Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library · Trial & Regulatory Tracker →

Efruxifermin (EFX, AKR-001): what the evidence says

Name: Efruxifermin (EFX, AKR-001)
Published: 2026-10-27

At a glance

What it is: a long-acting Fc-FGF21 fusion protein (a hormone analogue fused to part of an antibody), injected weekly. Developed by Akero Therapeutics, owned by Novo Nordisk since Dec 9, 2025. ^{R1, R2}

What the evidence says: in MASH with moderate-to-severe fibrosis (HARMONY, 126 people), 49% on the higher dose had fibrosis improvement at 96 weeks vs 19% on placebo. ^R3 In cirrhosis (SYMMETRY, 181 people) it missed its 36-week primary goal; a difference appeared at 96 weeks. ^R4 Phase 3 is ongoing.

Biggest risks: mostly mild-to-moderate diarrhea and nausea. No drug-induced liver injury was reported in HARMONY. ^R3

Rating


Human Human evidence	Moderate for liver fat and fibrosis in F2-F3 MASH ^{R1, R3} · Limited / mixed in cirrhosis ^{R5, R4} · No human data for weight loss or "metabolic" use outside trials
Animal Animal / lab evidence	Rat studies ^R6
Regulatory	Investigational · biologic, not on the 503A/503B lists or FDA's safety-risk page · WADA 2026 S2.3 lists fibroblast growth factors (FGFs); UNVERIFIED whether an FGF21 analogue is covered ^{R7, R8, R9, R10}
Established human dose	None (investigational). Study details lists what trials used

Evidence verdict: MASH with F2-F3 fibrosis: Moderate (phase 2b RCT, fibrosis improved) · MASH cirrhosis: missed 36-week goal, signal at 96 weeks · Not approved

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: all trials were funded by Akero. Fibrosis readings rely on biopsies, and only 88 of 126 HARMONY participants had week-96 biopsies. ^{R3, R4}

What is it?

FGF21 is a liver hormone that affects fat and sugar metabolism. Efruxifermin is a bivalent version engineered to last a week. ^R1 Related pages: Survodutide, Tirzepatide, Semaglutide.

Does it work?

Human BALANCED (phase 2a): 80 people; liver fat fell 12 to 14 points vs +0.3 on placebo at 12 weeks. ^R1
Human HARMONY (phase 2b): at week 96, fibrosis improved without MASH worsening in 30% (lower dose, not significant) and 49% (higher dose) vs 19% placebo. ^{R3, R11}
Human SYMMETRY (cirrhosis): 18% to 19% vs 13% at 36 weeks (not significant); 21% to 29% vs 11% at 96 weeks. ^{R4, R12}
Human BALANCED cirrhosis cohort: 30 people; markers improved over 16 weeks. ^R5

Is it safe?

Human GI events (diarrhea, nausea) more common than placebo, mostly mild-moderate. ^{R1, R3}
Unknown Long-term bone and other effects of FGF21 analogues in people are not yet known.

Gray-market "efruxifermin": extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe. A fusion protein is hard to make; a retail vial is very unlikely to contain the real molecule.

Pipeline (sponsor, trials, expected readouts)

Sponsor: Novo Nordisk (Akero). ^R2
SYNCHRONY Real-World (NCT06161571): safety, primary completion Mar 2026; results not yet published as of Oct 26, 2026. ^R13
SYNCHRONY Histology (NCT06215716): F2-F3, primary completion Feb 2033. ^R14
SYNCHRONY Outcomes (NCT06528314): compensated cirrhosis, primary completion Feb 2030. ^R15

Is it legal?

US (FDA): investigational only. Not on the compounding lists. ^{R7, R8}
Athletes: WADA 2026 S2.3 prohibits growth factors including FGFs at all times. ^R10

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
BALANCED 2021	80 adults with NASH F1-F3	SC weekly	28, 50 or 70 mg	16 weeks	Liver fat −12 to −14 points	PMID 34239138
HARMONY 2025	126 adults, MASH F2-F3	SC weekly	28 or 50 mg	96 weeks	Fibrosis improved 49% (50 mg) vs 19%	PMID 40818852
SYMMETRY 2025	181 adults, MASH cirrhosis	SC weekly	28 or 50 mg	96 weeks	Missed 36-week goal	PMID 40341827
BALANCED Cohort C	30 adults, NASH cirrhosis	SC weekly	50 mg	16 weeks	Markers improved	PMID 36644237

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Harrison SA, et al. Nat Med. 2021. PMID 34239138
^R2 Akero Therapeutics, press release on closing of acquisition by Novo Nordisk, Dec 9, 2025. https://akerotx.com/wp-content/uploads/2025/12/pr251209-akero-closing.pdf
^R3 Noureddin M, et al. Lancet. 2025. PMID 40818852
^R4 Noureddin M, et al. N Engl J Med. 2025. PMID 40341827
^R5 Harrison SA, et al. JHEP Rep. 2023. PMID 36644237
^R6 Tillman EJ, et al. Br J Pharmacol. 2022. PMID 34773249
^R7 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R8 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R9 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R10 WADA. The 2026 Prohibited List, S2.3. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R11 ClinicalTrials.gov NCT04767529, Akero, HARMONY, phase 2b MASH F2-F3, completed (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT04767529
^R12 ClinicalTrials.gov NCT05039450, Akero, SYMMETRY, phase 2b compensated MASH cirrhosis, completed (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT05039450
^R13 ClinicalTrials.gov NCT06161571, Akero, SYNCHRONY Real-World, phase 3 safety, active not recruiting, primary completion Mar 2026 (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT06161571
^R14 ClinicalTrials.gov NCT06215716, Akero, SYNCHRONY Histology, phase 3 F2-F3, recruiting, primary completion Feb 2033 (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT06215716
^R15 ClinicalTrials.gov NCT06528314, Akero, SYNCHRONY Outcomes, phase 3 compensated cirrhosis, recruiting, primary completion Feb 2030 (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT06528314

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Efruxifermin (EFX, AKR-001). It is investigational and given only in trials. Talk to a liver specialist, especially if you have cirrhosis, are pregnant, or have bone or growth concerns. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).