Ingredient review
Oxyquinoline Sulfate
INCI: Oxyquinoline Sulfate
Oxyquinoline Sulfate is a synthetic preservative that helps keep products fresh, but it can be irritating for sensitive skin and is less common in modern formulations.
In plain English
Oxyquinoline Sulfate is a man-made chemical added to cosmetics to stop bacteria, yeast, and mold from growing. Think of it like a tiny guard that keeps your cream or lotion from spoiling. However, because it can sometimes cause skin irritation, many brands now prefer gentler preservatives.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Oxyquinoline Sulfate can be useful, but watch for some irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Oxyquinoline Sulfate.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
Oxyquinoline Sulfate is the sulfate salt of 8-hydroxyquinoline, a synthetic compound with antimicrobial properties. It is used in cosmetics primarily as a preservative to extend shelf life by preventing microbial contamination.
How it works
It works by interfering with the cell membranes and metabolic processes of microorganisms, effectively killing or inhibiting their growth. In a cosmetic product, this helps maintain the product's safety and stability over time.
Pros
Broad antimicrobial protection
Oxyquinoline Sulfate works against a wide range of bacteria, yeast, and mold, helping keep your products safe from contamination.
Low use concentration
It is effective at very low levels (typically 0.1% or less), so it doesn't need to be a major ingredient in the formula.
Cons and cautions
Can cause skin irritation
For people with sensitive or compromised skin, this ingredient may trigger redness, stinging, or contact dermatitis.
Less popular in modern formulations
Many brands now opt for gentler preservatives, so products containing Oxyquinoline Sulfate are less common and may be harder to find.
Best for
- People with normal to oily skin who use products with short shelf lives
- Those who prefer synthetic preservatives with proven antimicrobial efficacy
Use caution if
- Individuals with sensitive, reactive, or eczema-prone skin
Usage tips
Safety summary
Oxyquinoline Sulfate is considered safe for use in cosmetics at regulated low concentrations, but it carries a moderate risk of skin irritation, especially for sensitive individuals. It is not a common allergen but can cause contact dermatitis in some people.
Research notes
Research confirms its antimicrobial efficacy against a range of microorganisms. However, studies also note potential for skin sensitization and irritation, leading to its reduced use in favor of milder preservatives.
Common label clues
- Typical concentration
- Typically used at 0.1% or less
- Regulatory status
- Approved for use in cosmetics in the EU and US at concentrations up to 0.1% in rinse-off products and 0.02% in leave-on products, though it is less common in modern formulations.
- Common uses
- Rinse-off products, Leave-on products, Hair care, Makeup
- Environmental note
- As a synthetic compound, its environmental persistence is not well studied, but it is generally used in very small amounts.
Good to know
- Oxyquinoline Sulfate is sometimes listed under the alias 8-Hydroxyquinoline Sulfate on ingredient labels.
- It is not the same as oxybenzone (a sunscreen ingredient) — the names are similar but the ingredients are completely different.
Common questions
What is Oxyquinoline Sulfate in beauty products?
Oxyquinoline Sulfate is a man-made chemical added to cosmetics to stop bacteria, yeast, and mold from growing. Think of it like a tiny guard that keeps your cream or lotion from spoiling. However, because it can sometimes cause skin irritation, many brands now prefer gentler preservatives.
What does Oxyquinoline Sulfate do in a beauty product?
It works by interfering with the cell membranes and metabolic processes of microorganisms, effectively killing or inhibiting their growth. In a cosmetic product, this helps maintain the product's safety and stability over time.
Is Oxyquinoline Sulfate safe for most people?
Oxyquinoline Sulfate is considered safe for use in cosmetics at regulated low concentrations, but it carries a moderate risk of skin irritation, especially for sensitive individuals. It is not a common allergen but can cause contact dermatitis in some people.
Who should be careful with Oxyquinoline Sulfate?
Individuals with sensitive, reactive, or eczema-prone skin
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.