FAQs

Peptides are short sequences of amino acids found naturally in the body, where they contribute to a range of biological functions. All products we offer are intended exclusively for laboratory research use.

No. Peptides and steroids are two entirely different classes of molecules with different chemistry, structure, and mechanism of action. Peptides are short chains of amino acids linked by peptide bonds — they are typically water-soluble and interact with receptors on the surface of the cell. Steroids, by contrast, are lipid-based compounds built around a four-ring carbon skeleton derived from cholesterol; they usually cross the cell membrane and bind to receptors inside the cell. Their regulatory classification also differs significantly. In short, a peptide is not a steroid, and calling one a version of the other is scientifically inaccurate.

Peptides sit at a useful intersection between chemistry and biology. They are large enough to carry highly specific biological information, yet small enough to be synthesized precisely in a laboratory. That combination makes them powerful tools across a wide range of research areas — including receptor binding studies, mapping of signaling pathways, development of analytical reference standards, and investigation of cellular processes such as metabolism, immune regulation, tissue maintenance, and cell communication. Their specificity and structural tunability are exactly what make peptides a central subject of modern biochemistry, pharmacology, and molecular biology research.

A polypeptide is a single, unbranched chain of amino acids joined together by peptide bonds. It is essentially a longer peptide. Shorter chains — typically between 2 and 50 amino acids — are usually called peptides, while longer chains are called polypeptides. When one or more polypeptide chains fold into a stable, functional three-dimensional structure, the result is what we call a protein. So the progression goes: amino acid → peptide → polypeptide → protein. The exact length cutoffs between these terms are not strictly defined and can vary between sources.

Hormones are typically larger molecules — often proteins or steroid compounds — that are secreted by specific endocrine glands and travel through the bloodstream to act on distant target tissues via dedicated receptors. Peptide bioregulators, by contrast, are very short sequences (usually 2 to 4 amino acids) and are studied as intracellular or nuclear-level regulators that interact more directly with chromatin and gene expression in the tissues from which they were originally isolated.

Functionally, hormones tend to coordinate large-scale, system-wide processes, while bioregulators are investigated as fine-grained, tissue-specific modulators. The two categories can overlap in the broader sense of signaling biology, but they are studied as distinct classes of molecules.

Peptides play multiple roles in tissue research. Some act as signaling molecules studied for their effects on fibroblast activity, angiogenesis, and extracellular matrix assembly. Others are investigated as modulators of inflammatory pathways relevant to tissue damage and matrix signaling. A third group serves as reference compounds in assay development and analytical workflows.

Because peptides can be synthesized with very precise control over sequence and purity, they are particularly useful in research models where specific molecular interactions need to be isolated and studied. This makes peptides a common and valuable tool across cell biology, extracellular-matrix research, and pharmacological investigation.

The melanocortin receptor system is a family of five G protein-coupled receptors designated MC1R through MC5R. Each subtype has a different tissue distribution and research-studied function: MC1R is associated with melanocyte biology and pigmentation, MC2R with adrenal cortex signaling, MC3R and MC4R with central nervous system pathways related to energy balance, and MC5R with exocrine tissues.

Research on melanocortin peptides is largely organized around which receptor subtypes a given peptide preferentially engages. This receptor selectivity is a key variable in how these compounds are studied in the laboratory.

α-MSH (alpha-melanocyte-stimulating hormone) is a 13-amino-acid peptide derived from POMC and is one of the best-studied members of the melanocortin family. It is investigated primarily in the context of MC1R signaling and pigmentation research, but it also interacts with other melanocortin receptors at varying affinities.

Synthetic analogs such as Melanotan I and Melanotan II were developed to study more stable or receptor-selective variants of the natural α-MSH sequence. These analogs retain the core structural features of α-MSH while differing in their stability and receptor preference, which makes them useful reference compounds in melanocortin-system research.

Neuropeptides are short chains of amino acids produced primarily by neurons and used as signaling molecules within the nervous system. Unlike classical neurotransmitters, which are small molecules stored in synaptic vesicles, neuropeptides are synthesized as larger precursor proteins and then enzymatically processed into their active short-chain form before being released.

Examples of widely studied neuropeptides include oxytocin, vasopressin, substance P, and neuropeptide Y. They are investigated in connection with mood, stress response, memory, pain signaling, social behavior, and a wide range of other neurobiological processes in research models.

Classical neurotransmitters such as glutamate, GABA, dopamine, and acetylcholine are small, non-peptide molecules. They are typically synthesized directly in the presynaptic terminal, stored in small clear vesicles, and released for fast point-to-point signaling across the synaptic cleft. Their action is usually short-lived and terminated by reuptake or rapid enzymatic breakdown.

Neuropeptides, by contrast, are larger, are produced from longer precursor proteins in the cell body, and are stored in dense-core vesicles. They are generally released under higher-frequency stimulation and tend to produce slower, longer-lasting, and more modulatory effects — often operating over larger spatial distances within the nervous system.

Small-molecule nootropics — such as racetams and various stimulants — are typically organic compounds with molecular weights in the low hundreds of daltons. They are usually orally bioavailable and studied for their direct interaction with discrete receptor, transporter, or enzyme targets in the central nervous system.

