What Is Peg-6 Stearylguanidine?
Peg-6 Stearylguanidine is a synthetic ingredient created by attaching roughly six units of ethylene oxide to stearylguanidine, which itself comes from stearyl alcohol, a fatty alcohol sourced from vegetable oils or animal fats. The result is a waxy, surfactant-like compound that blends the oil-loving stearyl chain with water-loving polyethylene glycol segments, letting it mix oils and water with ease.
Interest in stearylguanidine compounds began in textile and household care, where their antistatic knack helped keep fabrics from clinging. As cosmetic chemists searched for gentler, multi-tasking surfactants in the late 20th century, Peg-6 Stearylguanidine made the jump into beauty formulas thanks to its mildness and dual ability to reduce static and keep ingredients evenly dispersed.
The manufacturing process starts with hydrogenating natural stearic acid to obtain stearyl alcohol. This alcohol reacts with cyanamide to form stearylguanidine, then undergoes controlled ethoxylation, where six ethylene oxide units on average are added per molecule. Purification removes residual reactants, producing a creamy to pasty substance ready for formulation.
You are most likely to spot Peg-6 Stearylguanidine in rinse-off and leave-on hair conditioners, anti-frizz serums, detangling sprays, creamy shampoos, skin lotions that need a light non-greasy feel, wipes, makeup removers and some cream-based masks.
Peg-6 Stearylguanidine’s Cosmetic Benefits/Uses
In everyday beauty products this ingredient pulls its weight in a couple of key ways
- Antistatic – helps neutralize electrical charge on hair strands so they lie smooth, making combing easier and cutting down on flyaways
- Emulsifying – acts like a bridge between oil and water phases, giving creams, lotions and cleansing milks a stable, uniform texture that feels pleasant and stays mixed over time
Who Can Use Peg-6 Stearylguanidine
Peg-6 Stearylguanidine is generally suitable for normal, dry and oily skin because it is non greasy and helps bind water to the skin. Most combination skin types also tolerate it well. People with very sensitive or compromised skin should approach with caution as cationic surfactants can occasionally provoke stinging or redness if the skin barrier is already irritated.
Whether the ingredient fits a vegan or vegetarian lifestyle depends on the original source of the stearyl alcohol. Some manufacturers use plant derived fatty alcohol from coconut or palm while others may rely on tallow. Consumers who need a vegan or vegetarian option should look for brands that clearly state plant origin or carry a relevant certification.
The Cosmetic Ingredient Review panel has not flagged Peg-6 Stearylguanidine as a reproductive or developmental toxin so formulas containing it are generally considered low risk for pregnant or breastfeeding users. This is not medical advice and anyone who is expecting or nursing should check with a healthcare professional before introducing new personal care products.
The ingredient does not absorb UV light and is not known to cause photosensitivity. It is also odor free so it rarely interferes with fragranced products or causes scent related discomfort.
Potential Side Effects/Adverse Reactions
Side effects and reactions to the topical application of Peg-6 Stearylguanidine can vary from person to person. The following is a list of potential side effects only. When properly formulated most users will not experience these issues.
- Mild skin irritation such as redness or itching, most often on very sensitive or broken skin
- Allergic contact dermatitis in individuals already sensitized to cationic surfactants
- Eye irritation if the product accidentally gets into the eyes during use
- Product buildup on hair leading to a weighed down feel when used in very high concentrations or without adequate rinsing
If any of these reactions occur stop using the product immediately and seek medical advice if symptoms persist
Comedogenic Rating
Rating: 1 / 5
Peg-6 Stearylguanidine is largely water dispersible thanks to its polyethylene glycol segments, which prevents it from sitting in pores the way heavier oils can. Its cationic nature means it tends to bind to the surface of hair or skin then rinse away rather than migrate deep into follicles. Trace amounts of the fatty stearyl chain keep the rating from being a perfect zero, but overall the molecule is unlikely to clog pores.
Suitable for acne-prone or breakout-prone skin in most cases.
Formulas that pair this ingredient with heavy occlusive oils or waxes could shift the overall product toward the comedogenic side, so the full ingredient list still matters.
Summary
Peg-6 Stearylguanidine serves chiefly as an antistatic and emulsifying agent. The long stearyl tail anchors to oils while the short chain of ethylene oxide units attracts water, letting it bridge the two phases and stabilize creams, lotions and conditioning rinses. Its positive charge neutralizes the negative charge that builds up on hair fibers, smoothing cuticles and reducing flyaways.
It is a workhorse rather than a superstar, showing up quietly in conditioners, wipes and gentle cleansers but rarely being highlighted on the front label. Chemists appreciate its mildness and dual function even if consumers are mostly unaware of it.
Current safety data shows low irritation potential at typical use levels, no evidence of reproductive or developmental toxicity and minimal risk of pore clogging. As with any cosmetic ingredient it is smart to patch test a new product first to confirm personal compatibility.