Trenbolone Hexahydrobenzylcarbonate (Parabolan) — Dosing, Cycles, Half-Life & Side Effects
Trenbolone Hexahydrobenzylcarbonate (Parabolan) is a 19-nortestosterone derivative with a half-life of ~14 days (hexahydrobenzylcarbonate ester; no human PK data - extrapolated from ester-chain class). CRITICAL WARNINGS: (1) 19-nor compound with RISK OF PERMANENT SUPPRESSION. Metabolites persist for months. (2) SIGNIFICANT MENTAL HEALTH EFFECTS including insomnia, night sweats, anxiety, paranoia, aggression. (3) Cardiovascular stress is substantial. (4) No human pharmacokinetic data published — ester-chain extrapolation only. Originally marketed as Parabolan (Negma Laboratories, France; discontinued 1997). Hexahydrobenzylcarbonate ester produces approximately 14-day release profile. ADVANCED USERS ONLY. Primary risks include strong HPTA suppression, prolonged 19-nor metabolite clearance affecting PCT timing. This page is educational harm-reduction reference compiled from peer-reviewed literature — not medical advice, not an endorsement, not a recommendation to use. Consult a licensed clinician before any decision.
Quick Facts
| Class | 19-nor |
|---|---|
| Half-life | ~14 days (hexahydrobenzylcarbonate ester; no human PK data - extrapolated from ester-chain class) |
| Detection window | 150 days |
| Aromatization | No |
| Hepatotoxicity | None |
| Suppression | 10/10 |
| 17α-alkylated | No |
| 19-nor structure | Yes (extended metabolite clearance) |
| Administration | injectable |
Typical Dosing Ranges
Common dose range: 100-300mg per week
Cycle length: 8-12 weeks
Time to steady state: ~70 days
Dose ranges are compiled from published pharmacokinetic studies and community-reported usage. Where a value is community-reported rather than clinically studied, this page and its structured data flag it. Lower end of any range is always the safer starting point.
Stacking Considerations
- 19-nor compound — avoid stacking with another 19-nor (nandrolone/trenbolone) unless you accept extended and overlapping metabolite clearance.
- Incompatible combinations per internal rule set: Deca Durabolin (Nandrolone Decanoate), NPP (Nandrolone Phenylpropionate), tren-ace, tren-enan.
PCT Requirements
- This compound causes clinically meaningful HPTA suppression. Post-cycle therapy is recommended.
- As a 19-nor, metabolites persist for weeks after last dose — PCT start should be delayed until apparent half-life clearance plus adequate wash-out (typically 4–6+ weeks post-last-injection for nandrolone; longer for trenbolone-dominant stacks).
- Depot clearance estimate: ~70 days post-last-dose before SERM start (5 × apparent depot half-life of 336h).
- Never stack two SERMs. Extend a single SERM (tamoxifen OR enclomiphene/clomiphene) rather than combining.
- Use the cycle planner to generate a full protocol based on your complete stack, not this compound alone.
Side Effect Profile
- No human pharmacokinetic data published
- Original formulation discontinued - UGL only
- 19-nor metabolites persist for months; extended PCT required
- SEVERE MENTAL HEALTH EFFECTS (same as other trenbolone esters)
- Cardiovascular strain, prolactin elevation, night sweats
Known Interactions
Trenbolone Acetate + Clenbuterol
major — cardiovascularBoth significantly impact cardiovascular system. Trenbolone raises BP, clenbuterol stresses heart.
Recommendation: Avoid combination. If used, monitor BP and heart rate closely.
Monitor: Blood pressure, Heart rate, ECG
Trenbolone Acetate + T3 (Cytomel/Liothyronine)
moderate — cardiovascularT3 increases metabolism and heart rate while trenbolone affects cardiovascular health.
Recommendation: Use lowest effective doses. Monitor vitals closely.
Monitor: Heart rate, Blood pressure, TSH
Deca Durabolin (Nandrolone Decanoate) + Trenbolone Acetate
moderate — hormonalBoth are 19-nor compounds affecting prolactin and progesterone. Compounding effects on HPTA.
Recommendation: Consider prolactin management (cabergoline/P5P). Recovery may be prolonged.
Monitor: Prolactin, Progesterone, LH, FSH
Deca Durabolin (Nandrolone Decanoate) + Trenbolone Acetate
moderate — hormonalDeca and trenbolone are both 19-nors with long-lasting HPTA suppression.
Recommendation: Not recommended together. Choose one 19-nor per cycle.
Monitor: Prolactin, LH, FSH, Recovery timeline
Trenbolone Acetate + Tamoxifen (Nolvadex)
moderate — hormonalTamoxifen may up-regulate progestin receptors when used with 19-nor compounds.
Recommendation: Consider enclomiphene as alternative SERM for PCT after trenbolone cycles.
