Muscle biology and gene-transfer research
1Scope of investigation or explicitly identified community interest; not an established indication.
HormonalProtein
Follistatin 344
Follistatin gene delivery versus protein products
Lab studiesMuscle biology · gene transfer1
Investigational; this profile does not establish an approved use.
What does it do?
Myostatin/activin-binding protein precursor researched mainly through gene delivery. Gene-therapy outcomes cannot be transferred to short-acting research injections.
Approved & studied uses
Evidence limits
View research →Human gene-transfer results cannot establish a dose or safety profile for injected research protein.1
2 distinct primary sources or abstracts checked. Evidence may concern a parent compound, individual blend ingredient, animal, or cell model; it does not necessarily establish a benefit for this exact product.
Evidence definitions →Key safety information
All risks →Evidence boundary
Human gene-transfer results cannot establish a dose or safety profile for injected research protein.1
Investigational; this profile does not establish an approved use.
Amino-acid sequence
An exact sequence has not been verified for this formulation.
Reference identity · not independently confirmed16
Length344-residue precursor
Molecular weight · Da~37,800 Da (FS-315 mature form)
Formula, sequence notation & identity
344-residue precursor; processing produces FS315 in the cited gene-transfer work
Sequence and formulation must be confirmed for the exact material; similarly named products are not necessarily interchangeable.
Pep-Pedia identity details
344 amino acids (precursor); 315 amino acids (circulating form) · ~37,800 Da (FS-315 mature form)
Full sequence available in UniProt P19883Reference description; checked chemical identity above takes precedence when available.16
Pharmacokinetics
How long does it stay in the body?
Unverified reference estimateNot independently confirmed
Reference half-life1.5 hours15
Route / formulationSource page: Injectable. Exact PK route not verified.
Follistatin constructs and isoforms differ. This number does not establish elimination for every product sold as Follistatin 344.
50%of reference level
Illustrative scenario using an unverified reference estimate.
About 3% remaining after 7.5 h
Five half-lives in this estimated model. This is not a prediction of when effects stop.
Evidence and model details
Population: Not established by the reference estimate
Source’s stated attribution: Datta-Mannan et al. 2013
Source’s reported peak time: 9 min. This has not been independently confirmed and is not used in the elimination curve.
100 × 2−time / half-life. Time zero is a reference level, not the moment of administration. Absorption, repeated dosing, metabolites and clinical effects are not modeled. Five half-lives leaves 3.125%, not zero. This curve cannot determine a dosing interval.
What to expect
Study outcomes
Scope of evidence
Human gene-transfer results cannot establish a dose or safety profile for injected research protein.1
Community poll 10 topics · Pep-Pedia snapshot
Voluntary, unverified reports. These percentages do not measure effectiveness or safety.
Experience
Number of responses to this question: not disclosed.
Duration of use
Number of responses to this question: not disclosed.
Age range
Number of responses to this question: not disclosed.
Gender
Number of responses to this question: not disclosed.
Primary goal
Number of responses to this question: not disclosed.
Effectiveness
Number of responses to this question: not disclosed.
Side effects
Number of responses to this question: not disclosed.
Dosage frequency
Number of responses to this question: not disclosed.
Would recommend
Number of responses to this question: not disclosed.
How discovered
Number of responses to this question: not disclosed.
Source & limitations
The source displays “38 responses” for this profile. This is not a confirmed participant count or a denominator for individual questions.
- Voluntary self-reports from Pep-Pedia visitors; identity, treatment, outcomes and timing are unverified. These data are not efficacy or safety estimates.
- The source displays a profile-wide response label, not a confirmed unique participant count. It stays unchanged across questions. Question-specific denominators and absolute option counts are not exposed.
- Only the top five categories are displayed for some questions. Extra categories are retained as an undisplayed-category count; their labels and percentages are unavailable.
- Displayed percentages are rounded. They may not total 100%, especially where categories are hidden.
- This is a dated snapshot, not a live survey or current recommendation.
Protocols
Doses & schedules
Compare purpose, amount, route, frequency, and duration.
Source corrections
Source-reported compatibility categories do not establish safety; dramatic hypertrophy claims largely concern sustained gene expression.
