RESEARCH DIGEST / QUESTIONS
Thymulin FAQ
Direct, cited answers on what thymulin is, why zinc switches it on, what doses were studied, and where it differs from thymosin alpha-1.
What is thymulin?
Thymulin is a zinc-dependent nonapeptide hormone produced by thymic epithelial cells, biologically active only when bound to zinc in a 1:1 ratio [2]. Its molecular weight is 858.86 Da. Endogenously it drives T-cell differentiation and acts in a thymus-neuroendocrine axis [4]. It is not FDA-approved and is handled as a research peptide. The overview page answers what is thymulin in fuller detail.
What is thymulin peptide?
Thymulin is the nonapeptide pyroGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn [2]. The zinc-bound form (Zn-thymulin) is the active research peptide; the zinc-free chain is inactive [1]. There is no marketed thymulin peptide product and no approved human use.
Is thymulin the same as serum thymic factor (FTS)?
Yes — they name one molecule. Serum thymic factor (FTS, facteur thymique serique) is the original name for the zinc-free peptide. When zinc binds, FTS becomes FTS-Zn, which the 1982 authors renamed thymulin [1]. FTS is the apo-form; thymulin is the active zinc-bound form.
How is thymulin different from thymosin alpha-1?
Thymulin is a zinc-dependent nonapeptide; thymosin alpha-1 is a different, longer thymic peptide with its own sequence and pharmacology. They are chemically and pharmacologically distinct compounds, not interchangeable, and consumer sources frequently conflate them in error [16]. A study of one is not evidence about the other — see thymulin vs thymosin alpha-1 on the overview page.
What is the amino acid sequence of thymulin?
Thymulin is the nonapeptide pyroGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn (<Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn), molecular formula C33H54N12O15, molecular weight 858.86 Da [2]. The first residue, pyroglutamate, is a cyclized blocked N-terminus.
Why does thymulin need zinc to work?
Zinc binding in a 1:1 ratio creates the specific three-dimensional conformation required for activity [2]. The zinc-free apopeptide is inactive, and chelating the zinc (for example with Chelex 100) abolishes activity, which is restored by adding zinc back [1]. The fold is the function.
What does thymulin do in the body?
Endogenously it drives T-lymphocyte differentiation and acts as a hypophysiotropic peptide within a thymus-neuroendocrine axis, signaling to the pituitary [2][4]. These are physiological roles studied in models. Described effects are research findings in named species, not therapeutic claims in people.
What are the benefits of thymulin peptide?
Research describes immune-modulating and anti-inflammatory effects in animal and in-vitro models — T-cell differentiation [2], suppressed NF-kB signaling [6], and reduced inflammatory hyperalgesia in rodents [8]. No human benefits are established, and the compound is not FDA-approved [16].
What are the benefits of thymulin?
Reported research outcomes include T-cell differentiation [2], anti-inflammatory signaling changes [6], anti-hyperalgesic effects in rodents [8], and gene-therapy reversal of established asthma in mice [7]. All are preclinical or limited-human findings in named species — not established human benefits.
Does thymulin boost the immune system?
In models, thymulin promoted T-cell differentiation and its activity tracked zinc status [2][3]. This is described as a physiological and research effect, not a human immune-boost claim. There is no FDA-approved thymulin immune product.
What is the dosage of thymulin peptide?
There is no established human dosage [2]. The literature reports research doses by species — for example nanogram-to-microgram amounts in rodents (1/100/1000 ng i.p.) — for laboratory study only [8]. These are study findings, not dosing guidance.
How is thymulin administered in research?
Studied routes include intraperitoneal, subcutaneous, intracerebroventricular, intratracheal (gene therapy), intramuscular (vector), topical (a zinc-thymulin pilot), and in vitro [2][7][8][13]. The route depends on the model, and gene-therapy studies deliver a vector rather than a peptide dose [7].
Is thymulin taken as an injection?
In animal research it has been given by injection — for example intraperitoneal and subcutaneous [8][13]. It is a research peptide with no approved human injectable product. Nothing here describes human administration.
What is the half-life of thymulin?
As a small peptide its circulating half-life is short, but a precise human pharmacokinetic half-life is not well established in the public literature [2]. Gene-therapy approaches were developed specifically to sustain circulating thymulin because the native peptide clears quickly [5].
What doses of thymulin were used in animal studies?
Reported research doses span nanogram-to-low-microgram amounts — for example 1, 100, and 1000 ng intraperitoneal and roughly 0.1-1 microg intracerebroventricular in rodents [8], and 3-100 microg/day subcutaneous in a radioprotection study [13]. These are study findings, not dosing guidance.
Does thymulin reduce inflammation?
In animal and in-vitro models, thymulin was associated with reduced pro-inflammatory cytokines and suppressed NF-kB and SAPK/JNK signaling [6], and lower skin IL-1beta and NGF in an inflammatory-pain model [8]. This is a research finding, not a human anti-inflammatory treatment.
Is thymulin studied for pain relief?
In rodent inflammatory- and neuropathic-pain models, thymulin and its analog PAT were associated with dose-dependent reductions in hyperalgesia [8][9][10]. Thymulin alone did not change baseline pain thresholds — the effect appeared only against an inflammatory background [8].
Does thymulin act on the brain?
Yes, in research models. Intracerebroventricular thymulin-related peptide modulated central inflammation and reduced endotoxin-induced hyperalgesia and fever in rats [12], and thymulin acts as a hypophysiotropic peptide on the pituitary within the thymus-neuroendocrine axis [4].
What is PAT, the thymulin-related peptide?
PAT (peptide analog of thymulin) is a synthetic thymulin-related peptide studied mainly for analgesic and anti-inflammatory effects in the nervous system [11]. In rats it matched thymulin's anti-hyperalgesic activity [9] and has been proposed as a neuroinflammation candidate [11].
What research exists on thymulin?
Decades of preclinical work span immune/T-cell, anti-inflammatory, neuroinflammation/analgesia, neuroendocrine, lung, metabolic/autoimmune, and gene-therapy models, plus limited and dated human data [2][3][4][7]. Several human studies used the synthetic analog nonathymulin rather than native thymulin [15].