# FSH (Follitropin) > A heterodimeric glycoprotein gonadotropin that drives follicle growth and spermatogenesis — the workhorse of IVF stimulation, and a sister molecule to HCG and LH. - Also known as: Follicle-stimulating hormone, Follitropin alfa, Gonal-f, Follistim, Puregon - Class: Reproductive - FDA approved: Yes - Canonical page: https://www.americanpeptide.com/catalog/fsh ## Overview Follicle-stimulating hormone is one of the three pituitary glycoprotein gonadotropins, and like its siblings LH and HCG it is built from a shared alpha subunit paired with a hormone-specific beta subunit, heavily glycosylated. FSH is the signal that recruits and grows ovarian follicles in women and supports sperm production in men, which makes recombinant FSH (follitropin) the central tool of assisted reproduction — the drug that drives controlled ovarian stimulation in IVF. FSH completes the gonadotropin picture alongside HCG and LH in this catalog: the same alpha subunit, a distinct beta subunit, and obligatory glycosylation that makes it a true glycoprotein hormone rather than a simple peptide. Its job is the front half of the reproductive cycle — recruiting and maturing ovarian follicles — where LH and the LH-mimicking HCG handle the ovulatory trigger that follows. Therapeutically, recombinant FSH (follitropin alfa, Gonal-f; follitropin beta, Follistim) is produced in mammalian cells so its glycosylation is human-like, and it is the backbone of controlled ovarian stimulation in IVF — driving the development of multiple follicles in a cycle — as well as treatment for anovulation and certain male infertility. Older urine-derived gonadotropin products (menotropins) supplied FSH and LH activity together; recombinant versions allow precise, consistent dosing. FSH is less surrounded by pop-culture drama than oxytocin or HCG, but it carries the same molecular lesson: glycoprotein hormones are assembled, glycosylated biologics whose sugar chains are part of the drug, which is why they are grown in cells and characterized by glycan and bioassay analytics rather than a simple purity figure. ## Mechanism Binds the FSH receptor on ovarian granulosa cells (driving follicle maturation and estrogen production) and on testicular Sertoli cells (supporting spermatogenesis). Its glycosylation governs its circulating half-life and activity. ## Chemistry | Property | Value | | --- | --- | | Molecular weight | 30000 Da | | UniProt | [P01225](https://www.uniprot.org/uniprotkb/P01225) | ## Research areas Studied in: Ovarian stimulation, IVF / assisted reproduction, Anovulation, Male infertility. ## Key research - Controlled ovarian stimulation — the core use; drives multi-follicle development for IVF. - Anovulation — used to induce follicle growth when ovulation fails. - Male infertility — supports spermatogenesis via Sertoli-cell FSH receptors. - Gonadotropin family — shares an alpha subunit with LH, HCG, and TSH; specificity is in the beta subunit. - Recombinant vs urinary — recombinant follitropin allows precise dosing vs older urine-derived menotropins. ## Storage, handling & synthesis **Storage.** Recombinant FSH products are refrigerated (2–8 °C) and protected from light and freezing; reconstituted/in-use pens follow the label’s window. Glycoprotein integrity is sensitive to heat and freeze–thaw. **Handling.** A glycosylated heterodimer sensitive to heat, freezing, and agitation, which can dissociate the subunits or aggregate the protein and reduce potency. **Synthesis.** Recombinant follitropin is produced in mammalian (CHO) cells so its essential glycosylation is human-like; its ~30 kDa mass is approximate and varies with glycosylation, so it has no single molecular formula. Characterization is glycoprotein-grade — subunit identity, glycan/isoform profiling, and bioassay potency — well beyond an HPLC purity number. ## FAQs ### What does FSH do? Follicle-stimulating hormone drives the growth of ovarian follicles in women and supports sperm production in men. As recombinant follitropin it is the main drug used to stimulate the ovaries in IVF. ### How is FSH related to HCG and LH? They are all glycoprotein gonadotropins sharing the same alpha subunit; their unique beta subunits give them different jobs. FSH grows follicles, while LH and the LH-mimicking HCG trigger ovulation. ### Why is FSH a glycoprotein biologic? It is a two-subunit, heavily glycosylated protein whose sugar chains are essential to its activity and half-life. It is made in mammalian cells so glycosylation is human-like — not by peptide synthesis. ### Is this medical advice? No — this is a research and educational reference, not dosing guidance. ## Latest research Recent trials and publications mentioning Follicle-stimulating hormone, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [Effects of Dietary Nitrate in Women With Secondary Amenorrhea](https://clinicaltrials.gov/study/NCT07019129) — TERMINATED · NA · NCT07019129 - [Apply Biphasic IVM for POSEIDON Group 1](https://clinicaltrials.gov/study/NCT07632300) — NOT_YET_RECRUITING · NA · NCT07632300 - [Iparomlimab and Tuvonralimab Plus Paclitaxel and Platinum as Neoadjuvant Therapy for Locally Advanced Cervical Cancer](https://clinicaltrials.gov/study/NCT07646301) — RECRUITING · PHASE2 · NCT07646301 - [A Study to Compare the Efficacy and Safety of Follitropin Alfa/Lutropin Alfa Versus hMG in Japanese Participants With LH and FSH Deficiency Undergoing ART (HINATA)](https://clinicaltrials.gov/study/NCT07340827) — RECRUITING · PHASE3 · NCT07340827 - [131I-apamistamab-based Conditioning for Hematopoietic Stem Cell Transplant (HSCT) in Advanced Sickle Cell Disease (SCD)](https://clinicaltrials.gov/study/NCT07015684) — RECRUITING · PHASE1 · NCT07015684 - [Mitigating Neural Hypoexcitability and Weakness During Disuse in Women](https://clinicaltrials.gov/study/NCT07166198) — RECRUITING · NA · NCT07166198 --- Source: AmericanPeptide.com — https://www.americanpeptide.com/catalog/fsh Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.