Blog
Patients
Testosterone Cypionate Sterile Injectable Blends
May 28, 2024
What Are Testosterone Cypionate Injectable Blends? Testosterone Cypionate is a synthetic form of testosterone replacement therapy, designed to absorb when […]
Anastrozole
Anastrozole is a nonsteroidal aromatase inhibitor that blocks the enzyme aromatase, limiting the conversion of testosterone to estrogen in peripheral tissues.
Common dosage forms
Capsule
Cream
Gel
Oral Tablet
Pellets
Troche
What is anastrozole?
Anastrozole is a nonsteroidal aromatase inhibitor that blocks the enzyme aromatase, preventing the overaromatization of testosterone to estradiol in peripheral tissues. Aromatase activity is present in fat, bone, muscle, hair, vascular, and breast tissue. Estradiol (E2) is the most potent form of estrogen. By lowering estradiol levels, anastrozole may help men with low testosterone that are experiencing excess aromatization with their testosterone therapy; an important component in understanding overall anastrozole uses.
Some patients with certain medical conditions like insulin resistance and obesity are more susceptible to over-aromatization of testosterone to estradiol. Estradiol is necessary in small amounts for men to help support heart, bone, and brain health. But this conversion when taken to excess can be associated with negative outcomes such as mood swings, fluid retention, and a lack of symptom improvement with testosterone therapy. Anastrozole can limit this from happening and help patients experience the intended benefit from their HRT.
Anastrozole is available through traditional and compounded prescription oral and sterile pellet forms as well as combination injectable with testosterone. In men, maintaining the appropriate testosterone/E2 ratio is essential for fertility, mood, and sexual function. Anastrozole may help limit over‑conversion of testosterone while supporting healthy levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH).
Because aromatase activity increases with body fat, dosing may vary, and understanding what anastrozole is, what anastrozole is used for, and when to take anastrozole with testosterone is important for individualized hormone management with a licensed provider.
Who May Benefit From Anastrozole Therapy?
Men on testosterone therapy or with fertility concerns
Men undergoing testosterone therapy who experience signs of excess estrogen—such as bloating, mood changes, chest or breast tenderness, or reduced response to therapy—may benefit from anastrozole’s ability to decrease aromatization and support a healthier testosterone‑to‑estradiol ratio. Men with fertility or sexual‑function concerns may also benefit, as estradiol plays an important role in sperm count, libido, and erectile function, and anastrozole may help when estradiol levels are too high.
Increased aromatase activity
Adults with higher body fat or other factors that increase aromatase activity may benefit from anastrozole because aromatase is abundant in adipose tissue and drives the conversion of testosterone into estradiol. By blocking this enzymatic activity, anastrozole may help stabilize hormone patterns, especially in adults whose baseline aromatase activity contributes to excess estrogen or disrupted hormone balance.
Access clinical studies on Anastrozole
- Osadchiy V, Munoz-Lopez C, Jiang T, Naelitz BD, Parekh N, Vij SC, Mills JN, Lundy SD, Eleswarapu SV. Combination clomiphene citrate and anastrozole duotherapy improves semen parameters in a multi-institutional, retrospective cohort of infertile men. Transl Androl Urol. 2024 Feb 29;13(2):245-251.
- Lockie AWC, Grice P, Mathur R, Pearce I, Modgil V. Diagnosis and treatment of hypogonadism in men seeking to preserve fertility – what are the options? Int J Impot Res. 2025 Feb;37(2):109-113.
- Ide V, Vanderschueren D, Antonio L. Treatment of Men with Central Hypogonadism: Alternatives for Testosterone Replacement Therapy. Int J Mol Sci. 2020 Dec 22;22(1):21. doi: 10.3390/ijms22010021.
- Glaser RL, York AE. Subcutaneous Testosterone Anastrozole Therapy in Men: Rationale, Dosing, and Levels on Therapy. Int J Pharm Compd. 2019 Jul-Aug;23(4):325-339
- Biundo B. Treatment Options for Male Hypogonadism.6 Int J Pharm Compd. 2024 Jan-Feb;28(1):6-14.
- Biundo B. Hormone Treatment Options for Males: What to do for Men with Low Testosterone. Int J Pharm Compd. 2024 Jan-Feb;28(1):28-32.
- Awouters M, Vanderschueren D, Antonio L. Aromatase inhibitors and selective estrogen receptor modulators: Unconventional therapies for functional hypogonadism? Andrology. 2020 Nov;8(6):1590-1597.
Access package inserts for Anastrozole
Commonly Asked Questions
Clinical studies show anastrozole does not typically cause significant weight gain. However, some adults—especially those under 60, smokers, or those who had a mastectomy—may be more likely to gain weight during therapy. Any weight gain that occurs is usually small and most often happens within the first year.
No, anastrozole is not a chemotherapy drug; it is a nonsteroidal aromatase inhibitor used as hormone therapy, lowering estrogen rather than killing cancer cells directly. Studies have shown that testosterone combined with a low dose of anastrozole may help relieve menopausal symptoms when estrogen therapy is not appropriate for breast cancer survivors or women at high risk for the disease. By reducing estradiol production, anastrozole may also be used in postmenopausal women with estrogen‑dependent breast cancer.
Anastrozole’s major side effects should be discussed with your medical provider. Some adverse effects include decreased bone mineral density which may increase the risk of osteoporosis and fractures, as well as musculoskeletal symptoms such as joint pain, stiffness, and back discomfort.
Related Medications
Related Insights
Blog
Patients
Belmar Pharma Solutions Answers 8 Commonly Asked Questions About Hormones
February 8, 2022
Life during menopause can be tough. Between the hot flashes, mood swings, and sleepless nights, hormones can be your best […]
Get Started
Submit a Prescription
Become a Provider
