Peptides Are Trending…Here’s Why I Don’t Recommend Them.

By: Mehdia Amini, MD

As an endocrinologist, I am asked about peptides all the time: BPC-157 for recovery. GHK-Cu for skin and hair. Ipamorelin for body composition. Melanotan II for tanning. MOTS-c for metabolism and longevity.

They are often described as natural, regenerative, or substances that simply “work with your body’s own biology.” That language sounds reassuring. It shouldn’t be. A substance does not become safe because it is natural or resembles something naturally produced by the human body. Insulin is natural. Steroid hormone is natural. Growth hormone is natural. Thyroid hormone is natural. I prescribe all of them. And every one of them can cause significant harm when used inappropriately. That is because these molecules are not passive. They change cellular signaling, metabolism, growth and physiology.

Peptides Aren’t the Problem. Unproven Peptide Therapy Is.

Some of the most important medications in modern medicine are peptides or peptide-based drugs. I have no objection to peptide medications.

What I do not recommend is the rapidly expanding market of unapproved peptides being used for anti-aging, recovery, body composition, skin rejuvenation and “optimization” without the level of clinical evidence we normally require before exposing patients to a drug. That distinction matters.

When a medication enters routine medical practice, it generally comes after years of scientific development: laboratory research, preclinical testing, Phase 1 studies, Phase 2 studies, large Phase 3 clinical trials, regulatory review and then continued safety monitoring after approval.

The FDA notes that clinical trials alone can take approximately six years, and the process examines not only whether a drug works, but its dosing, adverse effects, manufacturing and overall risk-benefit profile.

Consider GLP-1 medications.

Today, drugs such as semaglutide and tirzepatide are widely prescribed. The biology of GLP-1 has been studied for decades. Individual medications then underwent extensive clinical development. In the STEP 1 trial alone, 1,961 adults were randomized to semaglutide or placebo for 68 weeks. SURMOUNT-1 studied tirzepatide in 2,539 adults for 72 weeks. And the SELECT cardiovascular outcomes trial followed 17,604 patients for approximately three years to determine whether semaglutide actually reduced major cardiovascular events, not simply whether it caused weight loss.

That is the standard I am accustomed to in medicine. It does not make medications risk-free. It means we have actual data with which to discuss the benefits, risks and uncertainties.

For many wellness peptides, we are nowhere close to that level of evidence. The marketing has moved far faster than the science.

In fact, the FDA currently identifies a number of peptides popular in wellness medicine as substances that may present significant safety risks. Let’s look at a few examples.

BPC-157: When popularity gets far ahead of evidence.

BPC-157 is now marketed for tendon injuries, muscle recovery, gastrointestinal health, inflammation and tissue repair. You could easily encounter it online and assume that we have a substantial body of human clinical research supporting those claims. We do not.

A recent review of published literature found fewer than 30 total participants across three published human studies, none of which was a randomized controlled clinical trial capable of establishing efficacy. One frequently cited human safety study included only TWO participants.

Two people cannot tell me whether a treatment is safe for thousands of patients. They cannot tell me what happens after years of exposure. And they certainly cannot establish that BPC-157 safely improves recovery, healing or longevity.

The FDA has also scrutinized BPC-157 used in compounding and has identified important unresolved issues regarding its safety and manufacturing quality.

So when someone asks me whether I recommend BPC-157 for recovery, my answer is straightforward: No. The human evidence is not there. A promising mechanism, an animal study or a collection of testimonials is not a substitute for clinical trials.

Melanotan II: Here We Already Have Warning Signals

Melanotan II deserves even greater caution. It is a synthetic analogue of alpha-melanocyte-stimulating hormone. In other words, it deliberately stimulates melanocytes, the pigment-producing cells in the skin, to create a tan.

And unlike some peptides for which the concern is primarily a lack of data, Melanotan II already has published safety signals.

Medical literature has described new and rapidly changing atypical moles following Melanotan exposure, as well as new cases of melanoma occurring in temporal association with its use.

