Understanding Peptides and Their Function in Medicine and Biology

What Are Peptides?

Peptides are small chains of amino acids—the building blocks that make up proteins in your body. While proteins can contain hundreds or thousands of amino acids, peptides are typically much shorter, containing anywhere from 2 to 50 amino acids linked together. Think of them as short amino acid chains ACS Publications that can communicate specific instructions to your cells.

Your body naturally produces many different peptides that serve as hormones, signaling molecules, and part of your immune system. For example, insulin—a hormone that helps regulate blood sugar—is a peptide. Scientists have learned to create synthetic versions of these natural peptides, as well as design entirely new ones, to treat various medical conditions.

Why Peptides Matter in Modern Medicine

Peptide therapies are currently employed in managing and diagnosing diverse medical conditions, including diabetes mellitus, weight loss, oncology, and rare diseases Nature. What makes peptides particularly valuable as medications is their ability to demonstrate high receptor specificity, which minimizes off-target effects, along with enhanced therapeutic efficacy, biodegradability, low toxicity, and minimal immunogenicity ACS Publications.

In simpler terms, peptide medications can target specific cells or processes in your body with remarkable precision, much like a key fitting into a specific lock. This targeting ability often results in fewer side effects compared to traditional medications that may affect multiple body systems.

The peptide drug market has grown substantially. Sales statistics for the first half of 2023 showed semaglutide led global sales of peptide drugs at $90.217 billion Nature, demonstrating both their effectiveness and widespread adoption in clinical practice.

Current Medical Uses of Peptides

Diabetes and Weight Management

The most well-known peptide medications today are the GLP-1 (glucagon-like peptide-1) receptor agonists used for type 2 diabetes and obesity. The FDA approved the first GLP-1 agonist (exenatide) in 2005 Cleveland Clinic, and this class of medications has since transformed diabetes care.

These medications work by mimicking a natural hormone your intestine produces. Upon activation of the GLP-1 receptor, semaglutide enhances glucose-dependent insulin secretion, slows gastric emptying, increases pancreatic β-cell proliferation, and reduces glucagon release, contributing to an overall reduction in appetite NCBI.

Clinical trials demonstrate the superiority of GLP-1 receptor agonists to other antihyperglycemic drugs in improving glycemic efficacy, reducing weight and blood pressure, and having a cardioprotective effect, all without the risk of hypoglycemia NCBI. Currently available GLP-1 medications include liraglutide (Victoza®), semaglutide (Ozempic®, Wegovy®, Rybelsus®), dulaglutide (Trulicity®), and tirzepatide (Mounjaro®, Zepbound®).

An important milestone came when the approval of oral semaglutide (Rybelsus®) in 2019 for treating type 2 diabetes marked a significant milestone in the advancement of peptide therapeutics PubMed Central, as most peptides previously required injection.

Fighting Antibiotic-Resistant Infections

One of the most promising frontier applications of peptides is in combating bacteria that have become resistant to traditional antibiotics. Antimicrobial peptides (AMPs) are produced from synthetic and natural sources and demonstrate broad-spectrum antimicrobial activity with high specificity and low toxicity Springer.

These peptides work differently than traditional antibiotics. Rather than targeting specific bacterial processes that can mutate, many AMPs disrupt bacterial cell membranes directly, making it harder for bacteria to develop resistance. hLF1-11, a short synthetic peptide derived from the N-terminal region of human lactoferrin, shows highly effective in vivo activity against bacteria (Gram positive and negative) and fungi, including infections caused by methicillin-resistant S. aureus (MRSA), Klebsiella pneumoniae and Listeria monocytogenes PubMed Central.

Several polymyxin derivatives including SPR 206, QPX 9003, and MRX 8, along with the synthetic cyclic peptide murepavadin, are currently in clinical trials PubMed Central for treating multidrug-resistant bacterial infections.

Cancer Treatment

Peptides are being investigated extensively in cancer therapy. Clinical trials have been conducted on major peptide-based vaccines such as E75, GP2, AE37, P3, P4, P5, P7, P13, P14, and P15 ACS Publications for various types of cancer. These peptide vaccines work by training your immune system to recognize and attack cancer cells.

Additionally, CIGB-300, a peptide-based inhibitor of casein kinase 2 combined with cell-penetrating peptide, can stop phosphorylation which results in the death of cervical and non-small cell lung cancer cells ACS Publications. Other peptides are being designed to disrupt proteins that help cancer cells survive or to deliver chemotherapy drugs directly to tumor cells.

