Larazotide acetate vs Thymulin
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Larazotide, AT-1001
Larazotide is an 8-amino-acid oral peptide (GGVLVQPG) designed to tighten the junctions between gut lining cells, aimed at celiac disease. For years it was the furthest-along celiac drug in development and it gets talked about online as a 'leaky gut' or zonulin blocker. The honest story is short: one phase 2b trial found a modest symptom benefit at the lowest dose only, the phase 3 trial was stopped in 2022 when it could not show a clear effect, and the sponsor 9 Meters Biopharma filed for Chapter 7 liquidation in July 2023. It is not approved anywhere.
Also: Facteur thymique serique, FTS
Thymulin is a tiny nine-amino-acid hormone made by the epithelial cells of the thymus, first described in the 1970s as facteur thymique serique (FTS). It only works when bound to one zinc atom, which makes it an oddly neat marker of zinc status. It plays a part in training T cells, and animal work suggests anti-inflammatory and pain-reducing effects. It is sold online for immune support and hair loss, but there are no modern human trials of giving it, and the hair claims rest on lab dishes and a sponsor-linked cosmetic study.
Key Comparison Insights
- Both peptides belong to the Immune category, suggesting similar primary applications.
- Larazotide acetate has stronger research evidence (Human Trials) compared to Thymulin (Preclinical).
Detailed Comparison
| Attribute | Larazotide acetate | Thymulin |
|---|---|---|
| Category | Immune | Immune |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Larazotide is modeled on a fragment of Vibrio cholerae zonula occludens toxin, a region that overlaps with zonulin, the human protein that loosens tight junctions in the gut wall. The idea is that it blocks zonulin signaling and helps tight junctions reassemble, so gluten fragments have a harder time slipping between cells into the tissue underneath, where they trigger the immune reaction in celiac disease. It acts locally in the gut lumen and is not meant to be absorbed. That is a reasonable hypothesis with lab and animal support, but it is worth being clear: larazotide does not stop the immune response to gluten itself, and no human trial proved it protects the gut lining on biopsy. | Thymulin (sequence Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn) binds zinc in a 1:1 ratio, and only the zinc-bound form has biological activity. It promotes T cell differentiation inside and outside the thymus and influences T cell subsets and cytokine production. Its levels fall with age as the thymus shrinks, and fall with zinc deficiency. Researchers led by Goya and Reggiani have described a two-way link with the pituitary: thymulin seems to affect pituitary hormone release, and pituitary hormones affect thymulin secretion. In rodent models, thymulin and a synthetic analogue reduced inflammation and pain signalling, partly by dampening pro-inflammatory cytokines. How much of this applies to a peptide injected into a healthy adult is unknown. |
| Common Dosing | 0.5 mg three times daily before meals (trial dose) Three times daily, before meals | No established dose Unknown |
| Administration | Oral capsule taken before meals, alongside a gluten-free diet (not instead of it) | Sold for subcutaneous injection or topical use; neither route has been tested in controlled human trials |
| Typical Duration | 12 weeks of treatment in the phase 2b trial | Unknown; no human trials to guide duration |
| Best Time to Take | About 15 minutes before each main meal (trial protocol) | No evidence-based timing |
Possible Side Effects May vary by individual |
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| Research Summary | The key human study is a phase 2b trial published in Gastroenterology in 2015 (Leffler and colleagues, NCT01396213). It randomized 342 adults with celiac disease who still had symptoms on a gluten-free diet to 0.5 mg, 1 mg, or 2 mg three times daily or placebo for 12 weeks. Only 0.5 mg met the primary endpoint (symptom score 2.59 vs 2.88), with 26% fewer symptomatic days. The 1 mg and 2 mg doses did nothing measurable, an odd inverse dose response the authors could not explain (peptide aggregation was one guess), and most secondary endpoints missed. Safety looked similar to placebo. The phase 3 CedLara trial (NCT03569007) then tested the same 0.5 mg dose, but in June 2022 an interim analysis showed the number of patients needed to separate drug from placebo was too large to continue, and the trial was terminated. 9 Meters later pointed larazotide at COVID-related conditions such as MIS-C, then filed Chapter 7 in July 2023. We found no active development after that. Bottom line: one positive-ish phase 2b, one stopped phase 3, no approval. | Most of what is solid here is basic physiology. Dardenne and Pleau (1994) reviewed the zinc dependence: no zinc, no activity. Prasad and colleagues (JCI, 1988) showed that serum thymulin activity dropped in people made mildly zinc deficient by diet and came back with zinc supplementation, alongside shifts in T cell ratios and IL-2, so thymulin is a useful readout of zinc status. Reviews by Reggiani, Goya and colleagues (2012-2014) summarize anti-inflammatory and analgesic effects in rodents and gene therapy work in athymic mice, but frame human use as a future goal. On hair: Meier and colleagues (J Invest Dermatol, 2012) found a low dose of thymulin increased hair shaft growth in organ-cultured human scalp follicles, a dish result rather than a clinical one. A 2013 cosmetic study of a thymus peptide serum and shampoo reported less hair shedding on pull tests, but it was tied to the product maker and not a controlled regrowth trial. There are no controlled trials of injected or topical thymulin for immunity, aging or hair in people, and no human safety data. If you have low zinc, fixing that is better proven than adding the peptide. |
Frequently Asked Questions: Larazotide acetate vs Thymulin
What is the difference between Larazotide acetate and Thymulin?
Larazotide acetate is a immune peptide that larazotide is an 8-amino-acid oral peptide (ggvlvqpg) designed to tighten the junctions between gut lining cells, aimed at celiac disease. for years it was the furthest-along celiac drug in development and it gets talked about online as a 'leaky gut' or zonulin blocker. the honest story is short: one phase 2b trial found a modest symptom benefit at the lowest dose only, the phase 3 trial was stopped in 2022 when it could not show a clear effect, and the sponsor 9 meters biopharma filed for chapter 7 liquidation in july 2023. it is not approved anywhere. Thymulin is a immune peptide that thymulin is a tiny nine-amino-acid hormone made by the epithelial cells of the thymus, first described in the 1970s as facteur thymique serique (fts). it only works when bound to one zinc atom, which makes it an oddly neat marker of zinc status. it plays a part in training t cells, and animal work suggests anti-inflammatory and pain-reducing effects. it is sold online for immune support and hair loss, but there are no modern human trials of giving it, and the hair claims rest on lab dishes and a sponsor-linked cosmetic study. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Larazotide acetate or Thymulin?
Neither is universally "better" - the choice depends on your specific goals. Larazotide acetate is typically used for immune purposes, while Thymulin is used for immune. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Larazotide acetate and Thymulin be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Larazotide acetate and Thymulin together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.