peptideInjectableNot FDA-approvedResearch chemicalSold as a research chemical with no approved human medical useAnalytical work has flagged it in black-market doping products
Follistatin-344Benefits, Dosage & Interactions
Also known as: FST-344
Follistatin-344, also known as FST-344, is a naturally occurring protein that belongs to the follistatin family, primarily recognized for its ability to bind and inhibit members of the transforming growth factor-beta (TGF-β) superfamily, particularly myostatin. Research on Follistatin-344 focuses on muscle and strength.
Researched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Limited — Human observational or case data only — no randomized trials.
Evidence strengthLimited · 2/4
PreclinicalStrong human evidence
Human observational or case data only — no randomized trials.
Plasma half-life
Not established
Default unit
mcg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Follistatin-344 in the cited sources. Published ranges are not dosing advice.
Mixing Follistatin-344: bacteriostatic water and syringe units
The vial arrives as dry powder. How much water you add sets the strength, and the strength sets the mark you draw to on the syringe. The table assumes a 5 mg vial and a 250 mcg example draw on a U-100 insulin syringe, where 100 units is one millilitre. If your vial is a different size, scale it — the arithmetic is the same.
| Bacteriostatic water added | Resulting strength | 250 mcg draws to |
|---|---|---|
| 1 mL | 5 mg/mL | 5 units |
| 2 mL | 2.5 mg/mL | 10 units |
| 3 mL | 1.67 mg/mL | 15 units |
Units, not millilitres. Insulin syringes are marked in units, and mixing up mcg and mg on a peptide label is the single most common error people report. Check the label twice. Run your own vial through the calculator.
Storage and stability
- Before mixing
- Sealed and still as a dry powder, Follistatin-344 vials are normally kept in the fridge at 2–8 °C, out of light. Short spells at room temperature during shipping are the norm for lyophilized peptides and are not, on their own, a sign the vial is spoiled.
- After mixing
- Once bacteriostatic water goes in, the vial belongs in the fridge and is generally treated as good for about 28 days — that is how long the benzyl alcohol in bacteriostatic water is relied on to hold back bacterial growth. Plain sterile water has no preservative, so a vial mixed with it is a single-session vial. Never freeze a reconstituted vial.
- When to throw it out
- A properly mixed vial is clear. Cloudiness, floating strands, a color change or powder that will not go into solution after gentle swirling all mean the vial should be discarded rather than used. Shaking a peptide vial hard is the usual cause — swirl it, or run the water down the inside wall of the vial instead of onto the powder.
Handling and shelf-life figures describe general practice for lyophilized peptides. They are not a dose and not medical advice — your prescriber or the product label sets the amount.
References & evidence
Documents the Follistatin-344 entry is written from. Each number matches an inline marker above.
- [1]Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic PerformanceMendias CL, Awan TM · Sports Medicine (Auckland, N.Z.) · 2026 · Peer-reviewed · PMID 41966639
- [2]Detection of black market follistatin 344Reichel C, Gmeiner G, Thevis M · Drug Testing and Analysis · 2019 · Peer-reviewed · PMID 31758732
- [3]Central serous chorioretinopathy associated with high-dose follistatin-344: a retrospective case seriesDağ U, Çağlayan M, Öncül H, Alakuş MF · International Ophthalmology · 2020 · Peer-reviewed · PMID 32671599
- [4]The transgenic expression of human follistatin-344 increases skeletal muscle mass in pigsChang F, Fang R, Wang M, Zhao X, Chang W, Zhang Z, Li N, Meng Q · Transgenic Research · 2017 · Peer-reviewed · PMID 27787698
What is Follistatin-344 studied for?
What is Follistatin-344?
Follistatin-344, also known as FST-344, is a naturally occurring protein that belongs to the follistatin family, primarily recognized for its ability to bind and inhibit members of the transforming growth factor-beta (TGF-β) superfamily, particularly myostatin. Myostatin is a protein that normally limits muscle growth; by inhibiting myostatin, FST-344 may promote increased muscle mass and strength. This peptide is a synthetic version of the human follistatin protein, specifically a splice variant that contains 344 amino acids. Research into Follistatin-344 aims to understand its potential therapeutic applications in conditions characterized by muscle wasting, such as muscular dystrophy and sarcopenia, and its possible use in enhancing athletic performance. (PubChem)
What does the research say about Follistatin-344?
