This page describes pharmacological agents that may have legal restrictions, side effects, and drug interactions in your jurisdiction. Information is for educational research only — consult a clinician before considering any compound.
Surface here is educational only; do not use without medical supervision. Our editorial verdict is SKIP-FOR-NOW — current cost / risk / redundancy puts it below the line.
Nandrolone
19-nortestosterone AAS | Deca-Durabolin (decanoate, long ester) / NPP (phenylpropionate, short ester)
Aliases (13)
Overview
What is Nandrolone?
Nandrolone is a 19-nortestosterone-derived anabolic-androgenic steroid (AAS) — testosterone with the C19 methyl group removed. Originally FDA-approved 1962 (Deca-Durabolin) for anemia of chronic kidney disease, postmenopausal osteoporosis, AIDS-wasting, and certain breast cancers. Brand-name Deca-Durabolin discontinued in the US (Organon notified FDA in 2002; off the commercial market by 2024) but compounded nandrolone decanoate remains available via 503A pharmacies (Empower Pharmacy is the dominant US supplier as of 2026). Clinically used as the long-ester decanoate (Deca, t½ ~6-12 days) or short-ester phenylpropionate (NPP, t½ ~2-4.5 days). Schedule III in the US; WADA S1.1a banned at all times; 19-norandrosterone urine threshold 2 ng/mL with one of the longest detection windows of any AAS (12-18 months).
Key Benefits
Modest lean mass increase (+1.59 kg LST in 2026 Prokopidis meta-analysis of 20 RCTs; larger in athletic-population observation); RBC mass elevation (originally drove the FDA renal-anemia indication); bone mineral density gains in postmenopausal osteoporosis (Frisoli 2005); joint pain relief in hypogonadal middle-aged men (Tatem 2020 pilot — 52% pain reduction in responders, 27.8% reduced pain medication); type III collagen synthesis upregulation; low aromatization (~20% of testosterone); paradoxically REDUCED androgenic side effects in DHT-target tissues (scalp, prostate) because 5α-reductase deactivates nandrolone to weaker DHN.
Mechanism of Action
Nandrolone decanoate (Deca-Durabolin) — 19-nortestosterone with a 10-carbon decanoate ester at 17β-OH. After deep IM injection into oil depot, ester is slowly hydrolyzed in plasma releasing free nandrolone. Terminal half-life ~6-12 days; weekly-to-biweekly dosing in practice. Active nandrolone agonizes androgen receptor (AR) in skeletal muscle for protein synthesis + lean mass; AR in renal cortex for EPO/erythropoiesis; progesterone receptor (PR) with ~22% the affinity of progesterone (driving the signature 'Deca dick' mechanism — PR → dopamine suppression → prolactin elevation → ED + libido collapse). Aromatizes weakly (~20% of testosterone's rate). 5α-reduces to weaker 5α-DHN (the OPPOSITE of testosterone → DHT) — meaning DHT-target tissues see less androgenic effect, and finasteride PARADOXICALLY worsens androgenic side effects by blocking the deactivation pathway. HPG-axis suppression among the deepest in the AAS class — recovery routinely 6-18 months post-PCT for Deca due to long ester clearance + PR-mediated GnRH suppression.
Pharmacokinetics
Research Indications
1. Reduces aromatization to estradiol (~20% of testosterone's rate)
Removal of the C19 methyl alters substrate fit for aromatase (CYP19A1). The aromatized product is estradiol (the same E2 as from testoste…
2. Reduces 5α-reduction to a WEAKER androgen (the inverse of testosterone)
Nandrolone IS a substrate for 5α-reductase, but the product — 5α-dihydronandrolone (DHN) — is a *weaker* androgen than nandrolone itself,…
3. Distinctive: Progesterone Receptor (PR) Agonism — the "Deca dick" mechanism
This is the class-defining feature that separates nandrolone from every testosterone-derived AAS. Nandrolone binds the progesterone recep…
4. PR-pathway gynecomastia (NOT just estrogen-pathway)
Because nandrolone agonizes PR and elevates prolactin, gynecomastia can develop via the progesterone/prolactin pathway — a mechanism dist…
Other mechanism notes
Anabolic-to-androgenic ratio. Rated ~125:37 in classical rat ventral prostate / levator ani assays (vs. testosterone's 100:100). The high…
Peptide Interactions
Standard "TRT base" companion to Deca/NPP. Almost always required because Deca's HPG suppression eliminates endogenous T and Deca alone produces sexual dysfu…
Estrogen management adjunct; less critical than on T cycles (Deca aromatizes ~20%) but still useful especially with TRT base on top.
