Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of DSIP and Thymulin — mechanism, dosing, side effects, legal status, and pricing.
DSIP (Delta Sleep-Inducing Peptide) is a nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) isolated in 1977 by Schoenenberger and Monnier from cerebral venous blood of rabbits during electrically induced sleep. It has been studied as a putative sleep and stress modulator, but the evidence base is weak, largely pre-2000, and DSIP is not FDA-approved.
Thymulin is a zinc-dependent nonapeptide (pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn) secreted by thymic epithelial cells, originally isolated by Bach and colleagues in the 1970s as 'facteur thymique sérique' (FTS). It is NOT the same compound as Thymalin (a Russian bovine thymus extract) or Thymosin alpha-1 (a separate 28-amino-acid thymic peptide). Thymulin is not FDA-approved; use is research/investigational only.
DSIP
Thymulin
Category
Legal Status
Mechanism
Dose Range
Route
Frequency
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
DSIP
Thymulin
COA corpus from Disclosed Labs — independently tested batches only.
DSIP
69
COAs
99.4%
Avg purity
14
Labs
Thymulin
5
COAs
99.5%
Avg purity
4
Labs
DSIP is among peptides under FDA review for the Category 1 (503A) list; if added, it would require a prescription to be compounded by registered 503A/503B pharmacies — not yet authorized. Thymulin remains research-only. In April 2026 the FDA removed 12 peptides from Category 2, which does not place them on the Category 1 list or authorize compounding. The FDA's Pharmacy Compounding Advisory Committee is advisory and meets July 23–24, 2026 to review nominations and make recommendations to the FDA.
Schoenenberger & Monnier first isolated and characterized DSIP in 1977 (PNAS 74(3):1282-6, PMID 265572). Graf & Kastin's 1984 review (Neurosci Biobehav Rev, PMID 6145137) summarized the first decade of work, noting reported effects on sleep, pain, and stress but also substantial inconsistency across labs and species. Schneider-Helmert (Eur Neurol 1986, PMID 3792404) reported sleep normalization in 18 middle-aged and elderly chronic insomniacs given DSIP over one week — small, open, and never replicated at scale. Schneider-Helmert et al. (Dtsch Med Wochenschr 1987, PMID 3582201) explored phase-shifted insomnia. Kovalzon & Strekalova (J Neurochem 2006, PMID 16539679) summarized the field as a 'still unresolved riddle,' noting that no DSIP receptor or gene has been identified. No Phase 3 trials, no FDA approval, no modern controlled replication.
Key references
Bach and Dardenne originally characterized FTS/thymulin and its absolute zinc dependency (Bach & Dardenne, Med Oncol Tumor Pharmacother 1989, PMID 2657247). Prasad et al. (J Clin Invest 1988, PMID 3262625) showed that serum thymulin activity falls in human zinc deficiency and recovers with zinc supplementation. Mocchegiani et al. (Int J Immunopharmacol 1995, PMID 8582782) demonstrated partial reversal of thymic involution with zinc in aged mice. Dardenne & Pleau reviewed zinc-thymulin interactions (Met Based Drugs 1994, PMID 18476235). Safieh-Garabedian et al. (Br J Pharmacol 2002, PMID 12110619) reported analgesic/anti-inflammatory activity of a thymulin-related peptide in rats. There are NO large, modern RCTs of exogenous thymulin in humans; clinical use is experimental.
Key references
DSIP (Cognitive) and Thymulin (Immune) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Dosing Notes
Half-life
Side Effects
Contraindications
Lab Testing
Disclosed Labs