B7-33 (6mg)

(17 customer reviews)


B7-33 peptides are Synthesized and Lyophilized in the USA.

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Quantity5 - 910 +
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FREE - 30ml bottle of bacteriostatic water
(Required for reconstitution)
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SKU: B7-33-6mg Category:


What Is B7-33 Peptide?

B7-33 is a soluble synthetic single-chain peptide obtained from the larger, naturally occurring protein H2-relaxin, which has pleiotropic actions, impacting the musculoskeletal system, cardiovascular system, and reproduction[1]. It retains the anti-fibrotic properties of relaxin without enhancing cAMP production, stimulates ERK1/2 phosphorylation, and promotes matrix metalloproteinase 2 (MMP2) expression and the degradation of extracellular collagen.
The relaxin family peptides have four endogenous receptors divided into two pairs (RXFP1/2 and RXFP3/4)[2]. The function of these receptors is outlined as follows:
RXFP-1: Influences sperm motility, pregnancy, vascular endothelium, and joint health.
RXFP-2: Affects testicular descent.
RXFP-3: Mutations of this receptor affect schizotypal personality disorder and certain sleep disturbances.
RXFP-4: The role of this receptor is not clear. It is known to be expressed on sperm and alters insulin-like peptide 5, which in turn regulates hunger/satiation signaling.
The relaxin receptors are stimulated by cAMP, orexin, corticotropin-releasing factor (CRF), several insulin-like peptides, and GLP-1. The agonists exhibit anti-inflammatory, antioxidant, and wound healing properties. Research highlights that relaxin has all the properties apart from vasodilator, blood vessel growth stimulator, and antihypertrophic. Therefore, the peptide and its derivatives can be used in acute heart failure and other fibrotic disorders.


AKA: (B7-33)H2, GTPL9321


PubChem: 318164840

Reconstitution: Required

B7-33 Research

B7-33 Function
B7-33 preferentially stimulates the pERK pathway over the cAMP pathway[3]. The pERK pathway regulates cell cycle arrest in the G1 phase and has been implicated in several diseases like Alzheimer’s and Crutzfeld-Jacob.
By blocking cell cycle progression in cells with RXFP1 receptors, B7-33 exercises its anti-fibrotic effects through the ability to stimulate RXFP1-angiotensin II type 2 receptor heterodimering, which activates pERK1/2 signaling and thus triggers the increased production of the collagen-degrading enzyme matrix metalloproteinase (MMP) -2.

Ease of Production
B7-33 is easier to produce and is more economical. It has less complicated 2D and 3D structures; it is easier to produce a functional B7-33 protein than a full H2-relaxin protein.

Anti-Fibrotic Properties
Fibrosis involves scarring or unorganized tissue regeneration and is the end state of at least half of all chronic diseases. In 2012, H2-relaxin completed phase II clinical trials to treat acute heart failure[4]. The research revealed that H2-relaxin administration leads to instant vasodilation and reduces the long-term scarring seen following heart damage. This makes H2-relaxin the first new treatment approved for acute heart failure in 20 years.
Using the full relaxin protein as a therapeutic agent is challenging. H2-relaxin is difficult to produce and can only be administered via IV injection. It also increases heart rate and promotes cancer progression (particularly prostate cancer).
B7-33, the peptide increases MMP-2 production slightly more than H2-relaxin does. This significantly reduces cardiac fibrosis in rat models of MI-induced heart failure and improves cardiac function[5]. Similar effects were recorded in mouse models of asthma and lung fibrosis.
Further, B7-33 overcame tumor growth even when administered at higher doses than those producing anti-fibrotic effects. It works almost exclusively through the pERK pathway and does not stimulate cAMP production.

Blood Vessel Protection
Human relaxin-2 (serelaxin) is relevant as it protects the vasculature against endothelial dysfunction and long-term scarring. B7-33 replicates the vasoprotective effects of serelaxin by enhancing bradykinin-mediated endothelium-dependent relaxation in arteries by boosting endothelium-derived hyperpolarization in certain vascular beds[5]. Marshal et al. outlines that equimolar doses of B7-33 replicated the acute beneficial vascular effects of serelaxin in rat mesenteric arteries and also prevented endothelial dysfunction induced by placental trophoblast conditioned media in mouse mesenteric arteries. The selectivity of this molecule in causing vasorelaxation can be useful in certain cardiovascular conditions and preeclampsia during pregnancy.

