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The chemicals/materials for sale here are intended for laboratory and research use only, unless otherwise explicitly stated. They are not intended for human ingestion or for use in products that may be ingested.

What Is LIQUILETRO 3.5MG / ML | 60ML?

Letrozole is a third-generational non-steroidal aromatase inhibitor. It is an FDA-approved drug primarily indicated for the treatment of breast cancer in postmenopausal women. It has also been prescribed for ovulation induction in patients with PCOS. Furthermore, research shows that it can improve clinical response to endometrial cancer. Currently, it is undergoing clinical trials for its efficacy in hepatopulmonary syndrome. At Pinnacle Peptides, letrozole for sale is exclusively available for research and experimentation.

Structure Of LIQUILETRO 3.5MG / ML | 60ML

From Pubchem


IUPAC Name: 4-[(4-cyanophenyl)-(1,2,4-triazol-1-yl)methyl]benzonitrile
Synonyms: 112809-51-5, Femara
Molecular Formula: C17H11N5
Molecular Weight: 285.30 g/mol
CAS number: 112809-51-5
PubChem CID: 3902


Letrozole was first discovered by the Swiss company Ciba-Geigy AG in the 1980s in order to develop a drug that could inhibit the aromatase enzyme. The researchers found letrozole to be more potent than other drugs from the same class. This led to its accelerated development, resulting in its approval from the FDA in 1996 for the treatment of advanced breast cancer. In 2004, the FDA expanded its approval for adjuvant treatment.

Mechanism Of LIQUILETRO 3.5MG / ML | 60ML

Letrozole competitively inhibits the active site of the aromatase enzyme. Aromatase is a member of the CP450 superfamily monooxygenases enzyme. It catalyzes the demethylation of carbon 19 of androgen, resulting in the synthesis of estrogen. In postmenopausal women, aromatase is responsible for the major source of estrogen production in peripheral tissues, ovaries and the brain. By blocking the activity of aromatase, letrozole reduces the concentration of hormone, which reduces estrogen-mediated proliferation of cancer cells. Furthermore, low levels of estrogen in ovarian follicles send a signal to the hypothalamus to release gonadotropin-releasing hormone (GnRH). This, in turn, stimulates the ovaries to produce FSH and LH, leading to ovulation [1].

Pre-Clinical/Clinical Research

1. Endometrial Cancer

Research shows that endometrial cancer can be cured with traditional therapy and surgery in the majority of the patients. However, stats reveal that 8000 patients die annually because of the resistance to treatment. Literature indicates the association between the PI3K/AKT/mTOR signaling pathway and the progression and unfavorable prognosis of this disease. Additionally, estrogen receptor signaling contributes to the development of type 1 endometrial cancer and may boost the expression of proteins responsible for activating the PI3K/AKT/mTOR pathway.

One study showed that a combination of PI3K/AKT/mTOR pathway inhibitors and hormone therapy might hold promising results for individuals resistant to treatment. It is expected to yield a synergistic effect, potentially enhancing the response rates in patients with endometrial cancer. A phase II study specifically observed that the combination of letrozole and everolimus (PI3/AKT/mTOR inhibitor) significantly improved the clinical benefit ratio and response rates among women suffering from recurrent endometrial cancer [1].

2. Infertility

There is extensive research that proves the efficacy of letrozole in treating infertility. A meta-analysis compared the effect of eight different treatments for ovulation induction in women with anovulation. The result found that letrozole alone and the combination of clomiphene citrate and metformin have superior efficacy in terms of inducing pregnancy than other treatments. Furthermore, it found that letrozole treatment resulted in higher live birth rates as compared to clomiphene alone [2].

Furthermore, one study found that a combination of letrozole and clomiphene showed better results in inducing ovulation as compared to letrozole alone [3]. Research shows that letrozole along with GnRH therapy might prove helpful in preserving fertility in patients with endometrial cancer. One study found that it successfully enabled the retrieval of oocytes and embryo transfer, thus facilitating pregnancy [4].

3. Constitutional Delay in Growth and Puberty

Constitutional delay in growth and puberty (CDGP) is responsible for short stature that typically affects boys. Individuals with CDGP undergo a delay in the onset of pubertal growth. However, they catch up by the age of 18 during which their growth rate accelerates and they achieve normal height.

Children with CDGP often face psychosocial pressure, which makes the treatment important. Studies show that letrozole stimulates the hypothalamus-pituitary-gonad axis, which results in the quick growth of testicles and enhanced pubertal progression. Furthermore, it has been shown to be well tolerated and efficacious in improving testicular growth and delaying bone age progression as compared to testosterone [5].

