This is a working overview of thymalfasin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-02 and is reviewed periodically as new material appears.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
Reverse-phase high-performance liquid chromatography is the standard technique for assessing purity and concentration, because the peptide's hydrophobicity allows clean separation from related impurities. Mass spectrometry confirms molecular identity and detects sequence errors or truncations. Amino acid analysis and peptide mapping supply additional structural confirmation when required. Chromatographic purity values reported on certificates of analysis describe the proportion of the main peak and do not by themselves establish biological activity.
The name itself causes confusion, because several unrelated thymic peptides share the thymosin label. Thymosin beta-4, for example, is a different molecule with different functions. Naming conventions in the literature also mix descriptive research terms with assigned nonproprietary names, so a reader should confirm which entity a given paper addresses. Clarifying that point is usually the first step in interpreting any claim about this peptide.
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.
| Property | Value | Notes |
|---|---|---|
| Primary structure | 28 amino acid residues | N-terminally acetylated |
| Net charge at neutral pH | Negative | Acidic peptide |
| Typical purity assay | Reverse-phase HPLC | UV detection near 214 nm |
| Identity confirmation | Mass spectrometry | Matches expected molecular mass |
| Reconstitution solvent | Sterile water or saline | Follow supplier instructions |
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
The lyophilized peptide is generally stable for extended periods when kept cold and dry. Once dissolved, aqueous solutions are less stable; hydrolysis, oxidation, and aggregation can degrade the material. Storage at -20 °C or lower slows these processes. Repeated freeze-thaw cycles are best avoided because they can promote aggregation. The exact shelf life depends on formulation, pH, and concentration, so stability studies are typically performed for each specific product.
Quality control for thymosin alpha-1 focuses on identity, purity, and potency. Identity is confirmed by mass spectrometry and amino acid analysis, while purity is assessed by chromatography with limits on related substances and residual solvents. Potency assays may use cell-based immune readouts, but these are not standardized across laboratories. Regulatory status differs by jurisdiction; no product is approved in the United States for clinical use, whereas some other countries register injectable forms for specific indications.
Quantifying thymosin alpha-1 in a sample usually relies on reverse-phase high-performance liquid chromatography. The peptide lacks strong chromophores, so detection often occurs at 214 nm, where the peptide backbone absorbs. Mass spectrometry provides confirmatory identification and can detect sequence variants or truncations. Immunoassays have been used in biological matrices, but they may cross-react with related fragments. For purity assessment, chromatographic peak area gives the main component percentage, while mass accuracy verifies molecular identity.
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.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
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.
=== Other animals === GBS also causes severe epidemics in farmed fish, causing sepsis and external and internal hemorrhages, having been reported from wild and captive fish involved in epizootics in many countries. Vaccination is an effective method to prevent pathogenic diseases in aquaculture, and different kinds of vaccines to prevent GBS infections have been developed recently. GBS has also been found in many other animals, such as camels, dogs, cats, crocodiles, seals, elephants, and dolphins.
The vaccine is free of charge to users in Russia and Kazakhstan. The cost per dose would be less than US$10 (US$20 for the required two doses) on international markets, much less than the cost of mRNA vaccines from other manufacturers. Kirill Dmitriev, head of the fund, told reporters that over 1 billion doses of the vaccine are expected to be produced in 2021 outside of Russia. The head of the Gamaleya Research Institute Alexander Ginzburg estimated that it would take 9–12 months to vaccinate the vast majority of the Russian population, assuming in-country resources were adequate. The commercial release of the Gam-COVID-Vac was first scheduled for September 2020. In October, Mikhail Murashko said that the Gam-COVID-Vac would be free for all Russian citizens after the launching of mass production. Later on, the Russian Ministry of Health registered the maximum ex-factory price equal to 1,942 rubles for two components and included it into The National List of Essential medicines. There were also suggestions to include the vaccine in the National Immunisation Calendar of Russia. In the beginning of December 2020, Russian authorities announced the start of a large-scale free of charge vaccination with Gam-COVID-Vac for Russian citizens: the immunization program was launched on 5 December 2020 (with 70 medical centres in Moscow providing vaccinations). Doctors and other medical workers, teachers, and social workers were given priority due to their highest risk of exposure to the disease.
