Follistatin
A natural protein that binds and neutralizes myostatin and activin, which normally limit muscle growth.
Not approved. Research use only.
Look it up on Wikipedia8 listings across 7 independently tested vendors, ranked by price per milligram after coupon codes anyone can use. Vendors you can only order from by message are hidden.
Not an FDA-approved drug and not nominated for FDA's 503A bulks list, so US pharmacies can't legally compound it.
Daily price tracking started October 7, 2026; a price-history chart appears here once a few days have been collected.
| Vendor | Trust | Listing | Vials | Price | Per mg | |
|---|---|---|---|---|---|---|
Go Alpha Labs Peptides #51 by metascore · US |
Metascore 80Finnrick 52%Bought vials 100% of label · 11 testsTitrateLabNo report for thisConfirmed with lab: 37 of 37Online checkout |
Follistatin 344 (1mg) (10 Vials) | 10 × 1 mg = 10 mg | $799.99 $80.00 per vial |
$80.00 | Buy |
Amino Asylum #245 by metascore |
Metascore 71Finnrick 62%PepIndex 26/100Bought vials 100% of label · 15 testsTitrateLab · PeptideBaseLab report (image)Online checkout |
Follistatin 344 1mg | 1 × 1 mg | $99.99 | $99.99 | Buy |
Go Alpha Labs Peptides #51 by metascore · US |
Metascore 80Finnrick 52%Bought vials 100% of label · 11 testsTitrateLabNo report for thisConfirmed with lab: 37 of 37Online checkout |
Follistatin 344 (1mg) | 1 × 1 mg | $99.99 | $99.99 | Buy |
Amino Usa #136 by metascore · US |
Metascore 74 medium confidenceFinnrick 32%Bought vials 89% of label · 3 testsTitrateLabNo report for thisAccount needed |
Follistatin 344 1mg | 1 × 1 mg | $110.00 | $110.00 | Buy |
Pure Peptide Labs #53 by metascore · US |
Metascore 79 medium confidenceFinnrick 63%PepIndex 23/100Bought vials 102% of label · 4 testsTitrateLab · PeptideBase · Peptide CriticNo report for thisOnline checkout |
Follistatin 344 1 mg | 1 × 1 mg | $134.95 | $134.95 | Buy |
Peptidology #5 by metascore · US, AZ 85254 |
Metascore 87Finnrick 71%Bought vials 97% of label · 18 testsTitrateLab · PeptideBase · Peptide Critic · PeptideCheckedNo report for thisConfirmed with lab: 34 of 34Online checkout |
Follistatin 344 1 mg (1mg) | 1 × 1 mg | $143.99 | $143.99 | Buy |
Alpha BioMed #281 by metascore · US |
Follistatin 344 (1mg) | 1 × 1 mg | $170.00 | $170.00 | Buy | |
Paramount Peptides #133 by metascore · US CA |
Metascore 74Finnrick 64%PepIndex 55/100Bought vials 114% of label · 65 testsTitrateLab · Peptide CriticNo report for thisOnline checkout |
Follistatin 344 (1mg) | 1 × 1 mg | $182.75 | $182.75 | Buy |
Mixing a 1 mg vial
What each common amount of bacteriostatic water gives you on a U-100 insulin syringe. Pick a vial size above to change it.
| Water | Strength | Per 10 units (0.1 mL) | Per unit |
|---|---|---|---|
| 1 mL | 1 mg/mL | 100 mcg | 10 mcg |
| 2 mL | 0.5 mg/mL | 50 mcg | 5 mcg |
| 3 mL | 0.333 mg/mL | 33.3 mcg | 3.33 mcg |
| 5 mL | 0.2 mg/mL | 20 mcg | 2 mcg |
Published lab results
1 certificate of analysis that vendors publish for Follistatin. Numbers are only filled in where the document is readable text; image-only COAs are linked without numbers. A vendor's own COA shows one tested sample, not every batch.
