Small-molecule agents make up the majority of medicines in use today. These are drugs that treat and prevent diseases by modulating biochemical processes. Examples of small-molecule drugs are aspirin and diphenhydramine, which are common in pharmaceutical cabinets. Small-molecule drugs are dominant in treating many human diseases owing to their diverse mechanisms of action. Small-molecule drugs are typically low in molecular weight, giving them the advantage as effective enzyme inhibitors, therapeutics, and/or allosteric modifiers [1,3]. They also have unique physiochemical properties that target extracellular proteins, intracellular receptors, the central nervous system and nuclei.

Small-molecule drugs pose a significant therapeutic potential. They have a great advantage because of their relatively straightforward delivery [2]. The small molecule will target a larger molecule such as an enzyme and alter the activity of it to produce a therapeutic benefit [2].

Small molecule drugs are used in diverse therapeutic ways, including central nervous system, metabolic, orthopedic, oncology, immunology, respiratory, and many other areas [3].

Main Benefits of Small Molecule Drugs

Small molecule drugs have stood as a pillar in modern medicine for a long time. Here are some reasons why:

Relatively Simple to Manufacture

The manufacture and scaling of the production of small molecule drugs are relatively simple, and it is easier to ensure quality with small molecule drugs. The production methods are well established in most cases [5]. They can also be less expensive to manufacture than a lot of drugs.

The Options are Endless

With millions of small molecule drugs that can be made, the possibilities are endless when it comes to developing new drugs that can solve various health problems.

Administration Routes are Flexible

Drugs made with small molecules can be made into capsules, pills, injectables, inhalable, suppositories, and other methods, which gives a large amount of flexibility for the consumer, depending on the product.

Can Be Made Generic in Many Cases

Many forms of small molecule medications can be made into generic versions, which can make them less expensive and more accessible to those that need them.

Small Molecule Drug’s Mode of Action

Ligands and Inhibitors

Small-molecule drugs are effective because of their selective nature. Due to their small size, small-molecule drugs have a few chemical parts that can engage their target. They are effective because they directly target enzymes and receptors performing biochemical reactions [4].

Allosteric Modulators

Another advantage of small-molecule drugs is that they target the receptors and enzymes of interest. The target receptors are usually tiny to medium-sized proteins, and when the compounds bind with the receptor, they reduce the activating effect and modulate the signaling. The limitations of small-molecule drugs were remedied to a great extent by the development of positive and negative allosteric modulators of G protein-coupled receptors [5]. The feature makes them more effective than conventional orthostatic ligands.

Protein-Based Therapeutics

All cellular behaviors in the human body are wholly dependent on interactions of proteins with each other. Most of the extracellular signals act by disrupting interactions of specific proteins in the cell. The advantage of protein-based small-molecule drugs is that they can dictate what the cell can do. The ability of the signal to disturb protein-protein interactions gives the drug leverage over the cell by communicating to it in a language that it understands what to do and what not to do during a specific time. The mechanism poses a significant advantage scientifically because it clearly explains the mechanisms of cell signaling, one of the most significant challenges in biological research.


It is undeniably true that small-molecule drugs effectively fight disease. The drugs have distinct features as therapeutics, and their small weight gives them an advantage over their targets. Most small-molecule drugs can be administered orally because they can pass through the membranes to reach the target, and small molecule drugs are extremely flexible in means of administration. The development of these types of drugs continue to revolutionize the medical field and methods of treatments for patients.


  1. “What Are Small-Molecule Drugs?” Smolecule,
  2. “Small Molecule.” Amgen,
  3. Vrettos, Dr. John S. “Small Molecule Therapeutics: Solubility with Permeability to Achieve Better Bioavailability.” Drug Discovery World (DDW), 20 Jan. 2021,
  4. Kim, Sung-Kun, et al. “Interactions between Small Molecule Ligands and Target Enzymes.” Frontiers in Molecular Biosciences , Frontiers, 5 Mar. 2021,
  5. Lu, Shaoyong, and Jian Zhang. “Small Molecule Allosteric Modulators of G-Protein-Coupled Receptors: Drug-Target Interactions.” Journal of Medicinal Chemistry, U.S. National Library of Medicine,