This is a working overview of Reversed-phase HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-01 and is reviewed periodically as new material appears.
CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.
Two related peptides circulate under the CJC-1295 label, and they differ mainly in how long they persist in circulation. The version carrying a drug affinity complex includes a maleimidopropionic acid linker that forms a covalent bond with serum albumin. The other version, usually written as modified GRF(1-29) or tetrasubstituted GRF(1-29), lacks that linker and is cleared quickly. Mixing the two produces inconsistent readings of published half-life values, because the linker rather than the receptor-facing sequence drives most of the difference.
The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.
Enzymatic protection is a separate mechanism from plasma protein binding. The four substitutions in the backbone reduce recognition by dipeptidyl peptidase IV, which normally cleaves the natural hormone within minutes. Without the reactive group, this resistance still yields only a short window of activity, generally reported in the range of tens of minutes. With it, reported half-lives in early human work extended to several days. The size of that gap is the main practical distinction between the two materials.
Both forms act at the pituitary receptor for growth hormone-releasing hormone and increase growth hormone output, which in turn raises insulin-like growth factor 1. A long-acting analog produces sustained rather than pulsatile stimulation, and the physiological consequences of that pattern are not fully settled. Published human data on the extended form remain limited, and much of what circulates in discussion traces to early company reports rather than independent replication. How sustained exposure affects normal feedback remains an open question.
| Property | Value | Notes |
|---|---|---|
| Class | Synthetic peptide | GHRH receptor agonist |
| Sequence length | 29 amino acids | Derived from human GHRH |
| Molecular weight | About 3368 Da without linker | Albumin-binding form is heavier |
| Appearance | White to off-white lyophilized powder | Common form for research reference material |
| Typical storage | -20 °C or below, desiccated | Protect powder from light and moisture |
Peptide degradation proceeds mainly through hydrolysis, oxidation of methionine, and deamidation of asparagine or glutamine residues. The maleimide group on the albumin-binding variant can also react with thiols or hydrolyze in aqueous media. Because these pathways accelerate with temperature and pH extremes, handling conditions strongly influence measured stability. Stability data in the public literature are limited and often generated under differing conditions, so general statements about shelf life should be read as approximate.
Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.
Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.
Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.
Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.
CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.
Lyophilized material is typically stored at minus twenty degrees Celsius or lower. Keeping the vial dry and protected from light preserves peptide integrity. Repeated freeze-thaw cycles can cause aggregation or loss of activity. Once dissolved, solutions are generally kept at two to eight degrees Celsius. Stability data for reconstituted solutions vary, and long-term behavior is not fully established. Working aliquots reduce the number of times a stock container is opened.
Reverse-phase high-performance liquid chromatography is the standard tool for purity assessment. The technique separates the target peptide from truncated or modified byproducts. Mass spectrometry confirms molecular weight and supports sequence verification. Electrospray ionization and matrix-assisted laser desorption are both used. Amino acid analysis provides an independent check on composition. Purity values are commonly reported as area percentage from the chromatogram. Residual trifluoroacetate and water content are also measured in many quality programs.
Batch-to-batch consistency depends on solid-phase peptide synthesis and subsequent purification. Coupling efficiency, resin choice, and cleavage conditions all affect the final profile. Counter-ion content and moisture can shift the apparent mass of a batch. Documentation typically includes a certificate of analysis with chromatograms and spectra. Independent verification by a second laboratory is sometimes requested. Whether a given certificate reflects the actual vial contents depends on chain of custody. Analytical methods themselves carry uncertainty that should be stated alongside results.
A 2006 US government study of hospital emergency department (ED) visits found that sedative-hypnotics were the most frequently implicated pharmaceutical drug in visits, with benzodiazepines accounting for the majority of these. Clonazepam was the second most frequently implicated benzodiazepine in ED visits. Alcohol alone was responsible for over twice as many ED visits as clonazepam in the same study. The study examined the number of times the non-medical use of certain drugs was implicated in an ED visit. The criteria for non-medical use in this study were purposefully broad, and included, for example, drug abuse, accidental or intentional overdose, or adverse reactions resulting from legitimate use of the medication.