| Vendor | Lab | Date | Label | Measured | Purity | Batch | |
|---|---|---|---|---|---|---|---|
Amino Asylum |
Janoshik | 2026-05-28 | 1 mg | – | – | Janoshik #164121 (batch blank) | View (image) |
Doses studied in research Studied in people
What was given to people (or animals) in published studies and official labels, each linked to its source. This is not a recommendation: study products, purity and supervision differ from research-grade vials.
| Who was studied | Dose given | How often | For how long | What happened | |
|---|---|---|---|---|---|
| men with Becker muscular dystrophy (open-label phase 1/2a gene therapy) n = 6 |
AAV1.CMV.FS344 gene vector, 3 x 10^11 vg/kg/leg (cohort 1) or 6 x 10^11 vg/kg/leg (cohort 2) direct bilateral intramuscular injection into the quadriceps | single administration | single dose with follow-up | 4 of 6 improved 6-minute walk distance by 29-125 m, 2 showed no change; no adverse effects reported | PubMed |
| adults with sporadic inclusion body myositis (open-label gene therapy, with exercise regimen) n = 6 |
rAAV1.CMV.huFS344 gene vector, 6 x 10^11 vg/kg intramuscular injection into the quadriceps of both legs | single administration | single dose, outcomes annualized to about 1 year | 6-minute walk +56.0 m/year vs -25.8 m/year in 8 matched untreated subjects; a published letter disputes the claimed benefit (PMID 28927986) | PubMed |
Animal studies: Cynomolgus macaques received the AAV1-FS344 gene vector by intramuscular injection into the quadriceps (PMID 20368179); mouse studies also used gene delivery rather than injected protein.
All human data are for follistatin gene therapy (a viral vector dosed in vector genomes per kg), not for injected follistatin protein or peptide; no human study of injected follistatin peptide was found.
What the research says
Follistatin blocks myostatin and activin, and gene-therapy delivery of the FS344 isoform increases muscle size and strength in mice and monkeys. The only human data are a 6-patient open-label phase 1/2a gene therapy trial in Becker muscular dystrophy where 4 of 6 walked further; there are no controlled human trials, and no human data at all on follistatin given as an injected peptide.
Key papers ✓ 6✗ 1~ 2? 2
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A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy.Humans6 peoplePhase 1/2a open dose-escalation gene therapy trial (AAV1.CMV.FS344 by bilateral intramuscular quadriceps injection)
In an open-label phase 1/2a trial, AAV1-follistatin was injected into the quadriceps of six Becker muscular dystrophy patients; four improved their 6-minute walk distance by 29-125 metres while two showed no change, with no adverse effects and reduced fibrosis on biopsy.
Key resultCohort 1 (3 × 10(11) vg/kg/leg): +58 m and +125 m in two patients, no change in one; Cohort 2 (6 × 10(11) vg/kg/leg): +108 m and +29 m, one patient no improvement; no adverse effects
Study details
- Studied
- Six patients with Becker muscular dystrophy
- Compared with
- None (no control group)
- Main outcome
- Distance walked on the 6-minute walk test (6MWT)
- Sample
- 6 Becker muscular dystrophy patients in two dose cohorts
- Authors' conclusion
- Results are encouraging for treatment of dystrophin-deficient muscle diseases, with histological improvements especially at high dose.
- Limitations
- Six patients, no control group, proof-of-principle.
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Follistatin Gene Therapy Improves Ambulation in Becker Muscular Dystrophy.No new dataNarrative review including the first clinical gene transfer trial of FS344 in Becker muscular dystrophy
A review of follistatin as a genetic muscle enhancer summarizes the preclinical case and the first Becker muscular dystrophy gene transfer trial, and concludes further clinical trials are needed.
Study details
- Authors' conclusion
- The review examines evidence supporting follistatin (FS344 isoform) gene therapy as a muscle enhancer, including the first clinical trial in Becker muscular dystrophy, and future directions.
