Peg-105 Behenyl Propylenediamine: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: July 1, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Peg-105 Behenyl Propylenediamine?

Peg-105 Behenyl Propylenediamine is a synthetic ingredient made by attaching about 105 units of ethylene oxide to behenyl propylenediamine, a fatty amine derived from behenic acid found in plants such as rapeseed. The process, known as ethoxylation, turns the waxy fatty amine into a water-friendly compound that mixes well with both oils and water. First explored in the late twentieth century as chemists searched for better antistatic agents, it soon found a place in personal care products because it could calm flyaway hair without leaving a heavy feel. Today manufacturers include it in rinse-off and leave-in hair conditioners, smoothing creams, anti frizz serums, hair masks and some styling sprays where static control is needed.

Peg-105 Behenyl Propylenediamine’s Cosmetic Benefits/Uses

The main role of Peg-105 Behenyl Propylenediamine in cosmetics is as an antistatic agent. By reducing the build-up of electrical charge on hair fibers it keeps strands from clinging together or sticking out, making hair easier to comb and style while giving it a smoother, sleeker look.

Who Can Use Peg-105 Behenyl Propylenediamine

This antistatic ingredient is considered gentle enough for all skin and hair types. Its lightweight, water-soluble nature means it will not weigh down fine hair or leave a greasy film on oily scalps, yet it provides enough slip for coarser textures. Because the raw material is derived from plant-sourced behenic acid, products formulated with Peg-105 Behenyl Propylenediamine are generally suitable for vegans and vegetarians, provided the rest of the formula is free from animal-derived additives.

Current safety data show no specific concerns for women who are pregnant or breastfeeding when the ingredient is used as intended in rinse-off or leave-in hair care. That said, this is not medical advice and anyone who is expecting or nursing should run any new cosmetic product past their doctor just to be safe.

The molecule does not make skin or hair more sensitive to sunlight, so it will not increase the risk of sunburn. It is also safe for color-treated hair because it does not strip dyes or alter hair porosity.

Potential Side Effects/Adverse Reactions

Side effects from topical use of Peg-105 Behenyl Propylenediamine can vary from person to person. The issues listed below are possible outcomes, not the typical experience. When manufacturers use the ingredient at appropriate concentrations most people will not notice any problems.

  • Mild scalp or skin irritation, especially on already inflamed or broken skin
  • Allergic contact dermatitis in individuals sensitive to amine compounds
  • Eye irritation if product accidentally gets into the eyes during application or rinsing
  • Product build-up and limp hair when very high levels are used or when rinsing is inadequate

If you experience any of these reactions stop using the product and consult a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 1/5. Peg-105 Behenyl Propylenediamine is highly ethoxylated, making it readily soluble in water so it rinses away without leaving heavy residues that can block pores. The fatty portion is balanced by the large PEG chain which keeps the molecule dispersed rather than forming the dense films linked with breakouts.

Because of its low likelihood of clogging pores it is generally considered suitable for acne-prone or oily skin and scalp types.

As with most PEG-based ingredients the final formula matters; when paired with heavy oils or waxes overall pore-clogging potential can rise, so the full ingredient list is worth a glance.

Summary

Peg-105 Behenyl Propylenediamine is used in personal care mostly for its antistatic function. The long behenyl tail anchors to the hair shaft while the 105 units of ethylene oxide attract moisture, allowing the molecule to dissipate electrical charge and keep strands smooth and manageable.

It appears in a modest range of conditioners, leave-ins and styling sprays rather than across every product line, making it a useful yet niche choice for formulators who want lightweight static control.

Current safety reviews show it to be low risk for irritation or sensitization when used as directed. As with any cosmetic ingredient doing a quick patch test with a new product is a smart move to ensure personal compatibility.

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