If you have been reading about Thymosin fraction 5 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 2026-03-19. Numbers and descriptions here follow the published literature rather than marketing material.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
Thymosin alpha-1 is a short peptide of 28 amino acid residues first described in the 1970s as a component of thymic extracts. Its N-terminal residue carries an acetyl group, and the sequence is highly conserved across mammalian species. The peptide is not encoded as a standalone gene product; it is released by proteolytic cleavage from the N-terminus of prothymosin alpha, a larger acidic nuclear protein. That precursor relationship places it within a broader family of thymic and immune-associated peptides that have been studied for decades.
The activity of this peptide is generally described as immunomodulatory rather than directly antimicrobial. Experimental work links it to signaling through certain Toll-like receptors on dendritic cells and to downstream maturation of antigen-presenting cells. Reported effects include expansion of T cell subsets, shifts in cytokine profiles, and increased natural killer cell activity. These observations come largely from cell culture and animal models, and the precise receptor-level events in humans remain incompletely characterized.
The compound has been investigated as an adjunct in chronic viral hepatitis and as a vaccine adjuvant, with results that vary by study design and population. Regulators in some countries have approved a synthetic form for specific indications, while other agencies have not. Whether the peptide produces consistent clinical benefit across diverse patient groups is still an open question, and many trials have been small. Its status is therefore best described as investigational in many contexts and established only narrowly.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | About 3.1 kDa | 28 residues, N-terminally acetylated |
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in aqueous buffers |
| Storage temperature | 2 to 8 °C | Protect from light and moisture |
| Common synonyms | Thymalfasin; Tα1 | Same peptide sequence |
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
== F == Favorskii reaction Favorskii rearrangement Favorskii–Babayan synthesis Fehling test Feist–Benary synthesis Fenton reaction Ferrario–Ackermann reaction Ferrier carbocyclization Ferrier rearrangement Fétizon oxidation Fiesselmann thiophene synthesis Finkelstein reaction Fischer indole synthesis Fischer oxazole synthesis Fischer peptide synthesis Fischer phenylhydrazine and oxazone reaction Fischer glycosidation Fischer–Hepp rearrangement Fischer–Speier esterification Fischer Tropsch synthesis Fleming–Tamao oxidation Flood reaction Folin–Ciocalteu reagent Formox process Forster reaction Forster–Decker method Fowler process Franchimont reaction Frankland synthesis Frankland–Duppa reaction Fráter–Seebach alkylation Free radical halogenation Freund reaction Friedel–Crafts acylation Friedel–Crafts alkylation Friedländer synthesis Fries rearrangement Fritsch–Buttenberg–Wiechell rearrangement Fujimoto–Belleau reaction Fujiwara–Moritani reaction Fukuyama coupling Fukuyama indole synthesis Fukuyama reduction
== Pathology == Tuftsin deficiency can be hereditary or can occur following splenectomy, resulting in increased susceptibility to certain diseases e.g.: infected eczematous dermatitis with draining lymph nodes, otitis and sinusitis. Acquired tuftsin deficiency can occur in granulocyte leukemia, when blood neutrophils failed to show stimulation with synthetic tuftsin or with the serum leukokinin. Serum level of tuftsin was minimal or absent.
The armed forces of Brazil are the largest in Latin America by active personnel and the largest in terms of military equipment. It consists of the Brazilian Army (including the Army Aviation Command), the Brazilian Navy (including the Marine Corps and Naval Aviation) and the Brazilian Air Force. Brazil's conscription policy gives it one of the world's largest military forces, estimated at more than 1.6 million reservists annually. The Air Force is the largest in Latin America and has about 700 crewed aircraft in service and effective about 67,000 personnel. Numbering close to 236,000 active personnel, the Brazilian Army has the largest number of armored vehicles in South America, including armored transports and tanks. The states' Military Police and the Military Firefighters Corps are designated as auxiliary forces of the army by the constitution, but are under the control of each state's governor. Brazil's navy once operated some of the most powerful warships in the world with the two Minas Geraes-class dreadnoughts, sparking a naval arms race between Argentina, Brazil, and Chile. Today, it is a green water force and has a group of specialized elite in retaking ships and naval facilities, GRUMEC, unit specially trained to protect Brazilian oil platforms along its coast. As of 2022, it is the only navy in Latin America that operates a helicopter carrier, NAM Atlântico and one of twelve navies in the world to operate or have one under construction.
