Orals

19-Norandrostenedione

Updated · 24 sources · Editorial policy

19-Norandrostenedione (estr-4-ene-3,17-dione, sometimes called “nor-andro” or “19-NA”) is a steroid prohormone: a compound with weak activity of its own that the body converts into a stronger steroid. In its case that steroid is nandrolone (19-nortestosterone), the active hormone in Deca-Durabolin and NPP. In the late 1990s it was sold in the US as an over-the-counter “dietary supplement” alongside androstenedione (Uralets & Gillette, J Anal Toxicol 1999).

The most important facts are about drug testing, not muscle. Its urinary metabolites are the same markers used to detect nandrolone, and doses as small as a few micrograms (millionths of a gram) hidden in a supplement have produced positive doping tests (Watson et al., MSSE 2009). The few controlled human trials of oral products found no effect on muscle mass or strength. It has no approved medical use, it is a Schedule III controlled substance in the US, and it is prohibited in sport at all times.

This page summarizes what the human excretion studies, small supplement trials, animal studies and regulators report. It is for education only and is not medical advice.

Property Detail
Class Synthetic 19-nor steroid; prohormone (precursor) of nandrolone
Chemical name Estr-4-ene-3,17-dione; C₁₈H₂₄O₂; 272.4 g/mol; CAS 734-32-7. PubChem also lists the name bolandione
Medical approval None; no approved medical use
Route Oral (as former supplements); rat studies also used subcutaneous injection
Doses in human studies 156–344 mg/day of combined norsteroid products for 8 weeks; single doses of 1–10 µg to 50 mg in urine excretion studies
Half-life No human half-life has been published. Urinary metabolites were detectable for 7–10 days after a single 50 mg oral dose
Main urinary markers 19-norandrosterone and 19-noretiocholanolone, the same metabolites used to detect nandrolone
US status Schedule III anabolic steroid (named in 21 CFR 1308.13(f)); added by the Anabolic Steroid Control Act of 2004
WADA status Prohibited at all times (S1.1 anabolic androgenic steroids)

What it is

19-Norandrostenedione is androstenedione without the methyl group at carbon 19, the same structural difference that separates nandrolone from testosterone. Its formula is C₁₈H₂₄O₂ with a molecular weight of 272.4 g/mol, and PubChem lists synonyms including 19-nor-4-androstenedione, estr-4-ene-3,17-dione and bolandione (PubChem CID 92834).

It is a 17-keto steroid, so it is not itself the active hormone. An enzyme that reduces the 17-keto group to a 17β-hydroxyl group turns it into nandrolone. A German sports-research group described it as one of the most frequently misused prohormones and reported that after oral intake it is “readily metabolised” to nandrolone (Diel et al., Toxicol Lett 2008).

Compound Relationship
19-Norandrostenedione (this page) 17-keto prohormone; converted to nandrolone
19-Norandrostenediol Related prohormone, often sold in the same products; also named on the WADA list and in 21 CFR 1308.13
19-Nor-5-androstenedione Δ5 isomer, also sold over the counter (Uralets & Gillette, J Anal Toxicol 2000); also Schedule III
Nandrolone The active anabolic steroid both prohormones are meant to produce
Androstenedione (4-AD) The testosterone-side counterpart, with the 19-methyl group intact

We found no record of it being developed as a prescription drug. Its human literature comes almost entirely from anti-doping laboratories and a handful of small supplement trials.

It also occurs in trace amounts naturally and as an impurity

Small amounts of 19-norsteroids occur without any supplement use. In one study, urine taken before dosing contained 19-norandrosterone at 0.19 ± 0.14 ng/mL (Watson et al., MSSE 2009). 19-Norandrostenedione is also a known impurity in tablets of norethisterone, a progestin used in contraceptives and for menstrual disorders. A UK laboratory measured up to 1.01 µg per 5 mg norethisterone tablet, all within the British Pharmacopoeia limit of 0.1% (Walker et al., Steroids 2009).

How it works in the body

There are no formal human pharmacokinetic studies (blood levels over time) for 19-norandrostenedione. What is known comes from urine excretion studies run by doping-control laboratories.