THE distinctive Deca-cycle adjunct. Dopamine D2 agonist; prevents/reverses "Deca dick" via prolactin suppression. 0.25-0.5 mg 2×/week. Many advanced users ru…
Maintains testicular volume / responsiveness; used to ease PCT.
Common Tier-2 stack — both relatively mild AAS, both non-aromatizing or weakly aromatizing, both with reasonable lean-quality reputations. "Primo + Deca" is …
Mechanism-aligned for the joint-trophic effect Deca provides via type III collagen synthesis upregulation. Cheap, OTC, no side effects.
PARADOXICALLY WORSENS androgenic effects by blocking 5α-reduction of nandrolone to weaker DHN. The OPPOSITE of finasteride's effect on T-cycles. Documented i…
Stacking PR-active progestins (Deca + Tren are both 19-nor compounds with PR activity) compounds prolactin/dopamine signature severely. "Deca dick + Tren cou…
Compounds polycythemia risk.
Hepatotoxicity stacking; cumulative liver burden.
BP / kidney load stacking with the BP-elevating effect.
Some users report worsened sexual dysfunction with SSRI + Deca stack (compounded prolactin, compounded ED). Mechanistic basis is plausible.
Quality Indicators
Pharmaceutical-grade Rx (compounded)
US Rx via 503A compounding pharmacy (Empower Pharmacy is the dominant supplier as of 2026) — sterile, USP-grade ND in oil. Highest reliability path. Requires prescription; off-label use for hypogonadal joint pain is the most common Rx pathway.
Independent UGL HPLC + sterility testing
Reputable UGL vendors publish HPLC purity and sterility testing via Janoshik or Anabolic Lab. Verify batch-specific COA showing >97% purity, correct ester (decanoate vs. phenylpropionate), and sterility/endotoxin testing.
Underdosed product (common with ND)
Nandrolone decanoate is among the more frequently underdosed AAS in UGL testing — the long-chain ester takes ~30% of vial mass, tempting manufacturers to cheat the nandrolone:ester ratio. Independent testing has found vials labeled 200 mg/mL containing 100-150 mg/mL of actual nandrolone.
Carrier oil reactions / PIP
Cottonseed oil has higher reaction rate than sesame > MCT > ethyl oleate. NPP particularly aggravating to muscle tissue (post-injection pain common, sometimes lasting days). If persistent injection-site pain develops, investigate carrier oil composition.
Visible particulates or cloudy oil
Oil-based AAS products should be clear and free of particulates. Visible cloudiness, sediment, or color change indicates contamination or degradation. Discard.
Counterfeit Deca-Durabolin labels
Brand-name Deca-Durabolin (Organon) was discontinued in the US — any 'genuine Organon Deca-Durabolin' currently on the gray market is overwhelmingly counterfeit. Authenticate through compounded ND or verified UGL with independent testing instead.
Bacterial contamination signs
Inadequately sterilized UGL operations have produced abscesses, sterile abscesses, sepsis, and local-tissue infections. Any vial with visible contamination, leaking stopper, or unusual odor should be discarded immediately.
What to Expect
- Week 1Tolerability and dose-response.
- Week 2-4Early effect window.
- Week 4-8Peak benefit assessment.
- Week 8+Cycle decision point.
Side Effects & Safety 14
Side Effects
- 1HPG-axis suppression (deepest of the AAS class). Total T suppressed to single-digit ng/dL within 4-8 weeks. LH/FSH suppressed below detection limit. Recovery 6-18 months post-PCT for first cycle in healthy young adults; longer with stacking, age, prior cycles. Permanent HPG dysfunction / hypogonadism is a documented outcome for users who cycle aggressively at young ages or fail to PCT properly.
- 2"Deca dick" — PR-mediated erectile dysfunction + libido collapse. 20-50% of users, dose-responsive. Emerges weeks 4-8. Persists weeks-months post-cycle. The signature side effect of this compound.
- 3Prolactin elevation. Clinical biomarker for the Deca-dick mechanism. Often 2-5× upper limit of normal at typical bodybuilding doses without cabergoline.
- 4Polycythemia / hematocrit elevation. Hematocrit can climb from baseline 42-46% to 52-56% at typical doses. Clinically actionable; therapeutic phlebotomy may be needed.