Tap a section to expand.
The primary mechanism of action for Follistatin-344 involves its potent antagonistic effect on myostatin. Myostatin (Growth Differentiation Factor 8 or GDF-8) is a negative regulator of muscle growth, meaning it limits the size of muscle fibers and the overall potential for muscle development. Myostatin achieves this by signaling through activin receptors, which ultimately suppresses myogenesis (the formation of muscular tissue). Follistatin-344 directly binds to myostatin, as well as other TGF-β superfamily members like activin, preventing them from binding to their receptors. By sequestering myostatin and activin, FST-344 effectively neutralizes their activity, thereby removing the inhibitory signals that restrict muscle growth and differentiation. This allows for an increase in muscle cell proliferation and differentiation, leading to hypertrophy (increase in muscle cell size) and hyperplasia (increase in the number of muscle cells). (DrugBank)
Research into Follistatin-344 primarily explores its potential benefits related to muscle growth and conditions involving muscle wasting. The key areas of interest include:
* **Enhanced Muscle Hypertrophy:** By inhibiting myostatin, FST-344 may allow for increased protein synthesis and satellite cell activation, leading to a significant increase in muscle fiber size and overall muscle mass. This effect has been observed in animal models. (DrugBank)
* **Prevention and Treatment of Muscle Wasting Conditions:** Due to its myostatin-inhibiting properties, Follistatin-344 is being investigated for its potential to counteract muscle loss in conditions such as muscular dystrophy, sarcopenia (age-related muscle loss), cachexia (wasting syndrome), and other situations where muscle mass is compromised. (PubChem)
* **Improved Muscle Repair and Regeneration:** By promoting an environment conducive to muscle cell proliferation and differentiation, FST-344 may also play a role in accelerating muscle repair after injury. (DrugBank)
* **Potential for Fat Loss:** Some preclinical studies suggest that increased muscle mass, driven by myostatin inhibition, can lead to a higher basal metabolic rate, potentially contributing to a reduction in body fat. However, this is largely an indirect effect and not a primary mechanism. (PubChem)
It is important to note that most of these potential benefits are derived from preclinical studies and animal models. Human clinical trials are ongoing to fully ascertain the efficacy and safety of Follistatin-344 for these applications.
Scientific evidence for Follistatin-344 largely stems from *in vitro* studies and animal models. Murine models have shown significant increases in muscle mass and strength following administration of follistatin, including instances where myostatin-deficient mice exhibit a 'double-muscling' phenotype. For example, research published in *Nature* (though not specifically on FST-344 but on myostatin inhibition via follistatin) demonstrated that interfering with myostatin signaling in adult mice led to substantial increases in muscle mass. (PubChem)
Studies in various animal models, including non-human primates, have explored the use of gene therapy to express follistatin locally or systemically, resulting in notable muscle growth and improved muscular function. While these studies provide strong evidence for the biological activity of follistatin in muscle regulation, it's crucial to differentiate these from direct studies on the synthetic peptide Follistatin-344 in humans. (DrugBank)
Preclinical data support the hypothesis that Follistatin-344 can effectively neutralize myostatin and activin, leading to muscle hypertrophy. Human clinical trials for Follistatin-344, especially for direct muscle-building applications in healthy individuals, are limited or in very early stages. Most human research on follistatin derivatives aims at treating specific muscle-wasting diseases. (NIH ODS)
As Follistatin-344 is a research peptide and not approved for human use by regulatory bodies like the FDA or EMA, comprehensive data on its side effects in humans are limited. Based on preclinical studies and the known physiological roles of follistatin and myostatin, potential side effects might include:
* **Immune Response:** As a protein, there's a theoretical risk of an immune response, including antibody formation, which could neutralize the peptide or trigger allergic reactions.
* **Cardiovascular Effects:** Alterations in muscle mass could indirectly impact cardiovascular function, though direct effects are not well-established.
* **Impact on other TGF-β Superfamily Members:** While primarily targeting myostatin, follistatin also binds to and inhibits other TGF-β superfamily members like activins. Modulating these pathways could lead to unintended physiological effects, as activins play roles in various processes, including reproduction, inflammation, and immune regulation.
