This is a working overview of lyophilisation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-04-03. Anything still debated is marked as such rather than presented as settled.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
The peer-reviewed record is dominated by small early-phase studies, case reports and pharmacovigilance summaries rather than large randomised trials. Papers typically examine tanning response, receptor selectivity or patterns of reported adverse events. Many note that participants obtained the peptide outside a clinical setting, which limits verification of composition and administered amount. Reported events vary widely, and causality is frequently unclear because the identity and purity of self-sourced material are unknown. Open questions include whether repeated melanocortin receptor stimulation produces cumulative effects, and how often label claims match actual content.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
Melanotan II holds no marketing authorisation from the Food and Drug Administration, the European Medicines Agency, the UK Medicines and Healthcare products Regulatory Agency or Australia's Therapeutic Goods Administration. Products sold under that name are treated as unapproved new drugs, and their sale or import is prohibited in several jurisdictions. Other countries classify the peptide as a prescription-only medicine or place it among controlled substances, so the legal position changes with the destination market. No pharmacopoeial monograph supplies an official specification, because the material is not a licensed pharmaceutical. Consequently, products offered online are not manufactured to a shared public standard.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
Beta blockers, also spelled β-blockers and also sometimes known as β-adrenergic receptor antagonists, are a class of medications predominantly used to manage abnormal heart rhythms (arrhythmia) and to protect the heart from a second heart attack after the first one (secondary prevention). They are also used widely to treat high blood pressure, though they are no longer the first choice for initial treatment of most people. They can also be used to treat anxiety – a notable example being the situational use of propranolol to help dampen the physical symptoms of performance anxiety. Beta blockers are competitive antagonists that block the receptor sites for the endogenous catecholamines epinephrine (adrenaline) and norepinephrine (noradrenaline) on adrenergic beta receptors, of the sympathetic nervous system, which mediates the fight-or-flight response. β-adrenergic receptors are found on cells of the heart muscles, smooth muscles, airways, arteries, kidneys, and other tissues that are part of the sympathetic nervous system and lead to stress responses, especially when they are stimulated by epinephrine (adrenaline). Beta blockers interfere with the binding to the receptor of epinephrine and other stress hormones and thereby weaken the effects of stress hormones. Some beta blockers block activation of all types of β-adrenergic receptors and others are selective for one of the three known types of beta receptors, designated β1, β2, and β3 receptors. β1-Adrenergic receptors are located mainly in the heart and in the kidneys.
=== Pharmacokinetics === Met-enkephalin has low bioavailability, is rapidly metabolized, and has a very short half-life (minutes). These properties are considered undesirable in pharmaceuticals as large doses would need to be administered multiple times an hour to maintain a therapeutically relevant effect, making it unlikely that met-enkephalin will ever be used as a medicine. [D-Ala2]-Met-enkephalinamide (DALA), is a synthetic enkephalin analog which is not susceptible to degradation by brain enzymes and at low doses (5 to 10 micrograms) caused profound, long-lasting, morphine-like analgesia when microinjected into a rat’s brain.
In medicine, health, or physical fitness, weight loss is a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other connective tissue). Weight loss can either occur unintentionally because of malnourishment or an underlying disease, or from a conscious effort to improve an actual or perceived overweight or obese state. "Unexplained" weight loss that is not caused by reduction in calorific intake or increase in exercise is called cachexia and may be a symptom of a serious medical condition.
==== Effects in preclinical studies ==== Trazodone shows antidepressant- and anxiolytic-like effects in animals. However, it shows differences from certain other antidepressants, like the tricyclic antidepressants, in animals. For example, it does not reverse the behavioral effects of the monoamine depleting agent reserpine and does not potentiate the effects of amphetamine or levodopa. Similarly to antipsychotics, trazodone reduces spontaneous motor activity, spontaneous and elicited aggressive behavior, and exploratory behavior, among other effects. In addition, trazodone diminishes amphetamine-induced locomotor hyperactivity, although it does not inhibit apomorphine- or amphetamine-induced stereotypy. On the other hand, unlike antipsychotics, trazodone does not produce catalepsy, although it can do so at sufficiently high doses. Activation of the serotonin 5-HT2A receptor enhances striatal dopaminergic neurotransmission, while stimulation of the serotonin 5-HT2C receptor inhibits striatal dopaminergic neurotransmission. Trazodone is both a serotonin 5-HT2A and 5-HT2C receptor antagonist, but has about 15-fold greater potency as an antagonist of the 5-HT2A receptor relative to the 5-HT2C receptor. In addition, at higher doses, trazodone acts as a dopamine D2 receptor antagonist in animals. As a result of the preceding actions, trazodone may inhibit striatal dopaminergic neurotransmission. This may underlie exacerbation of parkinsonism seen in marmosets and in human case reports.