4. Breast Cancer

Letrozole is widely prescribed to treat local and metastatic breast cancer in postmenopausal women with hormone receptor-positive tumors or of unknown receptor status. Still, some patients with early-stage breast cancer face a continuous risk of recurrence. The Breast International Group (BIG) 1-98 study found that letrozole monotherapy significantly decreased the risk of recurrence and mortality in postmenopausal women with hormone-sensitive breast cancer compared to tamoxifen. However, the sequential treatment didn't show any better outcomes than letrozole monotherapy, but it still improved the tolerability of treatment [6]. Sequential treatment consists of the use of one drug for two years followed by another drug for three years.

Research suggests that resistance to letrozole can develop over time in some patients, leading to decreased responsiveness of breast cancer cells to the drug. Animal studies suggest that intermittent letrozole therapy could reverse this resistance. The SOLE (Study of Letrozole Extension) clinical study revealed that the extended intermittent treatment (9 months of therapy followed by a 3-month break) for five years effectively improves patients’ quality of life. Furthermore, the results suggested that it is safe for patients undergoing letrozole therapy to take temporary breaks in between the treatments [7, 8].


Letrozole is a non-steroidal aromatase inhibitor that suppresses the conversion of androgens into estrogen. The low exposure to estrogen reduces the proliferation of hormone receptor-positive breast cancer. Furthermore, it stimulates the hypothalamus-pituitary-gonadotropin axis to induce ovulation. Research shows that it can treat endometrial cancer and optimize growth in children with CDGP. At Pinnacle Peptides, we offer the option to purchase letrozole exclusively for research. Only buy letrozole if you are a qualified researcher.


  1. Slomovitz, B.M., et al., Phase II study of everolimus and letrozole in patients with recurrent endometrial carcinoma. J Clin Oncol, 2015. 33(8): p. 930-6.
  2. Wang, R., et al., Treatment strategies for women with WHO group II anovulation: systematic review and network meta-analysis. Bmj, 2017. 356: p. j138.
  3. Mejia, R.B., et al., A randomized controlled trial of combination letrozole and clomiphene citrate or letrozole alone for ovulation induction in women with polycystic ovary syndrome. Fertil Steril, 2019. 111(3): p. 571-578.e1.
  4. Azim, A. and K. Oktay, Letrozole for ovulation induction and fertility preservation by embryo cryopreservation in young women with endometrial carcinoma. Fertility and Sterility, 2007. 88(3): p. 657-664.
  5. Dutta, D., et al., Efficacy and Safety of Letrozole in the Management of Constitutional Delay in Growth and Puberty: A Systematic Review and Meta-analysis. J Clin Res Pediatr Endocrinol, 2022. 14(2): p. 131-144.
  6. Regan, M.M., et al., Assessment of letrozole and tamoxifen alone and in sequence for postmenopausal women with steroid hormone receptor-positive breast cancer: the BIG 1-98 randomised clinical trial at 8·1 years median follow-up. Lancet Oncol, 2011. 12(12): p. 1101-8.
  7. Colleoni, M., et al., Extended adjuvant intermittent letrozole versus continuous letrozole in postmenopausal women with breast cancer (SOLE): a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol, 2018. 19(1): p. 127-138.
  8. Ribi, K., et al., Quality of life under extended continuous versus intermittent adjuvant letrozole in lymph node-positive, early breast cancer patients: the SOLE randomised phase 3 trial. British Journal of Cancer, 2019. 120(10): p. 959-967.

What is Letrozole?

Letrozole is a drug that is primarily used to treat postmenopausal women with hormone receptor-positive breast cancer. It is a member of the class of medications known as aromatase inhibitors, which inhibit the body's ability to produce estrogen. Letrozole helps to slow or stop the progression of cancer by preventing the synthesis of estrogen, which is a growth factor for hormone-sensitive breast cancers. As an adjuvant therapy or as an alternative to tamoxifen, letrozole is frequently recommended. In women with hormone receptor-positive breast cancer, it has demonstrated efficacy in lowering the risk of cancer recurrence and increasing survival rates.

Letrozole Research

In the realm of oncology, letrozole, a drug designated as an aromatase inhibitor, has been the subject of substantial study, particularly in the treatment of hormone receptor-positive breast cancer. Its efficacy, safety, and prospective applications in different patient populations have all been examined in several research.

Treatment of Hormone Receptor-Positive Breast Cancer:

The use of letrozole to treat hormone receptor-positive breast cancer is one of the main areas of this drug's research. Letrozole is used after initial treatment, such as surgery or chemotherapy, to lessen the risk of cancer recurrence, and clinical trials have shown its effectiveness in this regard. Letrozole prevents the conversion of androgens to estrogen by inhibiting the enzyme aromatase. Letrozole effectively starves hormone receptor-positive breast cancer cells, delaying or halting their proliferation by lowering estrogen levels.

