A practical reference on Freeze-thaw: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-12 and is reviewed periodically as new material appears.
Direct human evidence is scarce. One trial in ulcerative colitis delivered the compound by enema and produced limited publicly reported results without a clear benefit. The compound is not an approved medicine in most jurisdictions. In many markets it is sold as a research chemical; in others it falls under prescription or controlled categories. Regulators have not confirmed any claimed medical use, and product labels rarely undergo premarket review.
Most published reports describe experiments in rodents rather than in people. These studies examine outcomes in tendons, ligaments, bone, stomach lining, and intestinal tissue. In rat and mouse models, a frequently reported effect is faster healing or reduced damage. Sample sizes are usually small, and a substantial share of the work originates from a small number of research groups. Independent replication is limited, so how far the findings extend to humans remains an open question.
Proposed mechanisms in the literature involve the nitric oxide system, vascular endothelial growth factor signaling, and epidermal growth factor receptor pathways. Some studies report changes in blood vessel formation or in inflammatory mediators, while others describe interactions with nervous tissue. Much of this evidence rests on molecular markers in cultured cells or animal models. Whether the same pathways operate the same way in humans has not been established. Authors therefore tend to describe mechanisms as hypothetical rather than settled.
Terminology in the literature is not fully standardised. Papers and product listings use BPC-157, BPC 157, and the longer phrase stable gastric pentadecapeptide BPC 157 interchangeably, and synonyms such as bepecin or PL 14736 appear in older or company-linked publications. Purity claims and reported masses can also differ between sources because peptide preparations may include counterions, residual solvents, or bound water. This variability complicates direct comparison of results across studies and makes the exact identity and grade of a given sample worth verifying. Discussions of the compound should therefore specify the source, salt form, and stated purity where those are known.
BPC-157 is a synthetic peptide composed of fifteen amino acid residues, with the sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val. Its name derives from body protection compound, a term used for a protein fraction identified in human gastric juice. Researchers in Zagreb first reported the pentadecapeptide in the early 1990s and described it as a stable fragment of that larger protein. The compound is also catalogued as PL 14736 and, in some commercial contexts, as bepecin. Its molecular formula is C62H98N16O22 and its monoisotopic mass is approximately 1419 daltons.
Most published work on BPC-157 consists of preclinical studies, including rodent models of tissue injury, gastrointestinal lesions, and vascular or tendon damage, together with in vitro cell assays. Reviews frequently note that the mechanisms proposed in these papers remain incompletely characterised and that findings have not been confirmed in large randomised human trials. The compound is widely sold as a research chemical rather than a licensed medicine, and labels commonly carry a statement that it is not for human use. Whether any of the reported animal effects translate to humans is an open question rather than an established result.
| Property | Value | Notes |
|---|---|---|
| Main study model | Rodents, rats and mice | Underpins most of the published data |
| Common routes in studies | Subcutaneous, intraperitoneal, oral | Varies with the experimental design |
| Common analytical method | Reversed-phase HPLC, LC-MS | Used for identity and purity checks |
| Human evidence base | Small | Few trials reported, with limited findings |
| Regulatory status | Varies by jurisdiction | Not an approved medicine in most places |
Evidence in humans is limited. Small clinical studies have examined the peptide in contexts such as ulcerative colitis and wound healing, but participant numbers are small and independent replication is scarce. It is not approved as a medicine by major regulatory agencies and is distributed mainly as a research material or compounded preparation. Long-term human safety data are not established, and questions about absorption through non-injected routes remain open rather than resolved. Claims about its effects are best read against these gaps.
BPC-157 is a synthetic peptide of fifteen amino acids, written in single-letter code as GEPPPGKPADDAGLV. The sequence corresponds to a partial fragment of a protein isolated from human gastric juice, described in early reports as body protection compound. The number 157 refers to a fragment designation in that work rather than to molecular mass. Initial descriptions appeared in the early 1990s, when the fragment was reported to protect gastrointestinal tissue in animal models. Commercial material is produced by solid-phase peptide synthesis rather than extracted from biological sources.
Laboratory research on this peptide has examined a wide and heterogeneous set of endpoints, including gastric ulcer models, tendon and ligament injury, wound closure, and intestinal inflammation. Most published findings come from rodent studies, and reported effect sizes are often large relative to controls. Because the compound has been tested across many unrelated injury models, the literature is frequently described as unusually broad for a single peptide. A substantial share of this work originates from a small number of research groups, which matters when assessing how widely results have been reproduced.
