The major drawback for competitive purposes is that in many cases nandrolone metabolites will be detectable in a drug screen for up to a year (or more) after use. This is clearly due to the form of administration. Esterified compounds have a high affinity to stay stored in fatty tissues. While we can accurately estimate the time frame it will take for a given dose to enter circulation from an injection site, we cannot know for sure that 100% of the steroid will have been metabolized at any given point. Small amounts may indeed be stubborn in leaving fatty tissue, particularly after heavy, longer-term use. Some quantity of nandrolone decanoate may therefore be left to sporadically enter into the blood stream many months after use. This process may be further aggravated when dieting for a show, a time when body fat stores are being actively depleted (possibly freeing more steroid). This has no doubt been the cause for many unexpected positives on a drug screen. The fact that nandrolone has been isolated as the "hands-off" injectable for the drug tested athlete is most likely due to its popularity (and therefore common appearance on drug screens). The same risk would of course hold true for other long chain esterified injectables such as Equipoise, and Primobolan.