PCT / AI / SERM

Anastrozole

  • CAS 120511-73-1
  • Formula C17H19N5
  • Half-life 40-50 hours (oral)
Chemical structure of Anastrozole
PubChem CID 2187 ↗

Clinical Notes

Mechanism, kinetics, and protocol-relevant pharmacology — reviewed by the editorial pharmacology lead.

Third-generation non-steroidal aromatase inhibitor — competitive binding to CYP19A1 without receptor degradation. Dose-response is steep and individual: 0.25 mg twice weekly is a functional starting point on 500 mg/week testosterone protocols; 1 mg doses reliably crash E2 below physiological threshold in the majority of lean subjects. Half-life of 48 hours allows twice-weekly dosing. Clinical error pattern: aggressive preemptive dosing produces the hypoestrogenaemic profile (arthralgia, cognitive dulling, lipid degradation, libido crash) faster than a gradual increase ever produces gyno. Correct sequencing: bloodwork at week 4–5 of cycle, dose to measured E2 value, retest after 3 weeks. AI-free protocols are clinically viable for low-aromatiser users.

Chemical Identity

CAS Number 120511-73-1
IUPAC Name 2-[5-(1H-1,2,4-triazol-1-ylmethyl)-2-methylphenyl]-2-methylpropanenitrile
Molecular Formula C17H19N5
Molecular Weight 293.37 g/mol
SMILES CC1=CC(=CC(=C1)C(C)(C)C#N)CN2C=NC=N2
InChIKey YBBLVLTVTVKRGT-UHFFFAOYSA-N
Melting Point 81-82 °C
Solubility Freely soluble in methanol, acetone; very slightly soluble in water
Half-life 40-50 hours (oral)

Pharmacological Profile

Aromatisation None
Hepatotoxicity Low

Known trade names

  • Arimidex
  • Anastrol
  • Armotraz

Cycles using this compound

External references

Data sourced from peer-reviewed pharmacological literature and authoritative chemical databases (PubChem, DrugBank, ChEBI). Provided for identification and research reference only — not medical advice.