Two hipotesys, vasoconstriction/nitric oxyd/blood flow and dopaminergergenic desregulation is the more accurated with Nandrolone and Trenbolone.
19nors does not tend to elevate prolactin as bros states in the forums (they use anti-prolactin/dopamine recap drugs that have temporary positive libido effect).
Also these two drugs are very harsh not just on the libido department, but at general as the Anabolic Doc explain in his videos (please watch, "that's amazing'!").
In my honest opinion these powerfull drugs does not worth the risks and we have more safer steroids around for use.
But it's a personal choice, be aware.
Tren and Deca are not considered to be comparable in terms of side effect profiles. Nandrolone has been used safely in long-term treatment of HIV patients with wasting syndromes at doses of 50-200 mg per week. Dr. Thomas O'Connell did not report in his videos (I have watched nearly all of them) that Deca was an extremely toxic anabolic steroid. He actually expresses significant caution to using any oral steroid or Tren, and states that the safest (relatively speaking) are primo, EQ, and Masteron. However, we know, and he has stated, that Masteron has significant negative side effects on lipids because of its anti-estrogenic effects; much more of a negative effect than nandrolone.
Clinically, nandrolone is considered one of the safest anabolic steroids to use, aside from testosterone.
Testosterone is an archetypal androgenic-anabolic steroid (AAS), while its exogenous administration is considered to be the gold standard for the treatment of male hypogonadism. The benefits are not due to its intrinsic nature alone but are due to ...
www.ncbi.nlm.nih.gov
"Nandrolone has been shown to possess a generally favorable side effect profile compared to most other AAS. Although any androgenic stimulation of the hair follicle and sebaceous sweat glands may result in alopecia, hirsutism, and acne, nandrolone’s weak androgenic activity makes these side effects uncommon (
28). As an injectable oil, nandrolone is not subject to first-pass hepatic metabolism and is not hepatotoxic. Interestingly, although not well-described in the literature, some users of nandrolone have complained of temporary ED that resolves with cessation of therapy (
13). This anecdotal side effect appears to be highly dependent on nandrolone dosage and the use or absence of concomitant testosterone. Although further studies regarding this are needed, plausible mechanisms for this include the insufficient androgenic activity of nandrolone itself and negative-feedback induced suppression of the HPG axis resulting in both reduced testosterone and DHT, the latter of which crucial to nitric-oxide mediated erectile function (
13,
29). Interference with the HPG axis also poses a significant risk to fertility and may risk the possibility for hypogonadism with long-term use in men who are not already testosterone deficient (
30).
It is important to note that the majority of the literature, which describes the adverse effects of nandrolone, does so in the setting of illicit AAS abuse (
11,
31,
32). This patient population is notorious for utilizing very high doses of AAS and is fraught with polypharmacy. Thus, the usefulness of extrapolating these studies’ findings to appropriate medical therapy with nandrolone is extremely limited (
33). In human studies, illicit, long-term AAS abuse has been associated with cardiovascular complications, such as cardiomyopathy and coronary artery disease (
34,
35). In rat models using approximately 20× the doses of nandrolone used clinically; cardiomyopathy has also been observed (
36-
38). It is unclear to what extent, if any, these risks would apply to nandrolone administration at a more reasonable dosage in a clinical setting. Thus far, the controlled clinical trials of nandrolone have been too small and too sparse to confidently assess the risks of physician-prescribed and monitored nandrolone treatment at appropriate dosing."