✔ Evidence-Based. Scientifically Reviewed by Michael Sharpe, MSc and Dr. Michael Tamber, MD.
Nandrolone decanoate, often known as Deca-Durabolin, is an androgen and anabolic steroid (AAS) that is mainly used to treat anaemias and wasting syndromes, as well as osteoporosis in postmenopausal women. (1)
It's illegal unless prescribed in most countries and is banned for use in WADA governed sports. (1)
Nandrolone typically comes attached to the decanoate ester giving it an elimination half-life of around 6-12 days, however it is also commonly attached to the phenylpropionate ester with a half-life of about 2.7 days. (2, 3) This article focuses specifically on nandrolone decanoate.
Table of Contents:
Medical Uses
Nandrolone decanoate is licensed in the United States for the treatment of anaemia caused by chronic renal disease, and it is approved in the United Kingdom for the treatment of osteoporosis in postmenopausal women. (6)
It is specifically licenced in Australia for the treatment of kidney failure, chronic renal disease, anaemia of kidney failure, aplastic anaemia, osteoporosis (in women who cannot take oestrogen), inoperable breast cancer, and patients on long-term corticosteroid therapy.
It is licenced in New Zealand for osteoporosis, inoperable breast cancer, and as an adjuvant to treatment for illnesses with a negative nitrogen balance. Off-label usage of the medication is common in HIV/AIDS patients and other wasting diseases to retain lean mass. (5, 6)
Previously, nandrolone decanoate was indicated and used for a variety of other conditions and situations, such as pre- and postoperative use for increasing lean mass, treating weight loss due to convalescence or disease, geriatric states (e.g., general weakness, fatigue), burns, severe trauma, ulcers, and selected cases of growth failure in children. (6)
Beginning in the 1970s, the indications for nandrolone decanoate were refined, and the drug's usage grew more selective and limited. Its usage in medicine is declining and becoming restricted, with sales having been halted in several countries. (6)
Nandrolone esters may be used to treat androgen deficiency in males as a kind of androgen replacement therapy. However, they have not been widely used for this purpose, and have instead been primarily used as anabolic agents. (24, 25, 26)
Nandrolone decanoate has been extensively used in postmenopausal women as a form of androgen replacement, for example, to maintain or improve bone mineral density and reduce the risk of osteoporosis. (27, 28)
It is one of only three androgens approved for postmenopausal androgen replacement, the others being testosterone (and its various esters) and methyltestosterone. (29)
Nandrolone esters have recently been proposed as a more widely used treatment for androgen deficiency in men due to favourable properties such as their high anabolic to androgenic effect and thus lower or negligible risk of scalp hair loss, prostate enlargement, and prostate cancer compared to testosterone. (24)
Nandrolone esters and similar substances such as trestolone and dimethandrolone undecanoate have also been investigated as androgen replacement agents in male contraceptive regimens under research. (24)
Non-Medical Uses
Competitive athletes, bodybuilders, and powerlifters utilise nandrolone decanoate to enhance their physique and performance.
Users take it in a variety of ways, often in 8-12 week cycles with some type of testosterone as a baseline.
Despite this, nandrolone decanoate is one of the most popular injectable AAS in the world, and nandrolone esters are widely utilised by bodybuilders and athletes. (6)
This is owing, in part, to nandrolone's strong anabolic to androgenic impact ratio and its low susceptibility for androgenic and estrogenic side effects. (6)
How It Works
Nandrolone decanoate is a nandrolone ester, often known as a nandrolone prodrug. As such, it is an androgen and anabolic steroid, acting as an agonist of the AR, which is the biological target of androgens like testosterone and DHT. (9, 10)
Relative to testosterone, nandrolone decanoate has increased anabolic effects and reduced androgenic effects, with respective potency ratios of 3.29-4.92 and 0.31-0.41 (about an 11:1 ratio of anabolic to androgenic effects). (9, 10, 11)
This is defined on a rodent model in which change in the weights of bulbocavernosus/levator ani muscles in rats (anabolic activity) and the ventral prostate or seminal vesicles in rats (androgenic activity) are compared with testosterone and then used to create a ratio. (10)
Together with oxandrolone (which has a ratio of roughly 10:1), nandrolone is regarded to have the greatest anabolic to androgenic activity ratio of any AAS. As a result, it is regarded as one of the most suitable AAS for medical usage in women and children. (6, 12)
Androgenic effects such as virilization are rare with nandrolone decanoate at prescribed dosages, although they may occur, particularly at larger doses or with prolonged usage. (6)
The low androgenicity of nandrolone decanoate is thought to be due to inactivation in tissues high in 5α-redcutase, such as the skin, hair follicles, prostate gland, liver, and brain.
