What Is Deca Durabolin?

Nandrolone Decanoate

Nandrolone Decanoate, also known as ‘Deca Durabolin’ and more commonly known as ‘Deca’, is a medium to slow-acting ester of the steroid nandrolone. It was designed to release steadily into the bloodstream once injected into the muscle.

Deca is usually stacked and ran alongside Sustanon, testosterone cyp or test e. The half-life of nandrolone decanoate is eight days making it a perfect partner to run alongside testosterone. 

Many users do also run deca as a standalone cycle and have reported considerable gains in strength and mass. Deca is often injected twice a week to keep steady hormone levels.

Deca, much like testosterone, is one of the few steroids which have been used by athletes and bodybuilders since the 1960s. Often referred to as the ‘bread and butter’ of bodybuilding,

Testosterone and deca cycles provide huge jumps in mass and strength throughout a cycle.

New users can often expect to see significant gains in muscle mass and strength on cycle. For more experienced users the effects can be less exaggerated, however, still substantial. 

Nandrolone Decanoate makes a fantastic base for a bulking cycle. It also provides much noticeable relief to joints making it much more favourable to strength athletes, also securing its position as a great bulking steroid due to being used at a time when people are eating increased calories and lifting heavier weights. 

Nandrolone is very similar to testosterone in its chemical structure except that nandrolone has a missing atom at the 19th position. It has a more substantial anabolic rating than testosterone but also a lower androgenic rating. 

Androgenic Rating: 37

Anabolic Rating: 125

nandrolone decanoate
Genesis Deca


Deca can be purchased in vials of 200mg. Depending on the country of origin, you can also find it in 50mg/ml and 250mg/ml dissolved in a carrier oil. 

Deca is typically run at doses of 200 – 400mg, so it is more common to find 200mg/ml vials.

Nandrolone Decanoate Price

Prices for nandrolone decanoate can vary depending on where you purchase it. It is available as a pharmacy grade product.

An average price range for purchasing from an underground lab can be from £25 per 10ml vial up to £40.

Nandrolone Decanoate Cycles

For many athletes, bodybuilders and strength athletes deca is the number one choice for adding chunks of muscle and strength in the offseason or for competition.

When running a cycle 200mg – 300mg per week is recommended and will increase muscle mass and strength. 

Deca is only used as a bulking compound, and it is very, very rare to see it used pre-competition, for bodybuilders. It is also unusual to see deca being run as a standalone steroid.

Deca can be run alongside other compounds to increase gains in mass and strength even further. In the off-season, many competitors will use deca alongside Dbol and Sustanon.

Beginner Test and Deca Cycle

Weeks 1 – 12

  • Monday – 250mg test 100mg deca
  • Thursday – 250mg test 100mg deca
  • AI (Aromatise inhibitor)
  • Weeks 12 – 14
  • PCT

More experienced Test and Deca Cycle

Weeks 1 – 12

  • Monday – 375mg test 150mg deca
  • Thursday – 375mg test 150mg deca
  • AI (Aromatise inhibitor)
  • Weeks 1 – 12.
  • PCT

Advanced Test and Deca Cycle

Weeks 1 – 12

  • Monday – 500mg test 250mg deca
  • Thursday – 500mg test 250mg deca
  • AI (Aromatise inhibitor)
  • Weeks 12 – 14
  • PCT

How To Inject Deca

For a step by step guide on how to safely inject deca, please see this article ‘How to inject steroids safely’.

nandrolone decanoate
British Dragon Nandrolone Decanoate

What Are The Side Effects of Deca Durabolin?

Any drug can have side effects and steroids are no different. Side effects of Nandrolone can come in various forms and are usually more prevalent for people who run continued length cycles or use more substantial doses.

Side effects from steroids can affect the cardiovascular system, estrogenic and androgenic. When using anabolic/androgenic steroids, it is essential to understand the risks associated with the use and also how to minimise the chances of them occurring. 

It is important to note that not everyone will experience side effects from steroids. It is essential to know and understand the risk associated with them, though. 

We can break down the side effects of steroids into the following subjects;

  • Estrogenic side effects
  • Androgenic side effects
  • Cardiovascular side effects
  • Hepatoxicity
  • Natural testosterone shutdown

Androgenic Side Effects Of Deca

With a low androgenic rating, most people assume that androgenic side effects would be close to nil while running deca. However, this isn’t entirely true. 

