What Are Peptides?

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what are peptides

I have been bombarded this past year with questions about peptides. What are peptides? What are they used for? Do I recommend them to my patients? So let’s dig in on this topic.

What Are Peptides?

Peptides are merely small fragments of proteins. Basically, they are a compound consisting of two or more amino acids, which are the building blocks of all proteins. That’s the chemical definition, but In the context of the term we’re using here, this is a catch-all word that refers to several peptides that are being sold as nutritional supplements or for “research use only” that are being used by athletes and patients for anti-aging and to heal injuries.

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Now that I’ve answered the “What are Peptides” question, what are some of the more common ones being sold? BPC-157 is the peptide I get asked about most often. What is it? What could it help? What’s the research?

BPC 157 is composed of 15 amino acids and is a partial sequence of the body protection compound (BPC) that was discovered in and isolated from human gastric fluid. While the compound has been shown experimentally to help different types of wounds heal, here I’ll focus on its musculoskeletal applications (1). Hence, let’s dive into what’s known about this compound and tendon healing.

In one study, BPC-157 was shown to help tendon fibroblast cells (tenocytes) survive an inflammatory challenge and increase their migration (2). However, we need to be VERY CAUTIOUS about these results. Why? From looking at the reported data in the paper, BPC-157 worked no better than the high dose platelet-rich plasma (PRP) that our lab research group tested in another study (3). Those diagrams from each paper are above (BPC-157 on the left and PRP on the right).

Hence, why would I expose my patient to the risks of an unknown compound that has never been tested rigorously in humans when I can get the same results with PRP which has been tested for orthopedic applications in dozens of randomized controlled trials in humans? Because I can store a vial of lyophilized BPC-157 powder in a vial on the shelf? That’s not a good enough reason for me.

BPC-157 and Ben Greenfield

Ben is a “biohacker” (shown above) which means that he’s someone who injects all sorts of stuff into his body, most of which is experimental and some of it illegal. He came on my radar when he had someone inject stem cells into his penis. Ben is keen on using BPC-157 so you can heal “like Wolverine”. For me, that’s not exactly a ringing endorsement.

How are Peptides Being Sold? Can You Buy BPC-157?

BPC-157, like all peptides used for these purposes, is in a regulatory “questionable” zone. Let’s explore how people are accessing this stuff.


There are companies (like the one below) selling BPC-157 as an oral supplement. This makes some sense, as it can survive at least 24 hours in gastric acids (which is where it normally lives). Sadly, I was unable to find a single human trial of taking BPC-157 orally, so we have no idea if this stuff works.

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Research Use Only

Another loophole for BPC-157 is that it’s sold as a lyophilized powder for reconstitution as “Research Use Only”. With company names like “Peptide Pros” and disclaimers like this one:

“Our USA peptides are not to be injected and are not intended for bodybuilding or tanning purposes of any kind. They are NOT for use as food additives, drugs, cosmetic, household chemicals, or other inappropriate applications. YOU MUST BE A MINIMUM OF 18 YEARS OF AGE TO ORDER FROM THIS SITE”

What could go wrong? Meaning, what you don’t see here is any verification that you are a researcher before buying these products. In addition, the problem with these websites is that given their number versus the number of publications, the entire world’s supply needed for research could likely be satisfied in one day’s worth of sales. Hence, these sites, despite protesting that the compound should only be used for research, in my opinion, likely know at some level that this compound is being used for human therapies.


This is from the US Anti-doping Agency, a resource for athletes to help them avoid being nailed for illegal drug enhancement (4):

Are Peptides Illegal? Is BPC-157 legal?

There appears to be no legal basis for selling BPC-157 as a drug, food, or a dietary supplement, and the Food and Drug Administration (FDA) confirmed there is also no legal basis for compounding pharmacies to use BPC-157 in compounded medications. However, there is evidence that BPC-157 is being illegally included in some wellness and anti-aging treatments and products.”

Hence, it’s unlikely that all of these companies selling BPC-157 are doing so legally.

Hormone Treatment Centers

Can you get BPC-157 from a doctor? Yep, check this out:

Courses for Peptides?

Are there physician courses that will teach doctors how to use BPC-157 and other peptides in their patients?

I should have known that the king of anti-aging certifications (like their “Stem Cell Fellowship”) A4M, wouldn’t be missing out on this gravy train.

Putting It All Together…

Would I use BPC-157 in my patients? No. Without any human safety data and tendon healing results that can be easily replicated with high-dose PRP, it would be medically irresponsible of me to do so. In addition, I’m pretty sure that purchasing and using this stuff, which exists only for research purposes in a lab and using it in humans is illegal.

The upshot? Now you know the answer to the question, “What are Peptides”. In addition, now you know my position on BPC-157. Unimpressive results with a very scary lack of human safety data.



(1) Gwyer D, Wragg NM, Wilson SL. Gastric pentadecapeptide body protection compound BPC 157 and its role in accelerating musculoskeletal soft tissue healing. Cell Tissue Res. 2019;377(2):153-159. doi:10.1007/s00441-019-03016-8

(2) Chang CH, Tsai WC, Lin MS, Hsu YH, Pang JH. The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. J Appl Physiol (1985). 2011;110(3):774-780. doi:10.1152/japplphysiol.00945.2010

(3) Berger DR, Centeno CJ, Steinmetz NJ. Platelet lysates from aged donors promote human tenocyte proliferation and migration in a concentration-dependent manner. Bone Joint Res. 2019;8(1):32-40. Published 2019 Feb 2. doi:10.1302/2046-3758.81.BJR-2018-0164.R1

(4) USADA. BPC-157: Experimental Peptide Creates Risk for Athletes. https://www.usada.org/spirit-of-sport/education/bpc-157-peptide-risk/ Accessed 8/8/20

This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

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7 thoughts on “What Are Peptides?

