"progesterone MAY be a potent 5AR inhibitor (something that I was not aware of) however to measure the progestenic nature of nandrolone based upon its inhibition of 5AR is inadequate. As a progestin, and not progesterone, nandrolone will have varying activty in different tissue types and in its effects on biochemical feedback"
You are correct in stating that 5-AR activity is a poor quantitative measure for progestin activity, since progesterone acts as a competitive inhibitor, and not through enzymatic regulation. Nandrolone may not share this trait as progesterone (which is a structural trait).
"What I am trying to say is that Deca dick is, in a very real way, in your head- it is a result of neurological effects of progestenic regulation of the GABA system."
Whether the primary reason is through progestagenic action, or reduced androgen action, it will definately be "in your head". DHT acts on libido through the central nervous system, not as a direct action on the erectile tissues. My reasoning is that similar problems are observed without the use of progestagenic agents, as in the example of finasteride, which causes libido loss through DHT reduction.
"By the tone of this, it sounds like you are disagreeing with me..."
Not disagreeing with you (except on the part of nandrolone to nortest), but simply expounding on a topic that I thought had been thoroughly covered for years now.
Here is an interesting study showing progesterone's action on 5-AR. It also has some useful info for those with hair loss problems...progesterone creams are OTC now (and maybe useful for prevention of gyno, I'll just let ya'll hang on this one).
J Invest Dermatol 1988 Nov;91(5):429-33
"Synergistic antiandrogenic effects of topical combinations of 5 alpha-reductase and androgen receptor inhibitors in the hamster sebaceous glands."
Matias JR, Malloy VL, Orentreich N.
Biomedical Research Station, Orentreich Foundation Inc., Cold Spring-on-Hudson, NY 10516.
The androgenic action of dihydrotestosterone (DHT) is antagonized by agents that compete with testosterone for the 5 alpha-reductase enzyme and by agents that block the binding of DHT to its receptor. The topical synergistic effect of 5 alpha-reductase (5 alpha RI) and androgen receptor inhibitors (ARI) was determined by measurement of the sebaceous gland size (SGS) of the ventral ear skin of the intact, sexually mature male Syrian hamsters. Progesterone (P), a 5 alpha RI, and spironolactone (SL), an ARI, produced a dose responsive decrease in SGS at topical concentrations of 0.01% to 5.0%. At concentrations of 1, 3, and 5%, P and SL combinations produced neither an additive nor synergistic inhibition of SGS. At very low concentrations of up to 0.10%, neither P nor SL alone produced any effect on SGS. When combinations of these two steroids were applied at low concentrations, SGS decreased unilaterally to approximately 50%. This synergy occurred best at a P:SL ratio of 1:2. The lower effective concentrations of P may be explained by its greater percutaneous absorption. Synergy was also demonstrated at low concentrations with other antiandrogens: cyproterone acetate, canrenone, hydroxyflutamide, and N-N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane- 17 beta-carboxamide. The use of anti-androgen combinations at low concentrations is of value because of the decreased risk of systemic side effects while maintaining potent topical efficacy
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