B7-33 in Preeclampsia
Preeclampsia is a common complication of pregnancy that leads to high blood pressure and reduced fetal weight. While manageable to a large degree, preeclampsia can be difficult to control and, in some cases, life-threatening to both mother and fetus. In the most extreme cases of preeclampsia, immediate delivery of the baby is necessary, making it a common cause of pre-term delivery. Research, however, suggests that relaxin and thus B7-33 may prove useful in controlling preeclampsia even in severe cases[6].
B7-33 binds to the RXFP-1 receptor to increase VEGF production in cytotrophoblasts. These cells, found in the developing fetus, are crucial to establishing blood flow between the maternal circulation and the developing fetus. By triggering VEGF production, B7-33 promotes the growth of blood vessels and thus improves the blood supply between mother and child.
Studies reveal that lipidated B7-33 has a prolonged in vivo half-life and that lipidation does not affect the activity of the peptides[6]. A longer half-life would make B7-33 an even more effective therapeutic.

B7-33 in Anti-Fibrotic Materials
B7-33 finds application in producing anti-fibrotic materials or materials that resist the foreign body response. Fibrosis becomes problematic for implanting a medical device, like a cardiovascular stent, into the body. In these cases, fibrosis can lead to dysfunction or degradation of the implant and even lead to artery occlusion, reduced blood supply, and eventually a heart attack.
B7-33 offers an ideal coating for use in implants. Research has shown that the release of B7-33 from the coating of a device reduced fibrotic capsule thickness by nearly 50% over a 6-week trial and opened up the possibility of a range of improved implantable medical devices[7]. The use of B7-33 and similar peptides could avoid the use of systemic substances (e.g., Plavix or aspirin when cardiac stents are placed) to reduce fibrosis of implanted medical devices. This reduction makes the devices safer and allows them to be implanted in a wider range of patients (e.g.patients with more severe disease).

B7-33 is a novel peptide with potent anti-fibrotic effects. It is actively studied to reduce fibrosis in acute and chronic diseases like heart failure and lung inflammation. The peptide has reduced fibrosis by roughly 50% in animal studies, leading to prolonged survival following injury and one of the first few offerings for treating heart failure in 20 years. The peptide holds the potential to reduce fibrosis and the rejection of implanted medical devices.
B7-33 further reduces blood pressure and protects vasculature, being of greatest interest. Studies in animal models of preeclampsia suggest that the peptide might be useful in treating this difficult-to-manage disease, potentially allowing more women to carry children to term in a safe manner for both mother and baby.


  1. Praveen, P., Kocan, M., Valkovic, A., Bathgate, R., & Hossain, M. A. (2019). Single chain peptide agonists of relaxin receptors. Molecular and cellular endocrinology, 487, 34-39.
  2. Yegorov, S., Bogerd, J., & Good, S. V. (2014). The relaxin family peptide receptors and their ligands: new developments and paradigms in the evolution from jawless fish to mammals. General and comparative endocrinology, 209, 93–105. https://doi.org/10.1016/j.ygcen.2014.07.014
  3. Hossain, M. A., Kocan, M., Yao, S. T., Royce, S. G., Nair, V. B., Siwek, C., Patil, N. A., Harrison, I. P., Rosengren, K. J., Selemidis, S., Summers, R. J., Wade, J. D., Bathgate, R. A. D., & Samuel, C. S. (2016). A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor, RXFP1. Chemical science, 7(6), 3805–3819. https://doi.org/10.1039/c5sc04754d
  4. Teerlink, J. R., Cotter, G., Davison, B. A., Felker, G. M., Filippatos, G., Greenberg, B. H., Ponikowski, P., Unemori, E., Voors, A. A., Adams, K. F., Jr, Dorobantu, M. I., Grinfeld, L. R., Jondeau, G., Marmor, A., Masip, J., Pang, P. S., Werdan, K., Teichman, S. L., Trapani, A., Bush, C. A., … RELAXin in Acute Heart Failure (RELAX-AHF) Investigators (2013). Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trial. Lancet (London, England), 381(9860), 29–39. https://doi.org/10.1016/S0140-6736(12)61855-8
  5. Marshall, S. A., O’Sullivan, K., Ng, H. H., Bathgate, R. A. D., Parry, L. J., Hossain, M. A., & Leo, C. H. (2017). B7-33 replicates the vasoprotective functions of human relaxin-2 (serelaxin). European journal of pharmacology, 807, 190–197. https://doi.org/10.1016/j.ejphar.2017.05.005
  6. Afroze, S. H., Pantho, A. F., Sprague, D. C., Kuehl, T. J., Bathgate, R., Zawieja, D. C., … & Uddin, M. N. (2019). Abstract P3042: Novel Peptide B7-33 and It’s Lipidated Derivative Protect Cytotrophoblasts From Preeclampsia Phenotype in a Cellular Model of the Syndrome. Hypertension, 74(Suppl_1), AP3042-AP3042.
  7. Welch, N. G., Mukherjee, S., Hossain, M. A., Praveen, P., Werkmeister, J. A., Wade, J. D., … & Thissen, H. (2019). Coatings releasing the relaxin peptide analogue B7-33 reduce fibrotic encapsulation. ACS applied materials & interfaces, 11(49), 45511-45519.
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17 reviews for B7-33 (6mg)