Other AAS like testosterone are potentiated via transformation by 5α-reductase into more potent AR agonists like DHT in specific tissues, nandrolone is instead transformed by 5α-reductase into the low-affinity AR ligand 5α-dihydronandrolone (DHN). (6, 7, 10)
This is considered to result in a substantially decreased incidence and quantity of facial/body hair growth, scalp hair loss, and perhaps prostate concerns such as prostate enlargement and prostate cancer development when compared to testosterone. (6, 11, 12)
Nandrolone decanoate has modest estrogenic action (through its metabolite estradiol) but moderate progestogenic activity in addition to its strong anabolic to androgenic activity. This may lead to adverse effects including fluid retention and gynocomastia. (6)
Nandrolone decanoate, like other AAS, exhibits antigonadotropic properties. Following 6 weeks of therapy, it was discovered to reduce testosterone levels by 57% at a dose of 100 mg per week and 70% at a dosage of 300 mg per week in males. (6)
The androgenic and progestognenic properties of nandrolone decanoate may contribute to its antigonadotropic efficacy. The estrogenic action of nandrolone decanoate contributes far less to its antigonadotropic activity. (6)
Pharmacokinetics
Nandrolone decanoate is stored unmodified and slowly absorbed into the body after intramuscular injection in oil, which leads in the establishment of a long-lasting depot in the muscle. Once in the bloodstream, it is transformed into nandrolone, the active version of the hormone. (5, 7)
A significant increase in nandrolone levels occurs 24 to 48 hours after an intramuscular injection of nandrolone decanoate, followed by a gradual return to baseline levels within 2-3 weeks. (6)
The bioavailability of nandrolone decanoate with intramuscular injection ranges from 53% to 73% and varies depending on the place of injection, with the gluteal muscle having the maximum bioavailability. (4)
Nandrolone, like testosterone, is strongly protein-bound and is found in the blood in both bound and free fractions. It has a relatively low affinity for sex hormone-binding globulin (SHBG), about 5% that of testosterone and 1% that of DHT. (7)
Nandrolone decanoate is quickly hydrolyzed into nandrolone in the blood by esterases, with a terminal half-life of one hour or less. It seems that it is not hydrolyzed in muscle or fat. (5, 7, 14)
Nandrolone metabolism happens in the liver and is very similar to testosterone metabolism, including the following: (2, 7)
Reduction by 5α-reductase and 5β-reductase
Dehydrogenation by 3α-hydroxysteroid dehydrogenase, 3β-hydroxysteroid dehydrogenase, and 17β-hydroxysteroid dehydrogenase
Conjugation
5α-dihydronandrolone
19-norandrosterone
19-noretiocholanolone
19-norandrosterone is the major metabolite of nandrolone. Other metabolites include 19-norandrostenedione, 19-norandrostanediols, 19-norepiandrosterone, and conjugates. (7)
Nandrolone aromatizes into estradiol in the same way as testosterone does, but at a rate that is only around 20% of testosterone's or potentially even less; one study reported almost no aromatization of nandrolone in males. (6, 7, 15, 16)
The elimination half-life of nandrolone decanoate injected intramuscularly ranges between 6 and 12 days, as shown by the graphs below. (5, 6)
Graph on the left: The graph on the left above shows nandrolone levels after a single 100 mg intramuscular injection of nandrolone decanoate or nandrolone phenylpropionate in 4 ml or 1 ml arachis oil solution into gluteal or deltoid muscle in men. (20)
Studies on the duration of nandrolone decanoate based on its anabolic effects, such as nitrogen balance, discovered that a single 50 mg to 100 mg intramuscular injection had a duration of roughly 18 to 25 days. (17, 18)
Graph on the left: The graph on the left above shows nandrolone levels with a single 50 mg intramuscular injection of nandrolone decanoate or nandrolone hexyloxyphenylpropionate in oil solution in men. (23)
Graph on the right: The graph on the right above shows nandrolone levels after a single 50 mg, 100 mg, or 150 mg intramuscular injection of nandrolone decanoate in oil solution in men. (4)
The combined process of hydrolysis into nandrolone and elimination of nandrolone has a blood half-life of 4.3 hours. Nandrolone and its metabolites are mostly eliminated in the urine as conjugates. (5, 7)
Although nandrolone decanoate is often injected intramuscularly, it has been shown to be as effective when administered subcutaneously. (19)
Subcutaneous nandrolone decanoate pharmacokinetics are quite similar to intramuscular nandrolone decanoate pharmacokinetics. Subcutaneous injection, on the other hand, is said to be simpler, more convenient, and less painful than intramuscular injection. (19)
Furthermore, evidence reveals that the majority of intramuscular injections in practise are actually subcutaneous injections. (19)
Androgenic vs Anabolic Ratio
AAS have two types of effects: anabolic, which means they help cells grow, and androgenic, which means they affect the development and maintenance of masculine traits.