The main chemical liabilities of this sequence are peptide-bond hydrolysis and possible aspartate-related reactions, since the peptide contains aspartic acid residues but no cysteine, methionine, or tryptophan. Absence of those three residues removes the most common oxidation and disulfide pathways from consideration. Studies of related peptides indicate that aspartate isomerisation and aspartimide formation occur most readily at Asp-Gly and Asp-Ala positions, and open questions remain about how quickly those reactions proceed under ordinary laboratory conditions. Storage guidance typically emphasises cool, dry, dark conditions to slow hydrolysis.
Identity and purity are usually assessed with reversed-phase high-performance liquid chromatography, often paired with mass spectrometry using electrospray or MALDI ionisation. Amino acid analysis and peptide mapping by enzymatic digestion provide additional sequence-level confirmation. Purity is commonly reported as an area percentage from a chromatographic trace, and water content can be measured by Karl Fischer titration. Reported masses may differ by tens of daltons between sources because preparations can contain acetate or trifluoroacetate counterions, and such differences are not by themselves evidence of a different peptide.
BPC-157 is normally distributed as a lyophilised powder that ranges from white to off-white in appearance. The peptide dissolves readily in water, normal saline, and common aqueous buffers, and it is poorly soluble in nonpolar solvents such as hexane or vegetable oils. Lyophilised vials take up moisture if left open, which changes the mass of powder in the container and complicates any later weighing. Because the material is handled in small quantities, static and adhesion to glass or plastic can also cause noticeable losses during transfer.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated sequences and other synthesis by-products. Mass spectrometry, typically electrospray ionization coupled to liquid chromatography, confirms the expected mass and helps detect modifications. Amino acid analysis can verify composition when residue-level confirmation is needed. Because common impurities differ from the target by only one or two residues, chromatographic resolution often matters more than a single headline purity percentage. Impurity profiles are most informative when compared against a validated reference standard.
Lyophilized material is generally reported as stable for extended periods when kept cold, dry, and protected from light. In solution, the main degradation routes for a peptide of this type are hydrolysis of peptide bonds and aggregation. The sequence contains no cysteine, so disulfide-driven oxidation is not a primary concern, though methionine and tryptophan are also absent. Stability depends on pH, buffer composition, and concentration, with acidic conditions often reported as more favorable than neutral or alkaline ones. Repeated freeze-thaw cycles can promote aggregation, and how fast degradation proceeds at room temperature in specific formulations remains an open question.
BPC-157 is a synthetic peptide of fifteen amino acids, written as GEPPPGKPADDAGLV, whose sequence matches part of a larger protein identified in human gastric juice. That parent protein was described in stomach-secretion research, and the fifteen-residue fragment was named body protection compound, which gives the peptide its common label. Material used in experiments is produced by solid-phase peptide synthesis rather than extracted from tissue. The reported molecular weight is about 1419 daltons, and the chain contains several proline residues, a feature that appears in discussions of its resistance to enzymatic breakdown.
Most published findings come from rodent models, where the peptide has been examined in wound-healing, gastrointestinal-lesion, tendon, and vascular-injury preparations. A smaller number of early human studies have been reported, chiefly in inflammatory bowel conditions, but the public record is short and has not led to marketing approval in the United States or the European Union. Reviewers therefore classify the compound as investigational, and whether animal results carry over to people remains an open question rather than a settled one.
Outside laboratory supply channels, the peptide is sold as a research chemical, a category that carries no requirement to demonstrate purity, identity, or freedom from contamination. Because it is not an approved medicine, products labeled BPC-157 sit in a regulatory gap in many countries, and actual content may differ from the label. Sports organizations list it among prohibited substances, so its presence in an athlete's sample can produce a doping finding regardless of how the material was obtained.
=== Synthetic genomics === The formation of animals with a chemically manufactured (minimal) genome is another facet of synthetic biology that is highlighted by synthetic genomics. This area of synthetic biology has been made possible by ongoing advancements in DNA synthesis technology, which now makes it feasible to produce DNA molecules with thousands of base pairs at a reasonable cost. The goal is to combine these molecules into complete genomes and transplant them into living cells, replacing the host cell's genome and reprogramming its metabolism to perform different functions. Scientists have previously demonstrated the potential of this approach by creating infectious viruses by synthesising the genomes of multiple viruses. These significant advances in science and technology triggered the initial public concerns concerning the risks associated with this technology. A simple genome might also work as a "chassis genome" that could be enlarged quickly by gene inclusion created for particular tasks. Such "chassis creatures" would be more suited for the insertion of new functions than wild organisms since they would have fewer biological pathways that could potentially conflict with the new functionalities in addition to having specific insertion sites. Synthetic genomics strives to create creatures with novel "architectures," much like the bioengineering method. It adopts an integrative or holistic perspective of the organism.
