It has been mentioned several times throughout this profile that Parabolan is by no means a beginner level anabolic steroid, and even more so due to the fact that this is a long-acting variant of Trenbolone affixed with the Hexahydrobenzylcarbonate ester. This ester grants Trenbolone a 14 day half-life, which means that a slow rise in blood plasma levels is achieved over time, after which levels will remain steady (so long as administration schedules are consistent), and this also means that a much longer clearance time for Parabolan is required before the hormone is completely gone from the body. This means a lot for Parabolan side effects, especially considering Trenbolone is already regarded as an anabolic steroid that is a little harsher and more serious in the arena of side effects.
Trenbolone, where side effects are concerned, carries with it most of the typical side effects associated with all anabolic steroids. But it also carries with it a handful of side effects that are unique to the compound itself. These include: coughing fits during or shortly after injection (nicknamed ‘Tren cough’), excessive perspiration/sweating (especially at night), insomnia (nicknamed ‘Trensomnia’), significant increases in aggression and mood, and Progestogenic side effects. For a more complete and detailed description of all of these unique side effects attributed to Trenbolone, please see the Trenbolone Side Effects section of the Trenbolone profile. Parabolan side effects indeed share all of these same side effects being that it is a Trenbolone product, and that Parabolan must be approached with extra caution and extra diligence due to its long-acting nature.
Because Parabolan is a very long-acting variant of Trenbolone, more users are drawn towards the faster acting variant of Trenbolon (Trenbolone Acetate) when side effects are concerning to the user. This is because Trenbolone Acetate expresses a fast clearance out of the body, and because the side effects unique to Trenbolone can be very uncomforting for many users, it might be appealing to utilize a fast acting form of Trenbolone in the event that side effects become too great to handle. In such a situation, the ‘ride’ can be stopped quite quickly. This is not so with Parabolan, which requires almost 30 days before the hormone has completely cleared from the body, making undesirable side effects remain for much longer after the last injection has been made.
Estrogenic Side Effects
Parabolan side effects do not directly include estrogenic side effects due to the fact that Trenbolone itself cannot be aromatized into Estrogen at any dose. Estrogenic side effects manifested during a Parabolan cycle are more likely to occur due to the use of other aromatizable anabolic steroids used alongside Parabolan. It is very important to note, however, that Trenbolone exhibits significant Progestogenic activity in the body, expressing a greater affinity for the Progesterone receptor in the body than Progesterone itself . The Progesterone receptor and the Estrogen receptor hold close correlations with one another in the body, and it is well-known that the activation of the Progesterone receptor can and does result in an increased sensitivity and up-regulation of the Estrogen receptor. This can result in Estrogen-related side effects arising during the use of Parabolan in an environment where Estrogen levels are within normal (or close to normal) ranges, merely due to an up-regulation of the sensitivity of the Estrogen receptor to circulating Estrogens. There seems to be variation between individuals as to the sensitivity of this phenomenon. The use of SERMs (Selective Estrogen Receptor Modulators) such as Nolvadex (Tamoxifen) and possibly aromatase inhibitors (AIs) such as Aromasin (Exemestane) might possibly mitigate this issue, and prevent the possibility of gynecomastia or other Estrogen-related side effects from becoming a problem. Progestogenic side effects (which are nearly identical to estrogenic side effects, such as gynecomastia, bloating, water retention, etc.) are known to become more of an issue and more commonly experienced when Trenbolone is utilized in a high-Estrogen environment.
For more in-depth and detailed information in regards to the Progesterone-Estrogen interactions, please read through the Trenbolone profile, as well as the Trenbolone Side Effects sub-section.
Androgenic Side Effects
Because Trenbolone is a very strong androgen (5 times the strength of Testosterone), Parabolan side effects indeed do include androgenic side effects. As a matter of fact, androgenic side effects can become a significant issue with Parabolan when higher doses are used in particular. Androgenic side effects include: increased sebum secretion (oily skin), increased bouts of acne (linked to increased sebum secretion), bodily and facial hair growth, benign prostatic hypertrophy (BPH), and the increased risk of triggering Male Pattern Baldness (MPB) in individuals that possess the genetic trait required for the condition to manifest itself.
Because Trenbolone does not metabolize into a stronger androgen like Testosterone does, the relative androgenicity resultant from Trenbolone does not change and what androgenic strength it expresses is normally to be expected on average from Parabolan use. Because the 5-alpha reductase (5AR) enzyme does not metabolize Trenbolone into a stronger androgen, 5AR inhibitors such as Proscar, Finasteride, or Propecia will do nothing to reduce the androgenic strength or effects of Parabolan. In regards to the androgenic effects of Trenbolone in particular, increased aggression, loss of patience, anger, and possible mood alterations are a commonly discussed and/or experienced lot of Parabolan side effects.