Other Medical Applications

Beyond these major areas, peptides are being developed and used for:

• Rare diseases: Many peptide therapies target specific protein deficiencies

• Cardiovascular protection: GLP-1 receptor agonists can improve left ventricular ejection fraction, myocardial contractility, coronary blood flow, cardiac output, and endothelial function while reducing infarction size Nature

• Inflammatory conditions: Certain peptides can modulate immune responses

• Wound healing: Some peptides promote tissue repair

• Bone health: Peptides like teriparatide treat osteoporosis
  

How Peptide Medications Are Given

Most peptide medications are given by injection under the skin (subcutaneous injection), similar to insulin. This is because peptides are broken down by digestive enzymes if taken by mouth. GLP-1 agonists are most often injectable medications delivered in the fatty tissue just under your skin in areas like your belly, outer thighs, upper buttocks, and backs of your arms Cleveland Clinic.

However, researchers have made significant progress in developing oral formulations. The development of oral semaglutide represents a breakthrough—it's formulated with a special compound that protects it in the stomach and helps it absorb through the intestinal wall.

Depending on the medication, peptides may be given:

• Daily (like some GLP-1 medications)

• Weekly (like semaglutide and dulaglutide)

• Monthly or less frequently (for some other peptide therapies)
  

What to Expect: Benefits and Side Effects

Common Benefits

The advantages of peptide medications include:

• High specificity: They target specific receptors or cells, reducing unwanted effects on other body systems

• Effectiveness: Many show superior results compared to older medications

• Generally lower risk of drug interactions: Their specific targeting means less interference with other medications
  

Potential Side Effects

Side effects vary depending on the specific peptide medication. For GLP-1 receptor agonists, the most commonly reported include:

Nausea, diarrhea, vomiting, decreased appetite, dyspepsia, and constipation were the most commonly reported adverse events in clinical trials for liraglutide injection AJMC. These gastrointestinal effects typically improve over time as your body adjusts to the medication.

For antimicrobial peptides in development, researchers are working to minimize potential issues with stability and ensuring the peptides remain active at the site of infection.

It's important to discuss any side effects you experience with your healthcare provider, as they can often adjust dosing or provide strategies to manage symptoms.

The Future of Peptide Medicine

The field of peptide therapeutics is expanding rapidly. More than 80 peptides have reached the market, more than 150 peptides are in clinical development, and another 400-600 are in preclinical evaluation Taylor & Francis.

Researchers are working on several exciting advances:

1. Improved delivery methods: Scientists are developing better ways to give peptides orally and through other routes

2. Longer-lasting formulations: New technologies allow peptides to remain active in the body for longer periods, reducing injection frequency

3. Personalized peptide vaccines: Cancer treatments tailored to individual patients' specific tumor characteristics

4. Combination therapies: Pairing peptides with other medications for enhanced effectiveness

The integration of novel drug design and synthesis techniques, display library technology, delivery systems, bioengineering advancements, and artificial intelligence have significantly expedited the development of peptide-based drugs ACS Publications, addressing earlier limitations like rapid breakdown in the body.

Important Considerations

If your healthcare provider recommends a peptide medication:

1. Ask questions: Understand why this medication is recommended for your specific condition

2. Learn proper administration: If it's injectable, ensure you're comfortable with the technique or have support

3. Be aware of storage requirements: Many peptide medications require refrigeration

4. Report side effects: Keep your healthcare team informed about how you're responding to treatment

5. Don't stop suddenly: Always consult your provider before discontinuing peptide therapy

6. Obtain from legitimate sources: Only obtain drugs containing peptides with a prescription from a licensed healthcare provider, and obtain medicines only from state-licensed pharmacies NCBI

Conclusion

Peptide-based medications represent a significant advancement in modern medicine, offering targeted, effective treatments for conditions ranging from diabetes to infections to cancer. As research continues and new peptides enter clinical practice, these therapies will likely play an increasingly important role in personalized medicine—treatments tailored specifically to individual patients' needs.

While peptide medications may require different administration methods than traditional pills, their precision and effectiveness make them valuable tools in managing many health conditions. If you have questions about whether peptide therapy might be appropriate for your situation, discuss this with your healthcare provider, who can evaluate your specific medical needs and explain the potential benefits and risks.

Note: This information is for educational purposes and should not replace consultation with your healthcare provider. Always discuss treatment options, including risks and benefits, with qualified medical professionals before making healthcare decisions.