=== Hemoglobin synthesis and function === PLP aids in the synthesis of hemoglobin, by serving as a coenzyme for the enzyme aminolevulinic acid synthase. It also binds to two sites on hemoglobin to enhance the oxygen binding of hemoglobin.
Ernest O. Lawrence invents the cyclotron. 1934 Josef Mattauch and Richard Herzog develop the double-focusing mass spectrograph. 1936 Arthur J. Dempster develops the spark ionization source. 1937 Aston constructs a mass spectrograph with resolving power of 2000. 1939 Lawrence receives the Nobel Prize in Physics for the cyclotron. 1942 Lawrence develops the Calutron for uranium isotope separation. 1943 Westinghouse markets its mass spectrometer and proclaims it to be "A New Electronic Method for fast, accurate gas analysis". 1946 William Stephens presents the concept of a time-of-flight mass spectrometer. 1953 Wolfgang Paul and Helmut Steinwedel introduce the quadrupole mass filter. 1954 A. J. C. Nicholson (Australia) proposes a hydrogen transfer reaction that will come to be known as the McLafferty rearrangement. 1959 Researchers at Dow Chemical interface a gas chromatograph to a mass spectrometer. 1964 British Mass Spectrometry Society established as first dedicated mass spectrometry society. It holds its first meeting in 1965 in London. 1966 F. H. Field and M. S. B. Munson develop chemical ionization. 1968 Malcolm Dole develops electrospray ionization. 1969 H. D. Beckey develops field desorption. 1974 Comisarow and Marshall develop Fourier Transform Ion Cyclotron Resonance mass spectrometry. 1976 Ronald MacFarlane and co-workers develop plasma desorption mass spectrometry. 1984 John Bennett Fenn and co-workers use electrospray to ionize biomolecules.
=== Oliver and Schäfer (1894) === British physician George Oliver and physiologist Edward Albert Schäfer, professor at University College London, collaborated on the physiological effects of adrenal extracts. They first published their findings in two reports in 1894, a full publication followed in 1895. Though frequently falsely attributed to secretin, found in 1902 by Bayliss and Starling, Oliver and Schäfer's adrenal extract containing adrenaline, the substance causing the physiological changes, was the first hormone to be discovered. The term hormone would later be coined by Starling.
In contrast to his father, Carl saw his mother as unreliable and inconsistent, which caused him to associate women more broadly as having an "innate unreliability" (Later, these early impressions were revised: "I have trusted men friends and been disappointed by them, and I have mistrusted women and was not disappointed."). Emilie was an eccentric and depressed woman; she spent considerable time in her bedroom, where she said spirits visited her at night. Though she was normal during the day, Jung recalled that at night, his mother became strange and mysterious. He said that one night, he saw a faintly luminous and indefinite figure coming from her room, with a head detached from the neck and floating in the air in front of the body. Jung had a better relationship with his father.
Sources: en.wikipedia.org
Audiences at WWE shows have since widely chanted the question during performer promos, and Austin has expressed his surprise at the staying power of the chant, stating in a 2011 interview: "it's been interesting!" Austin's entrance theme was composed by Jim Johnston, who said that in composing the song, he looked upon Austin's persona as an "ass-kicker guy who did not enter a room with subtlety. He needed something that reflected that." Looking to capture the unpredictable nature of the character, Johnston thought of using the sounds of a car crash and smashing glass, and recalled that he instantly felt the theme fit the character and that "it felt like it had already been his theme for years". Austin says the song was inspired by Rage Against the Machine's song "Bulls on Parade". The theme song was revamped in 2000, with the rock band Disturbed recording the new version, used for the first time at the Unforgiven PPV event in September. Austin reverted to the 1998 version of his theme song in December 2001, which he still uses to date. Austin's entrance theme is regarded as one of the greatest of all time, and one which defined the Attitude Era.