  1. Leland J Hoepfinger

    Nothing to do with peptides–but what is your opinion of your once suggested lion’s mane? I have been taking every since and am of the impression it helps????? LJH

    1. Chris Centeno, MD Post author

      That’s an oral supplement with good in-vitro data on tissues that normally have limited regeneration potential and where you can’t just inject PRP. I would never inject Lion’s Mane into anyone, but as an oral supplement, it’s worth a try.

  2. Vince

    I enjoy your posts and have learned a lot, however I am somewhat familiar with this topic and I think you need to expand your thinking and really explore this properly for your practice and your readers.

    There are a number of questionable statements in this post, specifically:

    – Most regenerative peptides (I believe all but GHRP6) are available by prescription from the Tailor Made compounding pharmacy, and many of the Growth Hormone secretagogues are available from other compounding pharmacies, all of which are FDA-approved facilities

    – The main educational body for most peptides is the International Peptide Society and while I have not taken their programs, I understand they are quite comprehensive. As with any therapy, profiteers will emerge, however that is no reason to highlight a potentially shady operation and ignore well-respected ones

    – Thymosin Beta 4, for example, is at least as well-known as BPC-157 for general tissue repair and there are a number of studies on it for various conditions that are listed on the website for the company ReGeneRx (RGRX) which is developing various treatments using it.
    – Tesamorelin and Thymosin Alpha 1 are both available as prescription drugs (Egrifta and ZADXIN) and have many years of use and experience behind them.

    – The safety profile of well-manufactured peptides (excluding insulin) is generally believed to be far better that many more well-known compounds such as statins, acetaminophen, proton pump inhibitors and many “mainstream” compounds. There is a general belief in the peptide community that the only peptide you can really hurt yourself with in the short term is insulin.

    A more fundamental issue however is, if one is going to go to the much larger expense of PRP and/or Stem Cells, or any invasive treatment, how does someone maximize their overall healing/repair ecosystem to maximize the overall chance of success. For example, my understanding is it is well-established that high-normal (or greater) Growth Hormone levels, at least for a moderate period of time, are very supportive of healing and repair, which raises the question of why you would not want to ensure, potentially via secretagogues, that a patient’s GH (to cite just one example) is optimized. As Dr. Seeds, head of the International Peptide Society and also a Stem Cell practitioner has said, injecting stem cells into a patient with a poor healing environment, is like planting seeds in sand, and regenerative peptides are a big part of improving the healing ecosystem.

    Finally, as we’ve seen with the recent HCQ debacle, making decisions based substantially on studies, especially when what is being studied is a competitor to more profitable treatments, is not realistic. Even if good studies were attempted, there are so many variables (hormones, peptides, stem cells, PRP, patient-specific factors, etc.) that it would be very difficult to tease out a close approximation of what compound is doing what. Additionally, patients need to make decisions today and there is no guarantee that good studies will ever be done, let alone on the time-frame everyone over about 40 will need them.

    The bottom line is that anyone walking into your clinics who has done their homework is going to have a holistic view of healing, and a big part of that is driven by peptides and other growth factors, so if your team is not knowledgeable in the topic, patients are going to have to find someone else to cover that part of their treatment plan. At a minimum it would be good to know which, if any peptides or other treatments could conflict with PRP or Stem Cells to that at least people including other factors are not likely to create a problem.

    1. Chris Centeno, MD Post author

      Vince, if the peptide is an FDA approved medication, it can be compounded for injection or oral use (if applicable). If it’s not, compounding for injection is illegal. For example, there are GH substitutes that can be legally used. The fact that a physician can write a script to a compounding pharmacy doesn’t make it legal.
      My focus here was on BPC-157 and it’s in-vitro effects on tenocytes which is unimpressive. That’s an area of science I’m published in, if you have any publications on the effects of GFs on tenocytes, please post.
      Without any humans trials, the safety data is unknown, There are NO human trials performed with BPC-157.
      We tested the idea of manipulating hormones with human bone marrow and it didn’t help any measurable property of the bone marrow MSCs. In fact, it made them worse.
      Dr. Seeds has no expertise in stem cells. If you can find any publications of his in this area, please post. He would have taken a stem cell course from someone who learned from someone who learned from someone who learned from us.
      My patients trust me to understand the risk and benefits of all possible treatments. Just because someone can sell it and post a few in-vitro or animal studies doesn’t make it something I want to add. For BPC-157 in tendons, the benefit is mediocre and the risk in humans is unknown. Hence, that calculus is a total non-starter.

  3. Dane

    What about AOD9604? Sounds like it has potential for OA, but unfortunately all I can find is a single study in rabbits: https://pubmed.ncbi.nlm.nih.gov/26275694/

    1. Chris Centeno, MD Post author

      Yes, lots of stuff works on rabbit cartilage that doesn’t work on humans.

  4. spectre labs

    Very informative

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