Anabolic steroidAndrogenInjectable19-nortestosteroneNandrolone ester

Nandrolone Undecanoate

Also known as Nandrolone Undecanoate · Deca Undecanoate

Written by enwyReviewed 15 Jul 20261 sources0 comments

A long-acting nandrolone ester using the 11-carbon undecanoate chain, giving a slow, extended release similar to (or slightly beyond) decanoate. Effects match nandrolone; it is an uncommon preparation with limited ester-specific human data.

01 Overview

Nandrolone undecanoate esterifies 19-nortestosterone with undecanoic acid, producing a slow-releasing depot comparable to nandrolone decanoate. It is rarely encountered commercially and has not been the subject of large human trials, so most understanding is inferred from nandrolone itself and from analogous long esters.

Once hydrolysed the hormone is nandrolone, giving the familiar deca profile of strong anabolism, low androgenicity, progestogenic activity and pronounced suppression. The undecanoate chain simply extends the release window. Given sparse ester-specific evidence, ester claims are graded observational.

02 Mechanism

Esterases cleave the undecanoate ester to release nandrolone, which acts on the androgen receptor with a high anabolic-to-androgenic ratio and has progestogenic activity; 5-alpha reduction yields the weaker DHN.

03 Dosing

Tier	Dose	Route	Notes
Common (nandrolone-equivalent)	200–400 mg/wk	IM	Long ester; dosed every 1-2 weeks. Inferred from nandrolone.

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Increased lean massNandrolone's high anabolic activity with a slow-release ester.	steady	Observational
Joint comfortCommonly reported with nandrolone; mechanism uncertain.		Anecdotal
Increased red blood cellsNandrolone raises erythropoiesis.		Observational

05 Side effects

Effect	Severity	Frequency	Evidence
HPTA suppressionStrong, prolonged suppression of testosterone and spermatogenesis.	Severe	Universal	Clinical
Sexual dysfunction (deca dick)Low libido/ED tied to progestogenic activity.	Moderate	Common	Observational
Elevated prolactinProgestogenic activity can raise prolactin.	Moderate	Less common	Observational

06 Legal status

United States

Schedule III controlled substance

as of Jan 2026

United Kingdom

Class C controlled drug

as of Jan 2026

07 References

Nandrolone and its esters: anabolic pharmacologyEndocrinology literature

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.