Nandrolone Phenylpropionate (NPP) applications and side effects


Nandrolone phenylpropionate:

Androgen index 37

Anabolic index 125

Maternal hormone Testosterone

Chemical name 19-norandrost-4-en-3-one-17beta-ol, 17beta-hydroxy-estr-4-en-3-one

Estrogenic activity Low

Progesterone activity Moderate


Oral: 0.3-2.9% (pig)

Intramuscular: High

Metabolic pathway Metabolism blood (hydrolysis), liver (reduction)


  • Nandrolone
  • 5α-Dihydronandrolone
  • 19-Norandrosterone
  • 19-Noretiocholanolone
  • Conjugates

Half-life 2.7 days

Duration 5-7 days

Route of excretion Urine


Introduction to Norethindrone Phenylpropionate:

Durabolin is the trade name for nandrolone phenylpropionate, which is often confused with Deca-Durabolin Deca-Durabolin, both of which are nandrolones and can also be called Deca. At the same time, Durabolin is nandrolone decanoate and Durabolin is nandrolone phenylpropionate, both of which have different ester chains. The properties of this drug are essentially the same as those of Deca-Durabolin®, except for the difference in the ester chain, which uses decanoic acid esters. The main difference between these two formulations is the rate at which Nandrolone is released into the bloodstream. While nandrolone decanoate releases Nandrolone that lasts about three weeks in the injection area, nandrolone phenylpropionate does so for only one week. In clinical situations, Deca-Durabolin can be injected every 2 or 3 weeks, while Nandrolone Phenylpropionate Durabolin is usually injected every few days to once a week. Otherwise, the two drugs are virtually interchangeable.

History of Nandrolone Phenylpropionate:

Nandrolone phenylpropionate was first developed and marketed in 1957. Soon after, it became a prescription drug, sold by the international pharmaceutical giant Organon (now Merck/MSD) under the brand name Durabolin. When first introduced to the United States, uses for nandrolone phenylpropionate included preoperative and postoperative lean weight retention, osteoporosis, advanced breast cancer, weight loss due to rehabilitation or disease, geriatric states (generalized weakness and frailty), burns, severe trauma, ulcers, adjunctive treatment of certain forms of anemia, and selective cases of growth retardation in children. In the 1970s, the FDA began to modify the designated uses of this drug, and its scope of application was soon significantly narrowed. Looking ahead, the drug was primarily used to treat advanced metastatic breast cancer, and Durabolin was the focus of Organon’s marketing efforts just under a decade after its release. Another version, dextran Durabolin, was introduced in the 1960s, and nandrolone phenylpropionate, while still available, began to take a backseat. However, Organon did not completely abandon nandrolone phenylpropionate at the time because of slightly different therapeutic uses in certain countries, and thus continued to dominate the market for some time. As the anabolic steroid market continued to grow in size throughout the 1970s and 1980s, nandrolone decanoate attracted the most attention from other drug manufacturers, and nandrolone phenylpropionate became progressively less competitive in the market.

Nandrolone Phenylpropionate Common Specifications:

Nandrolone phenylpropionate is commonly available in 25 mg/mL or 50 mg/mL and is currently marketed as a 100-200 mg/ml oil formulation.

Nandrolone phenylpropionate is a modified form of Nandrolone in which the phenylpropionate ester is linked to the 17-beta hydroxyl group. Esterified steroids are less polar than free steroids and are absorbed more slowly from the injection area. Once in the bloodstream, the ester is removed to give free (active) Nandrolone. Esterified steroids are designed to extend the window of therapeutic effect after administration, and the frequency of injection of esterified steroids can be less closely compared to the injection of free (unesterified) steroids. Nandrolone phenylpropionate is released, reaches peak serum levels within 24-48 hours after a deep intramuscular injection, and declines to near baseline levels within a week.

Nandrolone phenylpropionate has many positive characteristics similar to those of many anabolic steroids. However, this compound also has functional characteristics that go well beyond those of some steroids. Positive functional characteristics of nandrolone phenylpropionate include:

Increased IGF-1 Production: Insulin-like growth factor-1 (IGF-1) is a potent anabolic hormone that is also essential to our body’s ability to recover. It is a hormone that affects almost all cells in the body.

Suppression of glucocorticoids: These hormones are known as stress hormones (cortisol) and are essential to our health and well-being. However, glucocorticoids can also promote muscle loss and fat gain when they become dominant. Strenuous activity can lead to an increase in stress hormones. Hormones like Nandrolone can reduce the production of stress hormones.

Increased Nitrogen Retention: All muscle tissue is composed of 16% nitrogen. If retention decreases, we fall into a catabolic state. The more we retain, the more anabolic we are left with.

Increased protein synthesis: This is the rate at which cells build proteins, which are the building blocks of muscle tissue.

Increased red blood cell count: Red blood cells carry oxygen into and through the bloodstream. Higher efficiency improves muscle endurance and recovery.

Increased collagen synthesis and bone mineral content: This refers to the strength of bones and cartilage and the ability to strengthen and provide healing relief. This will apply to the joints more than anywhere else.

