At a glance
Effects
- Controls estrogen: Lowers estradiol strongly, preventing and often reversing estrogen-driven gynecomastia and bloating on aromatising cycles.[2]
- Treats breast cancer / aids fertility: Approved for hormone-receptor-positive breast cancer in postmenopausal women, and used off-label to induce ovulation.[1][3]
Nonsteroidal aromatase inhibitor
~2 days (45 h)
Oral
Blocks CYP19 aromatase
Contraindicated (fetal harm)
About Letrozole
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- 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.
What it is
Letrozole is a potent non-steroidal aromatase inhibitor: it blocks the aromatase (CYP19) enzyme that converts androgens into estrogens, sharply lowering estradiol.[1][2] Medically it treats hormone-receptor-positive breast cancer in postmenopausal women and is used off-label for ovulation induction; in a performance context it is used to control the estrogen - and the resulting gynecomastia and water retention - produced when testosterone aromatises.[1][3]
How it works
It binds the heme group of the aromatase enzyme, competitively blocking conversion of androstenedione to estrone and of testosterone to estradiol, which markedly reduces circulating estrogen.[2][4] Because it acts on the enzyme rather than the estrogen receptor, the drop is dose-dependent and can be steep; with a roughly 2-day half-life the effect accumulates over days.[2]
Risks & side effects
Safety & harm reduction
- Tamoxifen can lower letrozole blood levels; estrogen-containing products oppose its effect.[1]
Dosage context
Commonly-reported figures (NOT a prescription): the breast-cancer dose is 2.5 mg once daily.[1] For estrogen control on cycle, far smaller intermittent amounts are typically reported (a fraction of a 2.5 mg tablet, e.g. about 0.25-0.5 mg a few times weekly) precisely because letrozole is potent and over-suppression is the main hazard.[1][2] Reference figures only, not individual medical advice.
Sources
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.
Other options for Letrozole· 6 offers
Same compound from different labs/brands and pack sizes. Tap a row to switch brand — the price and buy button update instantly.
This compound comes in different forms (e.g. injectable vs oral vs topical). Cost per mg is only comparable within the same form.
| Brand | Form | Strength | Pack | Price | Per mg |
|---|---|---|---|---|---|
Royal Pharma | blister-pack | 2.5 mg/tab | 30 tab | 38,90 € | ★€0.519/mg |
Intex Pharma | blister-pack | 2.5 mg/tab | 60 tab | 94,90 € | €0.633/mg |
Generic | blister-pack | 2.5 mg/tab | 30 tab | 94,90 € | €1.265/mg |
Generic | oral-liquid | 5 mg/ml | 50 ml | 94,90 € | €0.380/mg |
GenericSelected | blister-pack | 2.5 mg/tab | 60 tab | 104,99 € | €0.700/mg |
Generic | oral-liquid | 5 mg/ml | 100 ml | 169,99 € | ★€0.340/mg |