Whether an offender displayed viciousness during the time of the commission of the offence of murder; Whether an offender demonstrated a blatant disregard for human life at the time of the killing; and Whether the offender's actions sparked an outrage of the feelings of the community. In Kho's case, the majority three of the five judges were satisfied that Kho, who had used a tree branch to bash Cao's head repeatedly (resulting in a completely shattered skull that caused Cao to die in a coma six days after the attack), had demonstrated both a blatant disregard for human life and viciousness while committing the crime, and Kho's actions were such that they had outraged the feelings of the community. Due to this, Kho was once again given the death penalty and he was eventually hanged on 20 May 2016, at 3:30 pm after his appeal for a stay of execution was dismissed that same morning, a rare occurrence of an execution not carried out at dawn on Friday. Consequently, the guiding principles from Kho's case also impacted several subsequent murder cases and influenced the sentencing or appeal outcomes of these murder cases, which include the 2010 Kallang slashing, the 2016 Gardens by the Bay murder, the 2016 Circuit Road murder, the 2016 Azlin Arujunah case and the 2013 murder of Dexmon Chua Yizhi, etc.
== History == To a certain extent, medical practitioners have long been specialized. According to Galen, specialization was common among Roman physicians. The particular system of modern medical specialties evolved gradually during the 19th century. Informal social recognition of medical specialization evolved before the formal legal system. The particular subdivision of the practice of medicine into various specialties varies from country to country, and is somewhat arbitrary.
Sources: en.wikipedia.org
The drugs characteristics, including its pKa. Redistribution through an organism's tissues: Some drugs are distributed rapidly in some tissues until they reach equilibrium with the plasma concentration. However, other tissues with a slower rate of distribution will continue to absorb the drug from the plasma over a longer period. This will mean that the drug concentration in the first tissue will be greater than the plasma concentration and the drug will move from the tissue back into the plasma. This phenomenon will continue until the drug has reached equilibrium over the whole organism. The most sensitive tissue will therefore experience two different drug concentrations: an initial higher concentration and a later lower concentration as a consequence of tissue redistribution. Concentration differential between tissues. Exchange surface. Presence of natural barriers. These are obstacles to a drug's diffusion similar to those encountered during its absorption. The most interesting are: Capillary bed permeability, which varies between tissues. Blood-brain barrier: this is located between the blood plasma in the cerebral blood vessels and the brain's extracellular space. The presence of this barrier makes it hard for a drug to reach the brain. Placental barrier: this prevents high concentrations of a potentially toxic drug from reaching the foetus.
is a constant in dilute solutions, an equilibrium constant value determined using the third option will simply be proportional to the values obtained with the first two. It is common practice in biochemistry to quote a value with a dimension as, for example, "Ka = 30 mM" in order to indicate the scale, millimolar (mM) or micromolar (μM) of the concentration values used for its calculation.
== Further reading == Theravada Walpola Rahula (1974), What the Buddha Taught P. A. Payutto, Dependent Origination: The Buddhist Law of Conditionality (translation for the fourth chapter of P. A. Payutto's Buddhadhamma) Ajahn Sucitto (2010). Turning the Wheel of Truth: Commentary on the Buddha's First Teaching. Shambhala. (pages 61–76) Jackson, Peter A. (2003), Buddhadasa. Theravada Buddhism and Modernist reform in Thailand, Silkworm Books Ajahn Amaro (2021), Catastrophe/Apostrophe: The Buddha's Teachings on Dependent Origination/Cessation, Amaravati Publications Tibetan Buddhism Chogyam Trungpa (1972). "Karma and Rebirth: The Twelve Nidanas, by Chogyam Trungpa Rinpoche." Karma and the Twelve Nidanas, A Sourcebook for the Shambhala School of Buddhist Studies. Vajradhatu Publications. Dalai Lama (1992). The Meaning of Life, translated and edited by Jeffrey Hopkins, Boston: Wisdom. Geshe Sonam Rinchen (2006). How Karma Works: The Twelve Links of Dependent Arising. Snow Lion Khandro Rinpoche (2003). This Precious Life. Shambala Thrangu Rinpoche (2001). The Twelve Links of Interdependent Origination. Nama Buddha Publications. Scholarly Frauwallner, Erich (1973), "Chapter 5. The Buddha and the Jina", History of Indian Philosophy: The philosophy of the Veda and of the epic. The Buddha and the Jina. The Sāmkhya and the classical Yoga-system, Motilal Banarsidass Bucknell, Roderick S.
Sources: en.wikipedia.org
The lyophilized solid is normally held at 2 to 8 °C in a sealed, light-protected container. Dry storage limits both hydrolysis and microbial growth. Material kept this way remains stable for the shelf life stated by the supplier.
Reverse-phase HPLC separates the peptide from related impurities and yields a purity estimate. Mass spectrometry confirms the expected molecular mass and flags sequence errors. The two techniques are commonly reported together on a certificate of analysis.
Short exposure during handling is not considered a major problem for the dry powder. Prolonged storage at ambient temperature, especially of reconstituted solutions, raises the risk of degradation. Cold storage remains the standard practice for longer periods.
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.