Bodybuilder showing his biceps muscles, personal fitness trainer. Strong man flexing his muscles

Nandrolone Phenylpropionate Use:

For the off-season athlete, during the off-season cycle, nandrolone phenylpropionate is one of the best steroids that he can choose to build muscle and gain weight. This is one of the best growth steroids, and most bodybuilders schedule him in their off-season program. Although this is a very fast nandrolone ester chain up in the nandrolone family, the growth will not happen quickly, but it will be steady, even, and significant. This is assuming you eat enough. For muscle growth, no steroid in the world can change this truth. However, if you go about each step carefully and correctly, you will get more of a perfect gain from a steroid like a nandrolone phenylpropionate. Nandrolone phenylpropionate can also be used in preparation for a race or within a fat loss cycle. However, it is usually considered unfavorable to be scheduled in preparation for a race and within a fat loss cycle. But nandrolone phenylpropionate will protect lean muscle mass better than many steroids can. When we diet, we have to burn more calories than we take in. This is the only way to lose body fat. Unfortunately, this can put our muscle tissue at risk. Often fat loss is more or less accompanied by a loss of some of our muscle, and a successful and perfect diet plan can also limit this loss, and Nandrolone can provide this protection. Many athletes use low doses of nandrolone phenylpropionate to help recover and reduce joint stress. These are not narcotics like painkillers but are real relief.

Nandrolone phenylpropionate side effects (estrogen):

Nandrolone has a low propensity for estrogen conversion, estimated to be only about 20% of testosterone. This is because, although the liver converts Nandrolone to estrogen, there are far fewer pathways for Nandrolone to convert to estrogen than steroids that would aromatize, which have more active sites in adipose tissue. Therefore, this drug has much lower estrogen-related side effects compared to testosterone. However, elevated estrogen levels can still be noted at higher doses and may cause side effects such as water storage, increased body fat, and gynecomastia. If they occur, anti-estrogen drugs such as clomiphene or tamoxifen may be needed to prevent estrogenic side effects. Alternatively, aromatase inhibitors such as anastrozole (Arimidex) may be used, which are more effective in controlling estrogen by blocking estrogen synthesis. However, compared to the anti-estrogen drugs mentioned above, aromatase inhibitors can be quite expensive and may also harm blood lipids.

Notably, Nandrolone has some activity as a progestin in vivo. While progesterone is a C-19 steroid, many C-19 anabolic steroids also show some affinity for the progesterone receptor. Side effects associated with progesterone are similar to those of estrogen, including inhibition of the HPTA hypothalamus and lipid storage. Progesterone also enhances the stimulatory effect of estrogen on breast tissue growth. There is also a strong synergistic effect between these two hormones, so gynecomastia may even be catalyzed by progesterone synergy in the absence of excessive estrogen levels. Anti-estrogen use is often sufficient to reduce gynecomastia caused by Nandrolone.

Nandrolone phenylpropionate side effects (androgenic):

Nandrolone phenylpropionate may have androgenic side effects, but they are not extremely likely in men. Hair loss in men prone to male pattern baldness is possible, as is acne in sensitive men. However, when it comes to this effect, this is one of the most tolerated steroids among all people. Genetic predisposition will play the biggest role.

In addition, the relative androgenicity of Nandrolone is reduced by its reduction to DHN in androgen-responsive target tissues such as the skin, scalp, and prostate. 5-alpha reductase is responsible for the metabolism of this Nandrolone. Concomitant use of 5-alpha reductase inhibitors such as finasteride or dutasteride interferes with site-specific reduction of Nandrolone’s effects and, in turn, greatly increases the tendency for Nandrolone to produce androgenic side effects.

Nandrolone phenylpropionate side effects (hepatotoxicity):

Nandrolone phenylpropionate is not a c-17 alpha alkylated steroid, no hepatotoxicity was found in clinical testing, and it is unlikely that nandrolone phenylpropionate has hepatotoxicity.

Nandrolone phenylpropionate side effects (cardiovascular):

Anabolic/androgenic steroids can have harmful effects on serum cholesterol. This includes a tendency to lower HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift HDL to LDL balance, thereby increasing the risk of atherosclerosis. The effect of anabolic/androgenic steroids on lipids depends on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Studies using 600 mg of nandrolone decanoate weekly for ten weeks showed a 26% reduction in HDL cholesterol levels. This inhibition was slightly higher than that reported with the equivalent dose of testosterone enanthate and is consistent with earlier studies showing a slightly stronger negative effect on HDL/LDL ratio with nandrolone decanoate compared to nandrolone decanoate. However, the effect of Nandrolone on serum lipids remains significantly lower than that of c-17α alkylating drugs.

Nandrolone phenylpropionate side effects (testosterone suppression):

All anabolic/androgenic steroids inhibit endogenous testosterone production when taken at doses sufficient to promote muscle gain. Studies using 100 mg nandrolone phenylpropionate have demonstrated rapid suppression of serum testosterone after a single injection. On day three after administration, testosterone levels decreased to approximately 30% of initial levels and remained suppressed for approximately 13 days. Regular use is expected to significantly prolong the endogenous hormone recovery window.

Dosage of Nandrolone Phenylpropionate:

Early prescribing guidelines recommend a dose of 25-50 mg per week for 12 weeks for general therapeutic pathway anabolic effects. The usual dose for muscle growth or athletic performance enhancement is 200-400 mg per week in 8 to 12-week cycles. Note that due to the rapid response nature of phenylpropionate, the weekly dose is usually broken down into two separate applications evenly spaced.

On Female Use

Early prescribing guidelines recommend doses of 25-50 mg per week for 12 weeks for general anabolic effects. The usual dose of 50 mg per week for muscle growth or athletic performance enhancement (administered as a weekly injection) is the most common, lasting 4 to 6 weeks of cycling. Higher doses or longer durations of use are discouraged due to potential androgenic side effects. Although only mildly androgenic, women occasionally experience symptoms of masculinization when using this compound. If masculinizing side effects become a problem, nandrolone phenylpropionate should be discontinued immediately.

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