Anabolic steroidAndrogen19-nortestosteroneAnabolic steroidVeterinaryOral17-alpha-alkylated

Mibolerone (Oral)

Also known as Cheque Drops · Dimethylnortestosterone · Checque

Written by enwyReviewed 5 Aug 20261 sources0 comments

Mibolerone (7alpha,17alpha-dimethyl-19-nortestosterone) is an extremely potent orally active 19-nor androgen originally licensed in veterinary medicine (Cheque Drops) to suppress estrus in dogs. In humans it is used non-medically in tiny sublingual/oral doses shortly before competition or heavy training for a short-lived surge in aggression; it is highly androgenic, progestogenic, hepatotoxic and dangerous at above micro-doses.

01 Overview

Mibolerone is a double-methylated (7-alpha and 17-alpha) nandrolone derivative, giving both oral activity and extreme receptor potency. Its veterinary use was estrus suppression in bitches; the human, non-medical use is a pre-workout or pre-fight 'aggression' aid taken in the low hundreds of micrograms.

Because of its potency and narrow margin, it is associated with rapid liver strain, severe suppression and pronounced mood/aggression effects. It is not suitable for sustained cycles and has no human therapeutic role.

02 Mechanism

Highly potent androgen-receptor agonist of the 19-nor class; 7-alpha and 17-alpha methyl groups block metabolism, giving oral potency and progestogenic activity.

03 Dosing

Tier	Dose	Route	Notes
Pre-event micro-dose	100–300 mcg	Oral	Micrograms, not milligrams; taken shortly before activity.
Anecdotal	300–500 mcg/day	Sublingual	Very short use only; risk rises sharply with dose/duration.

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Acute aggression/drive surgeUsed for a pre-competition aggression boost.	marked, short-lived	Anecdotal
Transient strength/intensityReported surge in training intensity.	acute	Anecdotal

05 Side effects

Effect	Severity	Frequency	Evidence
Severe aggression / mood disturbanceUncontrolled aggression and irritability.	Severe	Common	Anecdotal
Hepatotoxicity17-alpha-methyl group causes rapid hepatic strain.	Severe	Common with repeated use	Preclinical
HPTA suppressionSevere suppression even at small doses.	Severe	Universal	Preclinical

06 Legal status

United Kingdom

Class C

Anabolic steroid. · as of Jan 2026

United States

Schedule III controlled

Anabolic steroid; veterinary product. · as of Jan 2026

07 References

Mibolerone: pharmacology and veterinary use for estrus suppressionJournal of Veterinary Pharmacology and Therapeutics

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.