Due to its chemical structure nandrolone is weakly exposed to aromatase (only 20% of the aromatizing activity of testosterone). However, not estrogenic effects are its main concern: nandrolone has a potent progestogenic activity (20% of progesterone). While binding to progestogenic pituitary receptors nandrolone causes increased production of prolactin, which in effect is very similar to estrogen: its effect presents in reducing testosterone production, increasing fat mass and in gynecomastia. To prevent these side effects prolactin inhibitors (cabergoline) shall always be at hand when on nandrolones cycle.
Nandrolone decanoate (Deca-Durabolin) was injected intramuscularly into healthy volunteers. One group of females received one injection of 100 mg and three groups of males received one injection of 200 mg, two repeat injections of 100 mg or four repeat injections of 50 mg respectively. The serum levels of nandrolone (19-nortestosterone) were determined by radioimmunoassay and used to estimate pharmacokinetic parameters. The following pharmacokinetic parameters were found: a mean half-life of 6 days for the release of the ester from the muscular injection depot into the general circulation; a mean half-life of h for the combined processes of hydrolysis of nandrolone decanoate and of distribution and elimination of nandrolone; a mean nandrolone serum clearance of 1 X h-1 X kg-1. The half-life of hydrolysis of nandrolone decanoate in serum was of the order of one hour or less. The data are consistent with linear kinetics.
Decanoic acid acts as a non-competitive AMPA receptor antagonist at therapeutically relevant concentrations, in a voltage- and subunit-dependent manner, and this is sufficient to explain its antiseizure effects.  This direct inhibition of excitatory neurotransmission by decanoic acid in the brain contributes to the anticonvulsant effect of the MCT ketogenic diet .  Decanoic acid and the AMPAr antagonist drug perampanel act at separate sites on the AMPA receptor, and so it is possible that they have a cooperative effect at the AMPA receptor, suggesting that perampanel and the ketogenic diet could be synergistic.