Injection
Gonadorelin
A copy of the brain's own GnRH signal that keeps the testes producing testosterone and sperm, used alongside testosterone therapy and in fertility care. Prescribed and dosed by a licensed physician.
Starting at $159/mo
Estrogen controlAromatase inhibitor
Anastrozole Capsules
RxPrescription onlyTaken by mouth · Twice a week · 0.1–1.1 mg · Estrogen control · Aromatase inhibitor
Starting at $63/mo
Anastrozole (Arimidex): aromatase inhibitor that blocks estrogen production, used twice weekly when estradiol is elevated during testosterone therapy. Requires recent estradiol lab before starting.
How many capsules per month?
MonthlyEvery 3 months
9 capsulesper month
You'll receive 9 capsules per month. $79 billed monthly. Cancel anytime.
Real prices from our pharmacy. Longer plans cost less per month and are billed up front. Pause or cancel anytime.
- Blocks aromatase enzyme to lower estrogen production
- Used only when estradiol is high during testosterone therapy
- Twice-weekly dosing when needed for estrogen control
Every plan includes
- Personalized, physician-guided plan
- 9 capsules per month, monthly and 3-month
- Dispensed by a US-licensed compounding pharmacy
- Unlimited protocol adjustments and messaging
- Ongoing support and check-ins
- Pause or cancel anytime
- Reviewed by our in-house physicians
- Physician-guided care
- Ongoing, expert support
- 100% online
- Free, discreet shipping
What is anastrozole?
(a-NAS-tro-zole)
Anastrozole is an aromatase inhibitor (AI), an enzyme blocker that stops testosterone from converting to estrogen. It is used off-label in testosterone therapy when blood estradiol levels are too high, causing breast tenderness, mood changes, or water retention. Typical dose: 1 mg twice per week. It is only dosed when your latest estradiol lab shows elevation; routine use is not recommended.
- How it is taken
- Taken by mouth
- How often
- Twice a week
- Dose range
- 0.1–1.1 mg
- Form
- Estrogen control · Aromatase inhibitor
Estradiol-dependent
only used when your recent lab shows high estradiol
Anastrozole requires a recent estradiol level before your physician starts it. Over-suppression of estrogen can harm bone density and cardiovascular health. Dose is adjusted or stopped based on follow-up labs.
How it works,
week by week.
Day 1
A US-licensed physician reviews your symptoms on testosterone (breast tenderness, mood changes, water retention). Estradiol lab is ordered; results guide decisions on aromatase inhibitors or tamoxifen.
Week 1
Estradiol lab comes back. If high, your physician prescribes anastrozole 1 mg twice weekly or tamoxifen 10–20 mg daily, depending on the issue (high conversion vs. breast tissue sensitivity).
Weeks 2–4
Symptoms from high estrogen (breast tenderness, mood swings, bloating) begin to improve. Some people feel better within days; others take 3–4 weeks.
Week 6
Follow-up estradiol lab. If it is now in range, your physician adjusts or stops the AI/SERM. If still high, dose is increased or agent is switched.
Beyond
Estradiol is monitored every 6–12 weeks. Your physician aims to keep estrogen in a healthy range, not suppressed, not elevated, to preserve bone and cardiovascular health.
What you may notice,
and when.
Lab-guided dosing
estradiol levels drive decisions, not symptoms alone
Reduced breast symptoms
tenderness and swelling typically improve in 2–4 weeks
Stable mood and energy
when estrogen is in range, mood and water retention often normalize
Bone and heart monitoring
avoiding over-suppression protects long-term health
Individual results vary. Benefits reflect what Zepym Health members commonly report to their physician at check-ins; they are not the results of a clinical trial.
Safety first:
what to know before you start.
Important safety information and common side effects
Aromatase inhibitors (anastrozole, exemestane) and selective estrogen receptor modulators (tamoxifen) are prescribed off-label to manage estrogen during testosterone therapy. Estradiol must be tested before starting: over-suppression can reduce bone density and harm cardiovascular health. Common side effects: mild joint aches, hot flushes, mood changes. Tamoxifen carries a small risk of blood clots and endometrial changes with long-term use (>1 year). Tell your physician about bone health, prior thrombosis, or family history of clots. Stop and seek care for leg pain/swelling, chest pain, or signs of stroke.
The research behind
anastrozole.
Anastrozole is an aromatase inhibitor approved for breast cancer in women. In men it is used off-label to lower estradiol during testosterone therapy. Evidence in men is small and observational.
- Estradiol on therapyestradiol lower
In 2020, obese men with hypogonadism given anastrozole with a weight-loss programme for six months had higher testosterone and lower estradiol than men on placebo with the same programme (p 0.001 for estradiol). Symptoms and muscle strength did not differ between groups.
Colleluori et al., Front Endocrinol 2020 - Bone and estradiolestradiol matters
A 2009 review found that in adult men estradiol is more strongly linked to bone density, bone turnover and bone loss than testosterone is. Lowering estradiol too far is therefore a bone caution, not a free benefit.
Vandenput and Ohlsson, Nat Rev Endocrinol 2009 - Male infertility reviewreview
A 2021 review of aromatase inhibitors for male infertility. Read it for how the clinical evidence is graded before relying on any sperm or pregnancy claim.
Yang et al., Hum Reprod Update 2021
What the studies found
- Lowers estradiol while raising testosterone: men with obesity and hypogonadism given anastrozole with weight loss for six months had higher testosterone and lower estradiol than placebo (p 0.001 for estradiol; Colleluori et al., Front Endocrinol 2020).
- Raises the testosterone-to-estradiol ratio more than clomiphene does: estradiol fell on anastrozole, while the ratio rose more than on clomiphene (Helo et al., J Sex Med 2015).
