BPC-157 (Body Protection Compound 157) is a synthetic pentadecapeptide — a chain of 15 amino acids — derived from a sequence found in human gastric juice. It is a stable fragment studied for its wide-ranging biological activity in preclinical research, particularly in tissue healing, gut protection, and neurological effects.

What does the research say about BPC-157?

The majority of BPC-157 research comes from rodent and in vitro studies. These consistently show accelerated tendon-to-bone healing, protection against NSAID-induced gut damage, mucosal healing in IBD-like models, and modulation of dopamine and serotonin systems. Several independent research groups have replicated these findings. Large-scale human clinical trials have not been conducted.

Is BPC-157 FDA approved?

No. BPC-157 is not FDA approved and is not legal for human use. It is sold strictly as a research compound for laboratory and preclinical research purposes only.

How does BPC-157 work?

BPC-157 is thought to work through several mechanisms: modulation of the nitric oxide (NO) system; upregulation of growth hormone receptors at injury sites; activation of VEGF pathways driving angiogenesis; anti-inflammatory cytokine reduction; and interaction with dopamine and serotonin systems.

How is BPC-157 reconstituted for research?

BPC-157 is supplied as a lyophilized powder and reconstituted with bacteriostatic water (BAC water) before use. Add BAC water slowly to the vial wall, swirl gently (do not shake), and store at 2–8°C.

What is the difference between BPC-157 and TB-500?

Both are studied for tissue repair but through different mechanisms. BPC-157 is a 15-amino-acid gastric peptide fragment studied for tendon healing, gut protection, and neurological effects via NO/VEGF pathways. TB-500 (Thymosin Beta-4) is a 43-amino-acid peptide that primarily works by regulating actin polymerization, promoting cell migration and wound healing.

How should BPC-157 be stored?

Lyophilized BPC-157 should be stored at -20°C, away from light and moisture, where it can remain stable for 1–2 years. Once reconstituted in bacteriostatic water, store at 2–8°C and use within 4 weeks. Avoid repeated freeze-thaw cycles of the reconstituted solution.

A peptide is a short chain of amino acids — the same building blocks that make up proteins — linked together by peptide bonds. Peptides typically contain 2 to 50 amino acids. Longer chains are classified as proteins. In the body, peptides function primarily as signaling molecules, binding to specific receptors and triggering precise biological responses.

What is the difference between a peptide and a protein?

Size and structure. Proteins are long polypeptide chains that fold into complex three-dimensional shapes — enabling functions like enzymatic activity or structural support. Peptides are shorter chains that don't fold the same way. Instead, they act as targeted messengers: highly selective, fast-acting signals that trigger specific cellular responses without the structural complexity of proteins.

How do peptides work in the body?

Most peptides work by binding to cell-surface receptors, triggering intracellular signaling cascades that can alter gene expression, release hormones, activate enzymes, or change cell behavior. Some act through the nitric oxide (NO) system, others through growth factor pathways like VEGF or IGF-1.

What are the most studied research peptides?

Among the most studied are BPC-157 (tissue healing, gut protection), TB-500 / Thymosin Beta-4 (wound healing, anti-inflammatory), GHK-Cu (collagen synthesis, skin regeneration), CJC-1295 and Ipamorelin (growth hormone secretagogues), and Retatrutide (metabolic research).

Why are research peptides supplied as powder?

Peptides are shipped lyophilized (freeze-dried) because the dry powder form is far more stable than a liquid solution during storage and shipping. Lyophilized peptides stored at -20°C can remain stable for 1–2 years. Once reconstituted into liquid form with bacteriostatic water, shelf life drops to weeks.

What does 'research peptide' mean?

A research peptide is a synthetic peptide compound sold strictly for laboratory and scientific research purposes — not for human consumption or clinical use. These compounds are studied in preclinical settings to understand their biological effects, mechanisms, and potential applications.

Are peptides naturally occurring?

Yes. Many peptides are naturally occurring in the body. Insulin, glucagon, oxytocin, and endorphins are all peptides produced naturally. Research peptides are either synthesized versions of naturally occurring sequences or novel sequences designed to interact with specific biological pathways.

What is the difference between BPC-157 and TB-500?

BPC-157 is a 15-amino-acid peptide derived from human gastric juice, primarily studied for tendon and ligament healing, gut protection, and neurological effects via nitric oxide and VEGF pathways. TB-500 (Thymosin Beta-4) is a 43-amino-acid peptide that works primarily by upregulating actin, promoting cell migration, blood vessel formation, and wound healing. They work through different mechanisms and are often studied together due to their complementary effects.

