CJC-1295 + Ipamorelin (5mg/5mg) · Research brief

Buy Follistatin 344 — Research Buyer's Quality Checklist

Real Peptides Research TeamEditorial

Updated September 16, 20268 min read

53 WORDS

Short answer

The number in Follistatin 344 isn't a dose, a concentration, or a batch code. It's an amino acid count. And the single most common purchasing mistake in this category is ordering the 344 precursor when the experiment actually called for the 288 isoform, which behaves completely differently once it hits a cell surface.

Key takeaways

Follistatin 344 refers to a 344 amino acid precursor protein that is processed into circulating FST-315, while the alternative splice variant yields cell-surface-bound FST-288.
Follistatin antagonizes activin A and myostatin (GDF-8), the growth factor whose loss-of-function phenotype was described in myostatin-null mice in a 1997 Nature paper from McPherron and Lee at Johns Hopkins.
A certificate of analysis is only meaningful when the lot number on the document matches the lot printed on the vial you received.
Endotoxin data by LAL assay is essential for any follistatin material entering cell culture, because bacterial endotoxin independently drives inflammatory signalling.
Lyophilized recombinant protein is stored at -20°C or colder, reconstituted material is held at 2-8°C short term, and repeated freeze-thaw cycles cause avoidable degradation.
Anyone planning to buy Follistatin 344 should confirm isoform, expression system, and purity method before comparing prices, because those three variables explain nearly all price spread in this category.

Our team has spent years answering sourcing questions from labs working with recombinant proteins, and the pattern repeats. People scrutinize price for twenty minutes and spend thirty seconds on the certificate of analysis. That's backwards.

Where can you buy Follistatin 344 for research use?

Follistatin 344 is supplied as a lyophilized recombinant protein through research-chemical and biotech catalog suppliers, not pharmacies. Buy Follistatin 344 only from a vendor publishing a batch-specific certificate of analysis with HPLC purity and mass spectrometry identity data. Vials are commonly supplied in the 1 mg range and require cold-chain shipping.

Most people who buy Follistatin 344 assume they're purchasing a short synthetic peptide like the ones sold alongside it. They aren't. FST-344 is a full-length recombinant glycoprotein expressed in a host cell system, which changes how purity is verified, how the vial must be handled, and why the price sits so far above a 10 mg synthetic peptide. This guide covers isoform selection, how to read a real COA, lab handling that preserves potency, and the supplier red flags worth walking away from.

What the number 344 actually refers to

The 344 is an amino acid count on the precursor protein. The human FST gene produces two principal splice variants: a full-length precursor of 344 residues and a shorter 315-residue precursor. Once the signal peptide is cleaved, the 344 form yields FST-315, the isoform that circulates in plasma. The shorter variant yields FST-288, which binds heparan sulfate proteoglycans and stays anchored to cell surfaces. Same gene. Very different distribution behaviour.

Follistatin matters to muscle biology because of what it binds. It acts as a high-affinity antagonist of several TGF-beta superfamily ligands, including activin A and myostatin (also called GDF-8), the growth factor McPherron and Lee identified at Johns Hopkins in a 1997 Nature paper describing markedly enlarged musculature in myostatin-null mice. Cattle breeds carrying natural myostatin loss-of-function mutations, Belgian Blue and Piedmontese among them, display a comparable phenotype.

That sequestration mechanism is what most labs are probing when they buy Follistatin 344: a decoy that binds myostatin before it can engage the ActRIIB receptor and initiate Smad2/3 signalling.

Here's where purchasing goes sideways. Researchers buy Follistatin 344 when their assay design actually requires the heparin-binding FST-288 isoform, or they order FST-288 for a systemic distribution model that needed the soluble 315 form. The vials look identical. The lyophilized powder looks identical. The experiment fails weeks later and the compound gets blamed instead of the purchase order. Confirm the isoform against your model before the cart, not after.

Read the certificate of analysis before you buy Follistatin 344

A certificate of analysis is only useful if it's batch-specific. A generic PDF with no lot number, no analysis date, and no matching label on the vial is marketing, not documentation. Check that the lot printed on the vial matches the lot on the paperwork. If it doesn't, the document tells you nothing about what you received.

Four data points carry the weight. RP-HPLC or SDS-PAGE purity, typically specified at 95% or higher for research-grade recombinant follistatin. Mass spectrometry identity, usually ESI-MS or MALDI-TOF, confirming the protein is what the label claims. Endotoxin testing by LAL assay, reported in EU per mg, which is non-negotiable for anything touching cell culture because bacterial endotoxin triggers inflammatory signalling that will contaminate your readout. And expression system, since a mammalian-expressed protein and an E. coli-expressed protein differ in glycosylation and folding.

