What is Tren? And is it Dangerous?

What is Tren? And is it Dangerous?

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Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to steroid use.

Tren, short for trenbolone, is an anabolic steroid used by many bodybuilders off-label to promote muscle growth and mass gain. It can actually be more powerful than natural testosterone for muscle building.

But has tren actually been studied in medical trials, and if so what were the effects? What are the risks and downsides of its use? Is it legal in the US? And how do real tren users describe the effects and downsides of the drug?

In this article we’ll answer all of these questions and more as we review medical research on the potential benefits and the risks of tren use. We’ll overview its legality in the US, and feature real user reviews.

Is Tren Proven Effective for Muscle Building?

Tren is one of the most potent steroids in the world. A medical review published in the Steroids journal describes how tren binds to androgen receptors at three times the affinity of testosterone. This suggests that it can actually increase muscle mass and power to a higher degree than exogenous testosterone.

A 2015 clinical trial found that tren use decreased body fat and increased muscle mass in rats. Improvements to insulin sensitivity were also noted.

A medical review published in the Medicine & Science in Sports & Exercise journal analyzed the  effects of anabolic steroids in muscle cells in strength-trained athletes. Unsurprisingly, use of steroids increased muscle size and number of muscle cells in the athletes.

We conclude from the available research that tren is likely to be effective for increasing muscle mass, increasing muscle size and improving power and resistance exercise performance.

But what are the risks of its use? We’ll review in the next section.

Is Tren Dangerous?

All anabolic steroids have side effects, and tren is no different.

Tren can have negative effects on the cardiovascular system. A case report published in the Emergency journal documents a young man who experienced a heart attack due to tren use. The report states that tren use can cause high blood pressure and thrombosis (blood clotting).

A 2010 medical review examined the negative health effects of anabolic steroid use. The common side effects are reported as: sexual dysfunction, negative cardiovascular changes, liver toxicity and negative behavioral changes.

Another medical study published in the Journal of Internal Medicine reported that anabolic steroid users died at three times the rate of non-users, and more than 10% of them experienced acne, gynecomastia (enlarged breasts in men) and erectile dysfunction.

We consider tren to be dangerous based on a review of clinical literature, and we do not recommend its use, nor do we recommend the use of any anabolic steroids.

A YouTube video reviews some clips from a top bodybuilder named Larry Wheels who explains some of the downsides and negative side effects he’s experienced from tren use:

Before And After of Tren Use

A YouTube video from popular fitness and bodybuilding channel “More Plates More Dates” reviews before-and-after images from a real tren user who posted his journey on Reddit:

Is Tren Illegal in the US?

Anabolic steroids including trenbolone are currently illegal in the U.S. without a prescription. We haven’t come across any clinical situations where this compound is being prescribed, although it may theoretically be beneficial for testosterone deficiency or tissue wasting.

The Drug Enforcement Agency (DEA) explains that anabolic steroids are Schedule III substances under the Controlled Substances Act.

We strongly urge patients who are considering tren use to speak with a doctor first, both about their individual genetic risk and about the potential for a prescription, rather than purchasing it illegally.

Real Tren User Shares Experience

A YouTube creator named Brandon Harding has a video explaining how tren impacted his life including his training, his relationship and even his bloodwork:

Our Testosterone Support Picks

Bulletproof Magnesium is our top testosterone support pick, because magnesium is a mineral that is clinically shown to increase free and total testosterone in athletes and in sedentary individuals.

Bulletproof Magnesium costs under $17 at the time of updating this article.

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Illuminate Labs sells a Panax Ginseng Extract supplement which is third-party tested, and costs only $15 on a subscription basis. 

Stay up-to-date on our research reviews


Tren is an anabolic steroid that can improve muscle mass and exercise performance, but it comes with a significant risk of side effects including increased cardiovascular risk and erectile dysfunction. A medical study found that tren users were three times more likely to die than non-users over the study period.

We do not recommend using tren, and it’s important to note that the drug is illegal without a doctor’s prescription.

Tren doesn’t necessarily improve aesthetic appearance or strength in all individuals. Also, as we highlighted in a before-and-after video, some tren users experience physical changes that could be achieved without the drug.

Most of the clinical studies on tren are conducted on animals rather than humans, because it was originally approved for use in animals. It’s challenging to get clearance for compounds with known negative health effects in human trials.