Everything below concerns melanocortin receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-23. Numbers and descriptions here follow the published literature rather than marketing material.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
Bush authorized the CIA to use waterboarding and several other "enhanced interrogation techniques" that several critics, including Barack Obama, would label as torture. Between 2002 and 2003, the CIA considered certain enhanced interrogation techniques, such as waterboarding, to be legal based on secret Justice Department legal opinions arguing that terror detainees were not protected by the Geneva Conventions' ban on torture, which was described as "an unconstitutional infringement of the President's authority to conduct war". The CIA had exercised the technique on certain key terrorist suspects under authority given to it in the Bybee Memo from the Attorney General, though the memo was later withdrawn. While not permitted by the U.S. Army Field Manuals which assert "that harsh interrogation tactics elicit unreliable information", the Bush administration believed these enhanced interrogations "provided critical information" to preserve American lives. Critics, such as former CIA officer Bob Baer, have stated that information was suspect, "you can get anyone to confess to anything if the torture's bad enough." On October 17, 2006, Bush signed the Military Commissions Act of 2006 into law. The new rule was enacted in the wake of the Supreme Court's decision in Hamdan v. Rumsfeld, 548 U.S. 557 (2006), which allowed the U.S. government to prosecute unlawful enemy combatants by military commission rather than a standard trial. The law also denied the detainees access to habeas corpus and barred the torture of prisoners.
== Aftermath == In the aftermath of the incident, security protocols at the facility were strengthened, including tighter restrictions on tool access. The North Carolina prison system also improved safety by equipping guards with body armor and providing supervisors with tasers. On October 12, 2022—the fifth anniversary of the failed escape—staff at Pasquotank held a moment of silence and released balloons in remembrance.
Governorate of Brunswick (Braunschweig) Governorate of Hanover (Hannover) Governorate of Lunenburg (Lüneburg) Governorate of Weser-Ems On 1 January 2005 the four administrative regions or governorates (Regierungsbezirke), into which Lower Saxony had been hitherto divided, were dissolved. These were the governorates of Braunschweig, Hanover, Lüneburg and Weser-Ems.
=== Nutrition === Although powerlifting nutrition is subjective as there can be differences from person to person, there are general guidelines that athletes typically follow in order to perform optimally that can be applied to a strength sport setting. The primary concern of most diets is caloric intake as sufficient calories are needed to offset the energy expenditure of training allowing for adequate recovery from exercise. The International Society of Sports Nutrition recommends 40–70 kcals/kg/day for strength athletes who engage in 2–3 hours of intense training 5–6 days per week, compared to the 25–35 kcals/kg/day recommended for the average person engaging in a general fitness program, as regular training causes additional energy expenditure. Additionally, when powerlifters are in the off season, it is recommended that athletes increase their caloric intake in order to meet the recommendations of the ISSN and optimize their training. In addition to caloric intake, macronutrient intake plays a major role in the success of an athlete's diet. Protein, carbohydrates, and fats all play different roles in the performance and recovery process. Optimizing protein intake enables a powerlifter to build more muscle and recover properly from intense training sessions. The Journal of Sports Sciences recommends that strength athletes consume 1.6g–1.7g protein/kg/day in servings of 20 grams, 5 to 6 times a day for maximal muscle growth.
Sources: en.wikipedia.org
== Adverse effects == Prior to the approval of insulin glargine/lixisenatide, two studies were conducted to evaluate the safety of the formulation. Adverse reactions for at least 5% of people taking it were hypoglycemia, nausea, nasopharyngitis, diarrhea, upper respiratory tract infections, and headache. In Study A (N=469), symptoms of hypoglycemia were recorded in 25.6% of people with zero cases of severe symptomatic hypoglycemia. Study B (N=365) had a 40% incidence of hypoglycemic events with 1.1% incidence of severe hypoglycemia requiring assistance.
=== 2024 === During his 2024 campaign, polls generally showed that a majority of Americans believed that Trump was too old to serve as president. A February 2024 Ipsos poll finding that Joe Biden's age and health were major or moderate concerns for 86% of voters also found that 59% similarly thought Trump was too old to hold the office. During the course of the 2024 primary campaign, Trump made several gaffes, including confusing Nikki Haley for Nancy Pelosi, claiming he was running against Barack Obama (the Democratic candidate at the time was Joe Biden), and fearing the nation may enter World War II. A shift in Trump's speeches by 2024 towards shorter sentences, more tangents, more repetition, more all-or-nothing thinking, and more confusion of words and phrases could indicate cognitive decline. Basil Smikle of Columbia University argued in January 2024 that one reason Trump has not seen as much of the age criticism as Biden is that his rallies seem loud and vibrant, whereas Biden has a more old-school approach to politics. In January 2024, Jay Olshansky gave Donald Trump less than a 75% chance of living through a second term based on publicly available information about his health. Also in January 2024, red spots or sores were spotted on Donald Trump's hands. On June 14, 2024, Trump said that his longtime acquaintance Joan Rivers had told him that she had voted for him in the 2016 election, although Rivers had died in September 2014.
=== Stage IV: Scarring === The acute phase is over, but the patient's life is still at risk, and treatment is recommended. This stage lasts one to two weeks. The patient may experience trismus (difficulty moving/opening the jaw), scars will form, and any exposed teeth will set in place.
==== Tax expenditures ==== The term "tax expenditures" refers to income exclusions, deductions, preferential rates, and credits that reduce revenues for any given level of tax rates in the individual, payroll, and corporate income tax systems. Like conventional spending, they contribute to the federal budget deficit. They also influence choices about working, saving, and investing, and affect the distribution of income. The amount of reduced federal revenues are significant, estimated by CBO at nearly 8% GDP or about $1.5 trillion in 2017, for scale roughly half the revenue collected by the government and nearly three times as large as the budget deficit. Since eliminating a tax expenditure changes economic behavior, the amount of additional revenue that would be generated is somewhat less than the estimated size of the tax expenditure. CBO reported that the following were among the largest individual (non-corporate) tax expenditures in 2013:
== History == Before the development of the ELISA, the only option for conducting an immunoassay was radioimmunoassay, a technique using radioactively labeled antigens or antibodies. In radioimmunoassay, the radioactivity provides the signal, which indicates whether a specific antigen or antibody is present in the sample. Radioimmunoassay was first described in a scientific paper by Rosalyn Sussman Yalow and Solomon Berson published in 1960. As radioactivity poses a potential health threat, a safer alternative was sought. A suitable alternative to radioimmunoassay would substitute a nonradioactive signal in place of the radioactive signal. When enzymes (such as horseradish peroxidase) react with appropriate substrates (such as ABTS or TMB), a change in color occurs, which is used as a signal. However, the signal has to be associated with the presence of an antibody or antigen, which is why the enzyme has to be linked to an appropriate antibody. This linking process was independently developed by Stratis Avrameas and G. B. Pierce. Since it is necessary to remove any unbound antibody or antigen by washing, the antibody or antigen has to be fixed to the surface of the container; i.e., the immunosorbent must be prepared. A technique to accomplish this was published by Wide and Jerker Porath in 1966. In 1971, Peter Perlmann and Eva Engvall at Stockholm University in Sweden, and Anton Schuurs and Bauke van Weemen in the Netherlands independently published papers that synthesized this knowledge into methods to perform EIA/ELISA.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.