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Hepatotoxicity warning

Methyltrienolone is 17α-alkylated for oral bioavailability — a structural feature directly responsible for the most severe hepatotoxic class of AAS. Cholestatic injury, peliosis hepatis, and hepatic adenoma are all class-documented. Cycle length must be capped (typically < 6-8 weeks); LFTs (ALT, AST, GGT, bilirubin) baseline + every 2 weeks on cycle. Stop immediately on ALT/AST > 3× ULN or symptomatic jaundice.

Methyltrienolone

Extensively Studied

17α-methylated trenbolone — the oral version of the most potent mainstream injectable AAS, sold via gray-market UGLs and used in lab… | AAS · Oral

Aliases (6)
Metribolone · R1881 · Mtren · Oral Tren · Methyltrenbolone · RU-1881
TYPICAL DOSE
500-1000 mcg/day
ROUTE
Oral (tablet)
CYCLE
None
STORAGE
Room temp; original container
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Cycle structure & PCT AAS oral
Ester
enanthate
Cycle
1-2 week
Frequency
weekly
PCT
Required
Phase 1 — On cycle

Ramp dose over week 1, hold steady through cycle weeks. Track baseline labs (TT/FT/E2/SHBG/HCT/lipids/LFTs) at week 0; recheck at week 4 and end-of-cycle.

Phase 2 — Bridge / cease

On the last dose, the ester clears over its half-life window (enanthate = est. 7 days). PCT begins after the active compound has cleared.

Phase 3 — PCT (post-cycle therapy)

Standard PCT is enclomiphene 12.5-25 mg/day or clomid 50/50/25/25 over 4 weeks (or nolvadex 20/20/10/10). HCG bridge optional during cycle to preserve testicular volume + faster restart. Bloodwork at PCT week 4 + 8 to confirm HPG axis recovery (LH, FSH, TT back to baseline).

Overview TL;DR

17α-methylated trenbolone — the oral version of the most potent mainstream injectable AAS, sold via gray-market UGLs and used in lab science as the radioligand R1881. Combines tren-class psychiatric/CV/HPG damage with 17α-methyl class-leading hepatotoxicity (cholestasis, peliosis hepatis, adenoma risk). Never FDA-approved in 60+ years. Pre-contest bodybuilding lore caps use at 1-2 weeks for this exact reason. Categorical SKIP-PERMANENT for any user including Dylan; sits in the "essentially universally bad idea" AAS tier alongside fluoxymesterone and methyltestosterone.

Mechanism of action

Methyltrienolone is trenbolone (estra-4,9,11-trien-3-one) with a 17α-methyl group bolted on. That single structural change does two things:

  1. Makes it orally bioavailable — the methyl group blocks first-pass hepatic deactivation that destroys oral testosterone and oral trenbolone. This is the same trick used in methyltestosterone, fluoxymesterone, oxandrolone, stanozolol, and methandrostenolone (Dianabol).
  2. Makes it catastrophically hepatotoxic — the same 17α-methyl group is the structural feature responsible for the entire 17α-alkylated class's class-leading hepatic damage profile (cholestatic injury, peliosis hepatis, hepatic adenoma, hepatocellular carcinoma).

Layered onto trenbolone's already-extreme pharmacology:

  • AR binding affinity ~5× testosterone (per parent trenbolone) — methyltrienolone retains and arguably exceeds this; in laboratory binding studies R1881 is the gold-standard AR radioligand because of its high affinity and minimal cross-reactivity.
  • Glucocorticoid receptor (GR) agonist — drives anxiety, sleep destruction, cardiovascular damage, connective-tissue catabolism (the "tren-class" subjective profile).
  • Progestogenic activity — prolactin elevation, gynecomastia risk that aromatase inhibitors don't address.
  • Non-aromatizing — does not convert to estradiol, removing estrogen's cardioprotective effects (HDL crash, vascular endothelial damage).
  • 5α-reductase resistant — does not convert to DHT but is itself extraordinarily androgenic.
  • HPG suppression: among the most severe of any AAS — LH/FSH crash within days; recovery post-cycle slow and uncertain.

The clean way to think about methyltrienolone's risk profile: take trenbolone's already-extreme cost profile and add a 17α-methyl group's hepatotoxicity on top. There is no harm-reduction win anywhere in the molecule.

Pharmacokinetics No data
Pharmacokinetics data not available for this compound.
No half-life mentions found in the source notes.
Research indications5 use cases

Glucocorticoid receptor (GR) agonist

Most effective

drives anxiety, sleep destruction, cardiovascular damage, connective-tissue catabolism (the "tren-class" subjective profile).