As a baseline, testosterone and 5α-dihydrotestosterone (DHT) have a 1:1 ratio of androgenic and anabolic effects.
Nandrolone has an androgenic to anabolic ratio of 1:3 - 1:16. This means it has 3-16 times higher anabolic effects than androgenic effects. (2)
Receptor Affinities
Below is a table showing the relative affinities of nandrolone, testosterone, and estrogen on various receptors. (2)
Hormone | PR | AR | ER | GR | MR | SHBG | CBG |
Nandrolone | 20 | 154-155 | <0.1 | 0.5 | 1.6 | 1-16 | 0.1 |
Testosterone | 1-1.2 | 100 | <0.1 | 0.17 | 0.9 | 19-82 | 3-8 |
Estrogen | 2.6 | 7.9 | 100 | 0.6 | 0.13 | 8.7-12 | <0.1 |
Note: Values in the table above are in percentages (%).
Reference ligands (100%) were as follows:
Progesterone for the progesterone receptor (PR)
Testosterone for the androgen receptor (AR)
Estradiol for the oestrogen receptor (ER)
Dexamethasone for the glucocorticoid receptor (GR)
Aldosterone for the mineralocorticoid receptor (MR)
Dihydrotestosterone for sex-hormone-binding-globulin (SHBG)
Cortisol for corticosteroid-binding-globulin (CBG)
Below is a table showing the relative binding affinity of nandrolone and other steroids on rat prostate androgen receptors (rAR) and human androgen receptors (hAR). (2)
Hormone | rAR (%) | hAR (%) |
Metribolone | 100 | 110 |
Nandrolone | 75 | 92 |
Testosterone | 38 | 38 |
5α-Dihydrotestosterone (DHT) | 77 | 100 |
5α-Dihydronandrolone (DHN) | 35 | 50 |
What Does This Mean?
A high-affinity ligand binding has more attractive forces between the ligand and its receptor. A low binding affinity ligand has less attractive forces between the ligand and its receptor. Essentially the higher binding affinity a chemical has, the more effect it will have at the receptor.
Testosterone has a relative binding affinity on the androgen receptor of 100%, while nandrolone has a relative binding affinity of 154-155%. This means that nandrolone is more strongly attracted (about 54-55%) to the androgen receptor. (2)
Nandrolone also a roughly 20-fold higher affinity to the progesterone receptor than testosterone does. It has a similar affinity to the estrogen receptor, while having a much lower affinity to SHBG (1-16 for nandrolone vs 19-82 for testosterone). (2)
It has a higher affinity for the glucocorticoid and mineralocorticoid receptor, while having a lower affinity for corticosteroid-binding-globulin than testosterone. (2)
Adverse Effects
The side effects of nandrolone decanoate are dependent on dosage, duration of treatment, and individual sensitivity.
