Polyaminopropyl Biguanide

What is Polyaminopropyl Biguanide?

Polyaminopropyl Biguanide, also known as PHMB, is a synthetic cationic polymer composed of repeating biguanide units linked by hexamethylene chains. Developed as a broad-spectrum antimicrobial agent, it belongs to the family of polymeric biguanides originally used in medical and industrial disinfection. In cosmetics, it serves primarily as a preservative in water-based formulations such as lotions, creams, shampoos, and eye care products. Its mechanism involves electrostatic attraction to the negatively charged surfaces of microbial cells, where it penetrates and disrupts cell membranes, inhibiting growth of bacteria, fungi, and yeasts. Effective at low concentrations, it remains stable across a wide pH range and is compatible with most cosmetic ingredients, ensuring product safety without significantly altering texture or performance.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1-2 View on EWG →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Preservative
Protects the product from microbial contamination during storage and use, helping maintain safety, stability, and shelf life.

Benefits

Prevents microbial contamination to extend product shelf life.

Provides broad-spectrum protection against bacteria, yeast, and mold.

Compatible with various formulations for reliable preservation.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals using water-based skincare products like lotions and cleansers.
People with known sensitivity to biguanide compounds.
Consumers seeking stable, long-lasting cosmetic formulations.
Those experiencing contact dermatitis from similar antimicrobials.
Users of eye-area or sensitive-area products requiring gentle preservation.
Individuals with highly reactive skin prone to preservative allergies.

Safety Notes

  • Rated low hazard by major cosmetic safety databases at typical use levels.
  • Follow product instructions and discontinue use if irritation occurs.

Frequently Asked Questions about Polyaminopropyl Biguanide

What is Polyaminopropyl Biguanide used for in cosmetics?

It acts as a preservative to protect products from microbial growth, ensuring safety and stability.

Is it safe for sensitive skin?

Generally low irritation risk at standard levels, but patch test for personal tolerance.

Does it clog pores?

Rated non-comedogenic with zero comedogenic potential.