modified GRF(1-29) raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-12. Anything still debated is marked as such rather than presented as settled.
CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.
The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.
Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C152H252N44O42 | Cited for the form without the drug affinity complex |
| Molecular weight | About 3368 Da | Reported value for modified GRF(1-29) |
| Appearance | White to off-white powder | Lyophilised solid as usually supplied |
| Solubility | Soluble in water and polar solvents | Clarity depends on purity and salt content |
| Typical storage | -20 C or below, dry | Protect from light and repeated warming cycles |
CJC-1295 is the name used for a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound was described by a Canadian drug discovery company in the mid-2000s as a long-acting research tool. Two closely related molecules share the name in practice: one carries a drug affinity complex, or DAC, group, and one does not. The distinction matters because the two behave differently in circulation.
The peptide backbone corresponds to GRF(1-29), the first 29 residues of native growth hormone-releasing hormone, which retains most of the receptor-activating activity of the full-length molecule. Four substitutions distinguish the analog from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes slow cleavage by dipeptidyl peptidase IV, the enzyme that degrades native hormone in plasma within minutes. The outcome is improved enzymatic stability combined with a still brief residence time when no additional modification is present.
Naming in this area is inconsistent, and readers should treat product labels with care. In much of the literature and in vendor catalogs, the unqualified term refers to the albumin-binding version, while the version lacking the DAC group appears as modified GRF(1-29), mod GRF(1-29), or the same name with a without-DAC qualifier. Because one abbreviation has been applied to both materials, the only reliable way to identify a sample is to check the stated sequence and the presence of the linker.
Clearance profiles diverge sharply between the two versions. The albumin-binding molecule stays in plasma for several days, whereas the unmodified analog is largely gone within about half an hour in reported work. Cleavage by dipeptidyl peptidase IV is a major contributor to the short life of the unmodified sequence. These gaps mean the two versions cannot be substituted for each other in study design or in reading results side by side.
Reports on this compound commonly follow serum growth hormone and insulin-like growth factor 1 across defined time windows. Protocols differ in sampling frequency, assay platform, and participant characteristics, which makes direct comparison between publications difficult. Some work focuses on pulsatile release patterns instead of average concentrations. Whether repeated exposure alters endogenous hormone rhythms over long periods remains an open question, and the formal literature is thinner than the volume of informal commentary implies.
Once in circulation, the peptide binds the growth hormone-releasing hormone receptor displayed on pituitary somatotroph cells. Receptor activation couples to Gs proteins, elevates intracellular cyclic AMP, and drives protein kinase A signaling inside the cell. That cascade increases discharge of growth hormone into the bloodstream. The analog therefore operates through a receptor pathway that already exists for the body's own releasing hormone, rather than through an engineered artificial target.
Analytical confirmation usually relies on reversed-phase high-performance liquid chromatography for purity and on liquid chromatography coupled to mass spectrometry for identity. Mass data reveal the expected molecular mass and can flag truncated or oxidized species. Amino acid analysis and peptide mapping provide sequence-level verification. Immunoassays are used in some biological matrices, but antibodies raised against one releasing-hormone analog may cross-react with another. Reported purity figures depend heavily on the method used, so comparisons between suppliers require matching the analytical approach.
The two variants differ dramatically in how long they persist in circulation. The form lacking the albumin-binding group has a plasma half-life measured in tens of minutes, comparable to the natural hormone fragment. The version carrying the drug affinity complex binds albumin and shows a half-life of roughly six to eight days in human studies. That figure comes from small trials that tracked hormone levels over extended periods. The physiological consequences of sustained versus pulsatile stimulation are still debated and the literature does not settle the point.
Lyophilized peptide powder is comparatively stable when kept dry, cold, and protected from light. Once dissolved, the molecule is vulnerable to deamidation, oxidation, and aggregation, with the rate depending on pH, buffer composition, and temperature. Alkaline conditions and repeated freeze-thaw cycles accelerate loss of the intact peptide. The methionine present in the native sequence is a known oxidation site, which is one reason it was replaced in the modified fragment. Suppliers typically recommend cold storage of solutions and use within a short window.
== Longevity and Healthspan Human Trial == Ho launched DELTA, a N=1 trial where Ho is the test subject. Approved by an institutional review board (IRB), DELTA is a prospective, interventional study that is exploring the use of digital health to optimise metabolic performance, sleep, gut health, and other aspects of healthspan. Early results from this study were published in a peer-reviewed article in PNAS Nexus. . Ho has spoken at international longevity, AI, and healthspan conferences on the DELTA trial and the impact of N=1 Health on population healthspan optimization.
Aang, in the animated series Avatar: The Last Airbender and The Legend of Korra was vegetarian. According to the show's creators, "Buddhism and Taoism have been huge inspirations behind the idea for Avatar." As shown in "The King of Omashu" and "The Headband", a notable aspect of Aang's character is his vegetarian diet, which is consistent with Buddhism, Hinduism, and Taoism. In the Brahmajala Sutra, a Buddhist code of ethics, vegetarianism is encouraged. Other fictional characters who are vegetarians include Count Duckula in Count Duckula, Beast Boy in Teen Titans and Teen Titans Go!, Lenore in Supernatural, and Norville "Shaggy" Rogers in the animated series What's New, Scooby Doo?. Before the latter animated series, Shaggy was known for having an "enormous appetite" earlier in the Scooby-Doo franchise. The decision to make Shaggy a vegetarian occurred after his voice actor, Casey Kasem, convinced the producers to do so, since he was a vegan who supported animal rights and opposed factory farming, saying he would refuse to voice Shaggy unless the character was vegetarian. An October 2019 South Park episode, "Let Them Eat Goo", featured a vegetarian character. Additionally, Steven Universe, the protagonist in the show Steven Universe and the limited epilogue series, Steven Universe Future, is a vegetarian. In the episode "Snow Day" of Steven Universe Future, Steven tells the Gems he lives with that he has been a vegetarian for a month, drinks protein shakes and mentions that he does "his own skincare routine."