Peptide nootropics, by contrast, are short amino acid chains. They are generally investigated as modulators of neurotrophic signaling, stress-response systems, and neuropeptide pathways rather than as direct ligands of a single classical neurotransmitter receptor. Their structure and pharmacokinetics make them a distinct area of research compared with small-molecule nootropic compounds.

Mitochondria encode a small number of their own peptides in addition to nuclear-encoded proteins imported into the organelle. Peptides such as MOTS-c and Humanin are examples of mitochondrial-derived peptides (MDPs) that are studied as potential intracellular signaling molecules originating from the mitochondrial genome.

Additionally, some synthetic peptides — such as SS-31 — are designed to target mitochondrial membranes and interact with components of the electron transport chain environment. Together, these research threads make peptides a significant topic in mitochondrial biology investigations.

Cellular aging research examines processes such as mitochondrial dysfunction, telomere shortening, cellular senescence, chronic low-grade inflammation, and changes in gene expression over time. Cellular aging and senescence research peptides enter this research as tools for probing specific pathways — for example, mitochondrial-derived peptides for mitochondrial stress responses, or pineal-associated peptides for studies of circadian and gene-expression regulation.

By using short, well-defined peptides, researchers can target individual mechanisms within the broader hallmarks-of-aging framework in a controlled manner. This makes these peptides useful experimental probes in mechanistic studies of cellular aging and senescence.

Peptide hormones — such as insulin, glucagon, and growth hormone — are typically produced by specialized endocrine glands and act on distant target tissues as part of systemic regulation. Growth factors are usually produced by a wider variety of cell types and tend to act in a more local manner, through autocrine or paracrine signaling on nearby cells.

Another difference lies in their biological roles: peptide hormones are generally studied in the context of metabolic and endocrine regulation, while growth factors are more commonly studied in the context of development, extracellular-matrix remodeling, and proliferation. In practice, the categories overlap, especially for molecules like IGF-1 that behave in both ways.

Many vitamins serve as precursors for coenzymes that are essential in the biochemical pathways peptides interact with. For example, B-complex vitamins are precursors for coenzymes involved in amino acid metabolism, redox chemistry, and methylation pathways — all of which intersect with peptide biology. Including vitamin reference materials alongside peptides allows researchers to run more complete experiments without sourcing components from multiple suppliers.

This pairing is particularly common in metabolic, mitochondrial, and cellular aging and senescence research, where peptide signaling and vitamin-dependent coenzyme activity are often studied in parallel.

Recombinant human growth hormone is the full 191-amino-acid human GH protein, produced via recombinant DNA technology. It is essentially identical to the endogenous hormone itself. GH peptides, by contrast, are much shorter sequences — typically on the order of a few to a few dozen amino acids — that do not act as GH themselves but rather engage upstream receptors (GHRH-R or GHS-R1a) involved in the GH signaling axis.

This makes the two categories mechanistically distinct. Recombinant GH is a replacement of the hormone itself, while GH peptides are research tools for studying the regulatory machinery that controls endogenous GH release.

GHRH analogs are peptides modeled on the natural growth-hormone-releasing hormone sequence. They are studied for their ability to bind the GHRH receptor on the pituitary — the same receptor used by endogenous GHRH. Examples include Sermorelin (a GHRH 1-29 analog), Tesamorelin, and CJC-1295.

GH secretagogues are a structurally different class of peptides that act through the growth hormone secretagogue receptor (GHS-R1a), better known as the ghrelin receptor. Examples include Ipamorelin, GHRP-2, GHRP-6, and Hexarelin. The two classes engage different receptors and are therefore studied as distinct pharmacological families in research on GH signaling.

NAD+ (nicotinamide adenine dinucleotide) is a central coenzyme in cellular metabolism, involved in redox reactions and in the activity of enzymes such as sirtuins and PARPs. It is derived from niacin (vitamin B3) and is widely used in research on cellular energy metabolism, cellular aging, and mitochondrial function — areas where peptides such as MOTS-c and SS-31 are also studied.

Other B-vitamins, including B12 (cobalamin), serve as precursors for coenzymes involved in one-carbon metabolism and methylation, which are relevant to a wide range of peptide-related research. Supplying NAD+ and B-vitamins alongside peptide reference materials enables more integrated laboratory studies of these interconnected pathways.

The thymus is a small organ in the upper chest that is the primary site of T-cell maturation. Beyond this role in lymphocyte development, thymic tissue produces a number of signaling peptides — often grouped as thymic hormones or thymic factors — which are studied for their regulatory effects on immune system function.

Historically, the isolation and characterization of thymic tissue extracts led to the identification of a family of peptides that have since been synthesized and studied individually. These synthetic versions are the foundation of the thymic peptide research category today.

Thymosin alpha-1 is a single, well-characterized 28-amino-acid peptide with a defined sequence. It has been extensively studied in research on innate and adaptive immune responses and is one of the best-defined molecules in the thymic peptide category.

Thymalin, by contrast, is historically a peptide complex originally isolated from calf thymus tissue in Russian bioregulator research. It is studied as a short-peptide bioregulator associated with thymic function rather than a single defined sequence. The two are therefore studied in different research traditions, even though both are grouped under the broader thymic peptide category.