A number of common, uncommon, and rare side effects have been observed with the medication at recommended dosages. While less common or severe than with many other AAS, the most common side effect of nandrolone decanoate is virilization (masculinisation) in women. (2)
Uncommon side effects of nandrolone decanoate include the following: (2)
Fluid retention
Inhibition of spermatogenesis and testicular atrophy
Erectile dysfunction, increased frequency of penile erections, and increased penis size in pre-pubertal boys
Gynocomastia
Clitoral hypertrophy
Increased pubic hair growth
Oligomenorrhoea
Amenorrhea
Hyperlipidemia and decreased HDL cholesterol
Increased haemoglobin (to abnormal high levels) and hypertension
Nausea
Epididymitis
Bladder irritability and reduced urine flow
Benign prostatic hyperplasia
Priapism
Premature epiphyseal closure (in children)
Acne
Rare side effects include abnormal liver function, jaundice, peliosis hepatis, liver tumours, oily skin, greasy hair, rash, pruritus, exanthema, urticaria at the injection site, and furunculosis. Local injection site reactions may also occur. (2)
Unlike 17α-alkylated AAS such as methyltestosterone, nandrolone decanoate is not associated with liver toxicity. (2)
Another potentially serious adverse effect of nandrolone is its ability to increase left ventricular hypertrophy and cause growth and remodelling of the heart. It does this via a multitude of mechanisms, including the following.
Nandrolone has been shown to increase type I collagen deposition in the myocardium. (30)
Nandrolone has been shown to inhibit ventricular MMP-2, an enzyme that breaks down collagen during tissue remodelling. (31)
The pro-inflammatory cytokines IL-6 and TNF-a have been shown to be increased by nandrolone. Nandrolone has also been demonstrated to reduce the anti-inflammatory cytokine IL-10. (32)
Since Nandrolone increases the activity of ACE, this leads to an increase in ATII. Similarly, nandrolone has been shown to increase ATI receptors, which ATII binds to. These effects increase blood pressure. (32)
Nandrolone has been shown to decrease the amount of Cardiac Troponin I (cTnI) in cardiac myocytes. With a decrease in cTnI, contractility of cardiac muscle decreases. (32)
Nandrolone, as shown in one study, is actually 11x worse for the blood vessels and heart than testosterone. (34)
Virilization
As a typical side effect in women, nandrolone decanoate produces virilization, which includes acne, hoarseness of the voice, hirsutism (excessive facial/body hair development), and libido changes, among other symptoms. (2)
Clitoral enlargement is a relatively uncommon indication of virilization. (2)
Virilization is most common and noticeable at high nandrolone decanoate doses and/or with long-term therapy, and certain elements of virilization, such as voice deepening, are permanent. Hoarseness is often the first symptom of voice alterations. (2)
Despite being just minimally androgenic, nandrolone decanoate may infrequently produce virilization in women at appropriate doses, particularly when used long-term. (2)
In women treated with nandrolone decanoate for 12 weeks at a dose of 100 mg every two weeks, a small but statistically insignificant incidence of virilization was reported. (2)
Long-term (>1 year) trials, on the other hand, have revealed considerable virilization in women even at a dose of 50 mg every 2 or 3 weeks. (2)
5α-Reductase Inhibitors
The combination of nandrolone with a 5α-reductase inhibitor like finasteride or dutasteride will block the conversion of nandrolone into 5α-DHN. (33)
Unlike with testosterone and various other AAS, taking a 5α-reductase inhibitor considerably increases the propensity of nandrolone for producing androgenic side effects. (33)
Overdose
In animals, the acute toxicity of nandrolone esters is very low, and there have been no instances of acute overdosage with nandrolone decanoate in humans. (2)
Interactions
Anti-estrogens such as aromatase inhibitors and selective oestrogen receptor modulators may interfere with and prevent nandrolone decanoate's estrogenic effects. (2)
5-reductase inhibitors such as finasteride and dutasteride may prevent nandrolone from being inactivated in so-called "androgenic" tissues such as the skin, hair follicles, and prostate gland, potentially amplifying its androgenic adverse effects. (33)
In contrast, most other AAS are either potentiated by 5-reductase in such tissues or are not substrates of 5-reductase.
Anti-androgens such as cyproterone acetate, spironolactone, and bicalutamide may inhibit both the anabolic and androgenic effects of anabolic androgenic steroids such as nandrolone decanoate. (2)
Chemical Information
Formula of Base: C18 H26 O2
Formula of Ester: C10 H20 O2
Molecular Weight of Base: 274.4022
Molecular Weight of Ester: 172.2668
Trade Names: Deca-Durabolin, other
Other Names: Nandrolone decylate, 19-Nortestosterone 17β-decanoate
Bioavailability: 53-73% (intramuscular) (4)
Duration of action: 2-3 weeks (intramuscular) (6)
Excretion: Urine (5)
Androgenic to Anabolic Ratio: 1:3 - 1:16 (2)
Further Reading
References
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This evidence-based analysis of nandrolone decanoate features 34 references, listed below.
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