What Is Hydrogenated Polydicyclopentadiene?
Hydrogenated Polydicyclopentadiene is a synthetically produced polymer that comes from cyclopentadiene, a hydrocarbon often sourced from crude oil or coal tar. Chemists first dimerise cyclopentadiene into dicyclopentadiene, then join many of these units together to form a long-chain material. A final hydrogenation step stabilises the polymer, giving it a wax-like consistency and improving its resistance to heat and oxidation.
The cosmetic industry began looking at this ingredient in the late 20th century while searching for safer alternatives to natural tree resins and animal-derived waxes. Its consistent quality, lack of scent and good film-forming ability made it a reliable choice for modern formulations.
The manufacturing process starts with purified cyclopentadiene that is kept cold to prevent premature reactions. It is warmed to encourage dimerisation, then polymerised in a controlled reactor. Finally, hydrogen gas is introduced under pressure to saturate the double bonds, reducing reactivity and colour. The finished material is filtered, cooled and milled into flakes or pellets ready for blending.
You will most often find Hydrogenated Polydicyclopentadiene in stick and pot-style products such as mascaras, liquid eyeliners, brow waxes, hair removal waxes, solid perfumes, lip balms, styling pomades and certain long-wear foundations. Its ability to form a flexible yet strong film makes it a favourite in waterproof or smudge-resistant formulas.
Hydrogenated Polydicyclopentadiene’s Cosmetic Benefits/Uses
This ingredient serves more than one purpose, making it a versatile addition to a formulator’s toolkit.
- Binding – Acts like glue inside a formula, holding pigments, powders and other solids in place so the product stays uniform and does not crumble or separate during use
- Depilatory – Provides the solid, elastic base needed in hair removal waxes, gripping hairs firmly for cleaner removal and leaving less residue on the skin
Who Can Use Hydrogenated Polydicyclopentadiene
The ingredient is generally well tolerated by all skin types. Dry and normal skin benefit from the light occlusive film it creates, while combination and oily skin may find very wax-rich formulas feel heavier though the polymer itself is not greasy. Sensitive skin usually handles it well because it contains no fragrances or reactive impurities.
Because Hydrogenated Polydicyclopentadiene is fully synthetic and derived from petroleum feedstocks rather than animal sources it is suitable for vegans and vegetarians.
No data show that the ingredient penetrates the skin or enters the bloodstream so it is not expected to pose a risk during pregnancy or breastfeeding. This is not medical advice and anyone who is pregnant or nursing should check with a healthcare professional before using new cosmetic products.
The polymer does not absorb UV light and is not known to cause photosensitivity. It is also stable in sunlight so it will not break down into irritating by-products during daytime wear.
Potential Side Effects/Adverse Reactions
Every individual can react differently to topical ingredients. The points below outline potential side effects that have been reported or are theoretically possible. When the ingredient is used properly in a finished product most people will not encounter these issues.
- Mild skin irritation – rare redness or stinging, usually linked to very sensitive skin or damaged skin barriers
- Contact dermatitis – uncommon allergic response to trace by-products or other formula components rather than the polymer itself
- Eye irritation – tearing or burning if a product migrates into the eye area before it sets
- Clogged pores – low likelihood because the polymer is non greasy but heavy layers in occlusive formulas could trap sebum and debris in acne-prone skin
If you notice any discomfort or unusual reaction stop using the product and consult a healthcare professional
Comedogenic Rating
Rating: 1/5
Hydrogenated Polydicyclopentadiene is a large, inert polymer that sits on the skin’s surface without melting into the pores or interacting with sebum. It creates a thin film that locks other ingredients in place but does not carry the heavy oils or fatty acids typically linked to clogged follicles, which is why its rating is close to non-comedogenic.
Most people prone to acne or breakouts can use products containing this polymer without extra concern, though the overall richness of the finished formula still matters.
As with any film-forming ingredient, very thick layers or pairing it with high-oil content products could trap sweat and debris, so lighter applications are best for oily or congestion-prone skin.
Summary
Hydrogenated Polydicyclopentadiene is mainly a binder and depilatory base. Its long polymer chains form a flexible film that secures pigments, powders and waxes, giving makeup and hair removal products strength, uniform texture and smudge resistance. Despite these useful properties it remains a niche ingredient, chosen mostly for specialty formulations like waterproof mascaras, brow waxes and salon-grade strip waxes rather than everyday lotions or creams.
Current data show a low risk of irritation, toxicity or pore clogging, making it a safe addition to most cosmetic routines. As with any new product you introduce, perform a simple patch test first to confirm personal compatibility.