There’s a lot of buzz about what peptides can do for your skin, muscles and maybe even your weight. But what are they, and do they live up to the hype?
Peptides are strings of amino acids (the “building blocks” of proteins), and they’re a key part of our bodies. They have a smaller molecular structure than full proteins and can be absorbed easily by the body. Our bodies produce peptides naturally, and they can also be made in the lab. Some peptides are used in medications to treat conditions such as diabetes and multiple sclerosis. Others are marketed as anti-aging ingredients and sold in skincare products and dietary supplements.
The most common peptides are hormones and neurotransmitters, and they regulate a wide range of important bodily functions. They act as messengers that control cell growth, communication and metabolism and as catalysts that initiate various hormone and immune responses. There are many different types of peptide hormones, and they vary widely in size and shape. Some are water-soluble, while others are lipid-soluble or anchored to the cell membrane.
Insulin and the insulin-like growth factor (IGF-1) family of peptides are examples of well-studied hormones with clear physiological roles that include blood glucose regulation, weight loss, anti-inflammatory properties and cellular protection. Other peptide hormones such as GnRH, vasopressin and oxytocin play less well-defined roles in the body.
While most peptides are produced by the body, they can also be found in foods. Proteins in meat, fish, eggs and dairy are the best sources of peptides. The peptides in these foods are broken down by enzymes into amino acids, which are then absorbed by the body. Some peptides are designed to mimic the hormones in the body, and they’re often used in research, cosmetics and medicine.
In skincare, peptides are used to make the skin more resilient and firmer. They help create a stronger barrier against bacteria, UV rays and other pollutants. They’re also used to stimulate the production of collagen and elastin fibers, which reduce fine lines and wrinkles and keep skin looking smoother and younger.
Peptides have also been shown to improve gut health and boost the immune system. One of these peptides, called BP 157, is being studied for its potential to promote the growth of beneficial bacteria in the gut and protect against harmful bacteria that can cause digestive issues like bloating, gas and diarrhea.
In the lab, peptides are created by binding amino acids together in a process called solid-phase peptide synthesis (SPPS). The carboxylic groups on the amino acid chains are attached to a solid polymeric resin through which amides can be released. Various resins such as 4-methylbenzhydrylamine (HMBA), Wang resin, 2-chlorotrityl chloride (2-CTC) and Merrifield resin can be used to introduce amides or free carboxylic groups to the C-terminal ends of the amino acids. The resulting peptides can be further modified by chemical and biological methods to achieve desired functionality. The modified peptides can then be isolated and purified for use in medical and cosmetic applications.