Overview
Parabolan is a 19-nortestosterone derivative and one of the most potent anabolic-androgenic steroids in common use. As a long-ester formulation, it has a half-life of ~8 days (192 hours), allowing less frequent dosing. Trenbolone does not undergo aromatization to estrogen.
With a half-life of ~8 days (192 hours), Parabolan supports less frequent dosing schedules. Administered via IM injection, it has a bioavailability of approximately 95% via its primary route.
Half-life approximately 8 days. Slightly slower absorption rate constant than the enanthate ester. Brand name: Parabolan.
Mechanism of Action
Parabolan's pharmacological activity involves the following key pathways:
Androgen Receptor Binding
Parabolan binds to androgen receptors in skeletal muscle and other tissues, initiating transcription of androgen-responsive genes involved in protein synthesis and nitrogen retention.
Non-Aromatizing
Parabolan does not undergo aromatization to estrogen, which is a distinguishing pharmacological property among anabolic compounds.
Progestin Activity
Trenbolone has affinity for the progesterone receptor, which is a relevant pharmacological consideration alongside its androgenic activity.
Dosing Protocols
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Dose
50 mg/week
Route
Intramuscular
Frequency
Once weekly
Duration
8-16 weeks
Dose
400 mg/week
Route
Intramuscular
Frequency
Once weekly
Duration
8-16 weeks
Frequently Asked Questions
What is Parabolan (Trenbolone Hexahydrobenzylcarbonate) and how is it different from other trenbolone esters?
Parabolan is the brand name for trenbolone hexahydrobenzylcarbonate – the only trenbolone ester ever approved for human pharmaceutical use, originally produced in France in 1980 and discontinued in 1997. The hexahydrobenzylcarbonate ester is the heaviest and longest-acting of the three main trenbolone esters, giving Parabolan an elimination half-life of approximately 14 days versus roughly 7 days for trenbolone enanthate and 3 days for trenbolone acetate. Active trenbolone base content per 100 mg is approximately 65 mg, compared to 68 mg for the enanthate ester.
What is the half-life of Parabolan and how often does it need to be injected?
Trenbolone hexahydrobenzylcarbonate has an elimination half-life of approximately 14 days (336 hours). Due to this long half-life, injection frequency is typically once or twice per week – many users inject twice weekly to smooth out plasma level fluctuations, while some use a once-weekly schedule given the compound's slow release kinetics.
How long does Parabolan take to reach steady state?
At a 14-day half-life, steady-state plasma levels are reached at approximately 70 days (10 weeks) of consistent dosing. This means Parabolan cycles are often run for 12–14 weeks or longer to allow sufficient time at peak steady-state concentrations before the end of the cycle.
What is the typical dosage for Parabolan?
The original clinical ampoule contained 76 mg (equivalent to 50 mg trenbolone base), dosed once every 10 days. Community bodybuilding protocols typically range from 150–300 mg per week. Because the hexahydrobenzylcarbonate ester delivers less active base per milligram than the enanthate ester, milligram-equivalent dosing to trenbolone enanthate requires slightly higher total volume.
What compounds is Parabolan commonly stacked with?
Like all trenbolone esters, Parabolan fully suppresses endogenous testosterone and is almost always run alongside a testosterone base – commonly Testosterone Cypionate or Testosterone Enanthate at 400–500 mg per week. Halotestin is noted in advanced circles as a complementary compound for strength and hardness. Masteron Enanthate is frequently paired due to comparable injection scheduling and synergistic physique effects.
What are the side effects of Parabolan compared to other trenbolone esters?
Side effects of Parabolan are identical to those of all trenbolone variants: androgenic effects (hair loss in predisposed individuals, acne, body hair), cardiovascular strain, natural testosterone suppression, night sweats, mood changes, and cardiovascular impact on lipid profiles. The key practical difference from shorter esters is management: side effects from Parabolan take longer to subside after discontinuation due to the 14-day half-life, meaning it is less forgiving if unwanted reactions emerge during a cycle.