Aromatase Inhibitor Formestane Anti Estrogen Medicine Products Anti Cancer

Basic Information
Place of Origin: CHINA
Brand Name: GSP
Certification: GMP , ISO 9001:2008
Model Number: CAS: 566-48-3
Minimum Order Quantity: 10g
Price: Contact Us
Packaging Details: Stealth And Discreet Packaging
Delivery Time: Within 7 Working Days
Payment Terms: Bank Transfer - Bitcoin - Western Union - MoneyGram
Supply Ability: 300 KG/Month
Other Name: Lentaron MF: C19H26O3
MW: 302.41 Storage Temp: 2-8°C
Density: 1.19 G/cm3 Melting Point: 199-202°C
Boiling Point: 475.4° C At 760mmHg Flash Point: 255.4° C
Refractive Index: 1.545 Appearance: White Solid
Email: Whatsapp: +86-13657291547
Wickr: Sinosource
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anti estrogen products


anti estrogen drugs


Safe Steroidal Aromatase Inhibitor Formestane (Lentaron) Powder





Formestane is classified as a selective irreversible steroidal aromatase inhibitor. This agent is


structurally a derivative of androstenedione, differing from this well known prohormone only by the


addition of a 4-hydroxyl group. This group, however, is responsible for causing an irreversible


attachment between formestane and aromatase when the two come into contact with each other.



This means that formestane will bond with the enzyme and never let it go, permanently


deactivating it as a result. The enzyme will need to be replaced, through normal attrition, before


the body will recover its lost estrogen synthesizing capacity. This may take several days or more


following cessation of therapy. Given this mode of action, formestane is also referred to as a


"suicide" aromatase inhibitor, as the drug essentially sacrifices itself in the process of blocking


estrogen conversion. As a class of drugs, aromatase inhibitors are used (off-label) by male


bodybuilders and athletes to prevent the estrogenic side effects of certain anabolic/androgenic


steroids, and to increase fat loss and muscle definition while dieting.



Because of its potent estrogen-suppressing action, formestane has been used clinically to treat


breast cancer patients in a number of countries. It has been shown to be an effective option as a


second line of defense after tamoxifen, an estrogen receptor antagonist, has failed to elicit a


positive response with patients, and produces an overall response statistically similar to


tamoxifen when administered as the first-line therapy. In terms of overall potency, formestane is


not as strong as the selective third generation inhibitors like Arimidex (anastrozole) or Femara


(letrozole). One study, for example, notes a 79% level of suppression of estrogen levels with 4


weeks use of Arimidex 1 mg daily (on par with levels noted with Femara use), but only a 58%


level of suppression with intramuscular formestane injections (250 mg every two weeks). But next


to estrogen receptor antagonists like Clomid (clomiphene citrate) and Nolvadex (tamoxifen


citrate), formestane is significantly more effective at blocking the effects of estrogen in the body.




Formestane is used in the treatment of estrogen-receptor positive breast cancer in post-


menopausal women. It is available as an intramuscular depot injection.

Formestane is often used to suppress estrogen production from anabolic steroids or


prohormones. It also acts as a prohormone to 4-hydroxytestosterone, an active steroid which


displays weak androgenic activity in addition to acting as a mild aromatase inhibitor.

Formestane has poor oral bioavailability and as such is no longer popular as many orally


active aromatase inhibitors have been identified.




The most common version of formestane sold was in a topical gel form and it was dosed at


100 - 200mgs per application. Users would apply it onto clean, dry skin and rub in thoroughly;


usually on the thighs or upper arms. It took 1 to 5 minutes to dry.

The injectable version for both breast cancer purposes and bodybuilders is 125mgs twice per


week or 250mgs once per week.

Lab Test Result:


Product Name






White Solid


Test Items








By UV, To match with working standard




Related substances


Not more than 0.05%




Heavy metals






Loss on drying






Resiue on ignition






Melting point






Assay (HPLC)








It conforms to EP Standard

Aromatase Inhibitor Formestane Anti Estrogen Medicine Products Anti Cancer 0



Anti-Estrogen Series


Tamoxifen Citrate (Nolvadex)


Dutasteride (Avodart)


Clomifene Citrate (Clomid)


Finasteride (Proscar)


Letrozole (Femara)


Formestane (Lentaron)


Toremifene Citrate (Fareston)


Cabergoline (Caber)


Exemestane (Aromasin)


Raloxifene Hydrochloride


Anastrozole (Arimidex)






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Contact Details

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