While many people know about common performance-enhancing tactics like anabolic agents and blood doping, it may be surprising to learn that even substances in prescription medications used to fight breast cancer, like letrozole, may be abused to enhance performance.
Here’s what athletes subject to anti-doping rules need to know about letrozole and competing clean.
What is letrozole?
Letrozole is an aromatase inhibitor, meaning that it blocks an enzyme responsible for a key step in the formation of estrogens. More specifically, the enzyme aromatase is responsible for the conversion of androgens (e.g., testosterone) into estrogens. Letrozole inhibits this process, which reduces the amount of estrogen in the body.
Letrozole is in medications used to fight estrogen-dependent breast cancer in women. By decreasing the amount of estrogen in the body, letrozole can slow or stop the growth of some types of breast cancer cells that need estrogen to grow.
Legally, letrozole is only available with a doctor’s prescription. However, there are websites that illegally sell letrozole and other performance-enhancing drugs.
How is letrozole performance enhancing?
Athletes who abuse anabolic steroids might use an aromatase inhibitor like letrozole to prevent the formation of estrogens, and therefore reduce or prevent the unwanted and feminizing effects of anabolic steroid use. These side effects include male breast development (gynecomastia), water retention, and belly fat. In addition, male athletes may use abuse aromatase inhibitors like letrozole to boost their own natural levels of testosterone by preventing its breakdown.
Letrozole Effects for Gynecomastia and Estrogen Control
Letrozole is such a powerful AI and so effective at controlling estrogen that some steroid users have reported being able to successfully reverse the effects of gyno when using this drug. Even so, it is always preferable to try and prevent gyno from rearing its head at all rather than depending on any drug to reverse it; because while some people might have luck with this when using Letrozole, others will find that more advanced gyno is still not reversible without surgery.
Letrozole will reduce the entire circulating levels of estrogen in the body, unlike SERM drugs which will target specific receptors and are most useful for controlling gyno – while Letrozole will also be powerful for controlling water retention which is the other main adverse effect of steroid use that we all want to avoid.
When using Letrozole you can expect your estrogen levels to be reduced considerably as this is the most powerful AI we can access currently. In fact it could result in your estrogen dropping too low at times (yes, this can be an issue for men as we do require some small amount of estrogen for normal functioning). But during steroid cycle your main aim with an AI is to reduce, minimize and ultimately prevent the estrogenic side effects that are almost certain to come about when using steroids that aromatize.
There are additional benefits to this estrogen controlling power of Letrozole too: because it means you can prevent water retention, your physique will take on a much harder, drier and ripped appearance because you’re not holding on to water. This can make Letrozole particularly useful for competitive bodybuilders who want to eliminate as much fluid retention as possible and Letrozole is the best AI to help with this goal.
What are the side effects to using letrozole?
The use of letrozole is associated with many side effects, including an increase in cholesterol levels, a decrease in bone density, hot flashes, night sweats, nausea and vomiting, loss of appetite, constipation, diarrhea and heartburn, muscle and joint pain, fatigue and dizziness, swelling of hands, feet, ankles and lower legs, and difficulty sleeping.
As with all types of drugs, the effects that each individual experiences will vary and that means some people will be able to use Letrozole without a single side effects, while others might have one or more adverse reactions to the drug. The good news is that you have a good selection of other drugs available if Letrozole proves problematic for you.
The profile of possible side effects are comparable for Letrozole as the similar AI Arimidex. Fatigue, muscle aches, diarrhea, constipation, and chest pain are noted as specific side effects that Letrozole can experience but this usually applies to women using it long term as a cancer medication.
Most male steroid users who make use of Letrozole tolerate it well when it’s used at the recommended dosages. Many men will experience no noticeable side effects at all. Taking excessive doses of Letrozole provides an obvious increased risk of serious side effects.
Taking a closer look at some of the possible side effects of Letrozole can help you to be aware of any signs that you might need to lower your dose:
Is letrozole prohibited in sport?
Yes, letrozole is specifically listed as prohibited at all times (both in and out-of-competition) in the category of Hormone and Metabolic Modulators on the World Anti-Doping Agency Prohibited List.
Can I get a Therapeutic Use Exemption (TUE) for letrozole?
Yes, for athletes with a specific therapeutic need to treat certain medical conditions, such as breast cancer, it is possible to get a TUE. Here is more information about applying for a TUE.
Do dietary supplements contain letrozole?
Letrozole is a powerful drug that cannot be legally included and/or marketed as an ingredient in dietary supplements. USADA is not currently aware of any instances of a dietary supplement contaminated with letrozole. However, the use of dietary supplements is always at the athlete’s own risk. Please read USADA’s recommendation on how to reduce the risk of testing positive from dietary supplements.
My Conclusion and Recommendation
Letrozole is possibly the most powerful aromatase inhibitor for preventing gyno and this should be your ultimate goal: to stop the condition from starting to develop at all while you’re using steroids. Prevention is better than cure when it comes to gyno, but if you do find that you’re starting to get those early signs then Letrozole has in some cases stopped them and reversed them.
Fully developed gyno can’t be reversed by Letrozole or any other drug (only surgery) but it is a very effective AI overall for gyno and other estrogen related effects. As yet there are no known studies proving just how effective Letrozole might be at reversing or improving gyno, unlike with the SERM Nolvadex which has shown in studies to deliver very positive improvements to men with gyno.
If you enjoyed this guide and would like more real, NO-BS information on cycling steroids, then pick up Straight From the Underground (my recommended underground steroid handbook). Everything in this book is based on first hand experience, not theory.