There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
From the FDA Drug Label
- Nandrolone's Effect on Testosterone Levels: The drug label states that anabolic steroids suppress the gonadotropic functions of the pituitary 1. This suggests that nandrolone, being an anabolic steroid, may actually decrease testosterone levels by suppressing the pituitary's gonadotropic functions, rather than increasing them.
- Key Point: The label does not explicitly state that nandrolone increases testosterone levels. In fact, it implies the opposite, that it may suppress the body's natural production of testosterone.
From the Research
Effects of Nandrolone on Testosterone Levels
- The study 2 found that nandrolone increases testosterone levels at a concentration of 3.9 μM, but returns to basal levels at a concentration of 15.6 μM.
- In contrast, the study 3 demonstrated that moderate to high doses of nandrolone decanoate induced a diminished serum testosterone level and altered the expression level of key steroidogenic enzymes involved in testosterone biosynthesis.
- The review 4 highlighted the potential therapeutic applications of nandrolone for male health, but did not provide direct evidence on its effects on testosterone levels.
- The study 5 compared the receptor binding properties of nandrolone and testosterone, and found that nandrolone has a relatively strong effect on target tissues devoid of 5 alpha-reductase activity, but a relatively weak effect on tissues with high 5 alpha-reductase content.
- The study 6 found that nandrolone decanoate caused impaired recognition memory and diverse somatic effects, but did not specifically investigate its effects on testosterone levels.
Mechanisms of Nandrolone's Effects on Testosterone
- The study 2 found that nandrolone-induced testosterone increment was associated with upregulation of the steroidogenic acute regulatory protein (StAR) and downregulation of 17a-hydroxylase/17,20 lyase (CYP17A1).
- The study 3 found that nandrolone decanoate altered the expression level of key steroidogenic enzymes involved in testosterone biosynthesis, and induced degradation of the blood-testis barrier.
- The study 5 found that the difference in the effects of nandrolone and testosterone is caused by the fact that 5 alpha-reduction increases the affinity of testosterone and decreases the affinity of nandrolone.