Potassium O-Phenylphenate: 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: July 1, 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 Potassium O-Phenylphenate?

Potassium O-Phenylphenate is the potassium salt of o-phenylphenol, a compound that belongs to the biphenyl family. It looks like a white crystalline powder that dissolves easily in water. The ingredient is made by reacting o-phenylphenol with potassium hydroxide, a simple neutralization step that turns the parent acid into a stable salt. Its roots trace back to the early 1900s when o-phenylphenol compounds were prized for their germ-killing ability in household cleaners. Over time formulators saw the same benefit for personal care, so the potassium form found a place in cosmetics as a reliable preservative. Today you can spot it in products such as facial cleansers, body lotions, makeup removers, wet wipes, deodorant sprays and some rinse-off hair products where keeping bacteria at bay is essential.

Potassium O-Phenylphenate’s Cosmetic Benefits/Uses

In skincare and beauty formulas Potassium O-Phenylphenate serves one clear purpose that delivers several practical perks.

Its antimicrobial action stops bacteria, mold and yeast from growing inside a jar or bottle. This protection keeps the product safe to use over its shelf life, prevents spoilage so the texture and scent stay pleasant and lowers the chance of skin issues that can arise from contaminated products. By doing the heavy lifting on preservation it also lets brands use lower levels of other preservatives or reduce added fragrances that might otherwise mask spoilage odors.

Who Can Use Potassium O-Phenylphenate

Because Potassium O-Phenylphenate is present at very low levels in finished products and is rinsed off or left on the skin in a diluted state, most skin types can tolerate it, including oily, combination and normal skin. People with very sensitive or compromised skin should be aware that any preservative, including this one, can sometimes trigger irritation, so choosing formulas specifically labeled for sensitive skin may be wise.

The ingredient is synthetic and made without animal-derived materials which makes it suitable for both vegans and vegetarians.

Pregnant or breastfeeding women generally can use products containing Potassium O-Phenylphenate but this is not medical advice. Anyone expecting or nursing should review their entire skincare routine with a qualified healthcare professional to be safe.

The compound is not known to cause photosensitivity, so it will not make skin more prone to sunburn. As with any preservative it is most effective in well-formulated products that stay within recommended concentration limits.

Potential Side Effects/Adverse Reactions

Side effects from topical Potassium O-Phenylphenate vary from person to person. The points below list potential reactions, but they are uncommon when the ingredient is used correctly in a finished cosmetic product.

  • Skin irritation – mild redness stinging or itching can occur, especially on sensitive or broken skin
  • Contact allergy – a small number of users may experience an allergic rash or dermatitis
  • Eye irritation – if a product accidentally gets into the eyes it can cause watering or burning
  • Dryness or tightness – very infrequent reports of the ingredient leaving skin feeling dry particularly in leave-on formulas with higher preservative loads

If any irritation or adverse reaction develops stop using the product and seek medical advice if symptoms persist or worsen.

Comedogenic Rating

Rating: 0/5 – Potassium O-Phenylphenate is a water-soluble salt used in tiny preservative amounts so it does not sit on the skin or block pores, which is why it earns the lowest possible comedogenic score.

That makes it generally suitable for people who are prone to acne or breakouts.

Keep in mind that overall pore-clogging potential depends on the full formula, not just a single ingredient.

Summary

Potassium O-Phenylphenate is mainly an antimicrobial preservative that keeps bacteria mold and yeast from spoiling a product. It does this by disrupting the cell walls of these microbes so the formula stays safe stable and pleasant to use.

While not a buzzworthy ingredient in beauty marketing it keeps a steady presence behind the scenes in cleansers wipes and other everyday items where reliable preservation is needed.

Safety studies and long experience show it is well tolerated when used within regulatory limits yet it is wise to patch test any new product to make sure your skin agrees with the full mix of ingredients.

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