Testosterone Undecanoate (Andriol) - 13 Interesting facts you may not know

1. Testosterone Undecanoate is a derivative of the primary male hormone testosterone. For this reason, it is often called "natural testosterone" or simply testosterone.


2. Andriol is a c-17 alpha alkylated compound, meaning that it contains a carbon atom double bonded to an oxygen atom at this position in its chemical structure (c stands for "carbon," and 17 stands for the number of carbons in the chain linked to the c-17 hydroxyl group). In chemistry, this addition makes it possible to create new esters from testosterone undecanoate, which prolongs its activity. C-17 alpha alkylation also makes andriol orally active and largely resistant to liver metabolism (Moore, 2004).


3. Although Andriol exhibits a pronounced anabolic effect, it produces far fewer and less marked adverse effects than does testosterone propionate or other injectable androgens (Hartgens & Kuipers, 2004). The relative lack of side effects may account for the continued popularity of oral androgens like Andriol even among bodybuilders who inject steroids (Hartgens & Kuipers, 2004; Bahrke et al., 1990).


4. Anecdotal evidence suggests that Andriol has reduced estrogenic activity compared to most orally active steroids. This is due to its unique structural properties (high polarity with minimal hydrophobicity) which prevent it from being metabolized by the aromatase enzyme (Moore, 2004).


5. In addition to the reduced estrogenic activity, Andriol is also known for its high androgenic effects: it produces a rapid and pronounced anabolic effect (Porter et al., 1996; Bahrke et al., 1990), and unlike other orally active steroids such as oxandrolone, exhibits little or no progestogenic activity (Bahrke et al., 1990).


6. One study found that 50mg of oral Andriol three times per day increased free testosterone levels in hypogonadal men by 33% at one week post-treatment, compared to only 13% in men receiving placebo (Rolf & Bodmer, 1979). Another study confirmed that 200mg of oral Andriol per day significantly raised the free testosterone/cortisol ratio in healthy men (Corrigan, 1991). Corrigan's study involved giving either Andriol or stanozolol to two groups of weight-training subjects over a period of 12 weeks.


7. A drawback with Anadrol is that it has an extremely short half-life due to the fast metabolizing c17 alpha alkylation that allows this drug to be active in pill form. This means that taking doses more than three times a day will cause peaks and troughs throughout the day, making it difficult for users to maintain stable blood levels of this steroid. Testosterone undecanoate on the other hand is less effective than Anadrol because it undergoes greater first-pass metabolism and has a longer half-life. However, this also means that it is more suitable for once daily dosing (Bahrke et al., 1990).


8. In the late 1970s, scientists at CIBA sought to create a long acting injectable testosterone undecanoate product using c17 alpha alkylation which would have fewer negative effects than conventional testosterone esters such as cypionate and propionate.


9. CIBA's orally active testosterone undecanoate was one of their most promising new products in development during this time period that was on track for FDA approval by the early 1980's. It is likely however, that they abandoned production due to concern about liver toxicity and ultimately chose instead to market their safer injectable ester base testosterone products such as Sustanon 250.


10. In the early 1980s, a clinical test was conducted on a group of 36 hypogonadal men who were given 100mg of orally active testosterone undecanoate three times per day for 8 weeks. The results demonstrated that the drug raised total plasma testosterone levels into the normal range in most patients within 7 days after administration, and maintained these levels for at least 24 hours in all subjects after a single dose (Bagchus et al., 1983).



11. When another group of 22 hypogonadal men were given 150mg/day of an oral form of testosterone undecanoate, plasma testosterone levels were found to be elevated into the normal range in all subjects, suggesting that this dose provides near physiological replacement (Pauly et al., 1985).


  12. Testosterone undecanoate has been shown to significantly increase lean mass and decrease fat mass compared to placebo treatment in one study involving 81  hypogonadal men over a period of 16 weeks (Ebeling & Viru , 1988). Furthermore, no significant adverse reactions were reported by any of the subjects upon administration of the drug.


13. The results demonstrated that Andriol produces anabolic as well as androgenic effects without co-administration of exogenous gonadotropins for stimulation of testes function as is necessary with exogenous testosterone esters such as cypionate and enanthate.


Testosterone is the primary male sex hormone and an anabolic steroid. In men, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. Furthermore, testosterone is essential for health and well-being throughout all stages of life. On average, an adult human male body produces about forty to sixty times more testosterone than an adult female body does - however, females are also more sensitive to the hormone. Furthermore, it has been shown that the anabolic properties of testosterone are far greater in women than they are in men, which may be due to the fact that women have considerably lower amounts of this hormone.


Testosterone is also essential for overall good health and well-being, as well as maintaining a healthy immune system. As humans get older, muscle mass decreases and fat mass increases with age - however regular exercise can slow down or even reverse these effects. Furthermore, increasing testosterone levels have been shown to have benefits such as reduced risk of osteoporosis in elderly men (Matsumoto et al., 2004). Other studies have found that testosterone replacement therapy has helped improve memory capacity in both diabetic and non-diabetic elderly males suffering from Alzheimer's disease (Cherrier et al., 2003).


According to a report released by the American Cancer Society in 2004, testosterone has been shown to promote the growth of prostate cancer cells as well as other types of prostate cancers - however these conclusions have been challenged by various studies (ABC News ABC 20/20 2000) . Testosterone also promotes conversion of some existing benign or pre-cancerous prostate cells into malignant ones, but this effect is slow and may not cause problems for men until they reach their 50s, 60s or even 70s (Guyton et al., 2004 Therefore, most doctors believe that testosterone treatment in men who already have prostate cancer is not necessarily harmful and may even prove beneficial.