Roidipedia.Compound reference & reporting
06 AUG 2026
CompoundsAnabolic steroid Halotestin Injectable (Fluoxymesterone)
Anabolic steroidAndrogenInjectableTestosterone derivative17-alpha-alkylated

Halotestin Injectable (Fluoxymesterone)

Also known as Injectable Halo · Injectable fluoxymesterone

An injectable preparation of fluoxymesterone (Halotestin), a fluorinated 17-alpha-alkylated testosterone derivative normally taken orally. It is one of the most androgenic-per-milligram steroids, prized by strength and combat athletes for aggression and strength without weight gain. Injecting the unesterified molecule does not lessen its notorious hepatotoxicity, and it remains a harsh, poorly characterised compound in injectable form.

01 Overview

Fluoxymesterone is a highly androgenic, non-aromatising oral steroid used clinically for hypogonadism and certain anemias and breast cancers. In performance use it is valued for sharp strength and aggression increases with minimal mass gain, making it popular before powerlifting meets or fights. The injectable form circulates rarely on the underground market.

Because fluoxymesterone keeps its 17-alpha-alkyl group, injection does not reduce its substantial liver toxicity, and its strongly negative lipid effects persist. Its clinical potency and toxicity are documented, but the injectable presentation specifically has no formal characterisation, so it should be treated as a harsh, high-risk compound used only in short bursts.

02 Mechanism

Fluoxymesterone is a potent, non-aromatising androgen receptor agonist; the fluorine and 17-alpha-alkyl substitutions increase potency and confer hepatotoxicity retained by injection.

03 Dosing

TierDoseRouteNotes
Common70–140 mg/wkIMRoughly 10-20 mg/day equivalents; short pre-competition bursts.
High (harsh)140–280 mg/wkIMHigh doses sharply raise hepatic and cardiovascular risk.

Ester comparison

EsterHalf-lifeInjection freq.Testosterone by mass

04 Effects

EffectMagnitudeEvidence
Increased strength and aggressionFavoured for acute strength and drive without added bodyweight.Pronounced strength boostObservational
Minimal weight gainUseful for athletes needing to stay within a weight class.Low mass gainObservational

05 Side effects

EffectSeverityFrequencyEvidenceCountermeasures
Aggression / mood disturbanceMarked irritability and aggression are a hallmark of this compound.ModerateCommonObservational
HepatotoxicitySignificant liver enzyme elevation and cholestasis risk, documented clinically.SevereCommon at cycle dosesClinical
Adverse lipid changesSteep HDL suppression raising cardiovascular risk.SevereVery commonClinical

07 References

Fluoxymesterone (Halotestin) product information and pharmacologyFDA labeling / pharmacology reference

08 Discussion0 comments

?
Sign in to add a comment…
Create account
Discussion is moderated. No sourcing, vendor names or price talk — those comments are removed, and repeat posts are banned.
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.