Known more commonly as “Deca,” deca durabolin is an injectable steroid with a long and relatively positive history. It has been used to effectively treat HIV+ and AIDS and is known as a phenomenal steroid for building muscle mass. Deca Durabolin is often used in combination with other steroids such as Tren — this is made possible by the use of Dostinex which allows these two anabolics to be used together [even at the same time] without worries about hormones such as testosterone getting thrown way off balance.
Nandrolone Decanoate, aka “Deca Durabolin” is the brand name for the Organon produced product, first made available in the early 80’s. “Deca” is therefore just a brand name, although currently, the black market slang is to call any Nandrolone product with the Decanoate ester “Deca.” It’s a progestin, made by removing the carbon atom at the 19th position of the steran nucleus.
As a result, although it’s a progestin, Nandrolone doesn’t produce many purely estrogenic side effects, so it has been a favorite in many cutting and bulking cycles over the last couple of decades. Deca has a very low rate of aromatization (metabolic conversion to estrogen via the aromatase enzyme), equal to 20% the rate of Testosterone.
One of the really interesting properties about Deca is its ability to improve collagen synthesis  and bone mineral content , which is a huge help to athletes with connective tissue problems or other joint issues. Also, possibly due to its being a progestin, it may have beneficial effects on the immune mediated anti-inflammatory process, thereby soothing joints.
Deca is one of the few steroids which has been used successfully in AIDS patients to stimulate weight gain , and this effect has been experienced in many athletes and bodybuilders as well. Deca is both a very nice steroid for cutting and bulking cycles, although the shorter estered version of it, Nandrolone Phenylpropionate, is a more popular version to use for cutting cycles.
This brings up the fact that Deca Durabolin has a very long active life, and therefore, injections are typically spaced apart by a week, regardless of total dose. Also owing to this fact, Deca Durabolin is typically used for a period of no less than ten weeks, and usually for 12 weeks.
Both supply as well as demand for Deca Durabolin is high, and this makes it a relatively inexpensive product when buying from an underground lab, but not when purchasing from a human grade supplier or pharmacy. Up to $10 per amp is common, while $75-100 is the average price for a ten milliliter bottle, dosed at 200-300 mgs/ml.