Mibolerone (Cheque Drops)
Mibolerone ('Cheque Drops') is a 17α-methylated 19-nortestosterone (nandrolone) derivative originally a veterinary drug used to prevent oestrus in dogs. It is extraordinarily potent and androgenic, used by some strength and combat athletes for a very short-lived surge of aggression before competition. It is progestogenic, strongly hepatotoxic and considered one of the harshest steroids in use.
01 Overview
Mibolerone was marketed by Upjohn as 'Cheque Drops' for canine use. Because it is a 17α-methylated 19-nor compound of extreme potency, human use is confined to tiny microgram doses taken shortly before a fight or heavy lift for an acute aggression boost, not for building mass.
Its profile is uniformly harsh: intense androgenic and progestogenic activity, strong hepatotoxicity even at microgram doses, and pronounced aggression and mood changes. There is essentially no modern human safety data, and it is regarded as one of the most dangerous steroids used recreationally, warranting the most conservative characterisation.
02 Mechanism
Extremely potent androgen-receptor agonist derived from 19-nortestosterone with 7α,17α-dimethylation; strongly androgenic and progestogenic, non-aromatising in the classic sense but with progestogenic activity.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Threshold | 100–200 mcg/day | Oral | Microgram dosing; taken acutely before competition, not daily long-term. |
| Common | 200–500 mcg/day | Oral | Short-term pre-event use; side effects severe. |
| Heavy | 500–1000 mcg/day | Oral | Very high risk; not advisable. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Acute aggression and drive boostShort-lived surge of aggression and drive used immediately before competition. | Anecdotal | ||
| No meaningful mass benefitUsed for an acute psychological/androgenic effect, not for building muscle. | Anecdotal | ||
| Severe mood disturbanceIntense irritability, aggression and mood swings are characteristic. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Severe hepatotoxicityStrong hepatic strain despite microgram dosing, reflecting extreme potency of the 17α-alkylated molecule. | Severe | Common | Observational | |
| Severe androgenic and psychiatric effectsExtreme aggression, irritability and mood disturbance. | Severe | Very common | Anecdotal | |
| HPTA suppressionStrong suppression of endogenous testosterone; progestogenic activity compounds this. | Severe | Universal | Observational |