If you have been reading about lyophilization and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-06-29. Numbers and descriptions here follow the published literature rather than marketing material.
Clinical development has progressed through phase 2 trials in adults with obesity and type 2 diabetes, with phase 3 programs reported as ongoing. Reported outcomes include reductions in body weight and improvements in glycemic measures over defined treatment periods. Whether these effects translate into durable benefits after treatment ends remains an open question. Long-term safety data across broad populations are not yet complete, and regulatory decisions have not been announced.
Retatrutide is an investigational synthetic peptide engineered to activate three distinct hormone receptors within a single molecule. It targets the glucose-dependent insulinotropic polypeptide receptor, the glucagon-like peptide-1 receptor, and the glucagon receptor simultaneously. This triagonist design distinguishes it from earlier incretin-based compounds that act on one or two of these pathways. Structural modifications relative to native gut hormones extend its residence time in circulation. The molecule remains under clinical evaluation and is not approved for any indication.
化学修饰延长了分子在体内的停留时间，使较低频次的给药安排成为可能。脂肪酸侧链通过与白蛋白结合延缓清除，非天然氨基酸则降低酶解速率。这些修饰同时改变分子的溶解性与稳定性，需要在制剂设计和储存条件中一并考虑。修饰引入的免疫原性风险也属于开发过程中需要评估的项目。
该化合物处于临床试验阶段，尚未在多数地区取得上市许可。公开信息主要来自企业公告、学术会议摘要与试验注册平台记录，完整数据仍在逐步披露。关于长期疗效与安全性的判断，需要等待规模更大、随访更久的研究结果，目前不宜对最终结论作出预判。
| Property | Value | Notes |
|---|---|---|
| Receptor targets | GIP, GLP-1, glucagon | One molecule activates all three pathways |
| Research identifier | LY3437943 | Code used in published trial reports |
| Development stage | Phase 3, reported as ongoing | Not approved by any regulatory agency |
| Route studied | Subcutaneous | Administration form used in clinical trials |
| Studied populations | Adults with obesity or type 2 diabetes | Enrollment criteria vary between trials |
Development has progressed from single- and multiple-ascending-dose studies in healthy volunteers into larger randomized trials in adults with obesity, type 2 diabetes, and fatty liver disease. Early reports describe dose-dependent reductions in body weight and improvements in glycemic markers over treatment periods of several months. Whether the glucagon arm adds tolerability cost without added benefit is still debated. Long-term cardiovascular outcomes, effects after treatment stops, and performance in older or comorbid populations are open questions rather than settled findings. Approval status may change, so the current investigational label should be confirmed against regulatory sources.
Retatrutide is an investigational synthetic peptide developed under the code LY3437943, with a backbone derived from glucose-dependent insulinotropic polypeptide. Several non-proteinogenic residues, including alpha-aminoisobutyric acid, appear in that backbone, and a fatty diacid side chain attached through a linker extends circulation time. The molecule carries roughly thirty-nine amino acid units and a total mass near 4.7 kilodaltons. Administration is by subcutaneous injection once weekly. Published work uses both the name retatrutide and the code LY3437943.
Dissolution behavior depends on the amino acid sequence, the counterion content, and the buffer chosen. Many peptides disperse readily in water or mild aqueous buffers, while others require a small amount of organic co-solvent or a change in pH. Adsorption to plastic and glass surfaces can reduce the concentration of a solution over time, particularly at low concentrations. Filtration before analysis removes particulates, and aliquoting limits repeated freeze-thaw cycles that stress the material.
Research-grade peptide material is commonly supplied as a lyophilized powder, a form that limits degradation during transport and storage. Standard practice keeps such material cold and protected from light and moisture, with tighter conditions used for long-term archives. Once dissolved, solutions are generally considered less stable than the dry powder and are handled on shorter timescales. These established conventions derive largely from general peptide chemistry rather than from compound-specific evidence alone.
Human evidence remains limited to controlled studies. A phase 2 trial in adults with obesity reported large, dose-dependent reductions in body weight over 48 weeks, with gastrointestinal events as the most frequently recorded adverse effect. Phase 3 programs designated TRIUMPH, for obesity, and TRANSCEND, for type 2 diabetes, are intended to confirm efficacy and to characterize safety in larger populations. Related studies are examining conditions such as knee osteoarthritis in people with obesity and metabolic liver disease. Open questions include long-term tolerability, effects on lean mass, and what happens after treatment is stopped.
Retatrutide is an investigational synthetic peptide that acts on three receptor targets at once: glucose-dependent insulinotropic polypeptide, glucagon-like peptide-1, and glucagon. It is developed by Eli Lilly and appears in the literature and in trial registries under the code LY3437943. The molecule belongs to a class of engineered peptides designed to resist rapid breakdown and permit infrequent subcutaneous administration. No regulatory agency has approved it for clinical use, and all available human data come from controlled trials rather than from routine practice.
