Out of all the injectable steroids available, trenbolone is the one that should be used with extreme caution and only after plenty of research into its side effects and common cycles have been carried out. Trenbolone side effects can be very bad to many users, so much so that they will not use it despite its very positive effects on the body and strength. Firstly, as trenbolone is so androgenic, all side effects that are seen with strong androgens can be expected (if prone) with trenbolone. If one is prone to male pattern baldness (MPB) than trenbolone will likely speed this up. Some users find acne on trenbolone worse than when on any other steroid. Certainly Trenbolone is not recommended for female users due to its strong androgenic properties and the common side effects that manifest themselves in females who use strong androgens.
Despite the fact that trenbolone cannot aromatise, due to the progesterone route it can cause things like gynecomastia, but this will only really happen in the presence of estrogen. This does happen though in many users, as trenbolone is usually stacked with a testosterone, which obviously can and will convert to estrogen. Gynecomastia from trenbolone can be quite bad many will find, however if you do not suffer from this than other estrogenic side effects should not be of worry, as trenbolone does not cause any water retention or similar, but in fact often gives a hardened look and feel to the muscles.
Trenbolone also seems to give many users poor sleep patterns and insomnia. In addition, it can cause severe sweating in many, both during the night time and also just from doing the smallest of activities such as walking up stairs, etc. It also can impair to a certain degree, cardiovascular function, which means that it is not ideal for use in those who regular partake in such sports or activity that require a decent level of cardiovascular fitness.
Trenbolone also increases blood pressure in many users, some to such a degree that they have to cease using it. Thus it is recommended that one who wishes to use trenbolone, invests in a blood pressure monitor so they can regularly measure their blood pressure and keep an eye on it throughout the cycle.
Many people claim that trenbolone has a negative effect on the kidneys. There are many of these claims certainly across the Internet since its use has become more widespread. However, there is no real evidence for these claims, and certainly I have seen many long-term users of trenbolone have kidney function tests that are well within the normal range. Perhaps the reason for this theory is the fact that when using trenbolone, many find that their urine can become a much darker more orange-brown colour. However, this is due to the fact that trenbolone undergoes very little modification or breakdown and is excreted as a rust-coloured oxidised form in the urine. In addition to this, any damage to kidney may not even be directly due to the trenbolone, but more to do with the increased sweating and water loss from excessive body heat whilst on trenbolone, without the sufficient addition of water intake. Thus it is recommended if running trenbolone to keep the water intake high.
As trenbolone is such a strong steroid, it is very harsh on the HTPA axis and will shut down the body's natural testosterone production very easily and, for many, very harshly. It is comparable to 'deca dick' that people can experience with deca, and longer cycles may need to include the use of HCG to restore one's own natural production of testosterone. Recovery from cycles containing trenbolone is not easy, and requires a very well thought out and stringent PCT routine and diet.
It has also been suggested through research that trenbolone actually (although aiding slightly in fat loss) reduces endogenous T3 levels. Thus some advocate the use of 25mcg T3 throughout a trenbolone cycle. This writer does not personally think that this is necessary; however it is something that users may wish to consider when using trenbolone, especially if their natural T3 production is on the lower side of the normal range. It is a very good idea to get blood work done both before and after any cycle including trenbolone.
The so called 'tren cough' or 'Fina cough' is well known amongst many tren users. Some users seem to get the cough following every injection; others never or extremely rarely will get the cough. Usually it is manifested upon injection, with a tightness in the chest, and a metallic taste in the back of the mouth, followed by an uncontrollable violent cough which can be quite frightening, as anyone who has experienced it will tell you, whether it's for the first time or not. There have been some very elaborate theories about the reasons for getting the cough from trenbolone, some of which have had mechanisms involving molecules that only trenbolone affects resulting in bronchioconstriction, etc. However, the fact remains that many users have also experienced the same cough from steroids such as equipoise and testosterone cypionate. In addition, these mechanisms that are proposed are highly unlikely to occur immediately upon injection, as that is too fast a timescale for the proposed mechanism. Thus it must be the result of something entering the blood stream and traveling to the lungs for the cough to be manifested that quickly.
This leads us onto the next theory suggested by many which is that trenbolone is produced by many UGLs, and as such is made with higher percentages of Benzyl Alcohol (BA) than pharma grade products are, and it is the alcohol that is causing the reaction. The only problem with this theory is that trenbolone is made by most UGLs with the same BA percentages as things such as testosterone propionate, and nandrolone decanoate. If it was purely the BA concentration, than we would expect to see the cough with these other products as well, which we do not. Thus, as we have eliminated the oil, solvents and carriers, it leaves us with the Trenbolone product itself as the potential culprit.
One thing that you notice about trenbolone is that it is often a golden-brown / rust colour when in oil solution. If the hormone powder is refined to greater than 99.5% purity or so, then the colour of trenbolone in solution actually gives a very light golden colour, much like other testosterone products; however, refining the hormone to this level of purity is extremely difficult. This is why there is colour variation from batch to batch with different underground labs; something as small as 0.1% purity can affect the colour of the final product.
As mentioned above when discussing kidney effects of trenbolone, the oxidised trenbolone is a rust colour - much like the colour seen of trenbolone in oil solution. What you also notice with steroids such as Equipoise and to a lesser degree, testosterone cypionate, is that these steroids too are hard to very highly refine and often a browny-rust colour, more so than products such as testosterone propionate, etc. It is very likely then that these oxidised particles get into the blood stream upon injection and this causes some sort of anaphylactic (allergic) reaction in the lungs as the particles react with the alveoli, perhaps. This seems to be confirmed by the fact that the darker the trenbolone is the more likely one is to get a cough (personal and general experience). The best way to try and avoid this is to firstly inject very slowly and not move the needle around after aspirating, and also mixing the trenbolone with another product such as test prop.