World wide "Deca" is one of the most widely used anabolic steroids. Its popularity is due to the simple fact that it exhibits many very favorable properties. Structurally nandrolone is very similar to testosterone, although it lacks a carbon atom at the 19th position (hence its other name 19-nortestosterone).

The resulting structure is a steroid that exhibits much weaker androgenic properties than testosterone. Of primary interest is the fact that nandrolone will not break down to a more potent metabolite in androgen target tissues.

You may remember this is a significant problem with testosterone. Although nandrolone does undergo reduction via the same (5-alpha reductase) enzyme that produces DHT from testosterone, the result in this case is dihydronandrolone.

This metabolite is weaker than the parent nandroloness, and is far less likely to cause unwanted androgenic side effects. Strong occurrences of oily skin, acne, body/facial hair growth and hair loss occur very rarely. It is however possible for androgenic activity to become apparent with this as any steroid, but with nandrolone higher than normal doses are usually responsible.