Vitamin B12 is derived from a tetrapyrrolic structural framework created by the enzymes deaminase and cosynthetase which transform aminolevulinic acid via porphobilinogen and hydroxymethylbilane to uroporphyrinogen III. The latter is the first macrocyclic intermediate common to heme, chlorophyll, siroheme and B12 itself. Later steps, especially the incorporation of the additional methyl groups of its structure, were investigated using 13C methyl-labeled S-adenosyl methionine. It was not until a genetically engineered strain of Pseudomonas denitrificans was used, in which eight of the genes involved in the biosynthesis of the vitamin had been overexpressed, that the complete sequence of methylation and other steps could be determined, thus fully establishing all the intermediates in the pathway. Species from the following genera and the following individual species are known to synthesize B12: Propionibacterium shermanii, Pseudomonas denitrificans, Streptomyces griseus, Acetobacterium, Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Lactobacillus, Micromonospora, Mycobacterium, Nocardia, Proteus, Rhizobium, Salmonella, Serratia, Streptococcus and Xanthomonas.
== Regulation == Central to the physiologic maintenance of GFR is the differential vasoconstriction of the afferent (input) and efferent (output) arterioles. Vasodilation of the afferent or vasoconstriction of the efferent arteriole increases GFR. Conversely, vasoconstriction of the afferent or vasodilation of the efferent will decrease GFR. There are multiple mechanisms that the body has to regulate the constriction or dilation of these arterioles: local feedback within the kidney, hormonal regulation, and sympathetic nervous control. These systems are closely intertwined. The kidney can maintain a relatively constant GFR even as mean arterial pressure changes. Local feedback within the kidney (renal autoregulation) includes the myogenic response and tuberoglomerular feedback. In the myogenic response, increased stretch of the afferent arteriole due to higher blood pressure results in afferent vasoconstriction, thereby preventing an increase in GFR. With tuberoglomerular feedback, the macula densa cells at the downstream nephron tubule senses changes in ion levels. If sodium chloride sodium levels in the urinary filtrate are too high, the macula densa signals to constrict the afferent arteriole; if too low, the signal is to vasodilate the afferent arteriole and to release renin (activating the RAAS system). The RAAS system is the major hormonal control of GFR. Low blood pressure activates the RAAS system, increasing the amount of the hormone angiotensin II. Angiotensin II binds to receptors on the efferent arteriole; the resulting efferent vasoconstriction increases GFR.
Sources: en.wikipedia.org
Female puberty generally occurs between the ages of 9 and 13 and is characterized by ovulation and menstruation; the growth of secondary sex characteristics, such as growth of pubic and underarm hair, breast, uterine and vaginal growth, widening hips and increased height and weight, also occur during puberty. Male puberty sees the further development of the human penis and testicles. The female inner sex organs are the two ovaries, their fallopian tubes, the uterus, and the cervix. At birth there are about 70,000 immature egg cells that degenerate until at puberty there are around 40,000. No more egg cells are produced. Hormones stimulate the beginning of menstruation, and the ongoing menstrual cycles. The female external sex organs are the vulva (labia, clitoris, and vestibule). The male external genitalia include the penis and scrotum that contains the testicles. The testicles are gonads that produce the sperm cells which are ejaculated in semen through the penis. Unlike the egg cells in the female, sperm cells are produced throughout life. Other internal sex organs are the epididymides, vasa deferentia, and some accessory glands. Diseases that affect the reproductive system include polycystic ovary syndrome, a number of disorders of the testicles including testicular torsion, and a number of sexually transmitted infections including syphilis, HIV, chlamydia, HPV and genital warts. Cancer can affect most parts of the reproductive system including the penis, testicles, prostate, ovaries, cervix, vagina, fallopian, uterus and vulva.
Given the importance of the Kucha region in the transmission of Buddhism into China and the evidence we have about the movement of translators such as Kumarajiva, it is reasonable to suggest that the art (and possibly the artists) of Kizil influenced the early art of the Mogao Cave complex near Dunhuang, further east along the Silk Road. The earliest of the extant Dunhuang caves (dating from the beginning of the fifth century) show distinctly "Central Asian" features in their painting, stylistically similar to what we find at Kizil. Among the subjects depicted at Kizil and Mogao in strikingly similar fashion is that of the "Cosmological Buddha", whose robe displays images connected with the phenomenal world.
=== Pre-discovery use === The use of pitchblende, uranium in its natural oxide form, dates back to at least the year 79 AD, when it was used in the Roman Empire to add a yellow color to ceramic glazes. Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Gulf of Naples, Italy, by R. T. Gunther of the University of Oxford in 1912. Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic) in the Ore Mountains, and was used as a coloring agent in the local glassmaking industry. In the early 19th century, the world's only known sources of uranium ore were these mines.
Sources: en.wikipedia.org
It is a synthetic peptide analogue of growth hormone-releasing hormone. Four substitutions in its sequence make it more resistant to enzymatic degradation than the natural hormone. In the version carrying a drug affinity complex, the peptide binds albumin and remains in circulation for days.
No regulatory agency has approved CJC-1295 for clinical use. Human trials were conducted in the 2000s, but the development programme was discontinued before any marketing application succeeded. Material sold today is offered as a research chemical, and its purity depends on the supplier.
Sermorelin is an unmodified fragment of growth hormone-releasing hormone and is cleared quickly. CJC-1295 contains substitutions that resist breakdown, and the form with a drug affinity complex persists much longer. Both act at the same receptor but differ substantially in duration of action.
The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.