• Post-cycle testosterone restoration: Blocks estrogen receptors at the hypothalamus/pituitary, lifting negative feedback and stimulating LH/FSH release, which drives endogenous testosterone recovery after anabolic steroid use ^[5].
• Gynecomastia prevention / suppression: Acts as an estrogen antagonist in breast tissue, blocking the estrogenic signalling responsible for gynecomastia development in men ^[1][2].
• Estrogen receptor blockade: Active metabolite endoxifen competes with estradiol for ERα and ERβ binding, inhibiting estrogen-driven gene transcription in target tissues ^[1][3].
• Bone-protective (partial agonist): Exerts partial estrogenic agonism on bone tissue, helping preserve bone mineral density — a clinically useful property in post-menopausal contexts ^[4].
• Breast cancer risk reduction: FDA-approved to reduce invasive breast cancer incidence in high-risk individuals and as adjuvant therapy following diagnosis of ER+ breast cancer ^[2][6].

Est. delivery

3–7 business days · EU tracked

Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.

Tamoxifen Citrate (brand name Nolvadex) is a non-steroidal Selective Estrogen Receptor Modulator (SERM) used clinically to treat and prevent estrogen receptor-positive (ER+) breast cancer, and widely used in performance contexts as a post-cycle therapy (PCT) agent to restore natural testosterone production and manage estrogenic side effects ^[1][2].

Tamoxifen is a prodrug: it has relatively low affinity for the estrogen receptor on its own, but is converted in the liver — via CYP2D6 and CYP3A4 — into potent active metabolites (notably 4-hydroxytamoxifen and endoxifen) that bind estrogen receptors with up to 100× greater affinity than the parent compound ^[1][3]. These metabolites act as estrogen antagonists in breast tissue, blocking estrogen's effects, while acting as partial agonists in bone and the uterus — hence the term "selective" modulator ^[2][4]. In men and in PCT contexts, blocking estrogen receptors at the hypothalamus and pituitary removes the negative feedback that suppresses gonadotropin release, thereby stimulating the pituitary to secrete LH and FSH and consequently driving testicular testosterone production ^[5].

1. 1.NCATS Inxight Drugs — Tamoxifen Citrate
2. 2.News-Medical — Tamoxifen Mechanism of Action
3. 3.Medicine.com — Tamoxifen Dosage, Mechanism, Half-Life (CYP2D6 interactions)
4. 4.ScienceDirect Topics — Tamoxifen Citrate (SERM tissue selectivity)
5. 5.DailyMed — Tamoxifen Citrate Tablet (NLM / FDA label)
6. 6.Healthline — Tamoxifen: Side Effects, Dosage, Uses (clinical dose summary)
7. 7.FDA SOLTAMOX Label — Tamoxifen Citrate Oral Solution (contraindications, VTE, uterine cancer)
8. 8.RxList — Nolvadex (Tamoxifen Citrate): Warnings, Interactions, Side Effects
9. 9.Clinical Trial ICF — Tamoxifen Side Effects Summary (NCT04504331)
10. 10.ClinicalTrials Protocol — Tamoxifen Citrate Pharmacokinetics (NCT01196936)
11. 11.Clinical Trial Protocol — Tamoxifen Citrate Adverse Reactions ATAC data (NCT04059484)