Scroll to compare all columns →
| Route | Dose | Frequency | Goal / evidence | Duration | References |
|---|---|---|---|---|---|
| SubQ | 100 mcg | Once daily | Research Protocol (Anecdotal)Reference report | 10-30 days (anecdotal) | 16 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source-reported compatibility categories do not establish safety; dramatic hypertrophy claims largely concern sustained gene expression. Source tabs Injectable | |||||
| SubQ | 200 mcg | Once daily (max recommended) | Higher Dose Protocol (Anecdotal)Reference report | 10-30 days (anecdotal) | 16 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source-reported compatibility categories do not establish safety; dramatic hypertrophy claims largely concern sustained gene expression. Source tabs Injectable | |||||
No protocols match these filters.
Study and label doses retain their study context. Reference reports are unvalidated practices, not personal treatment instructions. Ranges remain ranges; escalation stages are labeled.
Reported use periods and breaks. These do not establish a safe cycle or prove that breaks prevent tolerance.
Injectable
- Use period
- 10-30 days (anecdotal)
- Break
- 3-4 weeks minimum between cycles (anecdotal)
Reported timing
Timing not established - some suggest morning administration
Side effects & safety
Evidence boundary
Human gene-transfer results cannot establish a dose or safety profile for injected research protein.
1Formulation boundary
Observations for the studied material do not establish safety of other routes or supplier products.
1Product identity
Testing documented products containing other growth-promoting peptides.
2Evidence mismatch
Injectable human safety is sparse; WADA-prohibited according to source.
Hormonal and tissue risks
Possible FSH/reproductive effects, lipid changes; theoretical bone/fibrosis risks. Cancer and pregnancy need particular caution.
Urgent symptoms
Vision changes, allergy, hormonal disruption, unexplained weakness, edema or joint pain.
Not a complete safety screen. Discuss health decisions with a qualified clinician.
Combinations & interactions
9 entriesCheck cautions and reported pairings. A compatibility claim does not establish that a combination is safe.
HGH
Caution reportedPotential excess anabolic signaling.16
Reference report · Pep-Pedia label: Monitor CombinationTestosterone/androgens
Caution reportedHuman combination evidence lacking.16
Reference report · Pep-Pedia label: Monitor CombinationACE-031
Avoidance reportedOverlapping pathway; vascular-risk history.16
Reference report · Pep-Pedia label: Avoid CombinationOther myostatin inhibitors
Avoidance reportedUntested off-target effects.16
Reference report · Pep-Pedia label: Avoid CombinationIGF-1 LR3
Unverified pairingUntested additive growth signaling.16
Reference report · Evidence context: UnknownBPC-157
Unverified pairingNo interaction studies.16
Reference report · Evidence context: UnknownTB-500
Unverified pairingNo interaction studies.16
Reference report · Evidence context: UnknownCJC-1295
Unverified pairingNo combination-safety data.16
Reference report · Evidence context: UnknownOther peptides and medicines
Not establishedA controlled interaction assessment for this exact compound and formulation was not identified in the sources checked. Absence of interaction data is not evidence of compatibility.3
Research contextNo matching interactions. Try another name or filter.
Reconstitution
A product-specific preparation or sterility protocol has not been verified.3
Dilution
A concentration calculation cannot establish a suitable diluent, compatibility, storage interval, or sterility. No universal bacteriostatic-water volume is assigned.3
Reference preparation details
Reported handling information, not a validated formulation or instruction to prepare an injectable product.
Injectable
The source distinguishes frozen dry protein from refrigerated prepared solution.
- Solvents mentioned
- Sterile water / Bacteriostatic water
- Reported parameters
- Dry material: reported −20°C. · Prepared solution: reported 2–8°C for 7 days; the source says not to freeze it.
The source describes gentle mixing and avoiding vigorous shaking.
Appearance & documentation
Appearance and a purity certificate cannot establish sterility, identity, or suitability for injection.
Reported variationExtremely limited human peptide dataReported variationVery short half-life (~90 minutes)Reported variationWADA banned substanceReported concernExcessive dosing riskReported appearanceThird-party testing essential
16Available forms
No verified packaging examples included.
Packaging examples, not a market survey. Approved and research products are not interchangeable.
Storage after mixing
Reconstituted research vials
Pep-Pedia reports these handling limits after mixing. They are not validated stability or sterility limits for your vial.
Full storage notes from Pep-Pedia
16Lyophilized: -20°C. Reconstituted: 2-8°C, use within 7 days
Storage depends on the formulation, diluent, container, and handling. Follow the specific product label or pharmacist’s instructions.