The intended pharmacology combines three signals in one molecule. GLP-1 receptor activation reduces appetite and slows gastric emptying, effects already exploited by approved incretin-based therapies. GIP receptor engagement is associated with improved insulin sensitivity and with direct effects on adipose tissue, although how much it contributes to overall outcomes is still debated. Glucagon receptor agonism raises energy expenditure and supports hepatic lipid handling, a mechanism that also tends to increase glucose output. The triple profile is hypothesized to produce a larger metabolic effect than single or dual agonism, but the relative weight of each receptor in humans is not settled.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. Chromatographic profiles reveal related impurities, truncated sequences, and oxidation products, while mass measurement confirms the expected molecular mass. Purity values for research material are typically reported as a percentage by peak area. Reference standards help calibrate retention behavior across instruments. Independent laboratories emphasize method suitability because results depend heavily on column chemistry, gradient, and detection wavelength. Batch-to-batch comparison relies on the same validated method.
Investigational peptide material is commonly distributed as a lyophilized powder in sealed vials. The solid form appears as a white to off-white cake or powder and is hygroscopic once opened. Peptides of this size are sensitive to moisture, repeated freeze-thaw cycles, and prolonged exposure to ambient light. Handling practices therefore emphasize desiccation, minimal vial opening, and cold storage. Working aliquots are often prepared to avoid repeatedly warming the bulk container.
Solid material is generally held at -20 °C or colder, while reconstituted solutions are kept at 2-8 °C and used within a short window. Buffers that maintain a slightly acidic to neutral pH tend to improve short-term peptide stability. Repeated warming and cooling of stock solutions promotes aggregation and should be avoided. Container closures should remain intact, since adsorption to some plastics can reduce the amount of peptide in solution.
=== Preclinical === ASD-002 - a child-specific (non-acidic, sustained-release) anti-hyper excitatory ester prodrug of the potassium channel modulator NSAID mefenamic acid (MFA, approved as Ponstel) to prevent toddlers from becoming non-verbal (developmental language disorder, DLD) Bryostatin-1 (MW-904) – protein kinase C stimulant CJRB-303 (CJRB-901, MRx-0006) – bacteria replacement Debamestrocel (growth factor-producing stem cell therapy) – dopaminergic cell replacement therapy FIN-211 – bacteria replacement and gastrointestinal microbiome modulator Levophacetoperane (NLS-3; (R,R)-phacetoperone; methylphenidate reverse ester) – norepinephrine and dopamine reuptake inhibitor and psychostimulant LIT-001 – small-molecule oxytocin receptor agonist MBDB – serotonin and norepinephrine releasing agent and weak serotonin 5-HT1 and 5-HT2 receptor ligand (entactogen) Psilocin (PLZ-1015) – non-selective serotonin receptor agonist and psychedelic hallucinogen QBM-001 – undefined mechanism of action (allosteric channel modulator; putative neuroprotective and anti-inflammatory agent)
The report also raised animal welfare concerns, stating that rBST often results in "severe and unnecessary pain, suffering and distress" for cows, and is "associated with serious mastitis, foot disorders and some reproductive problems". In Canada, rBST has not been allowed on the market since at least 2000. Health Canada refused to approve rBST for use on Canadian dairies, citing concerns over animal health. The study found the occurrence of an antibody reaction, possible hypersensitivity, in a subchronic (90-day) study of rbST oral toxicity in rats that resulted in one test animal's developing an antibody response at low dose (0.1 mg/kg/day) after 14 weeks. However, the board stated, with the exception of concerns raised regarding hypersensitivity, "the panel finds no biologically plausible reason for concern about human safety if rBST were to be approved for sale in Canada." The Codex Alimentarius Commission, a United Nations body that sets international food standards, has, as of 2017, refused to approve rBST as safe. The Codex Alimentarius does not have authority to ban or approve the hormone, but its decisions are regarded as a standard and approval by the Codex would have allowed exporting countries to challenge countries with a ban on rBST before the World Trade Organization.
== Potential biomarker == MFAP4 has received considerable attention as a possible biomarker for many conditions including Marfan syndrome, surgical repair of abdominal aortic aneurysms, cardiovascular disease, COPD, liver fibrosis, and various cancers.
== Further reading == Reiter, Nadine; El-Shabrawi, Laila; Leinweber, Bernd; Berghold, Andrea; Aberer, Elisabeth (2011). "Calcinosis cutis". Journal of the American Academy of Dermatology. 65 (1): 15–22. doi:10.1016/j.jaad.2010.08.039. PMID 21679811. Róbert, Lili; Kiss, Norbert; Medvecz, Márta; Kuroli, Enikő; Sárdy, Miklós; Hidvégi, Bernadett (2020). "Epidemiology and treatment of calcinosis cutis: 13 years of experience". Indian Journal of Dermatology. 65 (2). Medknow: 105–111. doi:10.4103/ijd.ijd_527_18. ISSN 0019-5154. PMC 7059479. PMID 32180595.
