Necessary for both men and women, testosterone is a sex steroid hormone that is especially important in men’s health. It promotes fat burning, supports muscle building, ensures that libido is high, and keeps you happy, among a variety of other benefits.

Testosterone has become a hot button topic lately because more and more guys are being found to have a lot less of it.

Even the guys that do have healthy levels want more.

A dip in testosterone levels can come with age, periods of inactivity, certain medications, changes in diet, medical issues or even treatments for cancer and most of those reasons are treatable and can be changed without too much change to your lifestyle.

The supplement industry has jumped on to the research for testosterone boosters, peddling a mix of both effective and unproven t-boosters.

One of the most famous testosterone boosters within the bodybuilding crowd is 6-OXO.

Can this compound skyrocket testosterone levels as many people claim?

Or is it just another hyped up snake oil?

What is 6-OXO?

Held to a very high standard among pros and amateurs alike, 6-OXO is considered one of the most effective testosterone boosters and aromatase inhibitors.

Placing it within a specific category is tricky for companies as some consider it a pro-hormone, others a testosterone booster, and even more an A.I. (aromatase inhibitor).

I’m of the mindset that because its supposed testosterone boosting effects come from the blocking of aromatase, which is the mechanism behind your testosterone being converted to estrogenic compounds, 6-OXO is best described as an A.I.

How Does 6-OXO Work?

4-Androstene-3,6,17-trione, commonly known as 6-OXO, has been the subject of studies since the 80s.

Back then, the focus was on its ability to bind to the aromatase enzyme and disable it from converting testosterone into estrogenic compounds, which had very important implications for men suffering from estrogen dominance.

Why is this important?

Testosterone vs. Aromatase

If you’re a man with low testosterone levels, you’re going to be experiencing a lot of negative symptoms including weight gain, muscle loss, depression, and man-boobs.

Low testosterone is a vicious cycle and one that’s hard to break out of.

Once your body increases the production of estrogen, your current levels of testosterone are more likely to continue to be converted into estrogen, pushing your t-levels further and further down. 6-OXO was thought to be an effective way to pull the plug on this conversion while promoting natural testosterone production.

Theoretically, the result would be testosterone levels that return to normal and aromatase that is permanently blocked from causing its mayhem. Sounds great, right?

What does science have to say about 6-OXO?

What Does Science Say about 6-OXO?

1. Increased Testosterone

A small-scale study involving 16 men had subjects supplementing with either 300 mg or 600 mg of 6-OXO for eight weeks.

During 5 blood samples, levels of the following were checked: total testosterone, free testosterone, dihydrotestosterone, estradiol, estriol, estrone, SHBG, luteinizing hormone, follicle stimulating hormone, growth hormone, cortisol, and FT/estradiol.

For many of these key variables, there wasn’t a big difference between the two groups; however, when it came to testosterone and DHT, this is where there was a dramatic difference.

Free testosterone levels had increased 90% for the 300 mg 6-OXO group and 84% for the 600 mg 6-OXO group.

As for DHT, which is a far more androgenic hormone than testosterone, levels increased 192% with 300 mg and 265% with 600 mg. (1)

A few important things to note about this study:

Body composition did not change in any of the subjects.

This may be due to the fact that the subjects were not taking part in a resistance training program.

I’ll talk more about the implications of the increase in testosterone and DHT below and how you can use this to your advantage.

Another important thing to note is that aromatase was not completely inhibited.

The implication here is twofold: First, while testosterone and DHT did increase significantly, there may be more room for improvement as the aromatase activity was not completely shut off.

The way to completely inhibit – if it’s possible at all – may be through manipulating the dosage level or length of the time you take the supplement but again, this is only speculation.

Secondly, since the aromatase action was not complete disabled, you may have to watch out for active conversion of the testosterone into estrogen. Supplements respond different for everyone and depending on the active aromatase in the body, testosterone gains may come and provide fuel for estrogen conversion.

I’d recommend getting your testosterone and estrogen levels tested regularly while going through your first cycle with this supplement to see how your body responds.

Since human studies are lacking, what follows is based on the implications of higher testosterone and DHT levels along with user reports.

As always, results may vary.

2. Increased Lean Muscle Mass

With a dramatic increase in free testosterone and DHT, your body will be supporting a highly anabolic environment, which may prompt muscle growth.