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Follistatin gene delivery enhances muscle growth and strength in nonhuman primates.Animalssize not reportedLong-term expressionNonhuman primate gene delivery study
Intramuscular AAV1-FS344 in cynomolgus macaque quadriceps produced pronounced and durable increases in muscle size and strength with no abnormal organ morphology or function.
Study details
- Studied
- Cynomolgus macaque monkeys injected in the quadriceps with AAV1-FS344
- Main outcome
- Muscle size and strength; organ morphology and function
- Authors' conclusion
- AAV1-FS344 induced pronounced, durable increases in muscle size and strength without abnormal organ changes; it may improve muscle mass and function in certain degenerative muscle disorders.
- Limitations
- Nonhuman primate study.
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Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease.No new dataReview of myostatin inhibition with emphasis on follistatin
A review of myostatin inhibition notes follistatin's potency but flags the risk of suppressing follicle-stimulating hormone, and describes using the alternatively spliced FS344 isoform to avoid reproductive off-target effects.
Study details
- Authors' conclusion
- Translational studies of AAV-delivered FS344 show increased muscle size and strength from mice to monkeys without adverse effects, supporting gene therapy trials in neuromuscular disease.
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AAV-mediated follistatin gene therapy improves functional outcomes in the TIC-DUX4 mouse model of FSHD.Animalssize not reportedMouse model characterization and AAV1.Follistatin gene therapy test
In the TIC-DUX4 mouse model of facioscapulohumeral dystrophy, AAV1-follistatin increased muscle mass and strength even while the toxic DUX4 gene was expressed.
Study details
- Studied
- Tamoxifen-inducible TIC-DUX4 mouse model of FSHD
- Compared with
- Untreated DUX4-expressing mice
- Main outcome
- Muscle mass and strength
- Authors' conclusion
- AAV1.Follistatin significantly increased muscle mass and strength even with DUX4 expression, suggesting myostatin inhibition may be a promising approach for FSHD-associated weakness.
- Limitations
- Mouse model; therapy does not target DUX4 itself.
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Follistatin N terminus differentially regulates muscle size and fat in vivo.Animalssize not reportedAAV overexpression of wild-type, N-terminus mutant/deleted and FST-I-I follistatin constructs
In mice, full-length follistatin increased muscle and decreased fat, but N-terminus-mutated or deleted versions increased no muscle and only modestly reduced fat, showing which domain does what.
Study details
- Studied
- Normal mice overexpressing follistatin constructs via AAV, plus C2C12 myotubes
- Compared with
- Different follistatin constructs
- Main outcome
- Muscle mass and fat mass
- Authors' conclusion
- Wild-type FST increased muscle and decreased fat; the N-terminal domain appears critical for myostatin blockade and muscle increase, informing future FST-based gene therapy design.
- Limitations
- Mouse and cell study.
-
Gene therapy for follistatin mitigates systemic metabolic inflammation and post-traumatic arthritis in high-fat diet-induced obesity.Animalssize not reportedAAV9-mediated follistatin gene delivery
AAV9-follistatin in high-fat-diet mice reduced obesity-related inflammatory adipokines and protected against post-traumatic knee osteoarthritis and bone remodelling.
Study details
- Studied
- Mice on a high-fat diet with joint injury
- Compared with
- Control mice
- Main outcome
- Systemic and synovial inflammation; post-traumatic osteoarthritis and bone remodeling
- Authors' conclusion
- FST gene therapy decreased obesity-induced inflammatory markers and protected mice from post-traumatic OA, suggesting a multifactorial approach for injury-induced OA and metabolic inflammation.
- Limitations
- Mouse study.
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New intranasal and injectable gene therapy for healthy life extension.Animalssize not reportedIntranasal and injectable CMV gene therapy lifespan study
A mouse study reporting that cytomegalovirus-vectored follistatin extended median lifespan by 32.5% has since been retracted, so its findings should not be relied on.
