Nandrolone Phenylpropionate (NPP)

Nandrolone Phenylpropionate (NPP), also known by its brand name Durabolin, is a synthetic androgen and anabolic steroid (AAS). It is an ester of the anabolic steroid nandrolone and has been used medically, primarily for treating breast cancer and osteoporosis in women, as well as anemia. It has also been used to treat muscle wasting in conditions like AIDS.

Other Names

Nandrolone Phenylpropionate is also known by the following names:

• Nandrolone phenpropionate

• 19-Nortestosterone phenylpropionate

• Nandrolone hydrocinnamate

Anabolic and Androgenic Ratio

NPP is known for having strong anabolic effects and relatively weak androgenic effects. While an exact, universally agreed-upon number is difficult to pinpoint, it is often cited as having an anabolic to androgenic ratio of approximately 10:1. This is a significant improvement over testosterone, which has a 1:1 ratio. This favorable ratio is one of the reasons it was considered suitable for women and children in a medical context, as it has a lower risk of causing masculinizing side effects.

Side Effects and Benefits

Benefits

• Anabolic Effects: It promotes muscle growth and tissue repair.

• Increased Bone Density: It can increase bone density, making it beneficial for conditions like osteoporosis.

• Increased Red Blood Cell Production: It stimulates the production of red blood cells, which can help in the treatment of anemia.

• Joint and Connective Tissue Support: Users often report relief from joint pain, which is thought to be due to its ability to increase collagen synthesis and water retention in connective tissues.

Side Effects

• Androgenic Side Effects: Despite its low androgenic ratio, it can still cause androgenic side effects, especially at higher doses. These can include:

  • Acne

  • Oily skin

  • Increased body/facial hair growth (hirsutism)

  • Male pattern baldness (in genetically predisposed individuals)

  • Voice deepening

  • Clitoral enlargement (in women)

• Cardiovascular Side Effects: Like other AAS, NPP can negatively impact cholesterol levels, decreasing HDL ("good") cholesterol and increasing LDL ("bad") cholesterol, which may increase the risk of cardiovascular disease.

• Progestogenic Side Effects: NPP has moderate progestogenic activity. This can lead to side effects similar to those caused by high estrogen levels, such as:

  • Gynecomastia (development of male breast tissue)

  • Water retention and bloating

• Endocrine and Hormonal Suppression: NPP can suppress the body's natural production of testosterone and other hormones. This suppression can lead to:

  • Testicular atrophy

  • Reduced sperm count and fertility

  • Sexual dysfunction

Progestogenic and Prolactin Effects

NPP is a 19-nor compound, meaning it lacks a carbon atom at the 19th position. This structural modification gives it progestogenic activity. It can directly activate progesterone receptors in the body. The progestogenic activity of NPP can lead to an increase in prolactin, a hormone that can cause gynecomastia (often referred to as "deca-dick" in bodybuilding circles), and can suppress the hypothalamic-pituitary-gonadal axis (HPGA), further contributing to a decline in natural testosterone production.

Dosage and Frequency

Nandrolone Phenylpropionate is administered via intramuscular injection. Due to its relatively short half-life compared to its decanoate counterpart, it requires more frequent injections. Medically, dosages for conditions like anemia or breast cancer in women ranged from 50 to 100 mg per week. For performance-enhancing purposes, dosages and frequency can vary widely. However, it's important to note that non-medical use is illegal in many countries and poses significant health risks.

Half-Life and Detection Time

• Half-life: The elimination half-life of NPP is approximately 2.7 days. This is why it is typically injected every few days, often 2-3 times per week, to maintain stable blood levels.

• Detection Time: The detection time for nandrolone metabolites in urine is very long. Even a single dose of nandrolone can be detectable for months, and in some cases, up to a year or longer. This is a major reason why it is a highly scrutinized substance in professional sports and anti-doping programs.