthline suggests at most 10mg for an adult — and even lower doses can interact poorly with many medications. Since we can’t confirm whether the amount of melatonin in iSatori’s proprietary blend is under 10mg, we cut iSatori.
A study in the European Journal of Clinical Nutrition that showed drops in cholesterol levels also highlighted the benefits of Fenugreek in controlling glucose levels (this is in fact what the trial was intended to test). When you eat, your glucose levels spike. Fenugreek helps stimulate insulin release to slow down the absorption of sugars in your intestinal tract. Fenugreek might help control blood sugar levels in diabetics.  Furthermore, high glucose levels create a poor environment for testosterone production.  This is why Tim Ferris, in his testosterone diet, advises against consuming sweets and simple starches when you are trying to increase T levels.
Tailor the above recommendations to your personal needs and lifestyle. If you’re a vegetarian drop the bacon and steak, but keep the whey protein and eggs. If you have an injury that prevents you from heavy weightlifting, move as much as you can in the way that you can. There are no studies out there which can tell you exactly what will happen if you do X and Y, but not Z. And I certainly can’t tell you either. Don’t be afraid of self-education – that’s how I learned all this – and embrace the idea of conducting your own experiment and being your own test subject. Incorporate as many of the recommendations above as you’re comfortable with, consult your doctor, and track your results.
I know the experiment didn’t simply bring me back to my pre-August levels because of the fact that when I learned that the original test I took can sometimes overestimate your T levels, I took a more accurate test around four months after the start of the experiment (I’ve continued the lifestyle changes made during the experiment) and my total T had gone up again to 826.9 ng/dL.

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.
If a young man's low testosterone is a problem for a couple trying to get pregnant, gonadotropin injections may be an option in some cases. These are hormones that signal the body to produce more testosterone. This may increase the sperm count. Hedges also describes implantable testosterone pellets, a relatively new form of treatment in which several pellets are placed under the skin of the buttocks, where they release testosterone over the course of about three to four months. Injections and nasal gels may be other options for some men.