Peukert argued for an integrated view of Nazi Germany with the social policies to encourage "healthy Aryan" families to have more children, the "social racism" that saw the bodies of "healthy Aryan" women as belonging to the volksgemeinschaft, the effort to sterilize "anti-social families" and the extermination of Jews and Romany as part and parcel of the same project. Likewise, Peukert argued that Nazi Germany was not some freakish "aberration" from the norms of Western civilization, as he noted that the ideas about eugenics and racial superiority that the National Socialists drew upon were widely embraced throughout the Western world. In the same way, Peukert noted in Inside Nazi Germany as part of his argument against the "freakish aberration" view of the Nazi era that homosexual sex had been made illegal in Germany with Paragraph 175 in 1871 and all the Nazis did with the 1935 version of Paragraph 175 was to make it tougher, as the 1935 version of Paragraph 175 made being homosexual in and of itself a criminal offense, whereas the 1871 version of Paragraph 175 had only made homosexual sex a criminal offense. Peukert also noted against the "freakish aberration" view of Nazi Germany that the 1935 version of Paragraph 175 stayed on the statute books in West Germany until 1969 as it was considered to be a "healthy law", leading to German homosexuals who survived the concentration camps continuing to be convicted all through the 1950s and 1960s under exactly the same law that sent them to the concentration camps under the Third Reich.
=== Inhalation === Incidental exposure to sulfur dioxide is routine, e.g. the smoke from matches, coal, and sulfur-containing fuels like bunker fuel. Relative to other chemicals, it is only mildly toxic and requires high concentrations to be actively hazardous. However, its ubiquity makes it a major air pollutant with significant impacts on human health. In 2008, the American Conference of Governmental Industrial Hygienists reduced the short-term exposure limit to 0.25 parts per million (ppm). In the US, the OSHA set the PEL at 5 ppm (13 mg/m3) time-weighted average. Also in the US, NIOSH set the IDLH at 100 ppm. In 2010, the EPA "revised the primary SO2 NAAQS by establishing a new one-hour standard at a level of 75 parts per billion (ppb). EPA revoked the two existing primary standards because they would not provide additional public health protection given a one-hour standard at 75 ppb."
Gardner, who was vice president, had political ambitions and left the company when he was elected to the United States House of Representatives in 1966. The 1964 menu included hamburger for 15 cents, cheeseburgers for 20 cents, french fries for 10 cents, apple turnovers for 15 cents, milk for 12 cents, coffee for 10 cents, soft drinks for 10 cents, and milkshakes (chocolate, strawberry, vanilla) for 20 cents. Strawberry milkshakes were created from vanilla by addition of a berry syrup which had to be mixed with a spindle.
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Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only 222Rn has a sufficiently long half-life (3.825 days) for it to be released from the soil and rock where it is generated. Radon isotopes are the immediate decay products of radium isotopes. The instability of 222Rn, its most stable isotope, makes radon one of the rarest elements. Radon will be present on Earth for several billion more years despite its short half-life, because it is constantly being produced as a step in the decay chains of 238U and 232Th, both of which are abundant radioactive nuclides with half-lives of at least several billion years. The decay of radon produces many other short-lived nuclides, known as "radon daughters", ending at stable isotopes of lead. 222Rn occurs in significant quantities as a step in the normal radioactive decay chain of 238U, also known as the uranium series, which slowly decays into a variety of radioactive nuclides and eventually decays into stable 206Pb. 220Rn occurs in minute quantities as an intermediate step in the decay chain of 232Th, also known as the thorium series, which eventually decays into stable 208Pb. Radon was discovered in 1899 by Ernest Rutherford and Robert B. Owens at McGill University in Montreal, and was the fifth radioactive element to be discovered.
: examples include water in a lake with the inlet and outlet on opposite sides and radioactive material introduced high in the stratosphere by a nuclear bomb test and filtering down to the troposphere.
