by Lauren Colenso-Semple, Ph.D.

I regularly point out the issues with health, nutrition, and exercise claims based exclusively on rodent data. I have posed the rhetorical question, ‘Would you take a drug tested only on rats?’ Apparently the answer is ‘Yes’ more often than I thought. This article examines the growing use of “wellness” drugs with no human safety or efficacy data.

Key Points

• Wellness clinics and influencers claim peptide drugs increase muscle mass, decrease body fat, and dramatically accelerate recovery from injury or surgery.
• Since they are not approved by the FDA, these peptides are manufactured in unregulated facilities and sold online “for research purposes only.” We know very little about the safety and efficacy of these compounds.
• The current peptide trend might be the most egregious case of scientific overreach I have ever seen.

Peptides have been popular in the “biohacking” community for several years, but now they’re in the mainstream wellness space. Influencers and wellness clinic websites present these peptides as “natural” and “gentle,” while simultaneously claiming they will dramatically increase muscle mass, decrease body fat, improve sleep, accelerate recovery, fast track healing, erase wrinkles, boost libido, and improve mood. To be clear, these peptides are drugs. Since they are not approved or regulated by the U.S. Food and Drug Administration (FDA), these drugs are sold online labeled “for research purposes only,” but wellness clinics don’t mention that part. 

What is a peptide?

It’s important to understand the distinction between peptides we produce in the body and the peptides on the internet. Peptides are “chemical messengers.” They are chains of amino acids that facilitate cellular communication for a range of physiological processes, including metabolic regulation, neurological function, and tissue repair. There are neuropeptides, like endorphins and oxytocin, and peptide hormones, like leptin and ghrelin. Generally speaking, peptides are initially synthesized as larger proteins, which are broken down into smaller chains. Endogenous peptides can be released from one organ into the bloodstream to signal to another organ (e.g. the pancreas releases glucagon, which travels to the liver with a message to increase blood sugar) or they can be secreted by cells to target nearby cells (e.g. fibroblasts release Vascular Endothelial Growth Factor [VEGF] with a message to create new blood vessels to support wound healing). Peptides act quickly; after they deliver a specific message, they are broken down by enzymes.

What is a peptide drug?

Drugs are broadly classified as small or large molecules. Small molecule drugs, like ibuprofen, are synthesized in a lab and can be ingested orally. Their low molecular weight allows them to survive digestion and move from the gut to the site of action via the blood stream and permeate through cell membranes (1). Small molecule drugs can inhibit the action of an enzyme or activate/block the activity of a receptor inside the cell. Ideally, the drugs are engineered to reach the target site without interacting with other proteins to maximize efficacy and minimize side effects, but that’s easier said than done.

Large molecule drugs, like monoclonal antibodies, are more complex and less stable; they don’t survive digestion and they can’t pass through the cell membrane (2). Thus, they typically need to be injected or delivered through an IV. Large molecule drugs can target proteins on the cell surface, which are often involved in cell communication, proteins that are secreted from the cell, like hormones, and these drugs can perform multiple simultaneous actions, making them more powerful.

Some large molecule drugs are extracted from animals or human donors. These are often referred to as naturally derived biologics (3). Others are grown in living cells, but are subsequently chemically modified. These structural tweaks can a) make a drug more resistant to enzymes that would break it down, meaning it lasts longer in the body or b) reduce the immune system’s response to the drug as a foreign substance.

Peptide drugs are “medium” sized. They typically need to be injected and they bind to receptors on the cell surface, sending a message to the cell. They can mimic the actions of a hormone or extend or block the duration of a natural signal. While endogenous peptides act quickly and are broken down by enzymes, peptide drugs are chemically synthesized to last longer (4). Endogenous GLP-1, for example, lasts for approximately two minutes before it’s broken down by enzymes. The GLP-1 drug semaglutide, the active ingredient in Ozempic and Wegovy, is engineered to allow it to circulate for days instead of minutes.

