What Is Octoxynol-33?
Octoxynol-33 is a synthetic, nonionic surfactant made by reacting octylphenol with approximately thirty-three units of ethylene oxide. The result is a molecule with an oil-loving tail attached to a long chain of water-loving ethoxy groups, giving it the ability to mingle with both oil and water. Developed in the mid-1900s when chemists were seeking gentler alternatives to soap, it quickly found a place in personal care because of its mild yet effective cleansing ability.
The manufacturing process, known as ethoxylation, involves adding measured amounts of ethylene oxide gas to octylphenol under controlled heat and pressure. By adjusting the number of ethoxy units producers can fine-tune properties like solubility and foaming, which is why you see different versions such as Octoxynol-9 or Octoxynol-40. The “33” simply tells formulators how many ethoxy groups are attached on average.
Today you will most often spot Octoxynol-33 in rinse-off products such as facial cleansers, body washes and shampoos where it helps remove dirt and makeup without stripping the skin. It also appears in lotions, sunscreens and makeup removers where its emulsifying talent keeps oil and water phases blended for a smooth, stable texture.
Octoxynol-33’s Cosmetic Benefits/Uses
Formulators rely on Octoxynol-33 for more than one reason, each tied to how its dual-natured structure behaves in a formula.
- Cleansing: The ingredient lowers the surface tension of water so it can spread easily over the skin or hair, surround oil and grime then rinse them away. This gentle action supports a fresh, comfortable feel after washing
- Emulsifying: By positioning itself between oil and water, Octoxynol-33 keeps creams, lotions and liquid cleansers from separating. A stable emulsion means consistent texture, even delivery of active ingredients and a longer shelf life
Who Can Use Octoxynol-33
Because Octoxynol-33 is generally mild it suits most skin types including normal, oily, combination and even sensitive skin when used in low to moderate amounts. Very reactive or highly compromised skin might still prefer formulas with fewer surfactants so checking the full ingredient list is wise.
The ingredient is made in a lab from petrochemical sources rather than from animals so it is considered suitable for vegans and vegetarians. As always the finished product also needs to be cruelty free for those following a strict ethical lifestyle.
Current cosmetic safety assessments have not flagged Octoxynol-33 as a concern for women who are pregnant or breastfeeding. That said this is not medical advice and anyone expecting or nursing should run their skincare routine past a healthcare professional just to be safe.
Octoxynol-33 does not make the skin more sensitive to sunlight so daily SPF habits do not need to change because of this ingredient. It is also odorless so it will not interfere with fragrance preferences.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient can differ from person to person. The points below outline possible side effects linked to topical use of Octoxynol-33, though most people will not experience them when the product is formulated and used correctly.
- Mild skin irritation, especially on very sensitive or broken skin
- Temporary stinging or redness if left on the skin for long periods
- Eye irritation if the cleanser or shampoo accidentally gets into the eyes
- Dryness or tightness when used in a high concentration or combined with other strong surfactants
- Rare allergic contact dermatitis in individuals already sensitized to phenolic compounds
If any discomfort or visible reaction occurs stop use right away and consult a qualified medical professional for guidance.
Comedogenic Rating
Rating: 1 out of 5. Octoxynol-33 is highly water soluble and usually rinsed off, so it does not linger in pores long enough to trap oil or debris. Its molecular structure is larger and more hydrophilic than typical pore-clogging agents, keeping its comedogenic potential low. This makes it generally fine for acne-prone or breakout-prone skin. Because it is most often used in cleansers or well-emulsified lotions the risk of buildup is minimal, especially when the product is removed with water.
One extra point worth noting is that Octoxynol-33 can appear alongside heavier oils or butters in a formula. In that case any clogging would more likely come from those richer ingredients rather than from the surfactant itself.
Summary
Octoxynol-33 works mainly as a gentle cleanser and an emulsifier. Its oil-loving tail grabs onto dirt, makeup and sebum while its water-loving ethoxy chain lets everything rinse away easily. The same ability to bridge oil and water also stabilises creams and lotions so they stay smooth and uniform on your shelf.
Although not the trendiest ingredient it remains a quiet staple in many everyday face washes, shampoos and light emulsions because it gets the job done without fuss. Safety reviews place it in the low-risk category for skin irritation when used at typical cosmetic levels. Still, skin can be unpredictable so it is wise to do a small patch test when first trying any product that contains Octoxynol-33.