The first problems to occur in obese children are usually emotional or psychological. Obese children often experience bullying by their peers. Some are harassed or discriminated against by their own family. Stereotypes abound and may lead to low self-esteem and depression.
Oleum (Latin oleum, meaning oil), or fuming sulfuric acid, is a term referring to solutions of various compositions of sulfur trioxide in sulfuric acid, or sometimes more specifically to disulfuric acid (also known as pyrosulfuric acid). Oleums can be described by the formula ySO3·H2O where y is the total molar mass of sulfur trioxide content. The value of y can be varied, to include different oleums. They can also be described by the formula H2SO4·xSO3 where x is now defined as the molar free sulfur trioxide content. Oleum is generally assessed according to the free SO3 content by mass. It can also be expressed as a percentage of sulfuric acid strength; for oleum concentrations, that would be over 100%. For example, 10% oleum can also be expressed as H2SO4·0.13611SO3, 1.13611SO3·H2O or 102.25% sulfuric acid. The conversion between % acid and % oleum is:
Sources: en.wikipedia.org
=== Single-molecule force spectroscopy === Single molecule techniques such as optical tweezers and AFM have been used to understand protein folding mechanisms of isolated proteins as well as proteins with chaperones. Optical tweezers have been used to stretch single protein molecules from their C- and N-termini and unfold them to allow study of the subsequent refolding. The technique allows the measurement of folding rates at single-molecule level; for example, optical tweezers have been recently applied to study folding and unfolding of proteins involved in blood coagulation. von Willebrand factor (vWF) is a protein with an essential role in blood clot formation process. It was discovered – using single molecule optical tweezers measurement – that calcium-bound vWF acts as a shear force sensor in the blood. Shear force leads to unfolding of the A2 domain of vWF, whose refolding rate is dramatically enhanced in the presence of calcium. It has also been shown that the simple src SH3 domain accesses multiple unfolding pathways under force.
=== Lifespan === Octopuses have short lifespans, living up to four years. The lifecycles of some species finish in less than half a year. For most octopuses, the ultimate life stage is senescence. It is the breakdown of cellular function without repair or replacement. It may last from weeks to a few months at most. Males senesce after mating, while for females, it comes after they lay an egg clutch. During senescence, an octopus does not feed, quickly weakens, and becomes sluggish. Lesions begin to form and the octopus literally degenerates. They may die of starvation or get picked off by predators. Senescence is triggered by the optic glands and experimental removal of them after spawning was found to extend their lifecycle and activity.
In the Netherlands, pentobarbital is part of the standard protocol for physician-assisted suicide for self-administration by the patient. It is given in liquid form, in a solution of sugar syrup and alcohol, containing 9 grams of pentobarbital. This is preceded by an antiemetic to prevent vomiting. It is taken by mouth for physician-assisted death in the United States states of Oregon, Washington, Vermont, and California (as of January 2016). In Switzerland, sodium pentobarbital is administered to the patient intravenously. Once administered, sleep is induced within 30 seconds, and the heart stops beating within 3 minutes. Oral administration is also used. A Swiss pharmacist reported in 2022 that the dose for assisted suicide had been raised to 15 grams because with lower doses death was preceded by a coma of up to 10 hours in some cases.
You can't field the ball deep. You have to get out in front of it." Remarked Bagwell, "I was basically being given a lesson from Ozzie Smith at first base during a pitching change. It's pretty cool." The next year, Bagwell hit .273, driving in 96 runs with 18 home runs. In 1993, the Astros improved to a third-place finish in the National League West division, and in mid-September, Bagwell was batting .320 with 20 home runs and 88 RBI. However, a pitch from the Philadelphia Phillies' Ben Rivera broke the fourth metacarpal bone in Bagwell's left hand, ending his season prematurely. It was the first of three successive seasons that ended early or was interrupted due to an incoming pitch breaking the same bone in that hand. His tendency to dip just before starting to swing made his hand more vulnerable to being hit by inside pitches. His .320 average was sixth in the NL. In February 1994, Bagwell and the Astros agreed to a one-year contract with a $2.4 million base salary (USD, $5.3 million today).