Let’s say you inject exogenous human growth hormone (GH). It targets receptors in the muscle and liver, signaling for an increased production of insulin-like growth factor (IGF-1). The system senses high GH in the bloodstream, downregulating endogenous production, causing difficulties when you stop using the drug. Further, it can lead to high blood sugar, because it opposes the actions of insulin, and users typically experience a range of unwanted side effects.

The peptide alternative is a GH secretagogue, which mimics the actions of growth hormone releasing hormone, stimulating the natural secretion of GH (5). The theory is that, in lieu of a blast of synthetic GH, the peptides signal the pituitary gland to release GH in pulses – capitalizing on the benefits without exposing oneself to the risks. Which sounds good…if it works.

What do we know about the popular peptide drugs?

CJC-1295 and Ipamorelin are two of the most popular GH secretagogues promoted by wellness clinics and influencers.

The Drug: CJC-1295 

CJC-1295 is an analogue of growth hormone releasing hormone designed to stimulate the release of GH and the secretion of IGF-1.

The Marketing Claims: Wellness clinic websites claim that CJC-1295 increases muscle mass and strength, decreases body fat, improves sleep, promotes recovery, and boosts mood.

The Science: The data demonstrating body composition changes after CJC-1295 injections are exclusively in genetically modified rodents, meaning the scientists breed a rodent without the gene for growth hormone releasing hormone. What does the human data show? A 2006 trial demonstrated that a single injection of CJC-1295 increased plasma GH concentrations for 6 days and plasma IGF-I concentrations for 9 days in humans (6). It was subsequently investigated as a treatment for lipodystrophy in HIV patients, but the trials were discontinued after a patient died of a heart attack. The effects of CJC-1295 on muscle mass, strength, body fat, sleep, recovery, or mood have never been investigated in humans.

The Drug: Ipamorelin

Ipamorelin is a ghrelin receptor agonist designed to interact with the growth hormone secretagogue receptor to stimulate the release of GH.

The Marketing Claims: Wellness clinic websites claim that Ipamorelin increases metabolism, improves sleep, enhances sex drive, erases wrinkles, increases muscle mass, and reduces body fat without diet or exercise. They recommend combining Ipamorelin with CJC-1295 to generate five times the benefits of each peptide alone.

The Science: The rodent data actually show an increase in body weight and body fat in response to Ipamorelin injections. A 1999 trial reported that infusions of Ipamorelin increased plasma GH (7). The most significant human study was a clinical trial investigating the therapeutic effect of Ipamorelin on postoperative ileus (absence of bowel function after abdominal surgery). The researchers hypothesized that the drug’s ability to mimic ghrelin would accelerate gastric emptying and promote the recovery of gastrointestinal function. Ipamorelin was well tolerated, but the drug was no more effective than a placebo. The results were published in 2014 (8) and there were no subsequent human clinical trials. The effects of Ipamorelin on metabolism, sleep, sex drive, wrinkles, muscle mass, or body fat have never been investigated in humans. There are no data on the effects of combining CJC-1295 with Ipamorelin.

The Drug: BPC-157

BPC-157 is a synthetic form of body protective compound-157, a naturally occurring peptide in gastric juices, designed to promote tissue regeneration through multiple interconnected pathways that influence angiogenesis (growth of new blood vessels), fibroblast activity (cells in connective tissue), and nitric oxide signalling (increasing blood flow, oxygen, and nutrient delivery) (9).

The Marketing Claims: Wellness clinic websites claim that BPC-157 accelerates recovery from injury or surgery, reduces inflammation, reduces pain, and supports gut health. This is sold in injectable and oral forms.

The Science: Almost everything we know about BPC-157 comes from the scientist who first isolated it. There are some pretty impressive data on the regenerative properties of BPC-157 in tendons, ligaments, muscle, and nerves. You guessed it – the data are in rodents. There are zero  human clinical trials. Trials were supposedly underway in Croatia in the early 2000s assessing the effect of BPC-157 in Ulcerative Colitis patients, but the results were never published. In 2015, a formal Phase I trial on 42 healthy volunteers was initiated to assess the safety and pharmacokinetics of oral BPC-157. The trial was marked as completed, but in 2016 they “cancelled submission of the results.” The only published human data includes a retrospective analysis of 12 patients, 7 of whom reported knee pain relief (10), and a pilot study with two participants that reported no measurable effects of a BPC-157 infusion on acute cardiac blood biomarkers (11). The effects of BPC-157 on tissue regeneration, inflammation, recovery from injury, or gut health have never been investigated in humans (12). 