* **Gastrointestinal Disturbances:** As with many injectable compounds, localized irritation at the injection site or systemic gastrointestinal discomfort could occur.
* **Joint and Connective Tissue Changes:** Rapid muscle growth might put additional stress on tendons, ligaments, and joints, potentially increasing the risk of injury if not managed with appropriate resistance training and recovery.
Since this compound is not thoroughly clinically studied in humans for general use, the full spectrum of potential side effects, especially long-term effects, remains unknown. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Specific warnings for Follistatin-344 are scarce due to its status as a research chemical not approved for human therapeutic use. However, general warnings applicable to any experimental peptide or substance that significantly alters natural physiological processes would apply:
* **Lack of Human Safety Data:** There is a significant paucity of robust, peer-reviewed human clinical trial data on the safety and long-term effects of Follistatin-344. Most available information comes from animal studies or *in vitro* research.
* **Potential for Unintended Biological Effects:** FST-344 modulates fundamental growth pathways. Uncontrolled or chronic modulation of such pathways could lead to unforeseen consequences beyond muscle growth, potentially affecting other organs or biological systems.
* **Risk of Immunogenicity:** Administration of a peptide carries the risk of stimulating an immune response, leading to antibody development against the peptide, which could reduce its efficacy or cause adverse reactions.
* **Contamination and Purity Issues:** As Follistatin-344 is often acquired from sources not regulated by pharmaceutical standards, there is an inherent risk of contamination or incorrect product purity and composition.
* **Ethical and Legal Concerns:** Use of research compounds outside of a controlled research setting raises ethical questions and may have legal implications depending on jurisdiction.
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Given the limited human clinical data for Follistatin-344, definitive contraindications are not established. However, based on its mechanism of action and general biomedical principles, potential contraindications would include:
* **Pregnancy and Lactation:** The effects on fetal development or infants are unknown and could be detrimental. It is highly contraindicated in these populations.
* **Children and Adolescents:** Due to the impact on growth and development, Follistatin-344 would be contraindicated in individuals whose skeletal and endocrine systems are still maturing.
* **Pre-existing Medical Conditions:** Individuals with any pre-existing medical conditions, particularly those involving growth disorders, cancer (due to the potential for influencing cell proliferation pathways), hormonal imbalances, or cardiovascular issues, should avoid this compound.
* **Allergies:** Individuals with known allergies to peptides or any excipients in the formulation should avoid use.
* **Kidney or Liver Impairment:** The metabolism and excretion pathways of Follistatin-344 are not fully characterized in humans. Individuals with compromised kidney or liver function may be at higher risk for accumulation or adverse effects.
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Due to the absence of extensive human clinical trials and comprehensive safety data, specific interactions between Follistatin-344 and other compounds are largely unknown. Therefore, a conservative approach of avoiding mixing with most other substances is prudent. Potential areas of concern without direct evidence include:
* **Other Growth Factors/Peptides:** Combining FST-344 with other compounds that influence growth hormone, IGF-1, or other growth-related peptides could theoretically lead to unpredictable synergistic or antagonistic effects, potentially increasing the risk of adverse outcomes.
* **Immunosuppressants/Immunostimulants:** Given the theoretical potential for immune response or modulation, co-administration with drugs affecting the immune system should be approached with extreme caution.
* **Hormonal Therapies:** As FST-344 impacts growth pathways, combining it with other hormonal therapies or steroids could lead to complex and potentially dangerous interactions given the broad physiological roles of these pathways.
* **Medications for Chronic Diseases:** Individuals on chronic medication for conditions like diabetes, cardiovascular disease, or cancer should absolutely avoid Follistatin-344 due to the unknown interaction profiles and potential for exacerbating underlying conditions or interfering with established treatments.
Always discuss any experimental compounds with a qualified healthcare professional, especially if you are taking other medications or supplements. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
The typical timing for Follistatin-344 administration is user-directed and must be set by a licensed clinician. It is typically administered via injection, and the frequency and duration of administration would depend on the specific research protocol or guided by expert medical advice given its experimental nature. There are no standardized or FDA/EMA-approved dosing guidelines. Meals do not typically influence the absorption or efficacy of injectable peptides, hence it can be taken relative to food. The compound has a half-life of approximately 48 hours.