Research findings
PreclinicalSource context
Source-reported compatibility categories do not establish safety; dramatic hypertrophy claims largely concern sustained gene expression.
Compound identity & other names
Follistatin research on an FS344 gene construct must be separated from products sold as injectable follistatin protein: the exposure and produced isoforms differ substantially.
Other names: FS344
Investigational; this profile does not establish an approved use.
How it may work
Neutralizes TGF-β-family growth signals; FS-344 precursor processing produces FS-315, making product identity important.16
Gene delivery, not protein dosing
Mouse AAV experiments delivered genetic instructions for follistatin production. Their results cannot be translated into a microgram schedule for a vial labeled FS344.
1Detection of black market follistatin 344
Only 9 of 17 tested black-market products contained follistatin. A label is insufficient evidence of identity.
2Research areas and evidence gaps
Muscle biology and gene-transfer research. Scope of investigation or explicitly identified community interest; not an established indication.1
- Human gene-transfer results cannot establish a dose or safety profile for injected research protein.
- The evidence does not validate the identity, purity or handling of a separately sourced research product.
Community reports Unvalidated
Pep-Pedia reports use in the research-peptide community. These reports are not clinical evidence.3
Community protocol tables are unvalidated descriptions, not treatment instructions.
Search coverage and review status
Additional primary or regulatory sources were checked. No further 2025–2026 exact-compound clinical outcome study was identified in this targeted search; this is not evidence that none exists.
- Checked
- 2026-10-12
- Search
- Follistatin 344 OR FS344 2025 2026 gene therapy study
- Catalog
- Pep-Pedia ↗ · 12 listed references retained
- Targeted search, not a systematic or exhaustive review.
- Retained bibliography entries marked Bibliography only have not been independently verified.
- Distinct URLs may refer to the same publication; component and formulation boundaries remain important.
AI-prepared summaries. Independent medical editorial review is pending.
References
Original sources and review status. Open a reference to read its summary.
1Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitorsGene delivery is not equivalent to administration of purified follistatin protein.Primary source checked
AI-PREPARED SUMMARY
AAV delivery of a follistatin-344 gene increased muscle measures in mice; the precursor is processed to circulating FS315.
Gene delivery, not protein dosing
Mouse AAV experiments delivered genetic instructions for follistatin production. Their results cannot be translated into a microgram schedule for a vial labeled FS344.
Pep-Pedia bibliography · Checked 2026-10-12
2Detection of black market follistatin 344Abstract checked
AI-PREPARED SUMMARY
Analytical testing of 17 black-market products detected follistatin in nine; other products contained different growth-promoting peptides.
Detection of black market follistatin 344
Only 9 of 17 tested black-market products contained follistatin. A label is insufficient evidence of identity.
Additional research · Checked 2026-10-12
3Pep-Pedia: Follistatin 344Community source checked
AI-PREPARED SUMMARY
Secondary community overview checked on 12 October 2026. Its practice tables and efficacy claims are not independently validated clinical guidance.
4Kota, J., Handy, C.R., Haidet, A.M., Montgomery, C.L., Eagle, A., Rodino-Klapac, L.R., et al. (2009). Follistatin gene delivery enhances muscle growth and strength in nonhuman primates. Science Translational Medicine, 1(6), 6ra15.Gene delivery is not equivalent to administration of purified follistatin protein.Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: Viral FS344 gene delivery increased macaque muscle size over 15 months; this cannot be equated with injecting follistatin protein.
Reported population / model
Primate
Reported study details
AAV1-FS344 · 1×10¹³ vg · Cynomolgus macaques · 15 months
Reported by Pep-Pedia; the linked publication, design, doses and result have not been independently verified here. Gene delivery is not equivalent to administration of purified follistatin protein.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
5Mendell, J.R., Sahenk, Z., Malik, V., Campbell, K.J., et al. (2015). A Phase 1/2a Follistatin Gene Therapy Trial for Becker Muscular Dystrophy. Molecular Therapy, 23(1), 192-201.Gene delivery is not equivalent to administration of purified follistatin protein.Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: Six BMD patients receiving gene therapy had variable walking and muscle/fibrosis improvements; this was a small uncontrolled gene-delivery study.
