Chlorphenesin (104-29-0), chemical name is 3-(4-chlorophenoxy)propane-1,2-diol, is generally synthesized by the reaction of p-chlorophenol with propylene oxide or epichlorohydrin. It is a broad-spectrum antiseptic and antibacterial agent, which has antiseptic effect on Gram-positive bacteria, Gram-negative bacteria, yeasts and molds. It has been approved for use in cosmetics by many countries and regions such as Europe, the United States, Japan, and China. The use limit approved by most national laws and regulations is 0.3%.
Chlorphenesin was not originally used as a preservative, but as an antigen-related immunosuppressant that inhibits IgE-mediated histamine release in the pharmaceutical industry. Simply put, it is anti-allergic. As early as 1967, the pharmaceutical industry had studied the use of chlorphenesin and penicillin to inhibit allergic reactions caused by penicillin. It was not until 1997 that chlorphenesin was discovered by the French for its antiseptic and bacteriostatic effects and applied for related patents.
1. Is chlorphenesin a muscle relaxant?
The evaluation report clearly pointed out: the cosmetic ingredient chlorphenesin has no muscle-relieving effect. And it is mentioned many times in the report: Although the English abbreviation of the pharmaceutical ingredient chlorphenesin and the cosmetic ingredient chlorphenesin are both Chlorphenesin, the two should not be confused.
2. Does chlorphenesin irritate the skin?
Whether for humans or animals, chlorphenesin has no skin irritation at normal concentrations, nor is it a skin sensitizer or photosensitizer. There are only four or five articles about the reports of chlorphenesin causing skin inflammation. And there are a few cases where the chlorphenesin used is 0.5% to 1%, far exceeding the concentration used in cosmetics. In several other cases, it was only mentioned that chlorphenesin was contained in the formula, and there was no direct evidence that chlorphenesin caused dermatitis. Considering the huge use base of chlorphenesin in cosmetics, this probability is basically negligible.
3. Will chlorphenesin enter the blood?
Animal experiments have shown that some of the chlorphenesin will enter the blood after it comes in contact with the skin. Most of the absorbed chlorphenesin will be metabolized in urine, and all of it will be excreted from the body within 96 hours. But the whole process will not produce any toxic side effects.
4. Will Chlorphenescine reduce immunity?
Will not. Chlorphenesin is a reversible antigen-related immunosuppressant. First of all, chlorphenesin only plays a relevant role when combined with the designated antigen, and it does not reduce the body's own immunity, nor does it increase the infection rate of diseases. Secondly, after termination of use, the immunosuppressive effect of the designated antigen will disappear, and there will be no sustained effect.
5. What is the final conclusion of the safety assessment?
Based on the existing applications and use concentrations in the United States (wash-off 0.32%, resident type 0.30%), the FDA believes that chlorphenesin is safe as a cosmetic preservative.

Post time: Jan-05-2022