Puregon

Mechanism: Recombinant human FSH (follitropin beta). Binds FSH receptors (FSHR) on Sertoli cells in the testes, activating cAMP/PKA, MAPK/ERK, and PI3K/AKT signalling cascades. Sertoli cells then provide the microenvironment necessary for spermatogenesis. FSH does NOT act on Leydig cells — testosterone production requires LH/HCG.

Dosage (Male Fertility Recovery — Post-AAS):

• Only added if spermatogenesis fails to recover with HCG + SERM after 3+ months
• Standard: 75-150 IU subcutaneously every other day (alongside continued HCG)
• Alternative: 75-150 IU 3x/week
• Escalation (if poor response): Up to 150-400 IU 2-3x/week
• Treatment duration: minimum 3-6 months; up to 12+ months may be needed
• Spermatogenesis takes ~74 days per cycle — patience is required

Dosage (Hypogonadotropic Hypogonadism):

• Phase 1: HCG alone (1500-2000 IU 2-3x/week) until testosterone normalises
• Phase 2: Add follitropin beta 225 IU 2x/week OR 150 IU 3x/week (~450 IU/week total)
• Continue HCG concurrently
• May take up to 12-18 months to achieve maximal spermatogenesis

Administration:

• Subcutaneous injection (abdomen preferred, rotate sites). 29-31g insulin needle.
• Pen cartridges (300/600/900 IU): Pre-filled, no reconstitution needed. Adjustable in 25 IU increments.
• Vials (50/100 IU): Reconstitute lyophilised powder with provided diluent. Use immediately.
• Storage: Refrigerate 2-8°C. May store at room temperature (≤25°C) for up to 3 months. Once pierced, use within 28 days.

Key Notes:

• FSH alone does NOT raise testosterone — always combine with HCG for testosterone normalisation
• Used as a "step-up" when HCG + SERM fails to restore spermatogenesis after 3+ months
• In the post-AAS context, HCG provides LH-like activity on Leydig cells; Puregon specifically targets Sertoli cells to rescue spermatogenesis
• Monitor: semen analysis every 2-3 months, hormones (FSH, testosterone, estradiol, inhibin B)
• Standard FSH immunoassays may not accurately measure exogenous recombinant FSH — levels may appear lower than actual
• Side effects in males are minimal: injection site reactions (~3%), gynecomastia (1-10%), acne. Rare: hypersensitivity reactions
• Contraindicated in primary gonadal failure (elevated endogenous FSH = non-responsive testes)
• Equivalent to Gonal-F (follitropin alfa) — both are recombinant FSH with similar efficacy
• Compared to HMG (Menopur): Puregon is pure FSH only (no LH activity), higher purity (>99%), more consistent batch-to-batch, pen device for easier self-injection
• WADA prohibited: gonadotropins are banned under S2 (peptide hormones) at all times

Where recombinant FSH sits in a fertility protocol alongside HCG: HCG and fertility on TRT: how to preserve your options.