Androstenetrione and Estrogen Control with 6-OXO 1. What is androstenetrione (6-OXO)?
Androstenetrione (4-androstene- 3,6,17-trione; androst-4- ene-3,6,17-trione), also known as 6-OXO, is a suicidal inhibitor of the enzyme aromatase. Aromatase is the enzyme responsible for the conversion of androgens such as testosterone to estrogens. Inhibition of this enzyme generally results in a lower production of estrogen, and because testosterone is a precursor to estrogen, this signals the body to produce more testosterone as a substrate for estrogen production in an attempt to bring estrogen levels back to normal. 6-OXO was one of the earliest discovered aromatase inhibitors, and it has been demonstrated to significantly increase testosterone levels without short-term adverse effects. For more information on this research, see 6-OXO Research Update by Patrick Arnold. 2. What is post-cycle therapy?
Natural production of testosterone is controlled by the Hypothalamic-Pituitary-Testicular Axis (HPTA). When the body senses the need for testosterone, the HPTA releases GnRH (Gonadotropin-Releasing Hormone), which signals the release of LH (Luteinizing Hormone), which in turn signals the production of testosterone. The increased testosterone then signals back to the HPTA that testosterone needs are met. This provides a negative feedback system that keeps natural testosterone levels within a certain range. However, when an exogenous steroid/prohormone is administered, it will also signal the HPTA that testosterone needs are met. The HPTA then stops signalling the production of testosterone, and this is what leads to the shutdown of natural production of testosterone during a steroid cycle. This is the reason that testicular shrinkage is experienced by many who use steroids/prohormones, especially for longer cycles.
After a cycle, natural testosterone production will slowly return to normal. However, depending on the severity of the shutdown, this process can take months. During this time, anabolic hormone levels will be minimized, and the gains made during the cycle may be lost. The goal of post-cycle recovery (PCT) is to restore both testosterone levels and natural production of testosterone as quickly as possible, among other ancillary goals. Agents commonly used for PCT include HCG (human chorionic gonadotropin), SERMs (selective estrogen receptor modulators) such as clomiphene (clomid) and tamoxifen (nolvadex), and aromatase inhibitors. In most cases, these are prescription drugs. 3. When is PCT necessary?
PCT is necessary after any steroid/prohormone cycle, no matter what the substance. Short cycles (1-2 weeks) may be an exception, although some amount of PCT is still wise in these cases. The length of PCT will generally depend on how long the cycle was. For a 4 week cycle, PCT will usually last 2-3 weeks, while for a 12 week cycle it may last as long as 6 weeks. For longer cycles, use of HCG if possible is highly recommended. 4. What is the role of 6-OXO in PCT?
6-OXO is the most effective PCT agent that can be legally sold as a supplement. By inhibiting estrogen production, the HPTA is signalled to increase testosterone levels to compensate – in other words, 6-OXO inhibits one of the negative feedback signals that decreases the signalling of testosterone production. This allows for faster restoration of natural testosterone levels, in addition to a lowering of estrogen levels which may be high post-cycle (depending on the prohormone/steroid used). Still, 6-OXO isn't perfect. Recovery of LH (recall that this is the signal for testosterone production) is not the only issue post-cycle, especially if testicular atrophy has occured. Also, if the steroid/prohormone used does not aromatise to estrogen, estrogen levels will be low to begin with (because if natural testosterone production is halted, natural estrogen production is decreased as well), in which case an aromatase inhibitor will presumably have less of an effect. Nevertheless, 6-OXO is still one of the best options out there for PCT. 5. What are the side effects of 6-OXO?
The side effects of 6-OXO are those that can be expected from increased testosterone (and DHT) production. The most common complaint is acne (although this also shows that the product is working). Increased sex drive is also common. With long-term use, risk of BPH (prostate enlargement) and male pattern baldness may be increased, and the possibility of these occuring may be reduced by concurrent use of finasteride (propecia, proscar) or, in the case of BPH, saw palmetto. 6. If I have access to clomid or nolvadex, should I use it instead of 6-OXO?
There is much debate on this topic, so there is no conclusive answer. More tend to lean towards the use of a SERM for multiple reasons, such as the fact that they are tried and true. The reasons to prefer one over the other is an in-depth debate that will not be covered here, but both are good options. Since feedback also varies, it may be best for the individual to give both substances a try and see what they like best. 7. Can 6-OXO be used as a standalone to increase testosterone levels?
Yes, although most users do not report positive results. The reported side effects (such as acne) usually outweigh the potential benefits. Another consideration is that continual use of 6-OXO will be quite expensive. Also, although the present research is promising in this regard, the long-term safety of 6-OXO is still not established. However, this still remains the most effective legal way of increasing testosterone levels without causing shutdown, and may be especially useful for those with low baseline testosterone. 8. What dose of 6-OXO should be used?
6-OXO should be started immediately post-cycle at a high dose, which is then tapered down weekly. The starting dose for the first week is usually 600 mg, although some go with 800 mg or more. Here are some examples:
After a 4 week cycle:
Week 1: 600 mg
Week 2: 300 mg
Week 3: 100 mg
After a 6 week cycle:
Week 1: 600 mg
Week 2: 400 mg
Week 3: 300 mg
Week 4: 200 mg
Dosing preferences will vary, but usually follow this general outline, although sometimes the high dose is used for longer than one week. 6-OXO only needs to be taken once daily, as aromatase levels take a long time to recover. Another potential route is transdermal 6-OXO, and users have reported good results at 100-400 mg using this method.