After a fire at the Washington National Records Center, unclassified, non-privacy-protected, water-damaged records were frozen on site and vacuum freeze-dried off site; most of the paper-based records looked essentially the same after drying.
==== MeSH D13.444.735 – rna ==== MeSH D13.444.735.130 – rna, algal MeSH D13.444.735.150 – rna, antisense MeSH D13.444.735.150.319 – micrornas MeSH D13.444.735.150.640 – oligoribonucleotides, antisense MeSH D13.444.735.150.700 – rna, small interfering MeSH D13.444.735.300 – rna, archaeal MeSH D13.444.735.473 – rna, bacterial MeSH D13.444.735.476 – rna, chloroplast MeSH D13.444.735.480 – rna, complementary MeSH D13.444.735.490 – rna, double-stranded MeSH D13.444.735.500 – rna, fungal MeSH D13.444.735.520 – rna, helminth MeSH D13.444.735.544 – rna, messenger MeSH D13.444.735.544.355 – codon MeSH D13.444.735.544.355.225 – codon, initiator MeSH D13.444.735.544.355.250 – codon, terminator MeSH D13.444.735.544.355.250.235 – codon, nonsense MeSH D13.444.735.544.500 – rna caps MeSH D13.444.735.544.500.710 – rna cap analogs MeSH D13.444.735.544.527 – rna, messenger, stored MeSH D13.444.735.544.550 – rna splice sites MeSH D13.444.735.544.875 – untranslated regions MeSH D13.444.735.544.875.880 – 3' untranslated regions MeSH D13.444.735.544.875.885 – 5' untranslated regions MeSH D13.444.735.615 – rna, neoplasm MeSH D13.444.735.628 – rna, nuclear MeSH D13.444.735.628.806 – rna, heterogeneous nuclear MeSH D13.444.735.628.818 – rna, small nuclear MeSH D13.444.735.628.818.800 – rna, small nucleolar MeSH D13.444.735.635 – rna, plant MeSH D13.444.735.635.575 – rna, chloroplast MeSH D13.444.735.640 – rna precursors MeSH D13.444.735.650 – rna, protozoan MeSH D13.444.735.686 – rna, ribosomal MeSH D13.444.735.686.650 – rna, ribosomal, 5s MeSH D13.444.735.686.660 – rna, ribosomal, 5.8s MeSH D13.444.735.686.670 – rna, ribosomal, 16s MeSH D13.444.735.686.675 – rna, ribosomal, 18s MeSH D13.444.735.686.680 – rna, ribosomal, 23s MeSH D13.444.735.686.690 – rna, ribosomal, 28s MeSH D13.444.735.686.845 – rna, ribosomal, self-splicing MeSH D13.444.735.721 – rna, satellite MeSH D13.444.735.721.250 – cucumber mosaic virus satellite MeSH D13.444.735.757 – rna, transfer MeSH D13.444.735.757.286 – anticodon MeSH D13.444.735.757.700 – rna, transfer, amino acid-specific MeSH D13.444.735.757.700.050 – rna, transfer, ala MeSH D13.444.735.757.700.075 – rna, transfer, arg MeSH D13.444.735.757.700.085 – rna, transfer, asn MeSH D13.444.735.757.700.090 – rna, transfer, asp MeSH D13.444.735.757.700.200 – rna, transfer, cys MeSH D13.444.735.757.700.400 – rna, transfer, gln MeSH D13.444.735.757.700.410 – rna, transfer, glu MeSH D13.444.735.757.700.420 – rna, transfer, gly MeSH D13.444.735.757.700.450 – rna, transfer, his MeSH D13.444.735.757.700.480 – rna, transfer, ile MeSH D13.444.735.757.700.500 – rna, transfer, leu MeSH D13.444.735.757.700.510 – rna, transfer, lys MeSH D13.444.735.757.700.525 – rna, transfer, met MeSH D13.444.735.757.700.650 – rna, transfer, phe MeSH D13.444.735.757.700.660 – rna, transfer, pro MeSH D13.444.735.757.700.700 – rna, transfer, ser MeSH D13.444.735.757.700.725 – rna, transfer, thr MeSH D13.444.735.757.700.740 – rna, transfer, trp MeSH D13.444.735.757.700.750 – rna, transfer, tyr MeSH D13.444.735.757.700.900 – rna, transfer, val MeSH D13.444.735.757.715 – rna, transfer, amino acyl MeSH D13.444.735.790 – rna, untranslated MeSH D13.444.735.790.099 – micrornas MeSH D13.444.735.790.149 – regulatory sequences, ribonucleic acid MeSH D13.444.735.790.199 – rna, catalytic MeSH D13.444.735.790.400 – rna, guide MeSH D13.444.735.790.530 – rna, small cytoplasmic MeSH D13.444.735.790.537 – rna, small interfering MeSH D13.444.735.790.545 – rna, small nuclear MeSH D13.444.735.790.545.800 – rna, small nucleolar MeSH D13.444.735.790.560 – rna, spliced leader MeSH D13.444.735.790.878 – untranslated regions MeSH D13.444.735.790.878.880 – 3' untranslated regions MeSH D13.444.735.790.878.885 – 5' untranslated regions MeSH D13.444.735.828 – rna, viral
