Peptide LibraryThymolin
Also known as: Thymic peptide complex
Thymolin (also called Thymic peptide complex) is a thymic peptide. Thymolin is marketed as a thymic immunomodulator, but the name is not an international nonproprietary name and does not map to one defined molecule; material sold under it may be a thymic extract, a synthetic fragment, or a preparation closely related to Thymalin.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- —
- Half-life
- Not established
- FDA status
- Not Approved
- Evidence level
- Insufficient Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
- Targets
- Thymic immune signaling (claimed)
Research summary
Vendor thymic-immune peptide listing; identity may overlap thymulin/thymogen/thymalin depending on supplier. Not FDA-approved.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trialsNone in reviewed sources
- Early or uncontrolled human studiesNone in reviewed sources
- Lab & animal studiesNone in reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
Peptide Library's Thymolin profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Thymolin dosage: no established human dose
Thymolin has no established human dosage. The name appears to be another spelling of thymalin, the calf-thymus peptide preparation: the only PubMed record containing "thymolin" is a thymalin study that uses both spellings. Thymolin is not thymulin, a separate single thymic peptide. No trial is registered on ClinicalTrials.gov under either name, and the indexed human abstracts do not state a dose.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Thymolin is not an international drug name and no product listing or certificate of analysis was available to confirm what is sold under it. The indexed evidence points to it being a variant spelling of thymalin, a mixture of peptides extracted from calf thymus. The thymalin studies are Russian and Ukrainian, and their indexed abstracts give no amounts, so no dose, interval or course length can be stated from verifiable sources. See the Thymalin profile for that preparation's evidence.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Not stated in the indexed human studies |
| Evidence level | Insufficient Evidence |
| Last reviewed | 2026-11-07 |
Preclinical and analog research
Not human dosing evidence. Listed for completeness and never extrapolated to a human dose.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Thymalin (analog evidence, spelled "thymolin" in the abstract) — idiopathic parkinsonism (1999)Clinical trial · Before-and-after clinical report, Russian-language publication; thymalin, the usual spelling of the same preparation (analog evidence for products sold as thymolin)Studied an analog, not Thymolin itself | Patients aged 45–72 with stage 1.5–2.5 idiopathic parkinsonism (n=15) | Not stated in the indexed abstract | Not stated in the indexed abstract | — | — | The author reports better well-being and parkinsonian symptoms, and EEG changes, after a course of treatment | Thymalin in the combined treatment of parkinsonism patients. Lik Sprava. 1999. |
| Thymalin (analog evidence) — long-term follow-up of thymic and pineal preparations (2003)Clinical trial · Controlled observational clinical study of thymalin (analog evidence for products sold as thymolin)Studied an analog, not Thymolin itself | Elderly and older adults (n=266, including epithalamin and combined groups) | Not stated in the indexed abstract | Not stated in the indexed abstract | — | Given during the first 2–3 years of 6–8 years of observation | The authors report fewer acute respiratory illnesses and lower mortality than controls | Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett. 2003. |
Where sources disagree
- Thymolin, thymalin and thymulin are easily confused. Thymalin is a calf-thymus peptide extract; thymulin (FTS-Zn, serum thymic factor) is a single zinc-bound thymic peptide. Evidence for thymulin does not apply here.
- Products sold as thymolin may not match the thymalin used in the studies above. A tissue extract's strength and make-up can differ between products.
Reconstitution
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Injection Sites
- Abdomen
- Timing Notes
- Prefer injectable forms; oral versions generally have low bioavailability and are not recommended.
Sequence & molecular data
| Half-life | Not established |
|---|---|
| Appearance | White lyophilized powder |
| Formulation | Lyophilized Powder |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Thymolin is marketed as a thymic immunomodulator, but the name is not an international nonproprietary name and does not map to one defined molecule; material sold under it may be a thymic extract, a synthetic fragment, or a preparation closely related to Thymalin. That ambiguity is the most important thing a reference can say about it, and the certificate of analysis should be checked to establish what a given product actually contains. Where the material is a thymic peptide preparation, the proposed activity is support of T-cell differentiation and maturation analogous to endogenous thymic hormones. There is no controlled human efficacy evidence for the named product.
Origin
Commercial thymic peptide label.
Targets
Studies
Research statistics
1 PubMed publications · 100.0% human clinical research · 0 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
Regulatory & research status
Thymolin is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
How FDA approval, compounding and research-only status differ
Benefits
Thymolin side effects
Thymolin has no controlled human safety data. The effects below are reported, not established, and absence from the list is not evidence of safety.
Side Effects
- Unknown / product-dependent
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Thymolin: frequently asked questions
What is Thymolin?
Vendor thymic-immune peptide listing; identity may overlap thymulin/thymogen/thymalin depending on supplier. Not FDA-approved.
How does Thymolin work?
Thymolin is marketed as a thymic immunomodulator, but the name is not an international nonproprietary name and does not map to one defined molecule; material sold under it may be a thymic extract, a synthetic fragment, or a preparation closely related to Thymalin. That ambiguity is the most important thing a reference can say about it, and the certificate of analysis should be checked to establish what a given product actually contains.
Is Thymolin FDA approved?
No. Thymolin is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What peptides are similar to Thymolin?
Compounds most often compared with Thymolin include Thymosin Alpha-1, Thymalin, Thymogen (Oglufanide) and Thymopentin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- [Thymalin in the combined treatment of parkinsonism patients] — Lik Sprava, 1999External reference
- Class-level evidence — Histiocytosis-X — N Engl J Med, 1981External reference
- Class-level evidence — Peptides and Ageing — Neuro Endocrinol Lett, 2002External reference
- Class-level evidence — Analogues in immunology — Ric Clin Lab, 1984External reference
- Class-level evidence — Precursors of thymic peptides as stress sensors — Expert Opin Biol Ther, 2020External reference
Related research, comparisons & guides
Related peptides
Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
This Thymolin profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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