What Are Peptides?

Peptides and proteins are both made up of amino acids that are linked together (by peptide bonds, hence the name) in long chains called polymers. The only thing that separates peptides from proteins is how big they are. While there is no absolute cutoff, peptides are made up of fewer amino acids than proteins and hence are much smaller. In general, any amino acid chain that is longer than fifty residues in length is referred to as a protein. This is because after growing beyond 50 amino acids, peptides start to fold back on themselves creating shapes and bonds that are referred to as secondary structure. Peptides are almost always linear, with minimal secondary structure (lariat loops are sometimes observed), hence the size cut off.

So, peptides are smaller, simpler versions of proteins. But saying that does not do justice to the role these biochemicals play in everyday life. Research shows that peptides are primarily signaling molecules used to alter the ebb and flow of major biological systems. Peptides influence things like immune regulation, growth hormone release, extracellular matrix production, nerve cell growth and migration, and much more. Peptides are the keys to starting and stopping major biochemical cascades and, as such, are of the utmost importance to proper biological function.

It’s important to remember that we consume peptides on a daily basis. Eggs, milk, beans, meat, oats, and wheat all contain peptides, proteins, and various other biologically active molecules. In addition, many popular supplements, energy drinks, and health foods are enriched with peptides that help to improve body composition, boost energy, and aid digestion. Examples of common peptides found in everyday products include collagen and creatine.

Peptide Classes

Peptides are generally divided into groupings based on their function. For instance, there are antibacterial peptides, vaccine peptides, and anticancer peptides. Unfortunately, these peptide categories often overlap, which makes strict categorization difficult and confusing. For instance, brain peptides and immune peptides often overlap. The same is true of skin peptides and immune peptides as well as skin peptides and tendon peptides. Categorizing peptides by where they are located is an untenable approach because they are often found in various tissues.

Another way to categorize peptides that may be more useful is to consider their major actions. In that case, it would be useful to think about healing peptides, growth peptides, longevity peptides, fat-burning peptides, anti-inflammatory peptides, and so forth. While this approach is better than the above, it is still complicated by the fact that most peptides cross category boundaries. BPC-157, for instance, is a healing peptide and an anti-inflammatory peptide.

It is important not to get caught up in categories like “brain peptide” or “healing peptide” as they often don’t capture the entirety of a peptide’s biological activity. The better way to approach them is to look at the biochemical pathways

Peptides Guide | What to Know in 2024

Peptides have played an important role in medicine starting with the advent of insulin therapy in the 1920s. Since then, more than 60+ different peptides have been approved for used in the United States. Clearly peptides have been around in the research community for some time, but 2023 marks a major shift in which discussion of peptides has penetrated the mainstream. More than ever before, the public is aware of the benefits and potential of peptides in everything from reducing cancer risk to weight loss and sexual well-being. With increased public interest, increases in research funding are sure to come. As of 2018, there were more than 150 peptides in active development that had entered human clinical trials. That number has only increased since[1]. This peptides guide looks at trends in peptides research and lists a few of the most popular peptide classes that you should know about in 2023.

What Are Peptides?

Peptides are basically shorter versions of proteins, which is to say chains of amino acids connected into a specific sequence. They are a naturally occurring product that, thanks to the miracles of modern science, can be synthesized in laboratories and on an industrial scale. Peptides, it turns out, are critical to a lot of signaling cascades within the body. They regulate energy balance, feeding behavior, sleep, fatigue, sexual arousal, brain function, and even how quickly we heal. Peptides have been shown to play important roles in the body’s response to exercise and injury. They even determine how quickly we age.

Trends in Peptide Research

As the ability to synthesize synthetic peptides has grown over the decades since the 1920s, something interesting has happened. Science has slowly but surely moved away from simply trying to mimic the structure of natural peptides, a practice which necessarily limited development to shorter peptides, and has instead focused on developing novel peptides that act on receptors of interest even if they bear no resemblance to native peptides.

Trend in peptide length by decade:

Source: Science Direct

On average, the development time for a peptide is about 9.4 years and there are often setbacks along the way. Sometimes, peptides that are rejected as unsuitable for use get a second chance when they are altered, combined with other peptides, or applied in a new setting. As the catalog of therapeutic peptides has grown, so too has the research grown with it. For instance, the rate of discovery of peptide-addressable targets for which no peptide has yet been discovered or developed has helped to spur a frenzy of research activity. For instance, development of a melanocortin 4 receptor (MC4R) agonist could be critical in the fight against obesity and is of intense research focus. Scientists have identified the receptor, now they