Key resultMedian lifespan extended by 41.4% (MCMV-TERT) and 32.5% (MCMV-FST)
Study details
- Studied
- Mice treated with mouse cytomegalovirus carrying TERT or follistatin
- Main outcome
- Median lifespan, glucose tolerance, physical performance
- Authors' conclusion
- CMV-delivered TERT or FST extended longevity in mice with no carcinogenicity or unwanted side effects reported; translation to humans could benefit healthspan.
- Limitations
- Mouse study; comparator not described in abstract.
-
Follistatin drives AR-independent prostate cancer through BMP signaling inactivation and microenvironmental remodeling.Humans + animalsMechanistic cell, animal and patient-association study; tested follistatin inhibition (FST-Trap), not follistatin supplementation
Safety signal: in prostate cancer models and patient data, follistatin upregulation drove resistance to anti-androgen therapy and metastatic traits, and high FST associated with poor outcomes in enzalutamide-treated patients; a follistatin-neutralizing trap resensitized tumors.
Study details
- Studied
- Prostate cancer cells and models plus enzalutamide-treated patient data
- Main outcome
- Resistance to AR-targeted therapy, tumor microenvironment, patient outcomes
- Authors' conclusion
- The authors identify FST as a biomarker and therapeutic target for AR-independent prostate cancer; neutralizing it resensitized resistant tumors.
- Limitations
- Studies the role of endogenous FST in cancer, not follistatin administered as a treatment.
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Follistatin Mitigates Atherosclerosis Through Activation of Arginine Metabolism and Adipose Browning.Animalssize not reportedAnimal study of AAV1-FST344 gene delivery with transcriptomic and metabolomic analyses
In Ldlr-knockout mice, AAV delivery of follistatin (FST344) reduced aortic lesion area, improved plasma lipids and lowered inflammatory markers, with more white-fat browning; mouse gene-delivery study.
Study details
- Studied
- Ldlr-/- mice (atherosclerosis model) plus Hybrid Mouse Diversity Panel gene-expression analysis
- Main outcome
- Aortic lesion area, plasma lipids, inflammatory and adhesion markers, UCP1 expression
- Authors' conclusion
- The authors identify Fst as a novel anti-atherogenic regulator protecting against vascular disease, possibly through Arg1-mediated macrophage reprogramming.
- Limitations
- Mouse model; gene delivery rather than injected follistatin protein.
-
Sequential VEGF-A165 plasmid and AAV-follistatin gene therapy enhances muscle hypertrophy and capillarisation in C57BL/6 miceAnimalssize not reportedSham/vehicle control115 daysFour-arm animal study: vehicle, AAV-FST, VEGF plasmid, combination (preprint)
Preprint (not peer-reviewed): In 36 mice, intramuscular AAV-follistatin alone gave a borderline muscle-mass gain (p=0.050); adding a VEGF plasmid gave the largest gain (p=0.004) and more capillaries, with no adverse hematological, biochemical or histopathological findings.
Key resultMuscle mass ratio R/L 1.176 for combination (p=0.004) vs 1.113 for AAV-FST alone (p=0.050)
Study details
- Studied
- C57BL/6 mice receiving intramuscular gene therapy in one hindlimb (other limb as control)
- Compared with
- PBS vehicle and contralateral limb
- Main outcome
- Hindlimb muscle mass ratio, FST expression, fibre size, capillary density, safety
- Sample
- 36 C57BL/6 mice (18 male, 18 female) in four groups of 6-10
- Authors' conclusion
- Combined AAV-FST and VEGF enhanced muscle hypertrophy and capillary density versus AAV-FST alone and was well tolerated, supporting further evaluation.
- Limitations
- Preprint; mouse study; AAV-FST alone showed only a borderline effect.
Reported side effects
The only human trial was an uncontrolled 6-patient gene therapy study that reported no adverse effects; there is no human safety data for follistatin administered as an injectable peptide, and follistatin's suppression of follicle-stimulating hormone is a theoretical reproductive concern raised in reviews.