Can BPC-157 and TB-500 be used together in research?

Yes. Many researchers study BPC-157 and TB-500 in stacked protocols due to their complementary mechanisms — BPC-157 targeting NO/VEGF healing pathways and TB-500 targeting actin upregulation and cell migration. The combination is hypothesized to produce more comprehensive tissue repair effects than either compound alone.

Which is better for tendon research: BPC-157 or TB-500?

Both show strong preclinical data for tendon repair but through different mechanisms. BPC-157 has more direct tendon-to-bone healing data. TB-500's actin-regulation mechanism makes it particularly relevant for cell migration and vascularization. They are considered complementary rather than competitive.

TB-500 is a synthetic version of Thymosin Beta-4, a naturally occurring 43-amino-acid peptide found in high concentrations at wound sites. By upregulating actin availability, TB-500 is studied for its effects on cell migration, angiogenesis, and tissue repair.

Is BPC-157 or TB-500 FDA approved?

Neither BPC-157 nor TB-500 is FDA approved. Both are research compounds sold strictly for preclinical laboratory research and are not approved for human use.

What does BPC-157 stand for?

BPC-157 stands for Body Protection Compound 157. The name refers to its origin as the 157th fragment identified in a research program screening gastric juice proteins for bioactive sequences.

How are BPC-157 and TB-500 stored?

Both peptides are supplied lyophilized and should be stored at -20°C until reconstitution. Once reconstituted in bacteriostatic water, store at 2–8°C and use within 2–4 weeks. Aliquot before freezing to avoid repeat freeze-thaw cycles.

What purity level should research peptides be?

The research standard is ≥98% purity, verified by HPLC (high-performance liquid chromatography). This level ensures that contaminants and synthesis byproducts are minimal enough to not interfere with research outcomes.

What is HPLC and why does it matter for peptides?

HPLC (high-performance liquid chromatography) is the gold-standard analytical method for measuring peptide purity. It separates the components of a sample and produces a chromatogram showing the percentage of the target compound vs. impurities.

What is mass spectrometry (MS) verification for peptides?

Mass spectrometry confirms the molecular identity of a peptide by measuring its molecular weight. HPLC tells you purity (how much of the compound is present); MS confirms identity (that the compound is what it's supposed to be). Together, HPLC + MS provide the most complete quality verification available.

What is a Certificate of Analysis (CoA) for peptides?

A Certificate of Analysis (CoA) is a document from the synthesizing or testing laboratory confirming the peptide's identity, purity (HPLC%), molecular weight (MS), and often additional properties. A legitimate CoA should be from a third-party or accredited lab.

What are common peptide synthesis impurities?

The most common impurities in synthetic peptides are deletion sequences, truncation sequences, oxidized residues (particularly methionine and cysteine), deamidated residues, and unreacted reagents from the synthesis process. HPLC at ≥98% keeps these to a minimum.

Does peptide purity affect research results?

Yes, significantly. Impurities can have their own biological activity, creating off-target effects that confound results. For reproducible, interpretable research, ≥98% purity is the minimum reliable standard.

What should I look for on a peptide supplier's CoA?

Look for: HPLC purity ≥98%, MS confirmation of molecular weight, test date, testing laboratory name (third party or accredited), batch/lot number, and amino acid sequence. Reject suppliers who cannot provide a CoA or only provide manufacturer self-certification.

How should lyophilized (freeze-dried) peptides be stored?

Lyophilized peptides should be stored at -20°C (standard freezer), away from light and moisture. Under these conditions, most peptides remain stable for 1–2 years. Keep them sealed until ready to reconstitute.

How long do reconstituted peptides last in the refrigerator?

Most peptides reconstituted in bacteriostatic water are stable at 2–8°C (refrigerator temperature) for 2–4 weeks. Always store away from light and note the reconstitution date on the vial.

Can reconstituted peptides be frozen for long-term storage?

Yes. Reconstituted peptides can be aliquoted into single-use doses and frozen at -20°C for extended storage — often 3–6 months. Minimize freeze-thaw cycles by aliquoting before freezing rather than re-freezing the same vial repeatedly.

Should peptides be kept away from light?

Yes. UV and visible light can break peptide bonds and cause oxidation, particularly in peptides containing tryptophan, methionine, or cysteine residues. Store all peptides in opaque or amber containers, away from direct light.

Can peptides be stored at room temperature?

Lyophilized peptides can tolerate room temperature for short periods during shipping, but should be returned to -20°C storage as soon as possible. Reconstituted peptides should never be stored at room temperature.

