Peptides are made up of α-amino acids linked together by peptide bonds. It’s also a proteolysis intermediate product.
The number of amino acids in a peptide is usually between two and nine. Peptides are given various names depending on the number of amino acids in them: a dipeptide is a compound produced by the dehydration and condensation of two amino acid molecules, and there are three comparison analogies. Peptides, tetrapeptides, and pentapeptides are examples of peptides. Polypeptides are peptides made up of three or more amino acid molecules. They have a molecular weight under 10,000 Da and can move across a semi-permeable membrane without being precipitated by trichloroacetic acid or ammonium sulfate. Peptides composed of 2-10 amino acids are referred to as oligopeptides (small molecule peptides); peptides composed of 10-50 amino acids are referred to as polypeptides; and peptides composed of more than 50 amino acids are referred to as proteins, according to the literature. Polypeptides, commonly known as peptides, were first found in the twentieth century.

The Birth of Peptide
According to Suresh Babu (2011), Emil Fischer (with E Fourneau) published an article in 1901 describing the partial hydrolysis of the diketopiperazine of glycine in the laboratory to produce the first dipeptide, glycylglycine. Fischer coined the term peptides (from pepsis = digestion or peptones = digestion products of proteins) at the 14th conference of German scientists and physicians on September 22, 1902 in Karlsbad. Peptides are tiny molecules that mimic proteins except that they have a higher molecular weight. Proteins are described as molecules containing 50 or more amino acids, whereas peptides are defined as molecules containing less amino acids. According to Fischer, the chemical processing of peptides entails the replication or perhaps recreation of Nature’s molecules. Fischer gave an illuminating analysis of his school’s efforts in peptide synthesis five years later, in January 1906, at the Deutsche Chemische Gesellschaft in Berlin, in his famed lecture, which sparked speculations about the eventual availability of synthetic living matter. He finally succeeded in synthesizing L-Leu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu-(Gly)3-LLeu- Fischer used the first urethane form protecting ethoxycarbonyl group (C2H5OCO) in the hopes of separating it from the amino nitrogen by reaction with mild alkali due to the lack of a process for removing the benzoyl or acetyl groups. By preparing amino acid chloride hydrochlorides, he was able to conduct peptide coupling at the carboxyl group.
In the 1930s, yeast extracts were used in wound-healing medicines. They enhanced collagen synthesis, increased blood vessel growth, and increased cellular oxygen consumption.
Later studies revealed that these results were caused by proteins (peptides) isolated from the yeast.
The peptides were discovered to have a low molecular weight and the capacity to up-regulate skin-healing cellular growth factors.
More than 500 proteins have been produced from yeast as of today (Saccharomyces cerevisiae). Casein, cotton, barley, maize, whey, and a variety of plants are also sources of peptides.

Peptide Effects
First, you can check Byrdie there about polypeptide.
Peptides, in general, can increase the water content of the skin, increase skin thickness, and minimize fine lines by promoting collagen, elastic fiber, and hyaluronic acid proliferation.
Peptides have anti-aging and anti-wrinkle properties in skin care. The two well-established are pentapeptide and hexapeptide; pentapeptide can prevent metalloproteinase and promote collagen regeneration; hexapeptide, also known as class Botulinum toxin, can obstruct nerve and muscle conduction. Three peptides are used for anti-aging, and other combinations of peptides are used to trigger the hormone estrogen, improve sagging skin, and reduce the appearance of eye bags. Since peptides have a 28-day active time, products containing peptides must be used consistently for 28 days to obtain the best results.
For different types of peptides, they have different effects, in general there is four types of peptides,
- Signal peptides
- Neurotransmitting-Inhibitor Peptides
- Enzyme Inhibitor Peptides
- Carrier Peptides
For the details of each types of peptide, we will talk about them in details in the near future and paste the link here, I am looking forward to write these peptides as well!
Reference List
Suresh Babu, V., 2011. One hundred years of peptide chemistry. Resonance, 16(7), pp.640-647.