===================== CLICK TO VISIT OUR ONLINE SHOP: https://t.co/0pdMsW5ou0 ===================== Gastrointestinal effects occurring during nandrolone (the active ingredient contained in Deca-Durabolin) therapy have included nausea, vomiting, and diarrhea. References. 1. Kuipers H, Wijnen JA, Hartgens F, Willems SM "Influence of anabolic steroids on body composition, blood pressure, lipid profile and liver functions in body builders." Int J ... Deca Durabolin Administration: Deca Durabolin is a very slow acting steroid that does not have to be injected all that frequently. In most therapeutic treatment plans the compound is only administered once every 2-4 weeks with every 3-4 weeks being far more common.