Finding Study
After a single 50 mg oral dose, 19-norandrosterone and 19-noretiocholanolone appeared in urine at high concentrations and were detectable for 7–10 days Uralets & Gillette, J Anal Toxicol 1999
After 10 µg in water, peak urinary 19-norandrosterone came 2.8 ± 1.9 h after ingestion; in an energy bar, 4.6 ± 2.4 h Watson et al., MSSE 2010
Total recovery of the two metabolites in urine was 28–30% of a 10 µg dose (water vs bar) Watson et al., MSSE 2010
Recovery of a 1–5 µg dose varied from 11% to 84% between people (mean 47 ± 18%) Watson et al., MSSE 2009
19-Norandrosterone usually exceeded 19-noretiocholanolone in the first ≈6 h; the ratio could reverse later Tseng et al., J Anal Toxicol 2005

In rats, both the parent compound and nandrolone (free and glucuronidated) were measurable in serum after oral and subcutaneous dosing, and the amount converted to nandrolone was similar for both routes (Parr et al., Toxicol Lett 2009).

Regulatory status

  • United States. The Anabolic Steroid Control Act of 2004 (Public Law 108-358, approved October 22, 2004) added “19-nor-4-androstenedione (estr-4-en-3,17-dione)” to the federal definition of anabolic steroid. Those amendments took effect 90 days after enactment (Public Law 108-358). It is now listed as a Schedule III substance, together with its Δ5 isomer and the 19-norandrostenediols (21 CFR 1308.13).
  • Sport. The WADA 2026 Prohibited List names “19-Norandrostenedione (estr-4-ene-3,17-dione)” under S1.1 anabolic androgenic steroids, prohibited in and out of competition, as a non-Specified Substance (WADA 2026 Prohibited List).
  • Medicine. There is no approved medical indication.

What the research shows

Muscle and strength in humans: no effect found

Three small controlled trials tested oral 19-norandrostenedione, two of them in products that also contained 19-norandrostenediol. None found a benefit.

Trial Design Daily dose Duration Result
Van Gammeren et al., Eur J Appl Physiol 2001 Randomized, placebo-controlled; weight-trained men doing resistance training 4 days/week 100 mg 19-norandrostenedione + 56 mg 19-norandrostenediol (156 mg) 8 weeks No significant change in DXA body composition, bench press strength, power or mood
van Gammeren et al., Nutrition 2002 Randomized, double-blind, placebo-controlled; n = 10 resistance-trained men (5 per group) 224 mg 19-norandrostenedione + 120 mg 19-norandrostenediol (344 mg) 8 weeks No significant change in body composition or 1-repetition-maximum strength in either group
Baume et al., Eur J Appl Physiol 2006 Double-blind; placebo (n = 9), testosterone undecanoate (n = 8) or 19-norandrostenedione (n = 8) during endurance training 12 oral doses over 1 month 1 month No difference in running performance or in markers of physical stress and recovery

These trials were very small, so they could miss a modest effect. A 2002 review concluded that oral norandrostenedione and norandrostenediol for up to 8 weeks had no effect on body composition or performance (Ziegenfuss et al., Can J Appl Physiol 2002).

Animal studies: depends on the route

In castrated rats, subcutaneous 19-norandrostenedione increased the weight of the levator ani muscle (a standard marker of anabolic effect) but left the prostate and seminal vesicles unaffected. In the same paper, the compound bound selectively to the androgen receptor in vitro, with about 10 times less ability than DHT to switch on androgen-receptor reporter genes (Diel et al., Toxicol Lett 2008). A 12-day study in castrated rats (1 mg/kg/day subcutaneously) found the same pattern and a shift in muscle fiber protein types similar to testosterone (Frese et al., Arch Toxicol 2011).

Oral dosing behaved differently. In castrated rats given 0.1, 1 or 10 mg/kg/day by mouth, neither the levator ani nor the prostate grew, and body weight fell in a dose-dependent way. The authors concluded that oral use, at least in the rat, “seems to be a very ineffective strategy” for gaining muscle (Parr et al., Toxicol Lett 2009).

These are rat results. Selective effects seen after injection in rats have not been shown in people.

About the “SARM-like” label. The 2008 rat paper described 19-norandrostenedione as having “SARM like properties” after injection. That finding came from castrated rats given subcutaneous doses. The follow-up oral study in rats found no anabolic effect, and no human study has shown tissue-selective effects.

Drug testing: microgram amounts can cause a positive test

Most human data on this compound concern doping control. Its main urinary metabolites, 19-norandrosterone and 19-noretiocholanolone, are the same markers laboratories use to detect nandrolone (Uralets & Gillette, J Anal Toxicol 1999). In the studies below, a urinary 19-norandrosterone level over 2 ng/mL was the reporting threshold in use at the time.