Sources: en.wikipedia.org
7-Eleven is the largest convenience store chain in Taiwan, and is owned by President Chain Store Corporation (PCSC). The first fourteen stores opened in 1979, and struggled to make a profit. Southland Corporation partnered with Uni-President to modernize the stores. However, business was still slow, and Uni-President opted to stock Asian foods. In 1986, 7-Eleven made its first profit in Taiwan. The 5,000th store was opened in July 2014. In January 2018, an experimental and unstaffed shop branded the X-Store was opened. 7-Eleven announced plans to operate a combination store in partnership with Domino's Pizza in February 2019. The 6,000th store was opened on February 20, 2021. The 7,000th store was opened on July 5, 2024.
== External links == Cut-Flower Care — How to Make Your Fresh-Cut Flowers Last by Rose G. Edinger, Brooklyn Botanical Garden, Spring 2003, retrieved October 21, 2006 — What are preserved flowers? Everything you want to know about preserved flowers Archived 2021-01-28 at the Wayback Machine by Floralonly, Albert, published 28, May 2020
In June the company announced it would acquire startup Emergence Therapeutics for an undisclosed sum and Sigilon Therapeutics for $300 million. The company's 2023 research and development focus has been reported to be on drugs in the obesity, diabetes, Alzheimer's and autoimmune areas. In March 2023, Eli Lilly announced a $35 cap on the price of monthly insulin to be put in place immediately in order to be in line with the Inflation Reduction Act. In July 2023, Lilly announced it would acquire Versanis for $1.93 billion. In October 2023, Eli Lilly acquired Point Biopharma for $1.4 billion. In November 2023, the FDA approved tirzepatide for the treatment of obesity under the brand name Zepbound. In 2024, the FDA and the UK approved Donanemab, sold under the brand name Kisunla, a monoclonal antibody used for the treatment of Alzheimer's disease. In January 2026, Eli Lilly agreed to buy Ventyx Biosciences for $1.2 billion. The transaction was expected to close in 1H 2026. In March 2026, Eli Lilly announced a drug discovery deal with InSilico for an estimated value of $2.75 billion. In July 2026, Eli Lilly entered into an agreement to acquire AtaiBeckley in 2026.
EGF is the founding member of the EGF-family of proteins. Members of this protein family have highly similar structural and functional characteristics. Besides EGF itself other family members include:
=== Agonists === Non-selective α-MSH β-MSH γ-MSH Afamelanotide Bremelanotide Melanotan II Modimelanotide Setmelanotide MC1-selective BMS-470,539 MC4-selective PF-00446687 PL-6983 THIQ Unknown (but for certain MC2-acting) Alsactide Tetracosactide
Sources: en.wikipedia.org
Diabetic retinopathy, caused by alterations in retinal microcirculation, leading to the growth of friable and poor-quality new blood vessels in the retina or capillary closure which causes ischemia or extravasation of intravascular content, causing edema (swelling of the macula). Retinopathy is the most common cause of blindness among non-elderly adults in the developed world. Diabetic nephropathy, damage to the kidney due to increased glomerular pressure and hyperfiltration can lead to end-stage chronic kidney disease that may require renal dialysis. In most parts of the world, diabetes mellitus is the leading cause of end-stage kidney disease (ESKD). Diabetic nephropathy is increasingly recognized as a significant cause of ESKD in renal allograft recipients. Diabetic neuropathy, Neuropathies in diabetes may cause sensory, mononeuritis, and autonomic neuropathy symptoms, muscle weakness, and potentially life-threatening complications like diabetic foot syndrome (Diabetic amyotrophy) and myocardial infarctions. Intensive insulin therapy is recommended to reduce neuropathy risk, while oral antidiabetic drugs are recommended for pain treatment. Diabetic encephalopathy, Diabetes causes brain functional and structural disturbances, known as diabetic encephalopathy. Various mechanisms are proposed, like alterations to the vascular supply of the brain, or changes in cerebral function and structure, including cognitive impairment, cerebral signal conduction, neurotransmission, and synaptic plasticity are more insidious.
