# PEG-MGF PEG-MGF is in limbo: it is not approved, and it is on neither FDA list for compounding. No pharmacy may lawfully make it. The evidence grade is insufficient: we found no published study of PEG-MGF itself. FDA found no data on any person given it. Status checked: 2026-10-25. Last verified: 2026-10-26. Primary source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks This page has not been individually reviewed by a clinician. Information, not medical advice. | Fact | Value | Tier | Checked | Source | |---|---|---|---|---| | Also called | Mechano growth factor pegylated | primary | 2026-10-25 | [source](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) | | Class | growth-hormone-axis | peer-reviewed | 2026-10-25 | [source](https://pubmed.ncbi.nlm.nih.gov/42395176/) | | Regulatory status | limbo | primary | 2026-10-25 | [source](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) | | Status source read | 2026-10-25 | primary | 2026-10-25 | [source](https://www.fda.gov/media/94155/download) | | Evidence grade | insufficient | our assessment | 2026-10-25 | [source](https://peptideindex.ai/methodology#evidence-grade) | ## Name PEG-MGF Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## Summary A lab-made peptide related to IGF-1, a growth signal, with a chemical chain called PEG attached. It is sold online as a research compound. Source: https://pubmed.ncbi.nlm.nih.gov/42395176/ ## Short answer PEG-MGF is in limbo: it is not approved, and it is on neither FDA list for compounding. No pharmacy may lawfully make it. The evidence grade is insufficient: we found no published study of PEG-MGF itself. FDA found no data on any person given it. Source: https://peptideindex.ai/methodology#short-answer ## Known risks - FDA warns that PEG-MGF made by a pharmacy may set off the immune system. It may also carry impurities [^1]. - FDA found no data on people exposed to PEG-MGF by any route [^1]. - In a 2010 lab study, a short MGF peptide made human prostate cancer cells grow [^18]. That peptide was not PEG-MGF, and the study was not in people [^18]. - A 2026 review warns that it is uncertain what peptides sold as research compounds contain [^21]. - The same review lists harms reported across this group of peptides, such as hormone and blood sugar changes [^21]. It does not tie each harm to PEG-MGF [^21]. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## What nobody knows yet - Nobody knows what PEG-MGF does in people. FDA found no data on any person given it [^1]. - We found no published study of PEG-MGF itself. The animal studies cited here used other forms of MGF [^11] [^13]. - Whether the short MGF peptide does anything is disputed. Scientists at two drug companies could not repeat its claimed effects on muscle cells [^16]. - No natural MGF peptide has been found in cells or tissue, a 2010 review says [^20]. So its role in the body is unclear. - Whether MGF peptides feed cancer growth in people is not known. One lab study raised the concern [^18] [^21]. - FDA has not set a date for its committee to meet on PEG-MGF [^4]. Its notice does not say which use the committee will review [^4]. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## What it is PEG-MGF is a lab-made peptide related to IGF-1, a growth signal in the body [^21]. MGF stands for mechano growth factor [^20]. That name is used for a form of IGF-1 that muscle makes after strain or injury [^20]. It is also used for a short lab-made peptide copied from one end of that form [^20] [^16]. PEG-MGF is MGF with a chemical chain called PEG attached, which is what pegylated means. FDA calls it mechano growth factor pegylated [^1]. Plain MGF, without PEG, is a different substance, and FDA lists it apart [^2]. A 2026 review groups PEG-MGF with peptides sold online as research compounds for muscle and sport [^21]. A US sports drug-testing lab found a different MGF variant in seized vials [^19]. Source: https://pubmed.ncbi.nlm.nih.gov/20130113/ ## Where it stands legally PEG-MGF is in limbo: FDA lists it as withdrawn from Category 2, and it has not added it to Category 1 [^1] [^2]. That is not approval, and it does not make compounding lawful. Checked 25 October 2026. Category 2 is FDA's list of substances that may raise significant safety risks [^1]. Category 1 is the list of substances under review that pharmacies may use while FDA decides [^3]. In April 2026, the groups that nominated PEG-MGF withdrew, so it came off Category 2 [^1] [^8]. Taking a substance off Category 2 does not by itself let pharmacies use it [^8] [^9]. FDA's 503A list of 14 May 2026 names plain MGF, without PEG, in Category 3 [^2]. That category holds substances nominated without enough support [^2]. Plain MGF is a different substance, so its place on the list says nothing about PEG-MGF. FDA's notice says its Pharmacy Compounding Advisory Committee will discuss PEG-MGF before the end of February 2027 [^4]. The notice gives no exact date and no meeting materials [^4]. Law and trade reports give the same time frame [^8] [^22]. The committee gives advice only. FDA decides by writing a rule [^8]. A June 2026 pharmacy column expected PEG-MGF to stay restricted [^23]. FDA's own page lists it as withdrawn from Category 2 [^1]. The FDA page is what this page follows. Until FDA acts, a pharmacy may not use PEG-MGF under the federal compounding law [^3] [^5]. