Description

Tamoxifen, commercially known as Nolvadex, is an anti-estrogen belonging to the triphenylethylene class. It is classified as a selective estrogen receptor modulator (SERM) and has a mixed action: antagonist in some tissues and agonist in others.

In men, tamoxifen acts primarily as an estrogen receptor blocker, preventing estrogen from exerting its effect in various parts of the body. At the level of the hypothalamic-pituitary-gonadal axis, Nolvadex reduces the negative feedback of estrogen on the hypothalamus, promoting an increase in GnRH secretion. This process stimulates the pituitary gland to produce LH and FSH, hormones that are essential for the resumption of endogenous testosterone synthesis and spermatogenesis.

Unlike other antiestrogens, tamoxifen does not directly reduce estrogen levels in the blood, but blocks its action at the receptor level. In bone tissue, however, it exhibits agonist activity, contributing to the protection of mineral density and reducing the risk of osteoporosis.

---

Tamoxifen vs. Clomiphene

Nolvadex (tamoxifen) and clomiphene both belong to the SERM category, but differ in terms of selectivity and tissue distribution:

• Clomiphene acts in a more targeted manner on the pituitary gland, proving particularly effective in rapidly reactivating the hormonal axis.

• Tamoxifen binds to estrogen receptors more uniformly throughout the body, making it particularly effective in the prevention and treatment of estrogen-dependent gynecomastia.

Neither drug alters estrogen metabolism: estrogen continues to be broken down by the liver and does not accumulate in the body.

---

Important warnings

Tamoxifen increases the expression of progesterone receptors. For this reason, it is not recommended in cycles based on progestin drugs such as nandrolone or trenbolone. In such contexts, clomiphene is preferable.

---

Dosages

The commonly used dosage of tamoxifen (Nolvadex) ranges from 10 to 40 mg per day, in one or two daily doses, depending on the objective and context of use (PCT, gynecomastia prevention, hormonal support).

---

Main effects

• Estrogen receptor blockade

• Stimulation of endogenous testosterone production

• Prevention of estrogen-induced gynecomastia

• Support for bone health

• Improvement in lipid profile (reduction in total cholesterol)

---

Side effects

The side effects of tamoxifen are generally rare and mild, but may include:

• Breast tenderness or discomfort

• Headache

• Nausea or gastrointestinal disorders

• Redness

• Transient visual disturbances (blurred vision)

---

Pharmacological profile

• Half-life: 5–7 days

• Frequency of intake: once a day

---

Contraindications

• Active anticoagulant therapy

• History of thromboembolism or stroke

• Endometrial disorders or uterine neoplasms

• Hematological disorders (anemia, leukopenia, thrombocytopenia)

• Cataracts or visual impairment

• Hypercalcemia

---

Storage

• Keep out of reach of children

• Store in a cool, dry place.

• Protect from direct sunlight

• Store at room temperature

• Do not use after the expiration date