=== Extrapolating in pharmacology === In pharmacology, IVIVE can be used to approximate pharmacokinetics (PK) or pharmacodynamics (PD). Since the timing and intensity of effects on a given target depend on the concentration time course of candidate drug (parent molecule or metabolites) at that target site, in vivo tissue and organ sensitivities can be completely different or even inverse of those observed on cells cultured and exposed in vitro. That indicates that extrapolating effects observed in vitro needs a quantitative model of in vivo PK. Physiologically based PK (PBPK) models are generally accepted to be central to the extrapolations. In the case of early effects or those without intercellular communications, the same cellular exposure concentration is assumed to cause the same effects, both qualitatively and quantitatively, in vitro and in vivo. In these conditions, developing a simple PD model of the dose–response relationship observed in vitro, and transposing it without changes to predict in vivo effects is not enough.
Since iron is primarily required for hemoglobin, iron deficiency anemia is the primary clinical manifestation of iron deficiency. Iron-deficient people will suffer or die from organ damage well before their cells run out of the iron needed for intracellular processes like electron transport. Macrophages of the reticuloendothelial system store iron as part of the process of breaking down and processing hemoglobin from engulfed red blood cells. Iron is also stored as a pigment called hemosiderin, which is an ill-defined deposit of protein and iron, created by macrophages where excess iron is present, either locally or systemically, e.g., among people with iron overload due to frequent blood cell destruction and the necessary transfusions their condition calls for. If systemic iron overload is corrected, over time the hemosiderin is slowly resorbed by the macrophages.
The Arab armies shall enter Palestine to rescue it. His Majesty (King Farouk, representing the League) would like to make it clearly understood that such measures should be looked upon as temporary and devoid of any character of the occupation or partition of Palestine, and that after completion of its liberation, that country would be handed over to its owners to rule in the way they like. The British Mandate of Palestine came to an end on 15 May 1948, on which day six of the then-seven Arab League states (Yemen being not active) invaded the now-former Mandate territory, marking the start of the 1948 Arab–Israeli War. The Arab Higher Committee claimed that the British withdrawal led to an absence of legal authority, making it necessary for the Arab states to protect Arab lives and property. The Arab states' proclaimed their aim of a "United State of Palestine" in place of Israel and an Arab state. The Arab Higher Committee said that in the future Palestine, the Jews will be no more than 1/7 of the population—i.e., only Jews that lived in Palestine before the British mandate would be permitted to stay. They did not specify what would happen to the other Jews.
The principal physiological function of glyoxalase I is the detoxification of methylglyoxal, a reactive 2-oxoaldehyde that is cytostatic at low concentrations and cytotoxic at millimolar concentrations. Methylglyoxal is a by-product of normal biochemistry that is a carcinogen, a mutagen and can chemically damage several components of the cell, such as proteins and nucleic acids. Methylglyoxal is formed spontaneously from dihydroxyacetone phosphate, enzymatically by triosephosphate isomerase and methylglyoxal synthase, as also in the catabolism of threonine. To minimize the amount of toxic methylglyoxal and other reactive 2-oxoaldehydes, the glyoxalase system has evolved. The methylglyoxal reacts spontaneously with reduced glutathione (or its equivalent, trypanothione),) forming a hemithioacetal. The glyoxalase system converts such compounds into D-lactate and restored the glutathione. In this conversion, the two carbonyl carbons of the 2-oxoaldehyde are oxidized and reduced, respectively, the aldehyde being oxidized to a carboxylic acid and the acetal group being reduced to an alcohol. The glyoxalase system evolved very early in life's history and is found nearly universally through life-forms. The glyoaxalase system consists of two enzymes, glyoxalase I and glyoxalase II. The former enzyme, described here, rearranges the hemithioacetal formed naturally by the attack of glutathione on methylglyoxal into the product. Glyoxalase II hydrolyzes the product to re-form the glutathione and produce D-lactate.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
Regulatory treatment varies by country. In the United States, the European Union and Australia it is an unapproved drug and its sale is restricted, while some other jurisdictions list it as prescription-only or controlled. The applicable rules depend on the country of import.