Many athletes running deca report breakouts of acne, especially on the back, oily skin and increased growth in body and facial hair. There is also the possibility of progesterone increasing causing gynecomastia and more. 

Nandrolone is also notorious for reducing libido in men. Many users report softer erections or the inability to climax while running a 19-nor compound.

Estrogenic Side Effects

Technically speaking, nandrolone converts to estrogen at a much lower rate than testosterone. However, users running larger doses or running multiple compounds have and continue to have to control and manage estrogen.

Estrogen is the primary sex hormone for females. This can cause an abundance of unwanted side-effects in men.

Estrogenic side effects of nandrolone decanoate can include water retention, an increase in body fat and gynecomastia. Estrogenic side effects can be controlled using compounds such as Nolvadex, Aromasin or anastrozole. 

Deca has also been known to increase progestin levels. The increased progestin in the body can lead to increased fat storage and breast tissue growth in men. These side-effects can occur even if estrogen levels are kept under control.

If you suffer from these effects using compounds such as Cabergoline can help to reduce and stop them.

Cardiovascular Side Effects

Steroids can increase muscle mass as well as causing the user to hold more ‘water weight’. This additional weight is often built up in short spaces of time and can result in added strain on the heart and organs.

Nandrolone decanoate can affect cholesterol levels by reducing HDL or ‘good cholesterol’ and increasing LDL ‘bad cholesterol’. This shift, over time, can result in the hardening of the artery walls and higher levels of fat in the bloodstream leading to strokes, or heart attacks if left unchecked and untreated.

The increase in muscle mass and water weight can also lead to higher blood pressure which can again, affect the heart and kidneys.

Running deca can also affect your blood ‘thickness’. 

It is highly recommended for anyone thinking about running a cycle, or who has already run one to get blood tests done at least every three months. This not only allows you to know what is going in regards to your health but also make any necessary adjustments before starting.

Deca effects on the liver

Nandrolone decanoate is not reported to have any direct effects on the liver for healthy individuals.

Natural Testosterone Shutdown 

Using any form of steroid will lead to the suppression of your natural test production. This often returns after the cycle has stopped. In rare cases or when users have been on cycle for prolonged periods, people can be shut down permanently or suffer from low testosterone levels for many years.

PCT ancillaries such as HCG can help keep the testes stimulated and producing natural testosterone. It is usually taken as a part of a PCT (post cycle therapy).

Benefits of Nandrolone Decanoate

  • Huge mass and strength builder
  • Readily available in pharma grade and UGL
  • Great for aching joints
  • Perfect for bulking up

FAQs for Deca Durabolin

What does Deca Durabolin do for you?

Deca is a very capable mass and strength builder. One of the worlds most popular steroids which was a favourite of many old school bodybuilders and is still a favourite among many world-leading athletes today.

Users can expect significant gains in all out size and strength when running deca alongside testosterone.

What are the side effects of Deca?

Deca can have side effects which we can break down into androgenic, anabolic, hepatoxic, and cardiovascular. Adding weight and injecting hormones into your body will, of course, come with the risk of side effects.

Most side effects can be managed and controlled with the use of aromatize inhibitors and SERMS(Selective estrogen receptor modulators). These tablets reduce the aromatisation of PEDs into estrogen which is one of the biggest factors of side effects.

Does Deca Durabolin build muscle?

Yes! Oh, boy does it! Deca is fantastic at building muscle. Although, it does add a fair amount of water weight too. Deca is a real calorie monster so make sure to feed it nutrient-dense food and hit the weights hard. You will definitely gain muscle on deca.

How quickly does Deca work?

Deca usually takes around 4 – 6 weeks to reach optimum blood levels. Once you reach that zone you will quickly notice strength and size increase quite quickly. Most users will notice the bulk of gains will come around weeks 4 – 8.


Nandrolone decanoate is what we would refer to as one of the ‘OG’ steroids. It has been around since the 60s and has proven time and time again that nothing can come close when it comes to building pure mass and strength.

When running a cycle is it essential to keep it fed. More often than not, people do not truly understand how amazing it can actually be when you keep calories high and weighs heavy. It is literally the perfect partner for all-out bulking.

When all is said and done, and the dust is settled, we can guarantee it will be in the bodybuilding/athlete scene for many, many more years to come. 

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