Reported population / model
Human
Reported study details
AAV1.CMV.FS344 · 6 BMD patients · Intramuscular · 1 year
Reported by Pep-Pedia; the linked publication, design, doses and result have not been independently verified here. Gene delivery is not equivalent to administration of purified follistatin protein.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
6Gilson, H., Schakman, O., Kalista, S., Lause, P., Tsuchida, K., Thissen, J.P. (2009). Follistatin induces muscle hypertrophy through satellite cell proliferation and inhibition of both myostatin and activin. American Journal of Physiology - Endocrinology and Metabolism, 297(1), E157-E164.Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: Mouse and cell findings implicate myostatin, activin A and satellite-cell pathways in muscle growth.
Reported population / model
Mouse
Reported study details
In vivo & in vitro · Muscle regeneration model
Reported by Pep-Pedia; the linked publication, design, doses and result have not been independently verified here.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
7Rodino-Klapac, L.R., Haidet, A.M., Kota, J., Handy, C., Kaspar, B.K., Mendell, J.R. (2009). Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease. Neuromuscular Disorders, 19(4), 239-246.Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: The review distinguishes circulating FS315 from tissue-binding isoforms; mechanistic rationale does not validate a commercial FS344 vial.
Reported population / model
Review
Reported study details
Multiple studies · Therapeutic potential assessment
Reported by Pep-Pedia; the linked publication, design, doses and result have not been independently verified here.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
8Datta-Mannan, A., Yaden, B., Engstrom, M., et al. (2013). An engineered human follistatin variant: insights into the pharmacokinetic and pharmocodynamic relationships. Journal of Pharmaceutical Sciences, 102(1), 227-237.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
9Kota, J., Handy, C.R., Haidet, A.M., Montgomery, C.L., Eagle, A., Rodino-Klapac, L.R., et al. (2009). Follistatin gene delivery enhances muscle growth and strength in nonhuman primates. Science Translational Medicine, 1(6), 6ra15.Gene delivery is not equivalent to administration of purified follistatin protein.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
10Mendell, J.R., Sahenk, Z., Malik, V., Campbell, K.J., et al. (2015). A Phase 1/2a Follistatin Gene Therapy Trial for Becker Muscular Dystrophy. Molecular Therapy, 23(1), 192-201.Gene delivery is not equivalent to administration of purified follistatin protein.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
11Haidet, A.M., Rber, L., Montgomery, C.L., et al. (2008). Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors. Proceedings of the National Academy of Sciences, 105(11), 4318-4322.Gene delivery is not equivalent to administration of purified follistatin protein.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
12Gilson, H., Schakman, O., Kalista, S., Lause, P., Tsuchida, K., Thissen, J.P. (2009). Follistatin induces muscle hypertrophy through satellite cell proliferation and inhibition of both myostatin and activin. American Journal of Physiology - Endocrinology and Metabolism, 297(1), E157-E164.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
13Rodino-Klapac, L.R., Haidet, A.M., Kota, J., Handy, C., Kaspar, B.K., Mendell, J.R. (2009). Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease. Neuromuscular Disorders, 19(4), 239-246.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
14Datta-Mannan, A., Yaden, B., Engstrom, M., et al. (2013). An engineered human follistatin variant: insights into the pharmacokinetic and pharmocodynamic relationships. Journal of Pharmaceutical Sciences, 102(1), 227-237.Linked reference · Not independently reviewed
REFERENCE NOTE
Reference retained from Pep-Pedia’s bibliography. The original source and the website’s description have not been independently verified; the listed title may not match the linked record.
Pep-Pedia bibliography · Checked 2026-10-12
15Pep-Pedia: Follistatin 344 — reported pharmacokineticsReference estimate; not independently verified human PKCommunity source checked
AI-PREPARED SUMMARY
Lists a half-life of 1.5 hrs and a peak time of 9 min. Stated attribution: Datta-Mannan et al. 2013. Follistatin constructs and isoforms differ. This number does not establish elimination for every product sold as Follistatin 344. Five half-lives is not complete clearance, and the source’s “cleared” value is not used as a measured endpoint.
Secondary reference page checked; the underlying quantitative claim is not independently confirmed. · Checked 2026-10-12
16Pep-Pedia: Follistatin 344 — route-specific referenceReference page checked; underlying claims require separate verification.Community source checked
AI-PREPARED SUMMARY
Source page checked across available routes. Protocols, cycles, storage, mechanisms and pairing claims are secondary reports; checking the page does not independently validate those claims. Original concise summaries are used here.
Content coverage audit · Checked 2026-10-12