How do I know if a peptide has degraded?

Visual indicators include cloudiness, precipitation, or color change in a reconstituted solution. However, peptide degradation is often not visible. For research accuracy, respect expiration dates, reconstitution dates, and storage conditions strictly.

What happens if peptides freeze-thaw repeatedly?

Repeated freeze-thaw cycles cause progressive degradation: ice crystal formation during freezing damages peptide structure, and thawing allows oxidation and aggregation. Best practice is to aliquot reconstituted peptide into single-use volumes before first freezing, so each vial is thawed only once.

MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA type-c) is a 16-amino-acid peptide encoded by mitochondrial DNA — making it one of the few known peptides produced directly by the mitochondria rather than the cell nucleus. Discovered in 2015 at USC, it functions as a mitokine: a signaling molecule that travels from mitochondria to other cells and tissues to regulate metabolism and stress responses.

What does MOTS-c do in the body?

MOTS-c primarily activates AMPK (AMP-activated protein kinase), a master metabolic regulator that governs energy homeostasis. Through AMPK and related pathways, MOTS-c influences insulin sensitivity, glucose uptake, fat oxidation, and mitochondrial biogenesis. It also activates the integrated stress response (ISR) and Nrf2 antioxidant pathways.

Is MOTS-c related to aging?

Yes. Blood levels of MOTS-c decline with age in both humans and animal models. Research suggests MOTS-c may counteract some aspects of metabolic aging: studies in aged mice show improved insulin sensitivity, reduced fat accumulation, and better physical performance after MOTS-c administration.

What is the relationship between MOTS-c and exercise?

MOTS-c is sometimes called an 'exercise mimetic' because its administration in animal models produces metabolic effects similar to those induced by physical exercise — improved insulin sensitivity, increased fat oxidation, and enhanced mitochondrial function. Physical exercise itself also raises MOTS-c blood levels in humans.

What is AMPK and why is it relevant to MOTS-c research?

AMPK (AMP-activated protein kinase) is often called the body's 'energy sensor' — it activates when cellular energy (ATP) is low and triggers pathways that restore energy balance. MOTS-c activates AMPK, which is one of the primary mechanisms through which it influences metabolism and longevity-related pathways.

How is MOTS-c different from other longevity peptides?

MOTS-c is unique in that it is encoded by mitochondrial DNA — almost all other peptides are encoded by nuclear DNA. This makes it part of a newly described class called mitochondria-derived peptides (MDPs). Its origin in the mitochondria and its direct action on AMPK give it a distinct profile compared to longevity peptides like Epithalon or GHK-Cu.

Is MOTS-c FDA approved?

No. MOTS-c is not FDA approved and is not intended for human use. It is a research compound available strictly for preclinical laboratory research.

What exactly is GHK-Cu and how does it differ from other copper compounds?

GHK-Cu is a specific tripeptide sequence (Glycine-Histidine-Lysine) forming a stable complex with a single copper(II) ion. Unlike inorganic copper salts or generic copper-amino acid chelates, GHK-Cu has a precisely defined structure that interacts with specific cell-surface receptors and intracellular signaling pathways. Its biological activity is not simply attributable to copper delivery — the peptide backbone plays an active role, and studies show the copper-free form (GHK alone) retains some but not all of the activity seen with the copper complex.

How does GHK-Cu stimulate collagen synthesis at the cellular level?

GHK-Cu activates TGF-β1 (transforming growth factor beta-1) signaling, which drives fibroblast differentiation and collagen gene transcription. Simultaneously, it suppresses TGF-β3, the isoform associated with scar formation, helping shift repair toward regenerative rather than fibrotic outcomes. The copper component activates lysyl oxidase, the enzyme that cross-links collagen fibers for mechanical strength — an enzymatic step that requires copper as a cofactor.

What Is BAC Water — And Why Does It Matter for Peptide Research?

Golden State BIO
Jun 25
4 min read

Updated: Jun 29

Research vials and tubes representing peptide reconstitution with bacteriostatic water

If you've ever ordered a research peptide, you've probably seen "reconstitute with bacteriostatic water" in the instructions. But what actually is BAC water, why does it matter, and what happens if you use something else? This guide covers everything you need to know — in plain terms.

What Is Bacteriostatic Water?

Bacteriostatic water (BAC water) is sterile water for injection that contains 0.9% benzyl alcohol as a preservative. The benzyl alcohol is what makes it "bacteriostatic" — it inhibits the growth of bacteria without killing them outright, which means it can safely preserve a solution over multiple uses without contamination becoming a concern.