=== In LTP === When alpha-CaMKII is knocked out in mice, LTP is reduced by 50%. This can be explained by the fact that beta-CaMKII is responsible for approximately 65% of CaMKII activity. LTP can be completely blocked if CaMKII is modified so that it cannot remain active. After LTP induction, CaMKII moves to the postsynaptic density (PSD). However, if the stimulation does not induce LTP, the translocation is quickly reversible. Binding to the PSD changes CaMKII so that it is less likely to become dephosphorylated. CaMKII transforms from a substrate for Protein Phosphatase 2A (PP2A), which is responsible for dephosphorylating CaMKII, to that of Protein Phosphatase 1. Strack, S. (1997) demonstrated this phenomenon by chemically stimulating hippocampal slices. This experiment illustrates that CaMKII contributes to the enhancement of synaptic strength. Sanhueza et al. found that persistent activation of CaMKII is necessary for the maintenance of LTP. She induced LTP in hippocampal slices and experimentally applied an antagonist (CaMKIINtide) to prevent CaMKII from remaining active. The slices that were applied with CaMKIINtide showed a decrease in Normalized EPSP slope after the drug infusion, meaning that the induced LTP reversed itself. The Normalized EPSP slope remained constant in the control; CaMKII continues to be involved in the LTP maintenance process even after LTP establishment. CaMKII is activated by calcium/calmodulin, but it is maintained by autophosphorylation. CaMKII is activated by the NMDA-receptor-mediated Calcium elevation that occurs during LTP induction.
This could be used, for example, in a touchscreen that registers reflected light from a finger or stylus. Many materials and biological systems are sensitive to, or dependent on, light. Grow lights use LEDs to increase photosynthesis in plants, and bacteria and viruses can be removed from water and other substances using UV LEDs for sterilization. LEDs of certain wavelengths have also been used for light therapy treatment of neonatal jaundice and acne. UV LEDs, with spectra range of 220 nm to 395 nm, have other applications, such as water/air purification, surface disinfection, glue curing, free-space non-line-of-sight communication, high performance liquid chromatography, UV curing dye printing, phototherapy (295 nm Vitamin D, 308 nm Excimer lamp or laser replacement), medical/ analytical instrumentation, and DNA absorption. LEDs have also been used as a medium-quality voltage reference in electronic circuits. The forward voltage drop (about 1.7 V for a red LED or 1.2V for an infrared) can be used instead of a Zener diode in low-voltage regulators. Red LEDs have the flattest I/V curve above the knee. Nitride-based LEDs have a fairly steep I/V curve and are useless for this purpose. Although LED forward voltage is far more current-dependent than a Zener diode, Zener diodes with breakdown voltages below 3 V are not widely available.
Sources: en.wikipedia.org
Animal experiments form the bulk of the published record. Rodent models of tendon, ligament, bone, and gut injury are the most common designs. Controlled human trials are rare, which limits confidence in any clinical claim.
They are best described as working hypotheses. Supporting data come mainly from cell cultures and animal tissue, using markers such as growth factors and inflammatory signals. Confirmatory human studies have not been reported.
Status depends on the country. In some places it is treated as a research chemical available without a prescription, while elsewhere it falls under prescription or controlled rules. It holds no general marketing approval as a therapeutic product.
BPC-157 is a synthetic fifteen-amino-acid peptide whose sequence corresponds to a fragment of a protein found in human gastric juice. It is studied mainly in preclinical research and is not an approved pharmaceutical product in major markets. Materials sold for laboratory use are typically labelled as research chemicals.