Peptides: What They Are, And Why The FDA Is Paying Attention

Key takeaways:

• The CDER recently published a draft guidance for peptide drug products.
• Peptides are increasingly being used for pharmaceuticals, supplements, and cosmetic products, but there are ongoing conversations about their potential risks. 
• While the draft guidance isn’t legally binding, it implies that there may be more regulations to come from the FDA around how peptides are manufactured, marketed, and used. 

The Center for Drug Evaluation and Research (CDER) recently published a draft guidance on clinical pharmacology and labeling considerations when developing peptide drug products.

This follows an update by the U.S. Food and Drug Administration (FDA) to Section 503A of the Food, Drug, and Cosmetic Act, which outlines the conditions under which drugs can be compounded. Specifically, the agency announced in October 2023 that several peptides would be added to Category 2, which are considered “Bulk Drug Substances that Raise Significant Safety Risks.” 

These recent developments reflect an ongoing effort by the FDA to start publishing best practices around peptide products, which have become increasingly popular in recent years — and are expected to continue doing so. (1)

So what does this mean for the future of peptide drugs and how they’re manufactured, distributed, and used?

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An overview of peptides

A peptide is a short string of amino acids — similar to proteins, but smaller — that help regulate specific cellular functions and facilitate certain biochemical processes in the body. (2) 

While peptides are made by your body and naturally found in foods, they’re also increasingly being used in synthetic forms for a variety of purposes, including: 

• Pharmaceuticals. Peptides used in pharmaceuticals, also referred to as therapeutic peptides, are a growing area of interest in the medical community. From 2016 to 2022, the FDA approved 26 peptides as drugs, leading to over 315 new peptide drugs approved in the same timeframe. Peptides are currently used in various treatments. GLP-1 agonists are also a class of peptide-based medications. (3)

• Supplements. Many peptides are sold in the form of supplements. Creatine, for instance, is a type of peptide that’s commonly used by athletes because it may help with muscle growth, offer a “quick burst” energy, and support strength. Growth-hormone releasing peptides, such as Ipamorelin and Sermorelin, are also being increasingly used to support fat loss, muscle repair, and recovery. While prescriptions are required for these peptides, they’re frequently prescribed off label. (4) 

• Skincare products. Peptides are also commonly used in cosmetic and skincare products because they may help reduce premature skin aging, support the barrier function of skin, moisturize the skin, protect it from UV damage, and contain properties that may alleviate acne and irritation. Certain peptides, such as antimicrobial peptides, can also help manage hyperpigmentation of the skin. (5, 6)

While peptides come with many potential benefits, there are precautions to take as well. It’s important to remember, for instance, that the FDA doesn’t regulate supplements and cosmetics the same way that it does medications. 

There are also ongoing conversations about potential peptide drug and hormone misuse, which can lead to critical side effects like motor paralysis, skeletal muscle damage and loss, diabetes mellitus, hypothyroidism, arterial hypertension, sweating, headaches, vomiting, and an increased risk for atherosclerosis, thrombosis, osteoporosis, and cancer. (7)

Given the potential for misuse, agencies like the World Anti-Doping Agency have banned many peptides from being used by athletes. And, as we’re seeing with the latest draft guidance from CDER, the FDA is paying closer attention to how peptides are manufactured as well. 

What does CDER’s draft guidance say? 

While the draft guidance the CDER released contains many suggestions, there are a few key ones to highlight:

• Guidance around methodology. According to the guidance, peptide drug developers should validate and report all bioanalytical methods according to FDA guidance on bioanalytical method validation and study sample analysis. This ensures that the methods used to measure drug and biomarker concentrations in biological samples are reliable and accurate.

• Suggestions for additional studies. The draft guidance also outlines suggestions for additional research, including how renal impairment, liver dysfunction, and immunogenicity are all affected by the pharmacokinetics of peptide drugs. 

• Considerations for labeling. The draft guidance also outlines what information should be included in the labeling of peptide drugs, such as pharmacokinetics and pharmacodynamics, metabolism, and any relevant immunogenicity information. This ensures that healthcare providers have the necessary information for the safe and effective use of these drugs.

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The implications of the new draft guidance for peptides

The FDA publishes guidance documents every year. The purpose of these documents is to explain how the FDA understands and interprets rules for things like how medical products should be made, labeled, promoted, and tested. (8)

While these guidance documents suggest best practices, they’re not legally binding. Meaning, manufacturers can follow different methods, as long as they’re meeting other existing legal requirements. 

Even though the draft guidance for peptides doesn’t have the power of law, it shows that the FDA is paying attention to how peptides are being manufactured and marketed. This — paired with the fact that several peptides were added to Category 2 under Section 503A of the Food, Drug, and Cosmetic Act — implies that there may be more regulations to come around use cases for peptides in the future.