One detail trips up newer buyers constantly. Follistatin expressed in mammalian systems is glycosylated, so it frequently runs as a diffuse band on SDS-PAGE at a higher apparent molecular weight than the calculated mass. That smear isn't contamination. It's carbohydrate. We've watched labs reject perfectly good material over this exact observation.

When you buy Follistatin 344, treat the COA as the product and the powder as the delivery format. Suppliers who publish their batch documentation openly, the way we do on our certificates of analysis page, are making a verifiable claim. Suppliers who send documentation only on request, after payment, are not.

The handling step most labs get wrong

The error isn't reconstitution volume. It's surface adsorption. At the low concentrations typical of follistatin work, a meaningful fraction of protein binds irreversibly to glass and polypropylene, meaning material disappears into the tube wall before it ever reaches the assay. Carrier protein, commonly BSA or HSA at low percentage, is standard practice for dilute recombinant protein stocks precisely for this reason. Skip it and your effective concentration is lower than your arithmetic says.

Two more mechanical points. Never vortex a reconstituted protein solution. Shear force and foaming denature tertiary structure, and unlike a short synthetic peptide, follistatin has structure to lose. Swirl gently until dissolved. Second, aliquot immediately. Repeated freeze-thaw cycling is the fastest way to degrade a vial you paid a premium for.

Storage convention for lyophilized recombinant protein is -20°C or colder, with -80°C preferred for long-term holding. Reconstituted material is generally kept at 2-8°C for short-term working use and frozen in single-use aliquots beyond that. Inspect the cold pack on arrival and document the condition before you open anything.

Labs that buy Follistatin 344 for in vivo animal models should coordinate protocol design with a licensed veterinarian and their institutional animal care and use committee before any study begins. Follistatin 344 is supplied for laboratory research use only, is not intended for human or veterinary consumption, and is not an approved drug product.

The practical upshot: when you buy Follistatin 344, budget for aliquot tubes, carrier protein, and freezer space in the same breath as the vial itself.

Follistatin 344 sourcing channels compared

Supply channels differ far more in documentation than in molecule. This table maps what each channel realistically delivers, so you can weigh what you get against what you pay before you buy Follistatin 344.

Sourcing Channel	What You Actually Receive	Documentation Standard	Cost Signal	Bottom Line
Large biotech catalog supplier	Well-characterized recombinant protein, defined expression system, small vial sizes	Full batch COA, endotoxin data, published datasheet	Highest per mg in the category	Strongest paper trail; the default choice when publication or grant reporting is involved
Specialist research peptide and protein supplier	Small-batch synthesis or expression with lot traceability	Batch-specific COA with HPLC and MS, published openly by the better vendors	Mid-range, often substantially below catalog pricing	Best balance for repeat lab work, provided the COA is lot-matched and public
Overseas bulk marketplace listing	Variable material, frequently no stated expression system	Generic or reused COA, often unmatched to the vial lot	Lowest advertised price	Verification burden falls entirely on you; expect to pay for third-party testing
Consumer wellness or 'gray market' site	Unclear isoform, packaging aimed at non-lab buyers	Rarely any analytical data at all	Marketed on outcome claims, not specs	Avoid for research use; outcome marketing on a research protein is a regulatory and quality red flag

What If: Sourcing and Handling Scenarios

What if my vial arrives warm with a melted cold pack?

Photograph the packaging, the cold pack, and the vial before opening, then contact the supplier the same day. Lyophilized protein is considerably more thermally forgiving than reconstituted solution, so short ambient exposure is not automatically fatal, but there is no home test that confirms structural integrity. A supplier who refuses replacement on documented cold-chain failure has told you how they'll handle every future order.

What if the certificate of analysis has no lot number?

Treat the material as undocumented and request the lot-matched version in writing before use. A COA without a lot number, analysis date, and method notation cannot be tied to the vial in your hand, which means it cannot support anything you publish. Generic documentation is the most common quality shortcut in this market, and it is trivially easy to spot once you know to look.

What if the vial looks completely empty?

Don't assume you were shorted. One milligram of lyophilized protein frequently presents as a nearly invisible film on the vial wall or base, especially after shipping vibration disperses the cake. Spin the vial briefly before reconstituting to collect material at the bottom, then add diluent slowly down the wall. Labs that buy Follistatin 344 for the first time report this more than any other concern.

What if the SDS-PAGE band runs higher than the stated mass?

Check the expression system on the COA before concluding the material is wrong. Mammalian-expressed follistatin carries glycosylation that increases apparent molecular weight and commonly produces a diffuse rather than sharp band. A bacterial-expressed protein running high, by contrast, is worth querying with the supplier alongside the mass spectrometry data.