Jack Straw (born 3 August 1946), Christian, of Eastern European Jewish ancestry; served in Cabinet under Labour governments of Tony Blair and Gordon Brown as Home Secretary and Foreign Secretary; has written for The Guardian, Daily Mail, El País, The Independent, The Mirror UK, The Sun, The Telegraph, Financial Times, The Times, POLITICO, LSE Connect, Prospect Magazine, The New European and is author or co-author of the following books; The English Job: Understanding Iran and Why It Distrusts Britain (2019) ISBN 978-1785903991; Implementation of the Human Rights Act 1998: Minutes of Evidence, Wednesday 14 March 2001 (2001) ISBN 0-10-442701-9; Making Prisons Work: Prison Reform Trust Annual Lecture (1998) ISBN 0-946209-44-8; Future of Policing and Criminal Justice (Institute of Police & Criminological Studies Occasional Paper S.) (1996) ISBN 1-86137-087-3 and Policy and Ideology (1993) ISBN 0-9521163-0-8 John Strawson, author of Encountering Islamic law, Partitioning Palestine: Legal Fundamentalism in the Palestinian-Israeli Conflict and editor of Law after Ground Zero and Tracking the Postcolonial in Law; also law professor at the University of East London School of Law, teaching International law and Middle East Studies; specialises in law and postcolonialism, with particular reference to middle east, Islam and international law; previous posts include visiting positions at Birzeit University (Palestine) and the Institute of Social Studies (The Hague Netherlands); researches encounter between western and Islamic law; is Director of Law Postgraduate Programmes at University of East London, and Director of the Centre on Human Rights in Conflict; believes use of term apartheid to describe Israel or Israeli policies does not apply to Israel, and use of analogy is unhistorical, and unhelpful. Jamie Susskind (b. 1989); barrister and author of Oxford University Press books on Marxism, freedoms, democracy and technology; was appointed as a research fellow at Harvard's Berkman Klein Center for Internet and Society; practises law at Littleton Chambers; his book Future Politics: Living Together in a World Transformed by Tech, listed by London School of Economics as one of top ten books of 2019; book approaches issues of technological change in political arena from legal standpoint, speculating on various ways technology would change interactions between citizens and political process; was awarded Book of the Year by Evening Standard and Prospect Magazine, Book of the Day by The Guardian and received the 2019 Estoril Global Issues Distinguished Book Prize; his book, The Digital Republic: On Freedom and Democracy in the 21st Century concerns dangers, problems, and solutions to Big Tech. Richard Susskind OBE FRSE (born 28 March 1961); author, speaker, independent adviser to international professional firms and national governments; IT adviser to Lord Chief Justice of England and Wales, holds professorships at the University of Oxford, Gresham College and Strathclyde University, is a past chair of Advisory Panel on Public Sector Information, and is president of the Society for Computers and Law; has authored nine books and is regular columnist at The Times. Adam Sutcliffe; Professor of European History at King's College London, journalist writing on Jewish history and identity for Times Literary Supplement, author of What Are Jews For: History, Peoplehood, and Purpose (Princeton University Press, 2020), Judaism and Enlightenment; coeditor of Philosemitism in History, The Cambridge History of Judaism: The Early Modern World, and History, Memory and Public Life: The Past in the Present. William Sutcliffe, novelist; New Boy (1986), Are You Experienced? (1997), Whatever Makes You Happy (2008), and The Wall (2013), set in an Israeli colony David Sylvester (21 September 1924 – 19 June 2001), prolific author, art critic, journalist and curator; trustee of the Tate Gallery; influential in promoting modern artists Francis Bacon, Joan Miró, and Lucian Freud; father of modern artist Cecily Brown; credited with coining the term Kitchen sink realism originally to describe a strand of post-war British painting. Mitchell Symons, writer Henri Tajfel (born Hersz Mordche; 22 June 1919 – 3 May 1982) was a Polish Jewish social psychologist and author, best known for his books and pioneering work on the cognitive aspects of prejudice and social identity theory, as well as being one of the founders of the European Association of Experimental Social Psychology. He also worked for the United Nations International Refugee Organization. Adam Thirlwell, FRSL (born 22 August 1978) is a British novelist. His work has been translated into thirty languages. He has twice been named as one of Granta's Best of Young British Novelists. In 2015 he received the E.M. Forster Award from the American Academy of Arts and Letters. He is an advisory editor of The Paris Review. Barbara Trapido (born 1941 as Barbara Schuddeboom), is a British novelist born in South Africa with German, Danish and Dutch ancestry. Born in Cape Town and growing up in Durban she studied at the University of Natal gaining a BA in 1963 before emigrating to London. After many years teaching, she became a full-time writer in 1970. Michael Tugendhat (born 21 October 1944),; retired High Court judge; was High Court's senior media judge; author and editor of The Law of Privacy and the Media Oxford University Press; Commercial Fraud: Civil Liability, Human Rights, and Money Laundering Oxford University Press; Les droits du genre humain : la liberté en France et en Angleterre (1159–1793), [The rights of mankind : liberty in France and England (1159–1793)] (with Elizabeth de Montlaur Martin, 