- 5Lipid disturbance. HDL-C suppression (often −30 to −50%; somewhat milder than testosterone), LDL-C and ApoB elevation. Class-typical AAS effect.
- 6Modest BP elevation. From RBC-mass-driven volume effect plus AR-mediated vascular effects. 24-hr ambulatory BP often shifts +5-10 mmHg systolic on cycle.
- 7Injection-site pain (PIP). Especially with NPP (the phenylpropionate ester is more aggravating to muscle tissue than decanoate). Some users report persistent post-injection soreness for days.
- 8Gynecomastia (PR/prolactin-pathway, NOT just estrogen). May develop despite adequate AI on board. Cabergoline addition often required.
- 9Galactorrhea / non-puerperal lactation. Documented at high doses with elevated prolactin.
- 10Acne, oily skin. Less than testosterone (5α-reductase pathway gives weaker DHN). Worse if finasteride is on board (paradox — see Mechanism).
- 11Hair loss / androgenic alopecia. In genetically predisposed individuals. Less than testosterone; paradoxically WORSE if finasteride is on board.
- 12Mood / cognitive flat affect. Some users report low motivation, dopamine-suppressed feel, "flat" emotional affect — likely the PR/dopamine mechanism.
- 13Anxiety, sleep disturbance. Reported in ~9% of abuse-cohort studies (Patané 2020); less than trenbolone.
- 14Mild ALT/AST elevation. Modest, reversible. Nandrolone is NOT 17α-alkylated; hepatotoxicity is mild and largely reversible — distinct from oral 17αAA AAS.
When to Stop
- Permanent HPG dysfunction / infertility. Documented for ND specifically. Among the highest-risk AAS for permanent HPG damage at young user ages.
- Cardiomyopathy. AAS-induced LV hypertrophy, diastolic dysfunction, fibrosis — class-wide effect, documented in long-term users including ND users.
- Sudden cardiac death. Documented in AAS-user case series.
- Thrombotic events (VTE/MI/stroke). From polycythemia + lipid changes + BP elevation.
- Hepatic peliosis / cholestatic jaundice. Rare for non-17αAA AAS; case reports exist.
- Prolactinoma exacerbation. Pre-existing prolactin-secreting pituitary tumors can flare on Deca.
- Severe gyno requiring surgical correction. Higher rate than testosterone due to the dual estrogen-pathway + PR/prolactin-pathway mechanism.
- Manufacturing contamination (research-chem path). UGL nandrolone has documented underdosing, sterility issues, oil-vehicle reactions.
- Weeks 4-8: First wave — hematocrit, BP, lipids, prolactin emergence, libido status check
- Weeks 8-12: Peak HPG suppression, gyno surveillance, mood/sexual function reassessment
- Post-cycle weeks 4-12: PCT initiation timing (after Deca ester clearance), HPG recovery monitoring
- Post-cycle months 6-18: HPG full recovery confirmation, sperm analysis if fertility-relevant
- WADA S1.1a banned + 12-18 month urine detection. Single use precludes any sanctioned MMA / amateur / pro competition for ~18 months. Career-impact level.
- HPG suppression at 20 = permanent-fertility / permanent-HPG-injury risk that swamps any body-comp gain.
- "Deca dick" + brain-priority conflict. Sexual function and cognitive/mood baseline are core to the user's stack philosophy. Nandrolone's PR/dopamine signature is the OPPOSITE of what brain-priority architecture should look like.
- Cabergoline workaround introduces additional drug + valvulopathy theoretical risk + prescriber friction.
- Joint-relief thesis is achievable cheaper, safer, and tested-compatible with BPC-157 + collagen + Vitamin C + load management. The user already has these tools available.
- Polycythemia + cardio-load. Combat sports require sustained cardiovascular output. Hematocrit 55+% adds blood viscosity, raises BP under load, theoretically impairs cardiac output during high-intensity rounds.
