Introduction to Peptides

Peptides have significantly influenced medicine since the 1920s saw the introduction of insulin therapy. Since then, the United States has approved the use of over 60 distinct peptides. While peptides have been part of the research community for decades, 2024 marks a pivotal shift with the discussion of peptides penetrating mainstream awareness. The public is increasingly aware of the benefits and potential of peptides in areas ranging from cancer risk reduction to weight loss and sexual well-being. With growing public interest, research funding is likely to increase. As of 2018, over 150 peptides were in active development, having entered human clinical trials—a number that has only grown since then. This peptides guide explores trends in peptides research and highlights some of the most popular peptides classes to know about in 2024.

 

What Are Peptides?

Peptides are shorter versions of proteins, consisting of chains of amino acids connected in a specific sequence. They are naturally occurring products that can be synthesized in laboratories and on an industrial scale. Peptides are crucial to many signaling cascades within the body, regulating energy balance, feeding behavior, sleep, fatigue, sexual arousal, brain function, and even the rate at which we heal and age. Peptides play important roles in the body’s response to exercise and injury, as well as in the aging process.

 

Trends in Peptide Research

As synthetic peptide synthesis has advanced since the 1920s, science has evolved from mimicking the structure of natural peptides to developing novel peptides that act on receptors of interest, even if they do not resemble native peptides.

Trend in Peptide Length by Decade

Over the decades, there has been a shift toward developing longer, more complex peptides. This evolution reflects the growing understanding of peptide interactions and the development of more sophisticated synthesis techniques.

Development Time and Challenges

On average, developing a peptide takes about 9.4 years, often with setbacks along the way. Peptides initially deemed unsuitable for use may be chnaged or blended with other peptides, or applied in new settings, giving them a second chance. The growing catalog of therapeutic peptides has spurred extensive research, particularly in discovering peptide-addressable targets for which no peptide has yet been developed. For instance, finding a melanocortin 4 receptor (MC4R) agonist is critical in the fight against obesity and is a focus of intense research.

Advancements in Peptide Drug Delivery

Peptide drug delivery techniques are constantly improving, making previously unstable, difficult-to-store, or complicated-to-administer peptides more attractive as potential therapeutics. This progress opens new avenues for peptide-based treatments.

 

Popular Peptide Classes in 2024

Peptides for Brain and Cognitive Health

Peptides active in the central nervous system can be categorized into those that treat dysfunction and those that enhance normal function. While many peptides span the gap between treatment and enhancement, it is useful to consider them in these terms.

• Semax and Selank: Developed in Russia, these are some of the earliest nootropics (cognitive enhancers). Selank modulates the expression of around 36 distinct genes involved in learning and reduces anxiety by acting at the GABA receptor, making it both an anxiety treatment and a cognitive enhancer. Semax boosts brain-derived neurotrophic factor (BDNF), enhancing cognition and protecting the brain from stroke and other insults.
• Other Nootropic Peptides: BPC 157, Cerebrolysin, Pinealon, Epitalon, and P21 enhance and protect cognitive health in various ways. These peptides have advanced our understanding of brain function and provided new insights into human cognition mechanisms.

Peptides for Healing

Certain peptides can regulate blood vessel growth, alter fibroblast responses, and stimulate extracellular matrix deposition, making them useful in accelerating healing and improving wound repair quality.

• BPC 157: Known for its ability to accelerate wound healing, promote blood vessel growth, and improve immune response to injury. It is of particular interest for tendon and connective tissue healing and treating gastrointestinal disorders like Crohn’s disease and ulcerative colitis.
• Other Healing Peptides: TB-500 (Thymosin Beta 4) and MGF are widely researched for their healing properties.
• GHK-Cu: A natural peptide with wound healing and anti-inflammatory effects. It suppresses free-radical damage and stimulates fibroblast activity, promoting skin health and counteracting some chemotherapy side effects.

Peptides for Longevity

Peptides have revealed that aging is, to some extent, a biological process controlled by signaling cascades that can be altered.

• Sermorelin: Often referred to as the "fountain of youth," Sermorelin is a natural growth hormone-releasing hormone agonist. It reduces scarring in the heart, improves renal function, combats dementia effects, and enhances sleep. Sermorelin is considered a potential treatment for somatopause, the decline in growth hormone with age linked to various dysfunctions in older individuals.

Peptides for Growth

Peptides for muscle growth typically stimulate the growth hormone axis, increasing growth hormone production and promoting muscle and bone growth while enhancing fat burning.

• CJC 1295: A synthetic derivative of growth hormone-releasing hormone that can increase GH release by up to tenfold.
• GHRP-2 and GHRP-6: These peptides promote GH increases by acting at the ghrelin receptor. They protect and enhance muscle structure, stimulate appetite, improve immune function, and alter sleep cycles.
• Ipamorelin: Similar to GHRP-2 and GHRP-6, it is highly selective and beneficial for bone health.
• Follistatin: A synthetic version of human follistatin that neutralizes myostatin, an enzyme that breaks down muscle protein. Research shows that eight weeks of follistatin treatment can increase muscle mass by 10%.

Peptides for Sexual Health

While drugs like Viagra and Cialis enhance sexual performance by boosting genital blood flow, peptides like m1, m2, and PT-141 operate on the melanocortin system, increasing sexual arousal in both men and women. These peptides also alter food cravings, help fight alcohol addiction, and regulate skin pigmentation.

• Melanocortin Peptides: Developed to treat erectile dysfunction, female hypoactive sexual desire disorder, and skin conditions that make sun exposure difficult.

Peptides for Weight Loss

Weight loss and targeted fat burning have become major targets of peptide research. Scientists have discovered that small shifts in certain peptide levels can profoundly impact whether the body stores or burns fat.

• AOD9604: A targeted fat-burning peptide that stimulates specific arms of the growth hormone axis. Research in rats shows it can reduce body weight by 50% in one month.
• Adipotide: Without damaging other body parts, it targets the blood supply of adipocytes, or fat cells. Adipotide can cause a 25% reduction in weight in three months by blocking blood flow to fat cells.
• Tesamorelin: Approved for treating HIV-associated lipodystrophy, this peptide can reduce adiposity by nearly 20% and improve triglyceride levels, demonstrating the potential of effective peptide research and development.

 

Conclusion

The peptide classes discussed here represent some of the most actively researched areas in the world. While this guide highlights key areas of peptide research, the literature on peptides and their potential benefits is vast. As peptide therapeutics continue to evolve, new tools and techniques will increase the pace of discovery. The future of peptide therapeutics looks promising, with ongoing research paving the way for innovative treatments.

As peptide researchers, it is essential to stay informed about these developments and contribute to the growing body of knowledge in this field. The advancements in peptide research not only enhance our understanding of biological processes but also hold the potential to revolutionize medicine and improve health outcomes worldwide.