Progestogenic activity

Effective

prolactin elevation, gynecomastia risk that aromatase inhibitors don't address.

Non-aromatizing

Effective

does not convert to estradiol, removing estrogen's cardioprotective effects (HDL crash, vascular endothelial damage).

5α-reductase resistant

Moderate

does not convert to DHT but is itself extraordinarily androgenic.

HPG suppression: among the most severe of any AAS

Moderate

LH/FSH crash within days; recovery post-cycle slow and uncertain.

Quality indicators4 checks
17α-alkylated = liver risk
Limit cycles to 4-6 weeks max; daily TUDCA + NAC; check ALT/AST at week 3.
Tablet integrity
Whole tablets, not crumbled. Coating intact, color uniform.
!
Underground UGL = unknown dose
Lab-test dose unless from a verified pharmacy source. Common to be 50-150% of label.
Tamper-evident packaging
Pharmacy-grade sealed bottles preferred over loose tablets in baggies.
What to expect Generic
  1. 1
    Week 1-2
    Frontload phase. Strength gains start; appetite up.
  2. 2
    Week 3-4
    Visible muscle fullness and recovery acceleration.
  3. 3
    Week 5-8
    Peak performance window. Monitor blood pressure + libido.
  4. 4
    Post-cycle
    PCT week 1-4. Bloodwork at week 6 post-cycle.
Side effects + safety
  • Common (>10% users): Insomnia, night sweats, severe mood lability, irritability, elevated BP, elevated resting HR, sexual dysfunction (mid-cycle ED), severe HPG suppression (universal at any meaningful dose), ALT/AST elevation within first 1-2 weeks, water retention modest.
  • Less common (1-10%): Cholestatic jaundice (yellowing, dark urine, pruritus), gynecomastia (progestogenic — AI does not address), aggression incidents, panic-attack-like episodes, severe acne, accelerated androgenic alopecia, kidney function decline, prostate symptoms.
  • Rare-serious (<1% but worth knowing):
    • Peliosis hepatis — blood-filled cystic lesions in the liver that can rupture catastrophically. 17α-methyl AAS are the primary pharmacologic cause; methyltrienolone is among the highest-risk in the class given its potency.
    • Hepatic adenoma / hepatocellular carcinoma — documented with prolonged 17α-methyl AAS use; methyltrienolone's potency means meaningful exposure happens at lower mg-doses than other 17α-AAS.
    • Acute liver failure — case reports exist for the 17α-methyl class with cholestatic liver failure progressing to ICU admission.
    • Cardiac event (MI, arrhythmia, cardiomyopathy) — HDL crash + hypertension + erythrocytosis + GR activation stack acutely on-cycle.
    • Acute kidney injury — case reports in the 19-nor / tren-class.
    • Psychotic episode, manic episode, suicidal ideation — vulnerable users.
    • Persistent post-cycle hypogonadism — failure to recover endogenous T after even short methyltrienolone exposures, given tren-class HPG suppression severity.
    • Tren cough analog — some users report acute respiratory reactions, though injection-route tren cough is not directly applicable to oral mtren.
  • Specific watch periods:
    • First 7 days: liver enzymes (ALT/AST/GGT/bilirubin) — methyltrienolone hits hepatic injury thresholds fastest of any commonly-discussed AAS.
    • Any RUQ pain, jaundice, dark urine, pruritus, or unexplained fatigue is an emergency stop.
    • First 4 weeks: psychiatric side effects peak (sleep, mood).
    • Mid-cycle through PCT: lipid panel, cardiac surveillance, kidney function.
    • 6-12 months post-cycle: ASIH may persist; some users never recover.
Interactions7 compounds
  • Other 17α-alkylated orals (methyltestosterone, oxandrolone, stanozolol, methandrostenolone, fluoxymesterone):Avoid
    hepatotoxicity additive and often catastrophic.
  • Other AAS:Avoid
    stacks tren-class CV/HPG damage non-linearly.
  • Stimulants (modafinil, amphetamines, high-dose caffeine):Avoid
    additive cardiovascular load.
  • Alcohol:Avoid
    additive hepatic stress (n/a for Dylan but noted for class context).
  • NSAIDs (chronic):Avoid
    additive hepatic + renal stress.
  • SSRIs / antidepressants:Avoid
    unpredictable interaction with AAS-mood axis.
  • Acetaminophen / paracetamol:Avoid
    additive hepatic stress on a 17α-methyl backbone is particularly poorly tolerated.
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