C11-15 Pareth-20: 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 24, 2025
Share:
Inside this article:

All information on this page is verified using The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is C11-15 Pareth-20?

C11-15 Pareth-20 is a synthetic liquid derived from fatty alcohols that contain 11 to 15 carbon atoms. These alcohols can come from plant oils like coconut or from petroleum. During manufacturing the fatty alcohols react with ethylene oxide twenty times on average, a process called ethoxylation. The result is a nonionic surfactant that dissolves in water and oil.

The ingredient first gained popularity in the 1960s when chemists searched for milder alternatives to soap. Its balanced mix of oil loving and water loving parts lets formulators create products that rinse clean without stripping skin.

Today you will spot C11-15 Pareth-20 in facial cleansers, shampoos, body washes, micellar waters, exfoliating masks, makeup removers, light lotions, sunscreens and even some anti aging serums where it helps keep multiple phases blended.

C11-15 Pareth-20’s Cosmetic Benefits/Uses

In skincare and haircare formulas C11-15 Pareth-20 delivers two key benefits

  • Cleansing: Its surfactant nature lifts away dirt oil and makeup then allows them to be rinsed off with water leaving skin and hair feeling fresh
  • Emulsifying: It helps mix oil and water based ingredients into a stable blend improving texture spreadability and shelf life of creams lotions and serums

Who Can Use C11-15 Pareth-20

C11-15 Pareth-20 is generally well tolerated by most skin types including normal oily and combination skin because it rinses clean without leaving a heavy residue. Those with very dry or highly reactive skin might prefer formulas that pair it with richer emollients or use it at lower levels since over cleansing can aggravate tightness or flaking.

The ingredient is synthetic and can be sourced from plant oils or petroleum. No animal derived matter is needed in its production so it is typically suitable for vegans and vegetarians as long as the finished product is certified cruelty free.

Current safety assessments find no specific risks for pregnant or breastfeeding women when C11-15 Pareth-20 is applied topically in cosmetic amounts. Skin absorption is minimal however this is not medical advice and anyone who is expecting or nursing should show any skincare product they plan to use to a qualified doctor for personal guidance.

C11-15 Pareth-20 is not known to cause photosensitivity so it will not make skin more prone to sunburn. It is also color safe for hair products and is compatible with leave on or rinse off formulas.

Potential Side Effects/Adverse Reactions

Reactions to topical C11-15 Pareth-20 vary from person to person. The effects listed below are potential outcomes only and are unlikely for most users when the ingredient has been formulated correctly.

  • Mild skin irritation such as redness or stinging especially on very sensitive or compromised skin
  • Dryness or tightness if used in high concentrations or in products not balanced with moisturizers
  • Eye irritation or watering if the product accidentally gets into the eyes
  • Rare allergic contact dermatitis presenting as itching or small bumps

If you experience any persistent discomfort discontinue use and consult a healthcare professional or dermatologist for further advice.

Comedogenic Rating

Rating: 1 / 5

C11-15 Pareth-20 is highly water soluble and does not sit on skin in a thick oily film that could clog pores. Its main role is to help rinse away oils rather than add them which keeps pore blockage risk very low. Trace amounts that remain after rinsing quickly dilute in skin’s surface moisture so they rarely build up inside follicles.

Because of this low rating most people prone to acne or breakouts can use products containing C11-15 Pareth-20 without added concern.

That said any formula can still cause issues if it contains several heavier ingredients so always look at the product as a whole when judging breakout potential.

Summary

C11-15 Pareth-20 works as a gentle surfactant and emulsifier cleaning away oil dirt and makeup while keeping water and oil phases blended for smooth stable textures. It does this by pairing a water loving head with an oil loving tail which lowers surface tension and lets the two phases mix then rinse off easily.

Though not as famous as plant oils or trendy acids this ingredient is a quiet workhorse found in many everyday cleansers shampoos makeup removers and light lotions because it offers reliable performance without a strong scent or color.

Current cosmetic safety reviews classify C11-15 Pareth-20 as low risk for irritation or toxicity when used in normal product levels. Still everyone’s skin is unique so perform a small patch test when trying any new product containing this ingredient to be on the safe side.

Was this article helpful?
More from Glooshi:
ADVERTISEMENT
Get all our top headlines in beauty.
Delivered right to your inbox each week. Zero spam, all goodness, opt-out at anytime.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Get the latest beauty news, top product recommendations & brand-exclusive discount codes direct to your inbox.
Send good feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Send bad feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Search