2021), ISBN 978-2-36517-110-6, Société de Législation comparée, Paris (awarded by the French Académie des sciences morales et politiques the Prix Édouard Bonnefous 2022); Liberty Intact: Human Rights in English Law (2016) Oxford University Press and Fighting for Freedom? (2017), ISBN 978-1-911128-49-6, Bright Blue (organisation) Jackie Walker (activist), anti Zionist playwright, pro-Palestinian, anti fascist author, of Sephardi Jewish and Jamaican origin. Arthur Waley (1889–1966); orientalist and sinologist of Ashkenazi ancestry; renowned for his translations of Chinese and Japanese poetry; awarded the CBE in 1952, the Queen's Gold Medal for Poetry; invested as a Companion of Honour in 1956. Natasha Walter (born 20 January 1967), feminist writer, novelist, human rights activist, founder of charity Women for Refugee Women; father was Nicolas Walter, an anarchist and secular humanist writer; of German Jewish ancestry; journalist forVogue magazine; Deputy Literary Editor of The Independent; columnist and feature writer for The Guardian; appear regularly on BBC2's Newsnight Review and Radio 4's Front Row; was judge on the Booker Prize and was a judge on the Women's Prize for Fiction (formerly the Orange Prize); was the founder in 2006 of the charity Women for Refugee Women, where she was the director until 2021. The charity supports women who seek asylum to tell their stories and challenges injustices they experience. She was recognized as one of the BBC's 100 women of 2013. Nicolas Walter (22 November 1934 – 7 March 2000) was a British anarchist and atheist writer, speaker and activist. He was a member of the Committee of 100 and Spies for Peace, and wrote on topics of anarchism and humanism. Fredric Warburg (27 November 1898 – 25 May 1981), author, publicist, publisher best known for association with George Orwell. Besides his own work as an author, he promoted and published Franz Kafka. Other notable publications included The Third Eye by Lobsang Rampa, Adolf Hitler's Mein Kampf and William Shirer's The Rise and Fall of the Third Reich. Ruby Wax (née Wachs; born 19 April 1953) is an American-British actress, author of popular self-help books, comedian, television personality, and popular mental health campaigner, of Austrian Jewish descent; appointed Chancellor of the University of Southampton; Wax also teaches business communication in the public and private sectors. 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Meanwhile, her writing about British government policy toward victims after the Holocaust and contemporary British antisemitism has appeared in The Independent and Haaretz. Stephen Winsten, (1893–1991) was the name adopted by Samuel Weinstein, one of the 'Whitechapel Boys' group of young Jewish men and future writers in London's East End in the years before World War I (the others included Isaac Rosenberg, John Rodker and Joseph Leftwich). In the First World War he was a conscientious objector, and imprisoned in Bedford and Reading gaols. He is now known for his works about George Bernard Shaw, and his writing on the life of Henry Salt. 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Richard Wollheim (5 May 1923 − 4 November 2003), prolific author noted for work on mind and emotions related to visual arts, specifically, painting; served as president of the British Society of Aesthetics; was Grote Professor of Mind and Logic, professor at Columbia University and University of California at Berkeley and lecturer at Balliol College, Harvard University, the University of Minnesota, Graduate Center, CUNY, the University of California at Davis; gave Andrew M. Mellon lectures in Fine Arts, National Gallery of Art, Washington; his book Art and its Objects considered one of the twentieth century's most influential texts on philosophical aesthetics; known for philosophical treatments of depth psychology, especially Sigmund Freud's Jonathan Wolff (born 1959) author of seven Oxford University Press academic books and numerous monographs and journals, philosopher and scholar; Professor of Values and Public Policy at the Blavatnik School of Government at the University of Oxford; Governing Body Fellow at Wolfson College; previously at University College London (UCL), where he was Professor of Philosophy and Dean of the Faculty of Arts and Humanities; was secretary of the British Philosophical Association and has been Editor and honorary secretary of the Aristotelian Society; presented a four-part series about the UK's National Health Service (NHS) for the BBC's Radio 3; was member of the Nuffield Council on Bioethics; was elected Fellow of the British Academy in 2023. 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Sources: en.wikipedia.org
Natural GHRH is degraded quickly by dipeptidyl peptidase-4 and related enzymes, giving it a half-life measured in minutes. CJC-1295 carries substitutions that slow that breakdown, so it stays intact longer. Both act at the same pituitary receptor and produce the same class of signal.
The label was first attached to the albumin-binding form during early development work. A shorter analog without the linker later became known by the same name in informal use. Published papers normally state which version was studied, so the methods section resolves the ambiguity.
It is a synthetic peptide rather than a steroid, and it does not occur naturally in the body. Its sequence is derived from a hypothalamic hormone called growth hormone-releasing hormone. It works as a receptor agonist rather than as a replacement for that hormone.
A maleimide moiety reacts with the thiol of cysteine-34, forming a covalent bond. The reaction occurs in circulation without enzymatic catalysis.