The catch is that you need to be using 6-OXO alongside a well-constructed workout program.

You can’t just take 6-OXO and assume you’re going to look like Arnold in eight weeks.

3. Anti-Catabolic

Higher levels of testosterone and DHT may be helpful to prevent protein breakdown or catabolism.

Since both are highly anabolic, lean muscle tissue may be safe especially if you are performing high intensity training, trying intermittent fasting, or both.

4. Increased Strength

One of the primary benefits that users report is the boost in strength levels during their workouts.

This makes complete sense as the anabolic environment that may be present while supplementing with 6-OXO may heighten recovery, which in turn will benefit muscle and strength.

Again, I cannot stress enough that you must be using this supplement as a part of a resistance training program.

How to Take 6-OXO

As demonstrated in the study, you can maximize the benefits by taking 300 mg of 6-OXO each day for one cycle of eight weeks.

Following the cycle, allow your body four weeks to recover.

Is 6-OXO Prohibited?

Absolutely.

While 6-OXO is readily available on a number of popular websites, it is not a supplement that is allowed in performance and sports-related competitions.

Ironically, the sport that it’s most popular with – bodybuilding – is also one that tests for it and will ban competitors who test positive.

Obviously, 6-OXO is easily detected in urine tests so be aware of this if you plan to use it.

You can check out the full list of banned supplements on the World Anti-Doping Agency website.

You also won’t find 6-oxo for sale in any stores like GNC, Vitamin Shoppe, Walgreens, Walmart, or CVS, so don’t even bother searching for it there.

Where To Buy

The most popular brands that you can obtain (online of course), would be:

• Ergo Pharm 6 OXO
• E-Control RX
• Acheter 6-oxo

Side Effects of 6-OXO

The number one side effect of 6-OXO has to do with estrogen suppression. Seems like a good thing, right?

Not exactly.

Just because you’re a man doesn’t mean your body runs on only testosterone.

Estrogen, believe it or not, is just as important for your health as testosterone.

Since 6-OXO is an aromatase inhibitor, which blocks the conversion of testosterone into estrogen. If levels of estrogen get too low, the side effects will mimic that of low testosterone!

Symptoms of low estrogen include:

• Fatigue
• Mood swings
• Low libido
• Muscle loss
• Fat gain

With that said, I must stress again that if you’re going to try 6-OXO, then you should get your testosterone and estrogen levels checked throughout the cycle.

Other common side effects from the increase of DHT while using 6-OXO include

• Hair loss – You can remedy this by taking saw palmetto
• Acne
• Prostate issues – Again, saw palmetto will be helpful here

Highlighted Benefits of 6-OXO

Shown to promote the following:

• Dramatic increase in testosterone
• Boosts dihydrotestosterone (DHT)

May help to trigger the following benefits:

• Protection from catabolism
• Lean muscle mass growth
• Increase in strength levels
• Support for fat burning

Conclusion

6-OXO is a proven testosterone booster and estrogen blocker.

If you have confirmed low testosterone levels, then 6-OXO may be a great alternative to expensive medical treatments.

Be warned though, if you have healthy t-levels, taking 6-OXO may cause estrogen suppression, which produces the same side effects as low testosterone.

Have you used 6-OXO (4-AT)?

Leave your review below!

References

1. Rohle D, Wilborn C, Taylor L, Mulligan C, Kreider R, Willoughby D.
   
   Effects of eight weeks of an alleged aromatase inhibiting nutritional supplement 6-OXO (androst-4-ene-3,6,17-trione) on serum hormone profiles and clinical safety markers in resistance-trained, eugonadal males.
   
   Journal of the International Society of Sports Nutrition. 2007;4:13. doi:10.1186/1550-2783-4-13.

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Author: Rob Miller

Rob Miller founded SupplementCritique.com over 7 years ago, and has been the chief editor ever since. He has a diploma in Advanced Dietary Supplements Advisor, and worked at GNC for 3 years. He KNOWS supplements, both inside and out. Rob currently resides in Jupiter, FL, with his wife of 4 years.  Learn more about him in his Bio here. Follow him on Twitter , Facebook, LinkedIn, or find him on Google +. View all posts by Rob Miller