This is distinct from regular sterile water for injection (SWFI), which contains no preservative and is intended for single-use only. BAC water, by contrast, is stable for multi-use for up to 28 days once opened when stored correctly.

Why BAC Water Is Used for Peptide Reconstitution

Research peptides are supplied lyophilized — freeze-dried into a powder — for stability during storage and shipping. BAC water is the standard solvent for most peptides for several reasons:

Multi-dose stability: The benzyl alcohol preservative prevents bacterial contamination across multiple draws from the same vial.
Peptide compatibility: The slightly acidic pH of BAC water (typically 4.5–7.0) is well-tolerated by most peptide structures.
Sterility: BAC water is sterile-filtered and produced under pharmaceutical manufacturing standards.
Extended shelf life: Reconstituted peptides in BAC water at 2–8°C typically remain stable for 2–4 weeks.

BAC Water vs. Other Solvents

Sterile water for injection (SWFI): Single-use only — no preservative means unused solution must be discarded after each use.
Normal saline (0.9% NaCl): Can accelerate degradation of some compounds. Not recommended as a default.
Acetic acid solution (0.1–1%): Used for peptides that don't dissolve well in water. Specialized case, not standard.
Tap or non-sterile water: Never appropriate — introduces contamination risk.

How to Reconstitute a Peptide with BAC Water

Swab the rubber stopper on both vials with an alcohol wipe before inserting any needle.
Draw the appropriate volume of BAC water into a syringe based on your target concentration.
Inject BAC water slowly into the peptide vial, aiming at the glass wall to minimize foaming.
Gently swirl — never shake — until the powder is fully dissolved.
Store reconstituted peptide at 2–8°C, away from light.

Calculating Concentration

The volume of BAC water you add determines the concentration. Example: 5mg vial + 1mL BAC water = 5mg/mL (5,000mcg/mL). Add 2mL for 2.5mg/mL. Knowing your concentration is essential for accurate dosing in any research protocol.

What You're Reconstituting Matters Too

See our guide on what peptides are and how they work for foundational context, and our BPC-157 research breakdown for a commonly reconstituted compound.

Frequently Asked Questions: BAC Water and Peptide Reconstitution

What is bacteriostatic water used for?

Bacteriostatic water is used to reconstitute lyophilized (freeze-dried) research peptides and other injectable compounds. Its 0.9% benzyl alcohol preservative makes it safe for multi-dose use from a single vial, unlike plain sterile water which is single-use only.

What is the difference between bacteriostatic water and sterile water?

The key difference is the preservative. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows multi-dose use for up to 28 days once opened. Sterile water for injection (SWFI) has no preservative and must be discarded after a single use.

How long does reconstituted peptide last in BAC water?

Most peptides reconstituted in bacteriostatic water remain stable for 2–4 weeks when stored at 2–8°C, away from light. For longer storage, aliquot and freeze at -20°C — but avoid repeated freeze-thaw cycles.

How much BAC water should I add to reconstitute a peptide?

The volume depends on your desired final concentration. A common approach: add 1mL of BAC water to a 5mg vial for a 5mg/mL (5,000mcg/mL) concentration. Add 2mL for 2.5mg/mL. Always calculate your target concentration before reconstituting.

Can I use saline instead of bacteriostatic water?

Saline (0.9% NaCl) can be used for single-dose protocols, but it lacks a bacteriostatic preservative making it unsuitable for multi-dose use. Additionally, the ionic environment of saline can accelerate degradation of certain peptides. Bacteriostatic water is the recommended standard.

Does bacteriostatic water go bad?

Unopened, BAC water is stable until the manufacturer's expiration date. Once opened, it should be used within 28 days when stored at room temperature, or longer when refrigerated. Discard if it becomes cloudy or shows particulate matter.

Why do peptides need to be reconstituted?

Peptides are shipped lyophilized (freeze-dried into powder) because this form is far more stable during storage and shipping than a liquid solution. Reconstitution with bacteriostatic water converts the powder back into a stable liquid solution ready for research use.

Get Research-Grade BAC Water from Golden State BIO

Golden State BIO bacteriostatic water for peptide reconstitution

Golden State BIO carries pharmaceutical-grade bacteriostatic water (0.9% benzyl alcohol) for research peptide reconstitution, alongside research supplies including alcohol prep pads and syringes.

Shop Research Supplies →

The Bottom Line

BAC water is the standard — and for good reason. Its bacteriostatic preservative, sterility, and multi-dose stability make it the right choice for reconstituting the vast majority of research peptides.