The FDA specifically identifies Melanotan II among substances that may present significant safety risks when used in compounding and cites published reports of serious adverse events, including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxicity and priapism.

Case reports cannot prove that Melanotan caused an individual melanoma.

But from a clinical standpoint, I have an unapproved compound designed to stimulate melanocytes, published reports of significant melanocytic changes and melanoma, and an absence of reassuring long-term safety data. There is no compelling medical reason for me to recommend that exposure to a healthy patient for a cosmetic tan.

GHK-Cu and the “Glow” Peptides

GHK-Cu is promoted for collagen production, skin rejuvenation, wound healing and hair growth.

The biology is interesting. But interesting biology is not the same as clinical medicine.

A laboratory study showing that a compound influences collagen, wound healing or gene expression does not tell us whether repeated injections improve meaningful outcomes in humans, or what repeated exposure may do five or ten years later.

The FDA has identified injectable GHK-Cu among peptide substances for which safety information is limited and has raised concerns related to the behavior and quality of the peptide when formulated for injection.

Growth-Hormone Peptides Concern Me Even More

As an endocrinologist, I am particularly cautious about peptides designed to manipulate the growth hormone–IGF-1 pathway.

Compounds such as ipamorelin and other growth-hormone secretagogues are promoted for muscle gain, fat loss, recovery and anti-aging. But growth hormone is not an anti-aging supplement. It is a powerful endocrine signal.

Growth hormone and IGF-1 influence glucose metabolism, fluid balance, tissue growth and cellular proliferation. We know from patients with chronic growth-hormone excess. – acromegaly - that excessive signaling can be associated with insulin resistance and diabetes, sleep apnea, cardiovascular complications and abnormal tissue growth.

That does not mean taking a growth-hormone secretagogue recreates acromegaly. It means that deliberately manipulating this pathway in healthy people deserves serious clinical evidence.

Can Peptides Cause Cancer?

“Peptides” are not one drug, so there cannot be one answer. But some of the pathways targeted by wellness peptides involve cellular growth, angiogenesis, tissue repair, melanocyte stimulation or growth-factor signaling. These pathways have normal physiological roles. They also intersect with pathways involved in tumor biology. That does not establish that every peptide causes cancer. It establishes that long-term safety studies are needed before we chronically manipulate these pathways in healthy people.

For many of these products, those studies simply do not exist. That absence of evidence is not reassurance. It is an unanswered safety question.

“But It Comes From a Compounding Pharmacy”

Compounding has an important and legitimate role in medicine. Some patients genuinely need formulations that are not commercially available.

But compounded does not mean FDA-approved. Compounded drugs do not undergo the same FDA premarket review for safety, effectiveness and manufacturing quality as FDA-approved medications. With injectable peptides, that distinction matters because the final product also raises questions about potency, stability, contamination and consistency, not merely whether the molecule itself has an interesting mechanism. A compounding pharmacy can prepare a drug. That does not create clinical evidence for it.

My Standard as an Endocrinologist

My specialty is built around powerful biological signals: insulin, thyroid hormone, cortisol, estrogen, testosterone, growth hormone and many others. I know how profoundly altering these pathways can affect the human body. So “natural” is not my standard. “Promising” is not my standard. And “we haven’t proven that it is dangerous” is certainly not my standard.

Before I recommend an elective therapy to a healthy patient, I want evidence that it works, a dose supported by human studies, a reasonably characterized safety profile and enough clinical experience to understand what we are exposing that patient to.

That is the standard we apply to medicine.

There may eventually be legitimate therapeutic roles for some of the compounds being marketed today. If strong clinical trials establish those roles, medicine will incorporate them, as it has with countless therapies before them. But as providers, we should follow the evidence, not get ahead of it, and right now, for many of the peptides being sold for anti-aging, recovery and “optimization,” the evidence has not caught up with the enthusiasm.

Until it does, I don’t recommend them.

To learn more, call, text, or click to schedule online with me, Dr. Mehdia Amini, board certified endocrinologist.