Comparison Studies:

Letrozole research has also included comparison studies comparing its efficiency to that of tamoxifen and other hormonal treatments that are frequently used to treat hormone receptor-positive breast cancer. These studies looked at whether Letrozole offers better outcomes in terms of overall survival, disease-free survival, and lowering the chance of cancer recurrence. Letrozole may be preferable to tamoxifen, particularly in postmenopausal women, according to a number of studies. The selection of therapy, however, should be made in conjunction with medical experts and frequently depends on the unique patient characteristics.

Extended Adjuvant Therapy:

The use of letrozole in prolonged adjuvant therapy has been the subject of more research. In order to further lower the risk of cancer recurrence, extended adjuvant therapy involves extending hormone treatment beyond the recommended time frame. Studies have suggested that prolonged Letrozole therapy for postmenopausal women may enhance disease-free survival rates and lower the risk of distant metastasis. One such study is the MA.17R trial.

Neoadjuvant Therapy:

Letrozole study has also looked into the use of the drug as neoadjuvant therapy, which is given prior to surgery in an effort to reduce tumor size and maybe enhance surgical results. Neoadjuvant Letrozole therapy has been demonstrated to significantly decrease tumor growth and, in some circumstances, increase the likelihood of breast-conserving surgery, offering an option to upfront surgery.

Adverse Effects and Safety:

Letrozole has also been the subject of studies looking at its side effects and safety profile. Hot flushes, joint pain, weariness, and bone density loss are typical adverse effects. Research has looked for ways to control these side effects and guarantee patients' wellbeing while undergoing therapy.

Where to Buy Letrozole

One of the wisest choices you could possibly make, if you are one of those who has been researching this chemical, is to buy Letrozole in its purest form. Now, the most dependable online retailer Pinnacle Peptides offers all of your peptide supplies in their purest form. Despite the fact that there are several vendors of peptides, research chemicals, and lab supplies, the majority of them offer these goods in diluted form. So you should exercise extreme caution while purchasing from these stores. Pinnacle Peptides is aware of your desire to purchase these products in their purest form, thus only the best materials are supplied to the market.

Get the top laboratory equipment available for your research from our website. LETROZOLE for sale here is just one of the chemicals, which you can buy with complete trust in its quality. This substance, also known as Femara, is a non-steroidal aromatase inhibitor. If are looking to buy letrozole online in smaller quantities, you may also purchase it from our website in 2.5 mg vials. Make your order with Pinnacle Peptides to receive the highest-quality goods if your field of study requires the use of this chemical. This will enable you to finish your assignments on schedule and with precise results. Moreover you can also have these high quality substances delivered at your place, anywhere in the world. Once you have seen the quality of the products from Pinnacle Peptides, you are assured that it will serve as your long standing partner.


The products we offer are intended for laboratory research use only. In purchasing any of these items, the customer acknowledges that there are risks involved with consumption or distribution of these products. These chemicals are NOT intended to use as food additives, drugs, cosmetics, household chemicals or other inappropriate applications. The listing of a material on this site does not constitute a license to its use in infringement of any patent. All of the products will be handled only by qualified and properly trained professionals. All customers represent and warrant that through their own review and study that they are fully aware and knowledgeable about the following: Government regulations regarding the use of and exposure to all products. The health and safety hazards associated with the handling of the products they purchase. The necessity of adequately warning of the health and safety hazards associated with any products. Pinnacle Peptides and reserves the right to limit and/or deny sales of products to any unqualified individuals if we have reason to believe that misuse will occur.

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DISCLAIMER: The products sold on this site are not a drug nor is it intended to treat, diagnose, cure or prevent any disease, nor is it meant for ANY cosmetic purpose. Pinnacle Peptides makes no claims of alleged beneficial properties of any product on this site if injected or ingested in any manner. Our Peptides are exclusively distributed legally within the laws of safe harbor for research peptides and are to be used for that purpose ONLY. If any country’s governing bodies feel we are in violation of their laws regarding peptides, we ask you contact us immediately via [email protected] so we may expeditiously rectify the situation.All customers represent and warrant that through their own review and study that they are fully aware and knowledgeable about the following:Their government regulations regarding the importation, purchase, possession and use of peptides. The health and safety hazards associated with the handling of peptides in a research setting. That peptides are NOT intended to be used as a food additive, drug, vitamin, supplement, cosmetic or any other inappropriate application. Such a sale would be otherwise denied.
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