Monitor: Progesterone, Prolactin, LH, FSH
Related compounds
Deca Durabolin (Nandrolone Decanoate)
19-nor · t½ 6-12 days (apparent depot terminal half-life; free nandrolone elimination ~4.3h after de-esterification; Minto CF et al. 1997 PMID 9103484)
Trenbolone Acetate
19-nor · t½ 3 days (72h from IM depot; no human PK data - veterinary compound)
Trenbolone Enanthate
19-nor · t½ 7 days (168 hours)
Anadrol (Oxymetholone)
Orals · t½ 8-9 hours
Monitoring (Bloodwork & Vitals)
- Comprehensive metabolic panel (baseline, mid-cycle, post-cycle)
- Lipid panel (total cholesterol, HDL, LDL, triglycerides)
- CBC (hemoglobin, hematocrit — watch for erythrocytosis)
- Sex-hormone panel (Total T, Free T, Estradiol sensitive, SHBG, LH, FSH)
- Blood pressure (weekly self-check; flag systolic >140 or diastolic >90)
Baseline bloodwork is recommended before any cycle. Discontinue if liver enzymes exceed 3× upper limit of normal or if hematocrit exceeds 54%.
Frequently Asked Questions
What is the half-life of Trenbolone Hexahydrobenzylcarbonate (Parabolan)?
Trenbolone Hexahydrobenzylcarbonate (Parabolan) has a half-life of approximately ~14 days (hexahydrobenzylcarbonate ester; no human PK data - extrapolated from ester-chain class). Clearance estimate: 336h × 5 = 1680h = 70 days (ester half-life; 19-nor metabolites persist months). This figure is used to determine injection frequency (for esters) and post-cycle clearance timing.
What is the typical dose range for Trenbolone Hexahydrobenzylcarbonate (Parabolan)?
Commonly reported ranges for Trenbolone Hexahydrobenzylcarbonate (Parabolan): 100-300mg per week. Cycle length: 8-12 weeks. These are compiled from published studies and community-reported usage — individual response varies and lower end is always preferred.
Does Trenbolone Hexahydrobenzylcarbonate (Parabolan) suppress natural testosterone?
Trenbolone Hexahydrobenzylcarbonate (Parabolan) causes severe suppression of the HPTA axis (score 10/10). Post-cycle therapy (PCT) is recommended after use. As a 19-nor compound, metabolites persist for weeks-to-months and shift PCT timing later than non-19-nor cycles.
Does Trenbolone Hexahydrobenzylcarbonate (Parabolan) aromatize to estrogen?
Aromatization profile: No. Minimal to no aromatization expected, so aromatase inhibitors are not typically indicated for this compound alone.
What is Trenbolone Hexahydrobenzylcarbonate (Parabolan) typically used for?
Trenbolone Hexahydrobenzylcarbonate (Parabolan) is commonly used for: ADVANCED USERS ONLY - not for beginners under any circumstances, Advanced 19-nor bulk/strength cycles, Those who have assessed and accepted mental health risks. Intended-use context does not imply safety — every use case carries the same underlying pharmacological risks.
Citations
- Minto CF et al.. 1997. J Clin Endocrinol Metab — Trenbolone hexahydrobenzylcarbonate (Parabolan) half-life extrapolated from hexahydrobenzylcarbonate ester-chain steroid literature - approximately 14 days. NO HUMAN TRENBOLONE-HEXA PK STUDIES EXIST. Original Parabolan formulation (Negma Labs, France) discontinued 1997
- Hartgens F, Kuipers H. 2004. Sports Medicine — 19-nor AAS class suppression - trenbolone hexa shares trenbolone's HPTA suppression; supports suppressionScore 10/10 with extended recovery (same as acetate/enanthate)
- Practitioner consensus + Liu 2025. 2025. Subst Use Misuse — Trenbolone hexa CV profile identical to other trenbolone esters. NO HUMAN RCT. Extrapolated cardioStrain 7/10
- Webster JP, Kover SC, Bryson RJ, Harter T, Mansell DS, Sedlak DL, Kolodziej EP. Transformation kinetics of trenbolone acetate metabolites and estrogens in urine and feces of implanted cattle. J Chromatogr A. 2015 Jan 30;1374:122-31. PMID: 25550108 (cattle residue studies - no human PK data)
Disclaimer
StackItSmart is an independent harm-reduction reference. The content above is compiled from peer-reviewed literature and is not medical advice, not an endorsement, and not a recommendation to use Trenbolone Hexahydrobenzylcarbonate (Parabolan). Performance-enhancing compounds carry legal, endocrine, cardiovascular, and hepatic risks. Consult a licensed clinician before any decision. StackItSmart does not provide sourcing, procurement, or dosing prescriptions.