Aromasin (Exemestane) in Bodybuilding: A Comprehensive Guide
Aromasin (Exemestane) is a steroidal aromatase inhibitor (AI) initially developed to treat hormone-sensitive breast cancer. However, it has gained significant popularity in bodybuilding for its ability to reduce estrogen levels and counteract estrogenic side effects caused by anabolic steroid use.
This guide provides an in-depth analysis of how Aromasin works, why bodybuilders use it, proper dosages, potential side effects, and how it compares to other aromatase inhibitors like Arimidex and Letrozole.
How Aromasin Works in the Body
Aromasin is a suicidal aromatase inhibitor, meaning it permanently deactivates the aromatase enzyme responsible for converting testosterone into estrogen. Unlike other AIs that temporarily block aromatase activity (such as Arimidex), Aromasin binds irreversibly to the enzyme, ensuring that estrogen suppression remains consistent.
This property makes Aromasin particularly valuable in bodybuilding since it effectively reduces estrogen without causing a severe rebound effect once discontinued.
Why Do Bodybuilders Use Aromasin?
Preventing Estrogenic Side Effects
Anabolic steroids such as testosterone, Dianabol, and Nandrolone can convert to estrogen via the aromatase enzyme. This excess estrogen can lead to undesirable side effects, including:
- Gynecomastia (man boobs) – Growth of breast tissue due to high estrogen.
- Excessive Water Retention – Leads to a bloated look and can increase blood pressure.
- Increased Fat Gain – Higher estrogen levels promote fat storage, particularly in the lower body.
By lowering estrogen, Aromasin prevents or minimizes these effects, helping users maintain a leaner and more defined physique.
Promoting a Harder, Drier Look
High estrogen levels contribute to water retention, which can blur muscle definition. Competitive bodybuilders often use Aromasin to achieve a hard, vascular, and dry appearance, especially during cutting cycles or pre-competition phases.
Increasing Natural Testosterone Production
Since estrogen suppresses natural testosterone production, reducing estrogen levels with Aromasin can boost testosterone output. This is beneficial during Post Cycle Therapy (PCT) when bodybuilders need to restore their hormonal balance after a steroid cycle.
Avoiding Estrogen Rebound
Unlike Arimidex or Letrozole, which only temporarily inhibit aromatase, Aromasin permanently deactivates the enzyme. This makes it less likely to cause an estrogen rebound, which can occur when stopping other AIs.
Aromasin Dosage for Bodybuilding
On-Cycle Estrogen Control (During Steroid Cycle)
- Dosage: 10–25 mg every other day
- When to Use: When taking aromatizable steroids like Testosterone, Dianabol, Deca-Durabolin, or Equipoise
- Goal: Prevent estrogen-related side effects while maintaining optimal estrogen levels
Post Cycle Therapy (PCT)
- Dosage: 12.5–25 mg per day for 2–4 weeks
- When to Use: After finishing a steroid cycle, typically in combination with Clomid (Clomiphene) or Nolvadex (Tamoxifen)
- Goal: Restore natural testosterone production and prevent estrogen rebound
How to Adjust Aromasin Dosage
- If experiencing joint pain, fatigue, or low libido, estrogen levels may be too low, and the dosage should be reduced.
- If symptoms of gynecomastia or water retention appear, dosage may need to be increased.
- Blood work (Estradiol test) is the best way to determine the correct dosage.
Aromasin Side Effects and Risks
While Aromasin is effective, excessive estrogen suppression can cause unwanted side effects, including:
Joint Pain and Stiffness
Low estrogen levels can lead to dry and aching joints, making movements uncomfortable.
Reduced Libido & Erectile Dysfunction
Although Aromasin can boost testosterone, too much estrogen suppression can negatively affect sexual function and mood.
Fatigue & Mood Swings
Estrogen plays a role in neurological function. If levels drop too low, users may experience lethargy, depression, or irritability.
Weakened Immune System
Low estrogen can impair immune response, increasing susceptibility to illness.
Bone Density Loss
Estrogen helps maintain bone strength. Long-term estrogen suppression may increase the risk of osteoporosis.
How to Prevent Side Effects
- Use the lowest effective dose to manage estrogen without crashing it.
- Monitor estrogen levels with blood tests to ensure they are in an optimal range.
- Incorporate joint support supplements (e.g., fish oil, glucosamine) if experiencing joint pain.
Aromasin vs. Other Aromatase Inhibitors (Arimidex & Letrozole)
Feature | Aromasin (Exemestane) | Arimidex (Anastrozole) | Letrozole (Femara) |
Type | Steroidal AI (irreversible) | Non-steroidal AI (reversible) | Non-steroidal AI (strongest) |
Estrogen Reduction | Moderate to High | Moderate | Very High |
Risk of Estrogen Rebound | Low | Moderate | High |
Impact on Cholesterol | Mild negative | Moderate negative | Severe negative |
Half-Life | 24–48 hours | 48 hours | 2–4 days |
Best Use Case | Balanced estrogen control, PCT | On-cycle estrogen control | Aggressive estrogen suppression |
Key Takeaways
- Aromasin is preferred for PCT and moderate estrogen control with a lower risk of rebound.
- Arimidex is commonly used on-cycle for gradual estrogen suppression.
- Letrozole is the strongest AI but can crash estrogen levels too much if not used carefully.
Final Thoughts: Should You Use Aromasin in Bodybuilding?
Aromasin is a powerful AI that effectively controls estrogen without causing a rebound. It is particularly useful for:
- Preventing gynecomastia and water retention during steroid cycles
- Enhancing a hard, dry muscular look
- Supporting testosterone recovery during PCT
However, overuse can lead to low estrogen side effects like joint pain, low libido, and mood swings. The key is proper dosing and blood work monitoring to maintain optimal estrogen levels.