The blunt truth about follistatin muscle claims

Let's be direct about this: there is no approved follistatin drug product, and the marketing that surrounds this molecule runs far ahead of the evidence. ACE-083, a locally acting follistatin-based fusion protein, advanced into mid-stage clinical work and development was subsequently halted. The follistatin gene therapy work conducted at Nationwide Children's Hospital used AAV-delivered FS-344 constructs, not injected recombinant protein, because delivery and persistence are the hard problems. Research suggests follistatin's binding activity is real and well characterized. Whether that translates into a usable intervention remains unresolved. Anyone selling this compound on outcome promises is selling something other than science.

Our published batch documentation sits on the certificates of analysis page, the full research catalog lists every compound we synthesize in small batches with exact amino-acid sequencing, and facility and shipping details are on our location page. Labs studying growth-axis signalling frequently cross-reference secretagogue tools such as CJC-1295 No DAC and Tesamorelin alongside follistatin work.

The decision to buy Follistatin 344 is really a decision about documentation, because the molecule itself is not what varies between suppliers. Sequence identity, glycosylation profile, endotoxin load, and cold-chain integrity are what vary, and every one of those is invisible in the vial and visible only on paper. Two labs can order the same nominal compound and run experiments that are not comparable to each other. The number on the label tells you which isoform you asked for. The certificate tells you what actually showed up.

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Questions

Follistatin 344 is sold through biotech catalog suppliers and specialist research protein vendors, not through pharmacies, because it is a research-use-only recombinant protein rather than an approved drug product. The practical selection criterion is documentation: choose a supplier that publishes a batch-specific certificate of analysis showing purity method, mass spectrometry identity, endotoxin data, and expression system. If the COA lot number does not match the vial label, the paperwork is worthless.

Research institutions and laboratories can buy Follistatin 344 for in vitro and approved in vivo research use, since it is supplied as a research chemical rather than a medicine. It is not approved for human or veterinary consumption and should never be marketed or purchased for that purpose. Regulations differ by jurisdiction and by institution, so confirm your own compliance requirements and import rules before ordering.

Recombinant follistatin costs substantially more per milligram than short synthetic peptides because it is a full-length glycoprotein produced through cell expression rather than solid-phase synthesis. Pricing varies widely by supplier, expression system, and vial size, so direct comparison only makes sense when purity method and endotoxin specification are identical. A cheap vial with no lot-matched certificate often costs more once third-party verification is factored in.

Follistatin 344 is the full-length precursor that is processed into FST-315, the soluble isoform found circulating in plasma. Follistatin 288 arises from an alternative splice variant and binds heparan sulfate proteoglycans, which keeps it associated with cell surfaces rather than freely distributed. They share binding targets but behave very differently in distribution, so isoform selection should be driven by your experimental model.

Research-grade recombinant follistatin is typically specified at 95% purity or higher, assessed by RP-HPLC, SDS-PAGE, or both. The certificate should also carry mass spectrometry identity confirmation, an endotoxin result from LAL testing expressed in EU per mg, a lot number matching the vial, and an analysis date. Purity alone is insufficient without identity and endotoxin data.

Lyophilized recombinant protein is conventionally stored at -20°C or colder, with -80°C preferred for long-term holding. After reconstitution, working solution is generally kept at 2-8°C for short-term use and frozen in single-use aliquots for anything longer. Repeated freeze-thaw cycling degrades protein structure, which is why aliquoting immediately after reconstitution is standard laboratory practice.

A one milligram lyophilized cake is often nearly invisible and can appear as a thin film on the vial wall rather than a visible powder at the base. Shipping vibration frequently disperses the cake, which makes the vial look unfilled. Spin the vial briefly to collect material at the bottom before adding diluent slowly down the inner wall.

No. There is no approved follistatin drug product for any indication, and Follistatin 344 sold to laboratories is a research reagent only. A follistatin-based fusion protein called ACE-083 reached mid-stage clinical testing and its development was subsequently discontinued. Research-use-only material carries no approval, no clinical dosing framework, and no authorization for human or veterinary administration.

They are not comparable products. Follistatin 344 is a recombinant protein studied for its high-affinity binding to activin A and myostatin in controlled laboratory settings. Over-the-counter myostatin supplements typically contain plant extracts or protein fractions with no demonstrated binding activity at that receptor pathway and no requirement to publish analytical data at all.

Ask for the lot-specific certificate of analysis in advance, the expression system used, the endotoxin result if the material is destined for cell culture, and the shipping method with cold-pack specification. Confirm the isoform explicitly, since the 344 and 288 forms are frequently confused at the point of order. A supplier who will not send lot-matched documentation before payment has answered the question.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA