What is Letrozole?
Letrozole is a third-generation non-steroidal aromatase inhibitor (Type II — reversible competitive CYP19A1 inhibition). ~99% estrogen suppression — most potent AI. Research: estrogen-sensitive cancer, T:E2 ratio manipulation, aromatase kinetics, male hypogonadism from aromatase excess, and Type I vs Type II AI comparison. CAS 112809-51-5.
Research Applications
Aromatase Inhibition
Reversible CYP19A1 competitive inhibition — ~99% estrogen suppression
Hormone-Sensitive Cancer
ER+ breast cancer estrogen deprivation models
T:E2 Ratio Manipulation
Testosterone/estradiol ratio titration in male models
AI Class Comparison
Non-steroidal (reversible) vs steroidal/irreversible AI mechanisms
Male Hypogonadism
Aromatase excess syndrome — estrogen-driven gonadotropin suppression
Quick Specs
| Form | Tablet — 2.5mg per tablet, 100-tablet bottle |
| CAS Number | 112809-51-5 |
| Molecular Formula | C₁₇H₁₁N₅ |
| Molecular Weight | 285.3 g/mol |
| Compound Type | SERM / Aromatase Inhibitor |
| Purity | ≥99% by HPLC — every batch |
| Identity | MS molecular weight confirmed — every batch |
| COA | Janoshik-independent, publicly verifiable |
| Manufacture | In-house synthesis — Qingdao, China |
| Storage | Room temperature sealed | cool, dry storage |
| Shelf Life | 24 months unopened |
Certificate of Analysis (COA)
Frequently Asked Questions
🧪 Peptide Research Tools: Use QSC’s free peptide calculators — reconstitution, BAC water, dosing, half-life, and mixing charts.
🌍 Domestic shipping: 🇺🇸 USA 5–7 days
🌏 International shipping: 7–14 days
