I recommend using a trans-mucosal DHEA cream. Applying it to the rectum or if you are a a woman, your vagina, will allow the mucous epithelial membranes that line your mucosa to perform effective absorption. These membranes regulate absorption and inhibit the production of unwanted metabolites of DHEA. I personally apply 50 milligrams of trans-rectal DHEA cream twice a day – this has improved my own testosterone levels significantly. However, please note that I do NOT recommend prolonged supplementation of hormones. Doing so can trick your body into halting its own DHEA production and may cause your adrenals to become seriously impaired down.

Oral/buccal (by mouth). The buccal dose comes in a patch that you place above your incisor (canine or "eyetooth"). The medication looks like a tablet but you should not chew or swallow it. The drug is released over 12 hours. This method has fewer harmful side effects on the liver than if the drug is swallowed, but it may cause headaches or cause irritation where you place it.
In addition to conjugation and the 17-ketosteroid pathway, testosterone can also be hydroxylated and oxidized in the liver by cytochrome P450 enzymes, including CYP3A4, CYP3A5, CYP2C9, CYP2C19, and CYP2D6.[155] 6β-Hydroxylation and to a lesser extent 16β-hydroxylation are the major transformations.[155] The 6β-hydroxylation of testosterone is catalyzed mainly by CYP3A4 and to a lesser extent CYP3A5 and is responsible for 75 to 80% of cytochrome P450-mediated testosterone metabolism.[155] In addition to 6β- and 16β-hydroxytestosterone, 1β-, 2α/β-, 11β-, and 15β-hydroxytestosterone are also formed as minor metabolites.[155][156] Certain cytochrome P450 enzymes such as CYP2C9 and CYP2C19 can also oxidize testosterone at the C17 position to form androstenedione.[155]
Transdermal preparations of testosterone utilize the fact that the skin readily absorbs steroid hormones. Initial transdermal preparations took the form of scrotal patches with testosterone loaded on to a membranous patch. Absorption from the scrotal skin was particularly good and physiological levels of testosterone with diurnal variation were reliably attained. The scrotal patches are now rarely used because they require regular shaving or clipping of scrotal hair and because they produce rather high levels of dihydrotestosterone compared to testosterone (Behre et al 1999). Subsequently, non-scrotal patches were developed but the absorptive capacity of non-scrotal skin is much lower, so these patches contain additional chemicals which enhance absorption. The non-scrotal skin patches produce physiological testosterone levels without supraphysiological dihydrotestosterone levels. Unfortunately, the patches produce a high rate of local skin reactions often leading to discontinuation (Parker and Armitage 1999). In the last few years, transdermal testosterone gel preparations have become available. These require daily application by patients and produce steady state physiological testosterone levels within a few days in most patients (Swerdloff et al 2000; Steidle et al 2003). The advantages compared with testosterone patches include invisibility, reduced skin irritation and the ability to adjust dosage, but concerns about transfer to women and children on close skin contact necessitate showering after application or coverage with clothes.
Testosterone replacement therapy is currently only FDA approved for men who have been diagnosed with hypogonadism, but it’s also prescribed off-label for older men who take it in hopes that it will improve their libido. The use of testosterone therapy is increasingly common in the United States, with more than 2 million men receiving the therapy. Not every man benefits from taking testosterone supplements. Testosterone is available in different forms, including topicals such as gels, creams, and patches; injections; and pellets that are surgically placed directly beneath the skin. (7)
Among the changes which occur with aging are those that affect several aspects of the endocrine system which reduces its secretions to varying degrees in different individuals. These reductions in secretions are identified by a poor but widely recognized appellation, the “pauses”: menopause (decreased ovarian function), adrenopause (decreased adrenal function, especially with regard to dehydroepiandrosterone secretion), somatopause (decreased growth hormone production), andropause (decreased hypothalamic-pituitary testicular function with diminished testosterone availability and impaired spermatogenesis) (Lamberts 1997).
Ashwagandha is shown to be effective at reducing cortisol which in turn helps with testosterone production. There are also numerous studies showing the effects on improving testosterone in infertile men (ref 80).  If you are using the Aggressive Strength product you don't need to supplement with ashwagandha as it's included in the test booster formula. Likewise if you're using Tian Chi (my daily herb drink).
The chemical synthesis of testosterone from cholesterol was achieved in August that year by Butenandt and Hanisch.[183] Only a week later, the Ciba group in Zurich, Leopold Ruzicka (1887–1976) and A. Wettstein, published their synthesis of testosterone.[184] These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 Nobel Prize in Chemistry.[182][185] Testosterone was identified as 17β-hydroxyandrost-4-en-3-one (C19H28O2), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e., esterification and alkylation.

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. 
Dr. Anthony’s Notes: DHEA is a powerful supplement for testosterone, energy, and overall well-being in our older Fit Fathers. A small dose of 25-50mg/day is enough to exert noticeable benefits. This supplement is over-the-counter. Verdict: this is one of the testosterone supplements that work. How To Take DHEA: Take 25-50mg once per day with food. Special Medical Note: DHEA is a MILD CYP3A4 inhibitor (a liver enzyme that processes MANY very common medications). This is the same isoenzyme that Grapefruit inhibits – albeit DHEA inhibits to a much weaker degree. If you’ve ever heard “don’t eat grapefruit with your Lipitor (cholesterol medication)”… this is the reason why. When we inhibit the CYP3A4 enzyme, more of the medications you're taking circulates (it’s not metabolized as fast). Check with your doctor for medication interactions before using DHEA.
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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.