Medical Literature Library

Understanding C. acnes: It’s Not the Villain You Think It Is

For a long time, the bacterial species Cutibacterium acnes (also known as C. acnes) has been blamed as the cause of acne. However, recent studies have shown that not all strains of this microbe are harmful. In fact, some strains can be highly beneficial, making it essential to have these health-related strains on our skin. And research has shown that it is not just the presence of any particular strain(s) of C. acnes that leads to skin health or acne. Rather, it is important to consider what other microbes are involved and how the skin and immune system respond to the presence of all these microbes and their metabolites. Environment, age, skincare regimen, other microbes, all these factors can influence the skin's microbiome and the presence of blemishes. When we compare skin samples, we often find that those who experience breakouts often have the same bacterial strains as those with clear skin.

In this case, we find that the old causation vs. correlation debate is still active as researchers and dermatologists strive to understand what causes acne. In fact, many studies have shown that acneic skin has relatively less C. acnes and more presence of other bacteria species, including an increase of Staphylococcus epidermidis, especially in the hair follicles where they can produce biofilms that can contribute to the blockage of the pore. Therefore, it is vital to understand the strains of C. acnes that are beneficial and those that are detrimental to skin health.


Why We Need C. acnes

Skincare professionals need to understand the truth about C. acnes to curate protective strains rather than try to eradicate them. In fact, skin biome care should be the first port of call for any dermatologist, especially when dealing with patients that have sensitive or acneic skins. Why? Well, consider this: C. acnes comprise most skin flora, so understanding how to cultivate protective strains is vital.


Surprising Benefits of C. acnes

Beyond the ability to prevent or inhibit skin pathogens, protective strains of C. acnes also produce several other beneficial skin elements.


  1. Protective strains of C. acnes bring several key benefits to the skin. Propionic acid is a targeted antimicrobial that actively suppresses the growth of pathogens like S. aureus, including MRSA. It also has broad-spectrum antimicrobial activity against Escherichia coli and Candida albicans.
  2. In addition, RoxP is a potent antioxidant that is specific to C. acnes. Surprisingly, research has suggested that it might even be as powerful as Vitamin C or Vitamin E.
  3. Disease-associated strains of C. acnes are known for producing porphyrins, which contribute to the development of acne. In contrast, protective strains of C. acnes have reduced porphyrin production, making them less likely to contribute to the development of acne.


For dermatologists and skincare professionals, it should be clear that not all strains of C. acnes are harmful and protective C. acnes strains are, in fact, highly necessary for skin health. As we treat patients and seek to know more about the causes of acne, it’s crucial that we understand the different species and subspecies of C. acnes and how they interact with other microbes and the immune system.


Thomas Hitchcock, Ph.D., is the Chief Science Officer for Crown Laboratories, where he oversees clinical development, medical affairs, biological sciences, product development, and research and development for the privately held, fully integrated global company dedicated to developing and providing a diverse portfolio of safe and effective scientific solutions for life-long healthy skin. Dr. Hitchcock is a formally trained scientist with expertise in molecular genetics, microbiology, and dermatology. He has 20+ years of research experience, including basic science, preclinical, and clinical research across several therapeutic areas. He has also been issued patents on his inventions in aesthetic medicine, dermatology, and microbiology. Dr. Hitchcock lectures and presents his research internationally. His work has been published in notable journals such as the “Journal of Biological Chemistry,” “Annals of the New York Academy of Sciences,” “Clinics in Plastic Surgery and Nature,” “Journal of Cosmetic Dermatology,” “Aesthetics Surgery Journal,” “Nucleic Acid Research,” and “Cell Transplantation.”