Anabolic steroidAndrogen19-nortestosteroneResearch chemicalProgestinTrienolone

Formyltrienolone (RU-2341)

Also known as RU-2341 · 17-Formyltrienolone

Written by enwyReviewed 15 Jul 20261 sources0 comments

Formyltrienolone (RU-2341) is a highly potent trenbolone-family (estra-4,9,11-triene) synthetic steroid characterised chiefly in preclinical endocrine research. It is an extremely strong androgen-receptor and progesterone-receptor ligand from the same Roussel-Uclaf lineage as metribolone and trenbolone, with no clinical use and essentially no human data.

01 Overview

Formyltrienolone belongs to the 19-nor trienic steroid series that includes trenbolone (Finaplix), metribolone (R1881) and dimethyltrienolone. These compounds are prized in laboratories as reference androgens because of their exceptionally high receptor affinity and resistance to metabolism.

RU-2341 itself is a research chemical rather than a marketed drug, and any bodybuilding presence would be as an extremely potent, non-aromatising but strongly progestogenic and suppressive designer androgen. Its potency and the near-total absence of human safety data make it one of the higher-risk trenbolone relatives.

02 Mechanism

Very high-affinity agonist at the androgen receptor with substantial progesterone-receptor activity; the 4,9,11-triene system prevents aromatisation and 5-alpha reduction while boosting binding potency.

03 Dosing

Tier	Dose	Route	Notes
No established human dose	1–5 mg/day	Oral	Speculative only; no validated human dosing exists

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Potent androgen-receptor activationVery high AR affinity predicts strong anabolic and androgenic signalling in vitro.		Preclinical
No aromatisationTriene structure blocks conversion to estrogen.		Preclinical

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Progestogenic side effectsStrong progesterone-receptor activity can drive progestin-mediated gynecomastia and libido suppression, as seen across the trenbolone family.	Moderate	Predicted	Preclinical
Severe HPTA suppressionHigh-potency androgens of this class strongly suppress endogenous testosterone.	Severe	Predicted	Preclinical

06 Legal status

Research chemical without marketing authorisation · as of Jan 2026

United States

Anabolic steroid analogue

Trenbolone-family steroid captured by anabolic steroid statutes · as of Jan 2026

07 References

Trienic 19-nor steroids as high-affinity receptor ligandsJournal of Steroid Biochemistry

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.