It is very important for every individual deciding whether or not to use parabola to realize that those who commonly have issues with their temper, anger, or patience to made the responsible decision and avoid the use of Parabolan (or any Trenbolone product). The other possibility is for the individual to exert proper self-control when one’s anger, temper, or patience tends to get the best of them. It is irresponsible for anyone to utilize a very strong compound such as Parabolan while knowing full well of its potential effects and allow oneself to lose control in a fit of anger and land themselves in trouble, and instead of laying the blame upon themselves for exercising poor self-responsibility, they would tend to blame the anabolic steroid. Although not all individuals exhibit irritability and increased anger with Trenbolone use, some do and it is best to be aware of the potential effects beforehand.
HPTA and Endogenous Testosterone Production Side Effects
It is a general rule for all anabolic steroids that when administered in supraphysiological doses, endogenous Testosterone and HPTA (Hypothalamic Pituitary Testicular Axis) production and function will either stop for the duration of use, or at the very least become severely suppressed. Following any anabolic steroid cycle, the use of Testosterone production promoting compounds should be utilized for a 4 – 6 week period. These include compounds such as HCG (Human Chorionic Gonadotropin), SERMs such as Nolvadex (Tamoxifen) and/or aromatase inhibitors. The combination of compounds taken for the 4 – 6 week period after an anabolic steroid cycle has ended is what is known as PCT (Post Cycle Therapy), and is essential to restoring normal hormonal function. Without the assistance of a PCT protocol, the human body might not fully or properly recover resulting in insufficient endogenous Testosterone production possibly for life (known properly as hypogonadism).
In the case of Parabolan side effects, Trenbolone in particular has demonstrated quite highly suppressive action on the HPTA in the initial testing that had been conducted upon its release in 1967 by Roussel-UCLAF, finding it to be approximately three times the strength of Testosterone in regards to the suppression of gonadotropin production when compared mg for mg.
Hepatotoxic Side Effects
Parabolan, being an injectable compound, is a Trenbolone variant that is not C17-alpha alkylated (C17AA), and therefore expresses no significant hepatotoxicity (liver toxicity). However, Trenbolone itself exhibits a very strong resistance to metabolism in the body, which does include metabolism in the liver. With that being said, Trenbolone has been linked to severe hepatotoxicity (cholestasis) in some bodybuilders who have utilized excessive doses of Trenbolone. It should be made clear that significant liver toxicity is highly unlikely with the use of Trenbolone, but that the possibility still does exist (especially when very high doses are used).
Cardiovascular Side Effects
All anabolic steroids express negative cardiovascular side effects, which include vascular reactivity (hardening of the blood vessels), increased blood pressure, increased hematocrit levels, and most impacting: the negative alteration of cholesterol values. Anabolic steroids have a tendency to temporarily reduce HDL (the good cholesterol), and many will also temporarily increase LDL (the bad cholesterol). This alteration can impact the risk the user has in developing cardiovascular disease, especially the longer the user remains on a cycle of anabolic steroids. Injectable anabolic steroids tend to be the least impacting, while oral anabolic steroids tend to be the worst (due to their route of administration and impact on the liver, which is essentially the cholesterol processing center for the human body). Parabolan, being an injectable anabolic steroid, possibly impacts cholesterol levels to a far lesser degree than oral anabolic steroids but at the same time impacts cholesterol levels negatively to a greater degree than most injectables due to the increased resistance to metabolism in the body. Cholesterol values tend to quickly return to normal once anabolic steroid use has ceased, and it is highly advised for the anabolic steroid user to engage in a clean diet alongside the supplementation of healthy omega-3 fats in order to maintain healthy levels of HDL cholesterol. The use of cardiovascular support supplements is also recommended.
 Characterisation of the affinity of different anabolics and synthetic hormones to the human androgen receptor, human sex hormone binding globulin and to the bovine progestin receptor. Bauer, Meyer et al. Acta Pathol Microbiollmunol Scand Suppl 108 (2000):838-46.
 Unique steroid congeners for receptor studies. Ojasoo, Raynaud. Cancer Research 38 (1978):4186-98.
 Disposition of 17 beta-trenbolone in humans. Spranger, Metzler. J Chromatogr 564 (1991 ):485-92.
 Cholestasis induced by Parabolan successfully treated with the molecular adsorbent recirculating system. Anand JS et al. ASAIO 2006. JanFeb;52(1 ):117-8.