Sources: en.wikipedia.org
The International Standard for the Prohibited List is the standard published by the World Anti-Doping Agency (WADA) that lists substances prohibited in competitive sport. It is updated at least once per year as required by the World Anti-Doping Code. The adoption of the first World Anti-Doping Code (the Code) occurred at the 2nd World Conference on Doping in Sport in March 2003 in Copenhagen, Denmark. It was there that WADA assumed the responsibility of maintaining, updating, and publishing the List of Prohibited Substances and Methods (the List) in sport. The List is to be updated and published by WADA at least annually. WADA specifies that the List generally includes any substance that meets any two of the following criteria: it enhances sport performance, it represents a health risk to the athlete, it violates the spirit of sport (as defined in the WADA Code). Substances and techniques that are prohibited by WADA fall into the following categories: S0 non-approved substances; S1 anabolic agents; S2 peptide hormones, growth factors, related substances, and mimetics; S3 beta-2 agonists; S4 hormone and metabolic modulators; S5 diuretics and masking agents; prohibited methods (M1 blood doping, M2 manipulation of samples, M3 gene doping); S6 stimulants; S7 narcotics; S8 cannabinoids; S9 glucocorticoids; P1 beta-blockers.
==== Scouting America ==== Scouting America refers to WOSM's emblem as the World Crest. It may be worn on Scouting America uniforms as an emblem of the worldwide Scout Movement. Scouting America first used the badge as an award for Scouts and Scouters who participated in an international Scouting event from early 1956 through 1991 with requirements devised by each council. In 1991, Scouting America made it part of the uniform for all Scouts and its International Activity Patch replaced the World Scout Crest as an award.
==== Electronics ==== An aqueous solution of copper(II) sulfate is often used as the resistive element in liquid resistors. In electronic and microelectronic industry a bath of CuSO4·5H2O and sulfuric acid (H2SO4) is often used for electrodeposition of copper.
== Function == Only a few methanogenic archaea have cell walls composed of pseudopeptidoglycan. This component functions much like peptidoglycan in a bacterial cell. Pseudopeptidoglycan is used by the archaeal cell to determine its shape and provide structure to the cell. It is also used to protect the cell from undesired molecules or anything harmful in its environment.
=== Livestock and crop predation === A limitation of food sources in early spring and wild berry and nut crop failures in summer may contribute to bears regularly feeding from human-based food sources. These bears often eat crops, especially during autumn hyperphagia when natural foods are scarce. Favored crops include apples, oats and corn. American black bears can do extensive damage in areas of the northwestern United States by stripping the bark from trees and feeding on the cambium. Livestock depredations occur mostly in spring. Although they occasionally hunt adult cattle and horses, they seem to prefer smaller prey such as sheep, goats, pigs and young calves. They usually kill by biting the neck and shoulders, though they may break the neck or back of the prey with blows with the paws. Evidence of a bear attack includes claw marks and is often found on the neck, back and shoulders of larger animals. Surplus killing of sheep and goats is common. American black bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals; whether this is intentional is not known. Occasionally bears kill pets, especially domestic dogs, which are most prone to harass a bear. It is not recommended to use unleashed dogs to deter bear attacks. Although large, aggressive dogs can sometimes cause a bear to run, if pressed, angry bears often turn the tables and end up chasing the dogs in return. A bear in pursuit of a pet dog can threaten both canid and human lives.
Sources: en.wikipedia.org
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.
It is usually classified as an immunomodulatory peptide rather than a classical hormone. It derives from the larger protein prothymosin alpha and acts mainly on immune cells. The thymosin label covers a group of distinct peptides, so the naming can be misleading.