Study Dose and setting Result
Catlin et al., JAMA 2000 Androstenedione 100 or 300 mg/day for 7 days (randomized, n = 24 treated); 10 µg 19-norandrostenedione (open-label, n = 4) The androstenedione product contained 19-norandrostenedione at 0.001%; 20 of 24 men on androstenedione exceeded 2 ng/mL. All samples from the 4 men given 10 µg contained 19-norandrosterone
Watson et al., MSSE 2009 1.0, 2.5 or 5.0 µg in a creatine drink; 11 men and 9 women Positive tests in 0% at 1.0 µg, 20% at 2.5 µg and 75% at 5.0 µg
van der Merwe & Grobbelaar, S Afr Med J 2005 One capsule of a contaminated supplement; 5 men All 5 exceeded 2 ng/mL from 2 h after the dose; 2 were still over it after 36 h; highest value 54.6 ng/mL
Walker et al., Steroids 2009 Single 1 µg dose Peak 19-norandrosterone 2.4 ng/mL at 2 h

The Loughborough group estimated that adding as little as 2.5 µg to a supplement serving (0.00005% contamination) may be enough to cause a doping violation in some people (Watson et al., MSSE 2009). Taking it in a solid energy bar rather than water raised the peak urinary concentration from 4.80 to 8.46 ng/mL after a 10 µg dose (Watson et al., MSSE 2010).

Norethisterone itself is metabolized to 19-norandrosterone. In women taking 5 mg three times daily for 10 days, peak values reached 51–63 ng/mL whether or not the tablets contained the 19-norandrostenedione impurity, showing that the impurity made only a minor contribution (Walker et al., Steroids 2009).

Side effects and risks

Very little human safety data

The only human safety data come from short, small studies. In a 10-day study, men took an over-the-counter product containing equal parts 19-norandrostenedione and 19-norandrostenediol (72 or 144 mg twice daily). Every participant tested positive for nandrolone in urine, and standard blood tests showed no change in kidney, liver, blood-count or bone-marrow markers (Colker et al., J Strength Cond Res 2001). Ten days of monitoring cannot show long-term safety.

Because it is converted to nandrolone, the risks described for nandrolone are relevant in principle, including suppression of the body’s own testosterone. These have not been measured for 19-norandrostenedione in controlled human studies. See the Deca-Durabolin page for nandrolone data.

A 2003 review of the oral “andro” prohormone class, including 19-norandrostenedione, found that studies of these products often showed falls in HDL (“good”) cholesterol and raised estrogen-related hormones. The review raised concern about long-term use (Broeder, Can J Appl Physiol 2003). The review does not report these findings separately for 19-norandrostenedione, and we found no controlled study that measured lipids or estrogens with it alone.

Animal and cell findings

  • Body weight (rats): oral dosing caused a dose-dependent drop in body weight (Parr et al., Toxicol Lett 2009).
  • Liver (rats): subcutaneous dosing did not change liver weight or liver expression of the tyrosine aminotransferase gene (Diel et al., Toxicol Lett 2008).
  • Chromosome damage (cell culture): in V79 cells, 19-norandrostenedione doubled the background rate of micronuclei (a sign of chromosome damage) at about 29 µM. The authors said a genotoxic hazard at very high misuse doses “cannot be ruled out” (Dorn et al., Toxicol Lett 2008). This is a cell-culture result, not evidence of harm in people.

Contaminated supplements

19-Norandrostenedione is a documented hidden contaminant: it was found undeclared in an androstenedione product at 0.001% (Catlin et al., JAMA 2000) and in a supplement capsule tested in South Africa (van der Merwe & Grobbelaar, S Afr Med J 2005). In an international study of 634 non-hormonal supplements bought in 13 countries, 94 (14.8%) contained anabolic steroids not declared on the label, mainly testosterone and nandrolone prohormones. Total intake of more than 1 µg of nandrolone prohormones led to positive tests for several hours (Geyer et al., Int J Sports Med 2004). A Taiwanese study found seven undeclared steroids in a single over-the-counter supplement (Tseng et al., J Anal Toxicol 2005).

Key takeaways

  • A nandrolone prohormone. The body converts 19-norandrostenedione to nandrolone, and it leaves the same urinary markers as nandrolone.
  • No benefit shown in people. Three small controlled trials of oral products found no gain in muscle, strength or endurance performance.
  • Route matters in rats. Injected doses built muscle in castrated rats with little prostate effect, but oral doses did not, and body weight fell.
  • Micrograms can fail a drug test. A 2.5–5 µg dose produced positive results in 20–75% of volunteers, and contamination of supplements is well documented.
  • Thin safety data. Human safety data are limited to a 10-day study; long-term effects have not been studied.
  • Controlled and banned. It is Schedule III in the US since the Anabolic Steroid Control Act of 2004 and prohibited at all times by WADA.

Sources

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  23. Code of Federal Regulations. 21 CFR 1308.13, Schedule III. 21 CFR 1308.13.
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