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 controlGynecomastia
Tamoxifen Tablets
RxPrescription onlyTaken by mouth · Twice a week · 10–20 mg · Estrogen control · Gynecomastia
Starting at $69/mo
Tamoxifen (Nolvadex, commercial brand): selective estrogen receptor modulator (SERM) for breast tissue, used for gynecomastia or elevated breast tissue during testosterone therapy. Oral, daily or as needed.
How many tablets per month?
MonthlyEvery 3 months
9 tabletsper month
You'll receive 9 tablets per month. $89 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 estrogen effects in breast tissue without lowering overall estrogen
- Reduces gynecomastia (enlarged breast tissue) during testosterone therapy
- Oral dosing, flexible scheduling
Every plan includes
- Personalized, physician-guided plan
- 9 tablets 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 tamoxifen?
(ta-MOX-i-fen)
Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks estrogen in breast tissue while allowing estrogen to work elsewhere in the body. It is used off-label when breast tissue enlarges or becomes tender during testosterone therapy, a condition called gynecomastia. Typical dose: 10–20 mg daily or as needed. Unlike aromatase inhibitors, tamoxifen does not lower overall estrogen; it only blocks it in the breast.
- How it is taken
- Taken by mouth
- How often
- Twice a week
- Dose range
- 10–20 mg
- Form
- Estrogen control · Gynecomastia
Tissue-selective
blocks estrogen in breast tissue only, not systemically
Tamoxifen is prescribed when gynecomastia appears or worsens during testosterone therapy. It does not lower estrogen system-wide, which preserves bone and cardiovascular benefits of estrogen. Long-term use (>1 year) requires monitoring.
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
tamoxifen.
Tamoxifen is a selective estrogen receptor modulator approved for breast cancer. In men it is used off-label for idiopathic infertility and gynecomastia. The male evidence is mostly meta-analyses of small trials and uncontrolled cohorts.
- Pregnancy rateOR 2.42
A 2013 meta-analysis of randomized trials of oestrogen antagonists (clomiphene or tamoxifen) in idiopathic male infertility found a higher pregnancy rate than controls (pooled odds ratio 2.42, 95% CI 1.47 to 3.94). It also found higher sperm concentration and motility.
Chua et al., Andrology 2013 - Later reviewuncertain
A later 2025 meta-analysis could not confirm the effect of SERMs on natural pregnancy, because the studies were limited and varied, and called the effect uncertain.
Search of PubMed for tamoxifen in male infertility - Gynecomastiauncontrolled data
The main gynecomastia evidence is an uncontrolled cohort, not a randomized trial. Reported response is high, but without a control group it cannot be separated from natural regression.
Search of PubMed for tamoxifen gynecomastia in men
What the studies found
- Higher pregnancy rate than controls in idiopathic male infertility: pooled odds ratio 2.42 (95% CI 1.47 to 3.94) across randomized trials of clomiphene or tamoxifen (Chua et al., Andrology 2013).
- Higher sperm concentration and motility in the same pooled trials (Chua et al., Andrology 2013).
- Used for gynecomastia in men off-label; the strongest evidence is an uncontrolled cohort, so the benefit is not proven against a control group.
Trial results are for tamoxifen in men with idiopathic infertility, not for other uses. Compounded tamoxifen was not the form studied, and the 2013 meta-analysis pooled small trials with differing methods.
What this does not say
- The fertility benefit is inconsistent across studies.
- Tamoxifen carries clot and endometrial risks that are established in women.
- Gynecomastia response is not compared with a control group in the strongest data.
The research
behind it.
Tamoxifen is a SERM: it binds to estrogen receptors in breast tissue and blocks estrogen signaling there, while allowing estrogen to act in bone and cardiovascular tissue. This makes it ideal for breast-specific effects.
In testosterone therapy, gynecomastia can appear when estrogen conversion is high or sensitivity is elevated. Tamoxifen reduces breast swelling and tenderness without system-wide hormone suppression.
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 Tamoxifen Tablets?
Taken by mouth, twice a week. The starting prescription is 1 tablet (10 mg) each time. Your physician sets your own dose and it is printed on your label.
What strengths does Tamoxifen Tablets come in?
The pharmacy carries 2: 10 mg, 20 mg. Your physician chooses which one you get.
How much arrives in each shipment?
9 tablets at the starting strength, shipped to your door from a licensed US pharmacy.
How long does tamoxifen take to reduce breast swelling?
Noticeable reduction in breast tenderness and swelling usually appears within 2–4 weeks of starting 10–20 mg daily. Full resolution may take 2–3 months. Continue regular check-ins with your physician; if gynecomastia worsens despite tamoxifen, you may need estradiol testing or dose adjustment.
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.
Tamoxifen 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
Capsule
Anastrozole Capsules
Anastrozole, an aromatase inhibitor used in men to control estrogen levels during testosterone therapy. 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
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.