B7-33 vs Teduglutide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: B7-33 relaxin, Single-chain relaxin-2 analog
B7-33 is a 27-amino-acid, single-chain peptide cut down from the B-chain of human relaxin-2, the hormone that loosens tissue during pregnancy. Relaxin itself has strong anti-scarring effects but is a complex two-chain molecule that is hard and expensive to make, so an Australian group (Hossain and colleagues, 2016) designed B7-33 as a simpler version. In rodent models it reduced heart and lung fibrosis about as well as full relaxin. It has never been tested in humans.
Also: Gattex, Revestive
Teduglutide is a 33-amino-acid GLP-2 analog approved for short bowel syndrome (SBS) in people who depend on IV nutrition or fluids. GLP-2 is the gut's own growth signal, and teduglutide makes the remaining intestine grow taller villi and absorb more, so some patients can cut back the hours they spend hooked to a drip. The FDA approved it as Gattex in December 2012 (children 1 year and older were added in 2019), and in Europe it is sold as Revestive. It works, but it is a serious daily injection with real monitoring requirements, not a gut-health supplement.
Key Comparison Insights
- Teduglutide is FDA approved, while B7-33 remains in research stages.
- Both peptides belong to the Healing category, suggesting similar primary applications.
- Teduglutide has stronger research evidence (FDA Approved) compared to B7-33 (Preclinical).
Detailed Comparison
| Attribute | B7-33 | Teduglutide |
|---|---|---|
| Category | Healing | Healing |
| FDA Status | Not FDA Approved | FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | B7-33 activates RXFP1, the relaxin receptor, but in an unusual way. In cells that naturally carry RXFP1 (like fibroblasts), it preferentially switches on the pERK1/2 pathway rather than the cAMP pathway, which made it the first described functionally selective (biased) RXFP1 agonist. Its anti-fibrotic action runs through RXFP1 paired with the angiotensin II type 2 receptor, increasing MMP-2, an enzyme that breaks down collagen. In other words, it pushes scar tissue to be broken down rather than built up. Two practical caveats: it binds RXFP1 poorly in standard engineered cell lines, so its potency depends heavily on the cell type, and it is short-lived in serum (roughly 6 minutes in lab tests), which is why researchers have tried fatty-acid versions to stretch its half-life. | Teduglutide differs from natural GLP-2 by one amino acid (glycine swapped in at position 2), which shields it from DPP-4 breakdown and stretches its half-life from minutes to roughly 2 hours in healthy people (1.3 hours in SBS). It binds GLP-2 receptors on cells in the intestinal wall, which release local growth factors that increase villus height and crypt depth, improve blood flow to the gut, and slow gastric emptying and secretions. Net result: more absorptive surface and more time to absorb. The same growth signal is the reason for its main safety concern, because it can also speed the growth of polyps or existing tumors in the gut, so the label requires colonoscopy before and during treatment. |
| Common Dosing | No established human dose Once to twice daily in mouse studies | 0.05 mg/kg once daily (labeled dose) Once daily |
| Administration | Intraperitoneal or subcutaneous injection (including osmotic minipumps) in rodents | Subcutaneous injection, rotating between abdominal quadrants, thighs, or arms |
| Typical Duration | 1-2 weeks in most rodent studies | Long-term, with assessment of benefit and ongoing monitoring; IV support is weaned as absorption improves |
| Best Time to Take | No evidence-based timing | Same time each day, any time of day |
Possible Side Effects May vary by individual |
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| Research Summary | The founding paper (Hossain et al., Chemical Science, 2016) reported that B7-33 prevented or reversed organ fibrosis and dysfunction in three rodent models of heart or lung disease with potency similar to full relaxin-2, and, unlike native relaxin, it did not promote prostate tumor growth in mice. That last point matters because relaxin has been linked to tumor growth. Later mouse work extended the findings: Devarakonda et al. (Journal of the American Heart Association, 2020) gave 0.25 mg/kg twice daily by injection after a heart attack and found smaller infarcts, better heart function, and less fibrosis at 7 days. A 2023 follow-up from the original group confirmed that B7-33 cannot be shortened further without losing receptor binding. Important context: the full hormone (serelaxin) went all the way to a large phase 3 trial in acute heart failure (RELAX-AHF-2) and failed both primary endpoints, a reminder that strong animal anti-fibrotic data in this family have not translated easily to people. For B7-33 itself there are no human studies, no human pharmacokinetics, and no human safety data. | In the pivotal adult trial (Study 1, NCT00798967), 86 adults with SBS were randomized to teduglutide 0.05 mg/kg daily or placebo for 24 weeks. 63% on teduglutide versus 30% on placebo were responders (at least a 20% cut in weekly IV support at weeks 20 and 24), and weekly IV volume fell 4.4 L versus 2.3 L. In the 2-year open-label extension, 93% of the 30 patients who completed 30 months reached at least a 20% reduction, and a minority came off IV support entirely. An earlier trial (Study 3) used a different primary endpoint that missed at the higher dose, though responder rates at 0.05 mg/kg were 46% versus 6%. A 24-week pediatric study of 59 children aged 1 to 17 led to the 2019 approval: 69% on 0.05 mg/kg cut IV support by at least 20%, and 3 of 26 weaned off. Honest caveats: it is a lifelong therapy for most, benefits fade if stopped, and colon-in-continuity patients often respond less dramatically than those with a stoma. Longer-acting GLP-2 drugs (glepaglutide, apraglutide) are trying to replace the daily shot. |
Frequently Asked Questions: B7-33 vs Teduglutide
What is the difference between B7-33 and Teduglutide?
B7-33 is a healing peptide that b7-33 is a 27-amino-acid, single-chain peptide cut down from the b-chain of human relaxin-2, the hormone that loosens tissue during pregnancy. relaxin itself has strong anti-scarring effects but is a complex two-chain molecule that is hard and expensive to make, so an australian group (hossain and colleagues, 2016) designed b7-33 as a simpler version. in rodent models it reduced heart and lung fibrosis about as well as full relaxin. it has never been tested in humans. Teduglutide is a healing peptide that teduglutide is a 33-amino-acid glp-2 analog approved for short bowel syndrome (sbs) in people who depend on iv nutrition or fluids. glp-2 is the gut's own growth signal, and teduglutide makes the remaining intestine grow taller villi and absorb more, so some patients can cut back the hours they spend hooked to a drip. the fda approved it as gattex in december 2012 (children 1 year and older were added in 2019), and in europe it is sold as revestive. it works, but it is a serious daily injection with real monitoring requirements, not a gut-health supplement. The main differences lie in their mechanisms of action and clinical applications.
Which is better, B7-33 or Teduglutide?
Neither is universally "better" - the choice depends on your specific goals. B7-33 is typically used for healing purposes, while Teduglutide is used for healing. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can B7-33 and Teduglutide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using B7-33 and Teduglutide 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.