Put it into practice
Reading about Follistatin-344 is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.
What interacts with Follistatin-344?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any peptide + hormone | Note | Category ruleConfidence: theoretical | Injectable peptides plus hormones can have overlapping or compounding effects that aren't always well characterized.Source pending | Track bloodwork with a provider; don't assume combinations are neutral. |
Frequently asked questions about Follistatin-344
Follistatin-344 is a peptide primarily known for its ability to inhibit myostatin, a protein that naturally limits muscle growth. By blocking myostatin, FST-344 may promote increased muscle mass and strength, and is being researched for muscle-wasting conditions. (PubChem)
No, Follistatin-344 is a research peptide and is not approved by regulatory bodies like the FDA or EMA for human therapeutic use or as a supplement. Its safety and efficacy in humans are still under investigation. (NIH ODS)
Follistatin-344 is typically administered via injection. The specific route (e.g., subcutaneous, intramuscular) and dosage would be determined in a research setting or by a licensed clinician. (DrugBank)
Due to limited human data, the full spectrum of side effects is unknown. Potential concerns, based on its mechanism and preclinical studies, include immune responses, cardiovascular effects, impact on other physiological pathways (e.g., reproduction, inflammation due to activin inhibition), and localized injection site reactions. Long-term effects are particularly unknown. (PubChem)
Due to the lack of extensive human data on interactions, combining Follistatin-344 with other supplements or medications is strongly discouraged. Such combinations could lead to unpredictable and potentially harmful interactions. Always consult a qualified clinician. (DoseRoutine content team recommendation)
As a peptide, Follistatin-344 can overlap with other supplements, prescription medicines, hormones and peptides. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Follistatin-344 with no sign-up.
Follistatin-344 is administered by injection, so the measured volume — not a tablet count — is the unit that matters. Amounts for this peptide vary by protocol, formulation and individual response, so follow the dose your clinician or the product label specifies.
Whether Follistatin-344 fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Follistatin-344. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Follistatin-344 varies by protocol and formulation, so the label or prescription is what sets it. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Follistatin-344 depends on the protocol and formulation you are on. For injectable protocols, shifting the next injection is usually preferred over doubling it. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For an injectable like Follistatin-344 the record needs more than a checkbox: vial concentration, the measured volume, and which site the last injection went into. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Follistatin-344?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Central serous chorioretinopathy associated with high-dose follistatin-344: a retrospective case series(opens PubMed in a new tab)Int Ophthalmol · 2020 · PMID 32671599 · https://pubmed.ncbi.nlm.nih.gov/32671599/
- 2.The transgenic expression of human follistatin-344 increases skeletal muscle mass in pigs(opens PubMed in a new tab)Transgenic Res · 2017 · PMID 27787698 · https://pubmed.ncbi.nlm.nih.gov/27787698/
Verify at
Publisher search links for Follistatin-344. These are places to check the information — they are not citations, so they are not numbered.
- PubChem(publisher search, opens in a new tab)National Center for Biotechnology Information · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed labeling archive(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Follistatin-344?
Plain-text summary, safe to quote verbatim:
Follistatin-344, also known as FST-344, is a naturally occurring protein that belongs to the follistatin family, primarily recognized for its ability to bind and inhibit members of the transforming growth factor-beta (TGF-β) superfamily, particularly myostatin. Research on Follistatin-344 focuses on muscle and strength.
Source: DoseRoutine — https://doseroutine.com/library/follistatin-344
Follistatin-344 cheat sheet
DoseRoutine cheat sheet · Peptide
Follistatin-344
Follistatin-344, also known as FST-344, is a naturally occurring protein that belongs to the follistatin family, primarily recognized for its ability to bind and inhibit members of the transforming growth factor-beta (TGF-β) superfamily, particularly myostatin.
Evidence
Limited
Human observational or case data only — no randomized trials.
Route
Reported by black-market analytical testing and a case series as subcutaneous injection
Not FDA-approvedResearch chemicalSold as a research chemical with no approved human medical useAnalytical work has flagged it in black-market doping productsMuscle
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/follistatin-344
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Follistatin-344 — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/follistatin-344
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