Are these peptides FDA-approved?

None of these peptides are FDA-approved for therapeutic use in humans, which shouldn’t come as a surprise given the absence of human data. The FDA drug approval process (Figure 1) takes years and is required for any drug that is to be sold in the United States. After the drug is developed, it is tested in multiple animal species to determine the safety and efficacy of the compound. Next, the drug sponsor submits an Investigational New Drug application to the FDA, which includes the pre-clinical data and proposes a plan for human trials. If that plan is approved, the drug will be tested in phase 1 clinical trials (typically 20-80 participants) to assess safety, followed by phase 2 clinical trials (hundreds of participants) to assess efficacy, and phase 3 clinical trials (thousands of participants) to evaluate the safety and efficacy of the drug at different doses, in various populations, and in combination with other drugs. The vast majority of drugs don’t make it from phase 1 clinical trials to final FDA approval (13).

Approved drugs are manufactured at FDA-approved sites, which must adhere to strict regulatory standards to ensure the drug is pure, the doses are accurate, it’s packaged properly, and there are no contaminants. Since none of these peptides are approved, they are sold solely as a research chemical with disclaimers like “usage is confined to in vitro testing,” “exclusively for laboratory experimentation” or “not for use in humans.”

There are legitimate concerns about the safety of these compounds. Increasing angiogenesis is great when we want more blood flow to damaged tissue, but angiogenesis also promotes tumor growth and metastasis (14). Therapeutic peptides can also trigger an unwanted immune response. Earlier in the article I mentioned that endogenous peptides act quickly and are broken down by enzymes, so peptide drugs are chemically synthesized and tweaked to make them last longer. The downside is the immune system can flag the compound as foreign and produce antibodies that block the drug’s action or cause adverse immune reactions like anaphylaxis. Immunogenicity risk is one of the biggest challenges in peptide drug development and is assessed comprehensively during pre-clinical and clinical trials (15). 

You might be wondering why people are using these drugs. My guess is the popularity and efficacy of GLP-1s, like Semaglutide, normalized injectables. Wellness clinics started promoting “microdosing” – which has not been studied – and marketing these drugs to the masses (including those who do not need to lose weight) with claims about longevity. Peptides are marketed as “natural” – the body makes them so they must be fine, right? People aren’t aware how much we don’t know. Some believe using these drugs is similar to “off-label” drug prescriptions. There’s a key distinction: a drug prescribed for something other than its approved indication is still an approved drug that has demonstrated its safety in thousands of people. There’s no “label” for these peptides, because they aren’t approved for anything.

Next Steps

Clearly we haven’t scratched the surface so there’s a lot of work to do before I’d be comfortable using these compounds or recommending them to a loved one. Unfortunately, I think the wellness industry will continue to put the cart before the horse as they attempt to make these unapproved peptides more mainstream. I imagine we’ll see custom blends of these drugs (and others) with custom “vitality” or “rejuvenation” or “toning” brand names before we see substantial data.

Application and Takeaways

There are no human data to support the claims that these peptides will increase muscle mass, decrease body fat, improve sleep, accelerate recovery, fast track healing, erase wrinkles, boost libido, or improve mood. We don’t know if these compounds are effective or safe for short or long term use. We don’t know how to dose them in humans, because they have only been studied in animals, primarily genetically modified rodents. We don’t know if there are side effects or interactions with other drugs. Since they aren’t approved, there’s no manufacturing or regulatory oversight, so we have no clue if they are produced in sterile environments, under- or over-dosed, properly stored, appropriately labeled, or contaminated with bacteria or heavy metals. The current peptide trend might be the most egregious case of scientific overreach I have ever seen.

References

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8. Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. 2014 Dec;29(12):1527-34. 
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