Ingredient review
PEG-105 Behenyl Propylenediamine
INCI: PEG-105 BEHENYL PROPYLENEDIAMINE
A gentle synthetic conditioning agent that helps detangle hair and improve product feel without heavy buildup.
In plain English
PEG-105 Behenyl Propylenediamine is a man-made ingredient that helps condition hair and skin. It works by coating the surface of hair strands to reduce friction, making hair easier to comb and softer to the touch. In skincare, it can help products spread smoothly and leave a silky feel. The 'PEG' part means it's water-soluble, so it rinses off easily without leaving a greasy residue.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-105 Behenyl Propylenediamine is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging PEG-105 Behenyl Propylenediamine.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic polymer derived from behenic acid (a fatty acid from rapeseed oil) and propylenediamine, modified with polyethylene glycol (PEG) chains to make it water-soluble and mild.
How it works
It has both water-loving and oil-loving parts, allowing it to adsorb onto hair or skin surfaces. The positively charged part binds to negatively charged hair or skin, reducing static and friction, while the PEG chains provide water solubility for easy rinsing.
Pros
Gentle detangling
Reduces hair breakage by making combing easier, especially for fine or chemically treated hair.
Non-greasy feel
Rinses cleanly without heavy buildup, so hair stays soft but not weighed down.
Cons and cautions
Synthetic origin
Not suitable for those seeking 100% natural or plant-based formulations.
Potential impurities
PEG compounds can be contaminated with 1,4-dioxane or ethylene oxide during manufacturing, though reputable brands purify them.
Best for
- People with dry or damaged hair seeking extra conditioning
- Those who prefer lightweight, non-greasy conditioners
Use caution if
- Individuals with known sensitivity to PEG compounds or synthetic surfactants
Usage tips
Safety summary
PEG-105 Behenyl Propylenediamine is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential. The main safety consideration is the purity of the PEG component, which reputable manufacturers control through strict quality processes.
Research notes
Limited peer-reviewed studies specifically on this ingredient, but it is structurally similar to other well-studied conditioning agents. Safety assessments by industry panels (e.g., CIR) for related PEG compounds support its safe use in rinse-off and leave-on products.
Common label clues
- Typical concentration
- 0.5% to 3%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. The EU CosIng database lists it as a surfactant and conditioning agent with no specific restrictions at typical use levels.
- Common uses
- Conditioners, Hair masks, Leave-in treatments, Body washes
- Environmental note
- As a synthetic PEG compound, it may not be readily biodegradable. However, its low use concentration and water solubility reduce persistence concerns.
Good to know
- The 'behenyl' part comes from behenic acid, a fatty acid found in rapeseed oil, but the final ingredient is fully synthetic.
- It is often used alongside other conditioning agents to balance slip and rinseability.
Common questions
What is PEG-105 Behenyl Propylenediamine in beauty products?
PEG-105 Behenyl Propylenediamine is a man-made ingredient that helps condition hair and skin. It works by coating the surface of hair strands to reduce friction, making hair easier to comb and softer to the touch. In skincare, it can help products spread smoothly and leave a silky feel. The 'PEG' part means it's water-soluble, so it rinses off easily without leaving a greasy residue.
What does PEG-105 Behenyl Propylenediamine do in a beauty product?
It has both water-loving and oil-loving parts, allowing it to adsorb onto hair or skin surfaces. The positively charged part binds to negatively charged hair or skin, reducing static and friction, while the PEG chains provide water solubility for easy rinsing.
Is PEG-105 Behenyl Propylenediamine safe for most people?
PEG-105 Behenyl Propylenediamine is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential. The main safety consideration is the purity of the PEG component, which reputable manufacturers control through strict quality processes.
Who should be careful with PEG-105 Behenyl Propylenediamine?
Individuals with known sensitivity to PEG compounds or synthetic surfactants
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.