7 registered human trials (2 active)
✓ positive · ✗ negative · ~ mixed · ? inconclusive, judged on each paper's own main outcome. Grades: A strong human evidence → D little or none. Papers and verdicts are drawn from PubMed, Europe PMC and Russian journals (CyberLeninka); not medical advice.
Registered clinical trials 7 on ClinicalTrials.gov · 2 active · 5 completed
All 7 Follistatin trials, with countries and summaries · Search ClinicalTrials.gov · Recruiting trials for every peptide
Discussions elsewhere
Experiences and questions about Follistatin on other sites. Treat anecdotes with care.
Follistatin: questions people ask
What is Follistatin?
Myostatin-binding protein. A natural protein that binds and neutralizes myostatin and activin, which normally limit muscle growth.
How much does Follistatin cost?
The cheapest Follistatin from an independently tested vendor is $80.00 per mg (Go Alpha Labs Peptides, Follistatin 344 (1mg) (10 Vials), $799.99). Across 8 listings from 7 vendors the median is $134.95 per mg.
Where can I buy Follistatin?
7 vendors tested by Finnrick sell Follistatin. The cheapest per mg right now: Go Alpha Labs Peptides ($80.00), Amino Asylum ($99.99), Amino Usa ($110.00). 0 of them publish a lab report (COA) for Follistatin; compare lab scores and reports in the table above before buying.
How much bacteriostatic water for 1 mg of Follistatin?
Adding 1 mL of bacteriostatic water to a 1 mg vial of Follistatin gives 1 mg/mL: each 10 units on a U-100 insulin syringe holds 100 mcg. With 1 mL it's 1 mg/mL (100 mcg per 10 units); with 3 mL, 0.333 mg/mL (33.3 mcg per 10 units). More water makes small amounts easier to measure. Mixing charts: 1 mg.
Is Follistatin FDA approved?
Not approved. Research use only.
Can Follistatin be compounded in the US?
Not an FDA-approved drug and not nominated for FDA's 503A bulks list, so US pharmacies can't legally compound it. Compounding status for every peptide.
Does Follistatin work? What does the research say?
Evidence grade C (mostly animal studies), from 11 papers: Muscle gains come from gene-therapy studies in mice and monkeys plus a 6-patient uncontrolled trial; no human data on injected follistatin peptide. Follistatin blocks myostatin and activin, and gene-therapy delivery of the FS344 isoform increases muscle size and strength in mice and monkeys. The only human data are a 6-patient open-label phase 1/2a gene therapy trial in Becker muscular dystrophy where 4 of 6 walked further; there are no controlled human trials, and no human data at all on follistatin given as an injected peptide. See the papers.
Are there clinical trials of Follistatin?
ClinicalTrials.gov lists 7 registered trials of Follistatin: 2 active, 5 completed. Examples: Possible Sarcopenia, Sarcopenia, and Functional Status in Patients With Primary Sjögren's Syndrome (Active, not recruiting, 120 people); CALM-AF-AI: Counteracting Age-related Loss of Muscle With AAV-Follistatin Combined With Angiogenesis-Inducing VEGF Plasmid Gene Therapy (Recruiting, Phase 1, Phase 2, 12 people); Evaluation of Serum Follistatin-Like Protein 1 Levels in Behcet's Disease and Its Association With Disease Activity (Completed, 80 people).
What dose of Follistatin was used in studies?
Follistatin is studied in people. men with Becker muscular dystrophy (open-label phase 1/2a gene therapy): AAV1.CMV.FS344 gene vector, 3 x 10^11 vg/kg/leg (cohort 1) or 6 x 10^11 vg/kg/leg (cohort 2) single administration; adults with sporadic inclusion body myositis (open-label gene therapy, with exercise regimen): rAAV1.CMV.huFS344 gene vector, 6 x 10^11 vg/kg single administration. These are amounts used in published studies or official labels, not a recommendation.