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## What the evidence shows The evidence grade is insufficient: we found no published study of PEG-MGF itself, in people or in animals. FDA found no data on any person given it [^1]. Every study below used a different form of MGF. A study of a related molecule does not show what PEG-MGF does. Animal studies of other forms of MGF: in sheep after a heart attack, a piece of MGF kept the heart pumping better than in untreated sheep [^11]. In mice after a heart attack, a lab-made MGF peptide slowed the decline in heart function [^12]. In injured mouse muscle, MGF did not help muscle fibers regrow, but it did reduce scarring [^13]. In rats with an injured Achilles tendon, a lab-made MGF peptide helped the tendon heal [^14]. In mice with a disease like ALS, an MGF gene, not the peptide, helped muscle strength and nerve cell survival [^15]. A result in an animal does not show what happens in people. Lab studies: in 2014, scientists at two drug companies could not repeat the claimed effects of the MGF peptide on muscle cells [^16]. A 2016 lab test found that the short MGF peptides did not switch on the IGF-1 receptor [^17]. A full-length form of MGF did [^17]. A 2010 review says no natural MGF peptide has been found in cells or tissue [^20]. A 2026 review says the claimed muscle and performance benefits of these peptides remain uncertain [^21]. Source: https://pubmed.ncbi.nlm.nih.gov/20130113/ ## Legitimate ways to get it There is no legal way to get PEG-MGF in the US today [^1] [^2]. In 2020, FDA said no approved drug contains it [^5]. A pharmacy may use a substance with no official quality standard only if it is in an approved drug or on the federal list [^5]. PEG-MGF is neither, and FDA is still deciding whether to add it [^2] [^4]. Any open trial would appear in the trials block below, with the date the registry was last checked. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## How people are getting it anyway This section describes what happens and is not a recommendation. A 2026 review says PEG-MGF is among peptides sold as "research compounds" that people take on their own [^21]. It warns that what such products contain is uncertain [^21]. FDA has warned a seller of research-use peptides that a "research use only" label does not stop a product from being a drug [^7]. That letter did not name PEG-MGF [^7]. Pharmacies are the other channel a federal record names [^5]. In 2020, FDA warned a compounding pharmacy that its PEG-MGF products did not meet the rules for compounding [^5]. Later that year, the pharmacy pleaded guilty to a federal charge of selling unapproved new drugs, PEG-MGF among them [^6]. FDA warns that PEG-MGF made by a pharmacy may set off the immune system [^1]. Source: https://pubmed.ncbi.nlm.nih.gov/42395176/ ## Access routes Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ### None Detail: There is no legal route to PEG-MGF in the US today. FDA lists it as withdrawn from Category 2, and it is not on the list of substances pharmacies may use. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## Unofficial channels Source: https://pubmed.ncbi.nlm.nih.gov/42395176/ ### Research use seller What it is: Websites that sell PEG-MGF as a research compound straight to the public, for people to take on their own. Legal position: FDA says a research-use label does not stop a product meant for people from being a drug. An unapproved new drug may not be sold across state lines. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026) Documented risks: - A 2026 review warns that it is uncertain what peptides sold as research compounds contain. (source: https://pubmed.ncbi.nlm.nih.gov/42395176/) - FDA found no data on people exposed to PEG-MGF by any route. (source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) Enforcement: - 2026-08-24: FDA warning letter to a seller of research-use peptides: a research-use label did not stop its products from being unapproved drugs. The letter does not name PEG-MGF. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026) Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026 ### Compounding outside the rules What it is: PEG-MGF made by a pharmacy from a bulk substance that is not on FDA's list. Legal position: A pharmacy may compound with a substance that has no official standard and is in no approved drug only if it is on FDA's list. FDA said in 2020 that PEG-MGF is not on that list. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/tailor-made-compounding-llc-594743-04012020) Documented risks: - FDA warns that PEG-MGF made by a pharmacy may set off the immune system and may carry impurities. (source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) Enforcement: - 2020-04-01: FDA warning letter to a compounding pharmacy: PEG-MGF was among bulk substances that made its products ineligible under section 503A. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/tailor-made-compounding-llc-594743-04012020) - 2020-10-29: Department of Justice: the same pharmacy pleaded guilty to distributing unapproved new drugs, PEG-MGF among them. (source: https://www.justice.gov/usao-edky/pr/nicholasville-compounding-pharmacy-and-its-owner-plead-guilty-unlawful-distribution) Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/tailor-made-compounding-llc-594743-04012020 ## Recruiting trials Snapshot date: 2026-10-25. A listing is not a recommendation. Trials have strict eligibility rules. Talk to your doctor and read the official record. None in this snapshot. Source: https://clinicaltrials.gov/api/v2/studies?query.intr=PEG-MGF+OR+pegylated+mechano+growth+factor&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState ## Sources Source: https://www.fda.gov/media/94155/download ### 1. FDA: bulk drug substances that may present significant safety risks, including those withdrawn from Category 2 Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ### 2. FDA: categories of bulk drug substances nominated under section 503A, list updated 14 May 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/media/94155/download ### 3. FDA: bulk drug substances used in compounding under section 503A Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act ### 4. FDA: notice of the next Pharmacy Compounding Advisory Committee meeting, no date posted Type: regulatory Tier: primary Source: https://www.fda.gov/advisory-committees/pharmacy-compounding-advisory-committee/meeting-pharmacy-compounding-advisory-committee ### 5. FDA warning letter to a compounding pharmacy, 1 April 2020 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/tailor-made-compounding-llc-594743-04012020 ### 6. US Department of Justice: a compounding pharmacy pleads guilty to distributing unapproved drugs, 29 October 2020 Type: regulatory Tier: primary Source: https://www.justice.gov/usao-edky/pr/nicholasville-compounding-pharmacy-and-its-owner-plead-guilty-unlawful-distribution ### 7. FDA warning letter to a seller of research-use peptides, 24 August 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026 ### 8. McDermott Will & Schulte: what the July 2026 committee votes on peptides mean Type: legal-analysis Tier: legal-analysis Source: https://www.mcdermottlaw.com/insights/bulk-list-bound-pcac-backs-majority-of-peptides-in-two-day-public-meeting/ ### 9. Goodwin: FDA signals a possible change in its stance on compounding some peptides Type: legal-analysis Tier: legal-analysis Source: https://www.goodwinlaw.com/en/insights/blogs/2026/05/fda-signals-potentially-evolving-stance-toward-compounding-of-certain-peptides ### 10. Sheppard Mullin: FDA pairs its peptide policy with action against unlawful sellers Type: legal-analysis Tier: legal-analysis Source: https://www.sheppard.com/insights/blogs/fda-balances-peptide-policy-with-enforcement-against-unlawful-peptide-sellers ### 11. The MGF E domain in sheep after a heart attack, 2008 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/17581790/ ### 12. A lab-made MGF E-domain peptide in mice after a heart attack, 2014 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/25606570/ ### 13. MGF in injured mouse muscle, 2019 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/31164836/ ### 14. A lab-made MGF E peptide on injured rat Achilles tendon, 2016 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/27334712/ ### 15. An MGF gene in mice with an ALS-like disease, 2009 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/19038252/ ### 16. The MGF peptide showed no effect on muscle cells in the lab, 2014 Type: in-vitro Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/24253050/ ### 17. Full-length MGF and short MGF peptides at the IGF-1 receptor, lab study, 2016 Type: in-vitro Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/26991004/ ### 18. MGF in human prostate cancer tissue and cells, lab study, 2010 Type: in-vitro Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/20564425/ ### 19. An MGF variant found in seized vials, lab study, 2017 Type: in-vitro Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/28035768/ ### 20. Minireview: mechano growth factor and the IGF-1 gene, 2010 Type: reference Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/20130113/ ### 21. Review: performance peptides that act on growth hormone and IGF-1, 2026 Type: reference Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/42395176/ ### 22. RAPS: FDA considers adding a dozen peptides to its compounding list Type: reference Tier: established-news Source: https://www.raps.org/resource/fda-considers-adding-a-dozen-peptides-to-its-bulk-drug-compounding-list.html ### 23. Pharmacy Times: a pharmacist on what the peptide category change means, 4 June 2026 Type: reference Tier: established-news Source: https://www.pharmacytimes.com/view/the-peptide-reclassification-everyone-s-talking-about-a-pharmacist-s-take-on-what-rfk-jr-s-announcement-actually-means Last verified: 2026-10-26. Sources: - https://clinicaltrials.gov/api/v2/studies?query.intr=PEG-MGF+OR+pegylated+mechano+growth+factor&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState - https://peptideindex.ai/methodology#evidence-grade - https://peptideindex.ai/methodology#short-answer - https://pubmed.ncbi.nlm.nih.gov/20130113/ - https://pubmed.ncbi.nlm.nih.gov/42395176/ - https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks - https://www.fda.gov/media/94155/download [^1]: FDA: bulk drug substances that may present significant safety risks, including those withdrawn from Category 2 https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks [^2]: FDA: categories of bulk drug substances nominated under section 503A, list updated 14 May 2026 https://www.fda.gov/media/94155/download [^3]: FDA: bulk drug substances used in compounding under section 503A https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act [^4]: FDA: notice of the next Pharmacy Compounding Advisory Committee meeting, no date posted https://www.fda.gov/advisory-committees/pharmacy-compounding-advisory-committee/meeting-pharmacy-compounding-advisory-committee [^5]: FDA warning letter to a compounding pharmacy, 1 April 2020 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/tailor-made-compounding-llc-594743-04012020 [^6]: US Department of Justice: a compounding pharmacy pleads guilty to distributing unapproved drugs, 29 October 2020 https://www.justice.gov/usao-edky/pr/nicholasville-compounding-pharmacy-and-its-owner-plead-guilty-unlawful-distribution [^7]: FDA warning letter to a seller of research-use peptides, 24 August 2026 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/peptide-partners-llc-735063-08242026 [^8]: McDermott Will & Schulte: what the July 2026 committee votes on peptides mean https://www.mcdermottlaw.com/insights/bulk-list-bound-pcac-backs-majority-of-peptides-in-two-day-public-meeting/ [^9]: Goodwin: FDA signals a possible change in its stance on compounding some peptides https://www.goodwinlaw.com/en/insights/blogs/2026/05/fda-signals-potentially-evolving-stance-toward-compounding-of-certain-peptides [^11]: The MGF E domain in sheep after a heart attack, 2008 https://pubmed.ncbi.nlm.nih.gov/17581790/ [^12]: A lab-made MGF E-domain peptide in mice after a heart attack, 2014 https://pubmed.ncbi.nlm.nih.gov/25606570/ [^13]: MGF in injured mouse muscle, 2019 https://pubmed.ncbi.nlm.nih.gov/31164836/ [^14]: A lab-made MGF E peptide on injured rat Achilles tendon, 2016 https://pubmed.ncbi.nlm.nih.gov/27334712/ [^15]: An MGF gene in mice with an ALS-like disease, 2009 https://pubmed.ncbi.nlm.nih.gov/19038252/ [^16]: The MGF peptide showed no effect on muscle cells in the lab, 2014 https://pubmed.ncbi.nlm.nih.gov/24253050/ [^17]: Full-length MGF and short MGF peptides at the IGF-1 receptor, lab study, 2016 https://pubmed.ncbi.nlm.nih.gov/26991004/ [^18]: MGF in human prostate cancer tissue and cells, lab study, 2010 https://pubmed.ncbi.nlm.nih.gov/20564425/ [^19]: An MGF variant found in seized vials, lab study, 2017 https://pubmed.ncbi.nlm.nih.gov/28035768/ [^20]: Minireview: mechano growth factor and the IGF-1 gene, 2010 https://pubmed.ncbi.nlm.nih.gov/20130113/ [^21]: Review: performance peptides that act on growth hormone and IGF-1, 2026 https://pubmed.ncbi.nlm.nih.gov/42395176/ [^22]: RAPS: FDA considers adding a dozen peptides to its compounding list https://www.raps.org/resource/fda-considers-adding-a-dozen-peptides-to-its-bulk-drug-compounding-list.html [^23]: Pharmacy Times: a pharmacist on what the peptide category change means, 4 June 2026 https://www.pharmacytimes.com/view/the-peptide-reclassification-everyone-s-talking-about-a-pharmacist-s-take-on-what-rfk-jr-s-announcement-actually-means