- Improves semen parameters in infertile men in clinical studies reviewed in 2021, though the trials are small and mostly observational (Yang et al., Hum Reprod Update 2021).
Trial results are for men in a weight-loss context, not for men on testosterone alone. Compounded anastrozole and provider-only tablets were not the product studied, and estradiol targets vary between clinics.
What this does not say
- No large randomized trial in men on testosterone shows that anastrozole improves symptoms or outcomes.
- Lowering estradiol too far can harm bone and lipids.
- Blood tests for estradiol are needed on treatment; the level, not the pill, is what the clinic should track.
The research
behind it.
Aromatase inhibitors block the conversion of testosterone to estrogen in fat and muscle tissues. When estradiol is high during testosterone therapy, anastrozole reduces it back to physiologic range.
Aromatase inhibitors are standard in testosterone therapy when estradiol is elevated. Your physician decides based on symptoms and lab values, not routine use. Excessive suppression of estrogen carries its own risks.
Testosterone beyond the gym:
what the trials show across body systemsSex drive, blood counts, bone, blood sugar and thinking: what the Testosterone Trials and T4DM found, and where the evidence stops.Read the researchTestosterone and the heart:
what TRAVERSE foundThe safety question most men ask first: heart events, fractures, prostate and blood counts, in the largest placebo-controlled trial of testosterone.Read the research
what the trials show across body systemsSex drive, blood counts, bone, blood sugar and thinking: what the Testosterone Trials and T4DM found, and where the evidence stops.Read the researchTestosterone and the heart:
what TRAVERSE foundThe safety question most men ask first: heart events, fractures, prostate and blood counts, in the largest placebo-controlled trial of testosterone.Read the research
Getting started
takes a few minutes.
- 1
Connect with a physician
Answer a few questions online and a US-licensed physician reviews your health, history and goals to make sure treatment is right for you. 100% online. No in-person visit required.
- 2
Get your discreet shipment
If approved, your treatment is compounded by a US-licensed, LegitScript-certified pharmacy, inspected for quality, and shipped discreetly to your door.
- 3
Receive continuous support
Start with one goal, then keep building over time. Unlimited physician messaging, easy refills and dose adjustments, all from the Zepym Health app.
Frequently asked questions
Contact supportHow do I take Anastrozole Capsules?
Taken by mouth, twice a week. The starting prescription is 1 capsule (0.1 mg) each time. Your physician sets your own dose and it is printed on your label.
What strengths does Anastrozole Capsules come in?
The pharmacy carries 7: 0.1 mg, 0.125 mg, 0.25 mg, 0.4 mg, 0.5 mg, 0.75 mg, 1.1 mg. Your physician chooses which one you get.
How much arrives in each shipment?
9 capsules at the starting strength, shipped to your door from a licensed US pharmacy.
When do I use anastrozole?
Only when your estradiol lab is elevated and you have symptoms like breast tenderness, mood swings, or bloating. Your physician orders an estradiol test, and if it is high, prescribes 1 mg twice per week. When your next lab shows estradiol in normal range, you may reduce or stop the dose.
Do I always need an aromatase inhibitor on testosterone?
No. Many men convert testosterone to estrogen at a normal rate and do not need an AI. Your physician orders an estradiol lab; if it is normal, no AI is needed. Only if estradiol is high and causing symptoms does your physician prescribe one.
Can I use tamoxifen and aromatase inhibitors together?
Not typically. They work differently (tamoxifen blocks estrogen in breast tissue; AIs lower overall estrogen). Your physician chooses the right tool for your issue: high overall estrogen calls for an AI; breast tissue sensitivity calls for tamoxifen.
What if I need an AI long-term?
Long-term aromatase inhibitor use can reduce bone density over time. Your physician may recommend bone density screening (DEXA scan) and calcium/vitamin D supplementation if AI use extends beyond 1–2 years.
How often do I check estradiol levels?
Initial check: before starting any AI or SERM. After starting or adjusting dose: 6 weeks. Then: every 3–6 months once stable, or when symptoms change. Annual bone health screening is recommended with long-term AI use.
Anastrozole educational content reviewed by our physician
Scott Nass, MD Doctor of Medicine, board-certified in Family Medicine
Charles R. Drew University and David Geffen School of Medicine at UCLA. Family Medicine residency at Ventura County Medical Center.
More options
in this area.
Capsule
Anastrozole - Men
A low-dose aromatase inhibitor for men on testosterone therapy whose blood work shows high estradiol, easing breast tenderness and water retention. Slow-release capsule, prescribed and dosed by a licensed physician.
9 capsules per month
Starting at $63/mo
Tablet
Anastrozole Tablets
FDA-approved anastrozole tablets, an aromatase inhibitor used at low doses in men on testosterone therapy whose estradiol runs high. Prescribed by a licensed physician only after blood work.
5 tablets per month
Starting at $63/mo
Dissolving tablet
Cabergoline Tablets
Cabergoline, a dopamine agonist used to manage prolactin levels. Commercial formulation, prescribed and dosed by a licensed physician. Requires periodic monitoring for valvular heart disease with long-term use.
Starting at $239/mo
References
- 1.Endocrine Society Clinical Practice Guidelines for testosterone therapy: managing estrogen with aromatase inhibitors. J Clin Endocrinol Metab, 2018
- 2.Tamoxifen for gynecomastia in testosterone replacement therapy: a review of evidence. J Clin Med, 2021
Prescription products require an online evaluation with a licensed medical professional who will determine if a prescription is appropriate. Products are compounded by a licensed pharmacy. The FDA has not reviewed or approved compounded products for any use for safety, efficacy, or quality. Compounded medications are not FDA-approved brand-name products.