  1. Anthony Holland

    Most things are always in stock and if not, they soon will be. They offer new information on how peptides can help the body. Great place to purchase peptides.

  2. Eleanor Horan

    I had some problems with the address, but they contacted me and still shipped it out the day after I placed my order

  3. Trona Buels

    I have been looking for this all over the internet and the few spots I found, it was either looking sketchy or it was outrageously expensive. Glad to have finally found the match. Thanks BP

  4. Sunanda Vaidheesh

    very very good service. very fast with the shipment. no problem

  5. Scott Vinkemeier

    Glad I found them when I did! They’ve only been around I think a little more than a year but they make me wish they opened up sooner. The products are fantastic and they seem to be in stock very often. Great at keeping their word and helping with refunds or sending out new orders if the one you had came in broken or just destroyed from the temp.

  6. Sarah Watkins

    Always a pleasure doing business with them

  7. Michelle Zkiab

    Very reputable company, peptides are always pure and always of great quality. I recommend them to every company I work with or any scientist I know working with peptides.

  8. Nate Porter

    I ran into an issue when checking out with them. For some reason they wouln’t accept my disocover card. It’s advertised that they do. Had to contact them through email and about 15 minutes later their representive called me to help solve the issue. I think I was dealing with Danny. They took my credit card info over the phone and within minuts I recived a confirmation order. No idea what happened but since then I have ordered again and have not ran into that issue.

  9. Ava Lee

    Customer service is nice, they answer any question I have and handle issues deligently.

  10. Isabella Gelbero

    Came across this site a while while ago. Luckily they had some peptides I needed in stock and the process was the typical buying method you’ll see anywhere. They did take more payment methods than most other places. My order came in when they said it would.

  11. Jasper Hall

    Just bought peptides from them for the first time after reading reviews, hope it lives to the expectations it has set.

  12. Peter Crossey

    I have ordered with them many times within the past year and their qulaity has never changed. I have had some issues with shipping and receiving products but those have been taken care of with a quick email/phone call.

  13. Doltan Hoover

    I had no issues recieving the products and I am based in Canada!

  14. cameron bryce

    Jamie is excellent and great at answering all my questions. I had an issue with my order and it seemed it got stuck at customs. They were able to reassure me that if the products came in and weren’t salvagable to email him and that he’d send a new batch free of charge.

  15. Alex Sanders

    I recommend them to any researcher out there doing work with peptides.

  16. Carla Jene

    Biotech peptides has been my go to for a while now. They were recommended by my mentor and it truly is a gem. My research is flourishing and doing much better than when I was using peptides from another company.

  17. Billay Ace

    Jamie is professional and was able to help me solve a missing peptide issue. I had ordered a few different types of peptides and typically I get it all together and without any issues. This time around ti seemed to come in a few batches and was missing one peptide completely. I have worked with Jamie before so I emailed seeking help from them and within a few hours I got a call back. I explained the issue and once they looked up my order they saw where the issue was. I guess that peptide was out of stock and the website had a glitch or was not updated yet so somewhere it got lost to cancel the order to contact me. Whatever it was we went ahead and placed the order as they had just restocked and they actually gave me some credit for my next order because of the mix up. So if you need any help, ask for Jamie and they’ll handle everything!

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