Thymosin α1
Human RCTTα1 · Zadaxin · related: Thymalin
Proposed to enhance innate and adaptive immunity by supporting T-cell maturation, dendritic-cell function and cytokine balance. It has been tested in large randomised trials in sepsis and as a vaccine and antiviral adjunct, with mixed outcomes across indications.
SDAAVDTSSEITTKDLKEKKEVVEEAEN
Approved in several countries (for example China and parts of Asia and South America) for hepatitis B/C and as an immune adjunct; not FDA-approved in the United States.
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KPV
Animal / in-vitro onlyLys-Pro-Val · alpha-MSH(11-13)
A three-residue fragment of alpha-MSH that suppresses NF-kB activation and pro-inflammatory cytokine output in colitis models. All supportive data are animal or cell-culture; no human trials have been published.
KPV
Not approved by FDA or EMA. Research use only.
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LL-37
Animal / in-vitro onlyCathelicidin · hCAP-18 C-terminal peptide
The only human cathelicidin. It disrupts bacterial membranes, recruits immune cells and supports wound repair, but at high concentrations it also drives inflammation and amyloid-related pathology.
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Naturally occurring human peptide. Not approved as a drug; investigational for topical antimicrobial and wound applications.
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Thymulin
Animal / in-vitro onlyFacteur thymique serique (FTS) · zinc-thymulin
A zinc-dependent thymic hormone that promotes T-lymphocyte differentiation and sits at the interface of the neuroendocrine and immune systems. Evidence is preclinical, with a large review literature.
EAKSQGGSN
Investigational research peptide. Not approved by FDA or EMA.
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Thymalin
ObservationalThymic polypeptide bioregulator complex
A thymic peptide complex promoted as an immune restorer and geroprotector. Reported long-term mortality benefits in elderly cohorts rest entirely on publications from the originating institute, so confidence is low.
Heterogeneous low-molecular-weight thymic polypeptide extract (no single sequence)
Registered as a medicine in Russia and CIS states only; not FDA/EMA approved. All human data come from one research group with no independent replication.
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ARA-290
Human trials (limited)Cibinetide · ARA 290
An erythropoietin-derived peptide engineered to keep EPO's tissue-protective, anti-inflammatory signalling without raising haematocrit. Phase 2 work showed improved neuropathic symptoms and metabolic control in type 2 diabetes.
Cyclic 11-residue peptide from the helix B surface of erythropoietin
Investigational; not approved. Unlike erythropoietin itself, it is not on the WADA prohibited list.
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Thymogen
Animal / in-vitro onlyGlu-Trp dipeptide · EW
A synthetic dipeptide promoted as an immune modulator and geroprotector. The rodent data are suggestive but come from a single research group with little independent replication.
EW
Registered as a medicine in Russia only; not FDA/EMA approved. Evidence comes almost entirely from one institute.
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Thymopentin
Human trials (limited)TP-5 · thymopoietin(32-36) · Timunox
Older human trials in rheumatoid arthritis, atopic dermatitis and HIV were small with modest and mixed results, and the drug never achieved durable global approval. Current interest is largely mechanistic, including cell-differentiation work in leukaemia lines.
RKDVY
Approved decades ago in a few markets as Timunox and similar brands; not FDA-approved and largely discontinued.
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Tuftsin
Animal / in-vitro onlyThr-Lys-Pro-Arg · IgG Fc fragment peptide
One of the earliest characterised immunostimulatory peptides, described in 1970, with decades of phagocyte-activation data in vitro and in rodent infection models. Human evidence is observational, reduced tuftsin activity after splenectomy, and no modern trials of exogenous tuftsin exist.
TKPR
Not an approved drug.
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Melittin
Animal / in-vitro onlyBee venom major peptide
Melittin has a large in-vitro and animal literature on antimicrobial and anticancer effects, but its non-selective membrane lysis and haemolytic toxicity have blocked systemic use. Current work focuses on nanocarrier targeting to restrict where it acts.
GIGAVLKVLTTGLPALISWIKRKRQQ-NH2
Not approved for any indication. Systemically haemolytic.
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