Dimethicone Peg-8 Phthalate: 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: June 27, 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 Dimethicone Peg-8 Phthalate?

Dimethicone PEG-8 Phthalate is a silicone based ingredient created by reacting dimethicone, a smooth flexible silicone, with PEG-8 and a small amount of phthalic acid. The result is a partial ester that mixes the silky feel of dimethicone with the water friendly nature of PEG. This blend helps the material stay stable in both oil and water phases, which is why formulators like it.

The compound was first explored in the late 1990s when brands were looking for lightweight silicones that could also dissolve in water based products. By adding PEG units and phthalic acid chemists found a way to keep the soft touch of dimethicone while making it easier to spread and wash off. Production starts with medical grade dimethicone. It is reacted with ethylene oxide to add eight PEG units, then a controlled amount of phthalic anhydride is introduced to form the ester bond. The finished material is filtered, tested for purity and shipped as a clear liquid.

You will most often find Dimethicone PEG-8 Phthalate in rinse off hair conditioners, leave in creams, anti-frizz serums, lightweight facial moisturizers, sheet masks and primers. Its dual nature lets it glide onto skin or hair, form a breathable film and rinse away without heavy buildup.

Dimethicone Peg-8 Phthalate’s Cosmetic Benefits/Uses

This ingredient brings several useful effects to beauty formulas

  • Hair Conditioning: Forms a thin coating on strands that smooths the cuticle, reduces friction and makes combing easier. Hair feels softer, looks shinier and is less prone to breakage
  • Skin Conditioning: Creates a light protective film that locks in moisture, leaves skin feeling silky and helps other actives spread more evenly. The film is non occlusive so skin can still breathe and it rinses clean without residue

Who Can Use Dimethicone Peg-8 Phthalate

Because it is lightweight and non greasy Dimethicone PEG-8 Phthalate generally works for all skin types. Oily and combination skin benefit from its breathable film that does not clog pores while dry and normal skin appreciate the softening moisture lock. Extremely sensitive or silicone reactive skin may still want to proceed carefully since any film-forming agent can on rare occasions trap heat or sweat and trigger redness.

The ingredient is made entirely from synthetic sources so it contains no animal derived matter which makes it suitable for vegans and vegetarians.

No studies have linked Dimethicone PEG-8 Phthalate with hormonal disruption or reproductive issues. Current safety data suggests it can be used during pregnancy or while breastfeeding but this is not medical advice and anyone who is pregnant or nursing should show the full product list to their doctor first to be safe.

Dimethicone PEG-8 Phthalate does not make skin more sensitive to sunlight and does not interfere with sunscreen filters so there is no special need for extra sun precautions beyond the usual daily SPF.

Potential Side Effects/Adverse Reactions

Reactions to topical Dimethicone PEG-8 Phthalate vary from person to person. The effects listed below are only potential outcomes and most users will never experience them when the ingredient is properly formulated into a finished product.

  • Mild skin irritation itching or redness in sensitive individuals
  • Contact dermatitis very rare allergy like response to the silicone or trace impurities
  • Eye irritation tearing or stinging if the product accidentally gets into the eyes
  • Build-up on hair limp or weighed-down strands if used in heavy leave-in formulas without adequate cleansing

If any discomfort swelling or rash appears stop using the product and consult a healthcare professional or dermatologist for guidance

Comedogenic Rating

Dimethicone PEG-8 Phthalate has a comedogenic rating of 1 out of 5. The molecule forms a light breathable film that sits on top of skin then rinses away easily so it is unlikely to block pores. Its water friendly PEG side helps prevent the thick build up sometimes linked to heavier silicones.

Because of the low rating most people prone to acne or breakouts can use products containing this ingredient without added risk.

As with any leave-on formula overall product design matters. If the final blend contains occlusive waxes or heavy oils the low rating of Dimethicone PEG-8 Phthalate will not cancel out the higher clogging potential of those other ingredients.

Summary

Dimethicone PEG-8 Phthalate works as a hair and skin conditioner. On hair it smooths the cuticle, lowers friction and boosts shine. On skin it lays down a thin protective veil that locks in surface water yet still lets skin feel light and comfortable. The dual silicone-PEG structure lets it spread in both oil and water formulas helping it rinse clean without residue.

You will spot this ingredient in a fair number of modern conditioners, serums and primers but it is not as common as classic dimethicone because it costs more to make and some brands choose to stay away from any material containing the word phthalate.

Current safety reviews show low irritation and no evidence of hormonal effects so overall it is considered safe for normal, oily, dry and sensitive skin. As with any new cosmetic doing a small patch test first is the easiest way to make sure your own skin agrees with it.

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