Sources: en.wikipedia.org
Starting in the late 1980s, under the rule of Mikhail Gorbachev, the Soviet government undertook a program of political reforms (glasnost and perestroika) intended to liberalise and revitalise the Union. These measures, however, had a number of unintended political and social effects. Political liberalisation allowed the governments of the union republics to openly express sentiments related to nationalism. In addition, the loosening of political restrictions led to fractures within the Communist Party which resulted in a reduced ability to govern the Union effectively. The rise of nationalist and right-wing movements, notably led by Boris Yeltsin in Russia, in the previously homogeneous political system undermined the Union's foundations. With the central role of the Communist Party removed from the constitution, the Party lost its control over the State machinery and was banned from operating after an attempted coup d'état. Throughout this period of turmoil, the Soviet government attempted to find a new structure that would reflect the increased authority of the republics. Some autonomous republics, like Tatarstan, Checheno-Ingushetia, Abkhazia, South Ossetia, Crimea, Transnistria, Gagauzia sought the union statute in the New Union Treaty. Efforts to found a New Union Treaty, however, proved unsuccessful and the republics began to secede from the Union. By 6 September 1991, the Soviet Union's State Council recognized the independence of Estonia, Latvia and Lithuania bringing the number of union republics down to 12.
Attempts have been made to target the overexpression of PSMA in prostate cancer cells for several decades, although PSMA is also found in other tissue. PSMA targeting molecules have included antibodies, aptamers, peptides, and small-molecule inhibitors. Initially, development focussed on the antibody capromab. Later research has focussed on small molecule ligands that bind to the extracellular active centre of PSMA, such as PSMA-11. These ligands for PSMA-scanning target the large extracellular region of the PSMA glycoprotein. PSMA however is also over-expressed in non prostate cancer cells, including kidney, salivary gland, lacrimal gland and duodenal mucosa, where physiological uptake may be seen on imaging.
=== Towards type I === According to Carl Sagan, Type I should be reached around 2100. Physicist and futurist Michio Kaku has suggested that, if humans increase their energy consumption at an average rate of 3 percent per year, they could reach Type I status in 100–200 years, Type II status in a few thousand years, and Type III status in 100,000 to a million years. Physicist Freeman Dyson has calculated that Type I should be reached in about 200 years, while Richard Carrigan has estimated that the Earth is just four-tenths of the way to Type I on the Sagan scale. If Type I is reached soon (in the year 3000 for Richard Wilson), it would be accompanied by profound social upheavals, but also by a significant risk of self-destruction. According to Per Calissendorff, energy consumption cannot be the main parameter to explain the transition from one type to another. Civilizations must have the means to maintain their growth rate despite climatic conditions and major natural disasters, even on the cosmic scale. A civilization moving towards Type II must have mastered space travel, interplanetary communication, stellar engineering, and climate. It must also have developed a planetary communication system, such as the Internet. For Michio Kaku, the only serious threat to a Type II civilization would be the explosion of a nearby supernova, while no known cosmic catastrophe would be capable of wiping out a Type III civilization. According to Philip T. Metzger, humanity has reached Type I, but faces an energy challenge.
== Safety == Allyl alcohol is hepatotoxic. In rats, in vivo, allyl alcohol is metabolized by liver alcohol dehydrogenase to acrolein, which can cause damage to the microtubules of rat hepatocyte mitochondria and depletion of glutathione. It is significantly more toxic than related alcohols. Its threshold limit value (TLV) is 2 ppm. It is a lachrymator.
== Endolithic fungi found in the eggs of Cretaceous dinosaurs == Evidence of endolithic fungi were discovered within dinosaur eggshell found in central China. They were characterized as being “needle-like, ribbon-like, and silk-like.". Fungus is seldom fossilized and even when it is preserved it can be difficult to distinguish endolithic hyphae from endolithic cyanobacteria and algae. Endolithic microbes can, however, be distinguished based on their distribution, ecology, and morphology. According to a 2008 study, the endolithic fungi that formed on the eggshells would have resulted in the abnormal incubation of the eggs and may have killed the embryos in infected eggs of these dinosaurs. It may also have led to the preservation of dinosaur eggs, including some that contained embryos.
Sources: en.wikipedia.org
It is a synthetic peptide triagonist that engages GIP, GLP-1, and glucagon receptors. Investigational compounds in this class are studied for metabolic conditions rather than for a single organ system.
No regulatory agency has approved it for any indication. It remains an investigational product studied within controlled clinical trial programs.
A dual agonist engages two receptor targets, typically GIP and GLP-1. A triagonist adds glucagon receptor activity, which is intended to influence energy expenditure alongside appetite and glucose handling.
指同一个分子能激活 GIP、GLP-1 和胰高血糖素三类受体。它与只激活一到两种受体的同类分子在设计思路上有所区别。这种设计的目的在于覆盖更多代谢调节通路。