References
Pan MM, Kovac JR (2016) — Beyond testosterone cypionate: evidence behind the use of nandrolone in male health and wellness (Translational Andrology and Urology 5:213-219)
narrative review of off-label male-health uses
View StudyTatem AJ, Holland LC, Kovac JR, Beilan JA, Lipshultz LI (2020) — Nandrolone decanoate relieves joint pain in hypogonadal men: prospective pilot study and review (Translational Andrology and Urology; PMC7108994; PMID 32257859)
joint-pain pilot, 52% pain reduction in responders
View StudyProkopidis K et al. 2026 — Effects of Nandrolone Decanoate on Muscle Strength, Body Composition and Bone Density: Systematic Review and Meta-Analysis (J Cachexia Sarcopenia Muscle, April 2026)
most current 20-RCT meta showing +1.59 kg LST, no handgrip improvement, inconsistent BMD
View StudyStorer TW, Woodhouse LJ, Sattler F, ... Bhasin S et al. 2005 — Nandrolone decanoate in HIV-infected men with weight loss (PMID 15914526)
A-tier RCT, AIDS-wasting indication
View StudyFrisoli A Jr, Chaves PH, Pinheiro MM, Szejnfeld VL 2005 — Effect of nandrolone decanoate on bone mineral density in elderly women with osteoporosis (J Gerontol A Biol Sci Med Sci 60:648-653; PMID 15972619)
A-tier BMD RCT
View StudySattler FR et al. 2005 — Nandrolone decanoate in HIV-infected women with weight loss (PMID 15767536)
multicenter RCT, female AIDS-wasting cohort
View StudyJohansen KL 2001 — The role of nandrolone decanoate in patients with end stage renal disease in the erythropoietin era (Int J Artif Organs; PMID 11394696)
renal anemia editorial
View StudyHansson H et al. 1992 — Recombinant erythropoietin and nandrolone decanoate in chronic hemodialysis (PMID 1606777)
controlled trial in hemodialysis anemia
View StudyPatané FG et al. 2020 — Nandrolone Decanoate: Use, Abuse and Side Effects (Medicina; PMC7696474; PMID 33187340)
adverse effects systematic review
View Studyvan Marken Lichtenbelt WD et al. 2004 — Bodybuilders body composition: effect of nandrolone decanoate (Med Sci Sports Exerc; PMID 15076791)
controlled bodybuilder cohort, +2.2 kg body mass at 8 weeks
View StudyCalado RT et al. 2022 — Nandrolone decanoate effects on telomere length in patients with telomeropathies (PMID 36579443)
specialized indication
View StudyForsdahl G, Geyer H, Hayward G, et al. 2016 — Atypical excretion profile and GC/C/IRMS findings may last for nine months after a single dose of nandrolone decanoate (Steroids; PMID 26853157)
detection-window evidence
View StudyFederal Register 2010 — Determination That DECA-DURABOLIN Was Not Withdrawn for Safety/Effectiveness
FDA discontinuation timeline
View StudyRasmussen JJ et al. 2016 — Former AAS users with persistent hypogonadism (J Clin Endocrinol Metab 101:1396)
long-term HPG dysfunction documentation
View StudyKanayama G, Pope HG Jr — Long-term cardiovascular consequences of AAS
class-wide CV outcome literature
View StudyWADA Prohibited List 2026
S1.1a confirmation for nandrolone and metabolites
View StudyDEA Diversion Control: Anabolic Steroids
Schedule III status, federal law context
View StudyNandrolone Decanoate — PubChem CID 9677 (C28H44O3, MW 428.65, CAS 360-70-3)
chemistry
View StudyNandrolone Phenylpropionate — PubChem CID 229455 (C27H34O3)
chemistry, NPP variant
View StudyCleveland Clinic — Nandrolone: Uses, Benefits & Side Effects
clinical reference
View StudyQuantification of 19-Norandrosterone and 19-Noretiocholanolone (WADA scientific research)
anti-doping metabolite detection
View StudyTransfeminine Science — Nandrolone monograph
comprehensive mechanism + pharmacology synthesis (notably good on the 5α-reductase / finasteride paradox)
View StudyTatem 2019 conference update — Joint pain improvement in 8 weeks (J Sex Med Supplement 17:S14)
8-week timeline data
View StudyEmpower Pharmacy — Nandrolone Decanoate Injection
current US compounded sourcing
View StudyLlewellyn W — *Anabolics* (11th ed., 2017)
community-standard AAS reference
View StudyHartgens F, Kuipers H — Effects of AAS in athletes (Sports Medicine 2004)
physiology + side-effect review
View StudyPope HG Jr et al. — Adverse Health Consequences of Performance-Enhancing Drugs (Endocrine Reviews 2014)
AAS adverse effects review
View StudyVanberg P, Atar D — Androgenic anabolic steroid abuse and the cardiovascular system (Handb Exp Pharmacol 2010)
CV mechanism review
View StudyHow was your experience with this compound?
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