Halotestin

An oral androgen with old prescription history (hypogonadism, breast cancer). Non-medical strength-sport use is reported, but controlled performance evidence is absent.

Fluoxymesterone is an anabolic-androgenic steroid — a methylated, fluorinated testosterone derivative. It does not aromatise. The strength-without-size account that circulates rests on historical animal potency ratios, which do not predict a human body-composition or performance phenotype, and NO controlled human trial establishes strength, hardness or aggression as effects of this compound. The label states plainly that anabolic steroids have not been shown safe and effective for athletic performance. Oral 17-alpha-alkylated steroids share one design feature: a methyl group added at the 17 position so the molecule survives first-pass liver metabolism. That modification is what makes them orally active and is strongly associated with the highest cholestatic risk in this class, though the exact injury mechanism is not settled.

The prescription-era record proves biological activity. The strength-sport reputation rests entirely on athlete anecdote — pharmacologically plausible androgen-CNS effects, never trialed.

• It has FDA-approved history in hypogonadism and in some breast cancer contexts, which is where its human pharmacology comes from.
• NONE SHOWN for the strength and aggression use it is actually taken for. There is no controlled trial of that application.
• Its label documents the serious hepatic risks of 17-alpha-alkylated steroids — cholestatic jaundice, peliosis hepatis and hepatic tumours. Ranking it against other oral steroids is not something the evidence supports, so this entry does not.
• The psychiatric effects — aggression, irritability, mood instability — are user report rather than controlled evidence for this compound specifically, and frequency is not established. Psychiatric harm including mania, paranoia, psychosis and aggression is well documented for anabolic steroids as a class.
• It is prohibited in tested sport.

Orally active, 17-alpha-alkylated and fluorinated. It does not aromatise, and adding drugs to manage steroid side effects is unapproved and belongs with a clinician. On suppression, be precise about what was measured: in a small 12-week study of nine healthy men, circulating testosterone was profoundly suppressed while LH and FSH did not fall significantly and sperm suppression was modest.

Among the most hepatotoxic orals in the published record, severe lipid disruption over short exposures, blood-pressure elevation, and a reported behavioral signature — irritability and aggression that users describe as the effect and the people around them experience as the problem. HPG-axis suppression is marked.

• Class-level severe outcomes reported with anabolic steroids, which no compound here is exempt from: cardiac arrest, heart attack, thickened heart muscle, heart failure and stroke; serious liver injury; and mania, paranoia, psychosis, hostility, aggression, dependence and depression on withdrawal.
• Pregnancy and breastfeeding: androgens can cause fetal harm including virilisation of a female fetus. Avoid in both.
• Anyone with any liver condition or unexplained enzyme elevation
• Anyone with a history of depression, mood instability or aggression problems
• Anyone with unfavourable lipids or cardiovascular disease
• Anyone with prostate or male breast cancer, or serious cardiac or kidney disease
• Anyone being treated for breast cancer, where the label calls for hypercalcaemia monitoring
• Women — virilisation includes irreversible voice change, and androgens can cause fetal harm in pregnancy

• Anticoagulants, which anabolic steroids can substantially potentiate.
• Alcohol, paracetamol and any hepatotoxic drug or supplement.
• Other oral 17-alpha-alkylated compounds, where liver burden is additive.
• Oxyphenbutazone, a labelled interaction.
• Glucose-lowering therapy, since anabolic steroids can alter insulin or oral medication requirements — a clinician needs to know, and nothing here is an instruction to change a dose.
• Anything affecting mood or impulse control, given the class psychiatric profile.

Documented interactions with other things people research. A compound not listed here does not mean the combination is safe — only that no specific interaction is on file.

• Liver enzymes and bilirubin, with the same limit as other orals in this class — normal values do not exclude peliosis or hepatic tumours.
• Lipids — the label notes cholesterol can rise. Compound-level comparative severity is not established.
• Blood pressure and haematocrit.
• Mood and aggression, honestly, and ideally with someone else's input — this is the effect the compound is known for and the one least visible from inside.
• Any jaundice, dark urine or abdominal pain — emergency assessment.

There are no controlled discontinuation data for strength or mood with this compound, so no timeline is offered here. The psychiatric, endocrine and hepatic course after stopping is individually unpredictable. Critically, biochemical improvement does not mean structural safety: the label warns of peliosis hepatis and hepatic tumours that can be silent, and enzyme recovery does not exclude them. Anyone whose mood or behaviour changed markedly during use should treat that as worth discussing rather than something that left with the compound.

US: Schedule III anabolic steroid under the CSA. Historically FDA-approved; current marketing status should be verified against the Orange Book.

Papers about this compound, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

• Randomized clinical trial of tamoxifen alone or combined with fluoxymesterone in postmenopausal women with metastatic breast cancer
  J Clin Oncol, 1988
• Tamoxifen and fluoxymesterone versus tamoxifen and danazol in metastatic breast cancer--a randomized study
  Breast Cancer Res Treat, 1988
• Induction chemotherapy of dibromodulcitol, Adriamycin, vincristine, tamoxifen, and Halotestin with methotrexate in metastatic breast cancer: an Eastern Cooperative Oncology Group Study (E1181)
  Am J Clin Oncol, 1998

• FLUOXYMESTERONEJ Am Med Assoc · 1957
• Fluoxymesterone; a new oral androgenBr Med J · 1959
• Fluoxymesterone-induced gynaecomastia in a patient with childhood aplastic anaemiaBMJ Case Rep · 2015
• Acceleration of delayed growth with fluoxymesteroneActa Paediatr Scand · 1982
• Fluoxymesterone ("halotestin"): a new androgenMed J Aust · 1959
• Fluoxymesterone and the development of sexual behavior in the golden hamsterDev Psychobiol · 1981
• Impact of androgen receptor expression in fluoxymesterone-treated estrogen receptor-positive metastatic breast cancer refractory to contemporary hormonal therapyBreast Cancer Res Treat · 2016
• Fluoxymesterone therapy in advanced breast cancerN Engl J Med · 1958
• The effects of fluoxymesterone administration on testicular functionJ Clin Endocrinol Metab · 1977
• [Anabolic action of fluoxymesterone]Dia Med · 1959
• Evaluation of tamoxifen doses with and without fluoxymesterone in advanced breast cancerAnn Intern Med · 1983
• [Fluoxymesterone in gynecological hormone therapy]Riv Ostet Ginecol Prat · 1959