What Is Solvent Yellow 33?
Solvent Yellow 33, also labeled on ingredient lists as CI 47000, is a synthetic yellow dye created by reacting phthalic anhydride (also called 1,3-isobenzofurandione) with quinoline and methylquinoline. The reaction forms a bright, oil-soluble pigment known for its vivid golden shade. First developed in the early 1900s to color industrial products, it was later refined for cosmetic use once manufacturers saw its strong tinting power and stability under heat and light.
Production starts with purified quinoline compounds that are condensed with phthalic anhydride under controlled temperature and pressure. After the reaction, the mixture is cooled, filtered and washed to remove unreacted material, then dried and ground into a fine powder. This powder dissolves readily in non-polar solvents such as oils or alcohols, making it easy to disperse in many beauty formulas.
Today you can spot Solvent Yellow 33 in a wide range of cosmetics that call for a warm yellow tone. It shows up in liquid and cream foundations, color-correcting primers, lipsticks, tinted balms, nail polish, hair dyes, bath oils, fragranced body sprays and some sunscreen products. Its ability to stay bright without fading helps brands keep shades consistent from the first use to the last.
Solvent Yellow 33’s Cosmetic Benefits/Uses
Below are the key ways formulators rely on this ingredient when creating beauty products.
- Colorant: Provides a rich yellow hue that blends easily with other pigments, allowing brands to fine-tune everything from pastel lotions to vibrant lip colors while maintaining good light stability and shelf life
- Hair Dyeing: Acts as a direct dye in semi-permanent and temporary hair color products, adding golden or warm undertones and helping cover dullness without the need for oxidative developers
Who Can Use Solvent Yellow 33
Because Solvent Yellow 33 is a non-reactive, oil-soluble dye, it is generally suitable for oily, dry and combination skin. Most skin types tolerate it well, though people with very sensitive or compromised skin barriers—such as those with active eczema or dermatitis—may prefer to avoid products that contain synthetic colorants altogether to reduce the chance of irritation.
The dye is fully synthetic and not derived from animal sources, so it is considered appropriate for vegans and vegetarians. Manufacturers typically use petroleum-based raw materials and standard chemical processes, with no need for animal-derived additives during production.
Current cosmetic safety assessments have not flagged Solvent Yellow 33 as a risk for pregnant or breastfeeding women when used on the skin or hair in normal product concentrations. Nonetheless this is not medical advice, and anyone who is pregnant or nursing should show any skincare or haircare product to a healthcare professional for personalized guidance.
Unlike some plant extracts or citrus oils, Solvent Yellow 33 is not known to heighten photosensitivity. Its molecular structure stays stable under UV light, so it will not make skin more prone to sunburn. The main extra consideration is its strong staining power: if a formula spills, it can tint fabric or bathroom surfaces.
Potential Side Effects/Adverse Reactions
Reactions to topical Solvent Yellow 33 vary from person to person. The points below list potential, not guaranteed, side effects; most consumers will not experience any issues when using a well-formulated product.
- Temporary skin staining
- Mild redness or irritation in those with very sensitive skin
- Allergic contact dermatitis presenting as itching or small bumps
- Eye irritation if the raw powder or a concentrated product accidentally contacts the eyes
- Scalp dryness or itching after prolonged exposure in hair dyes
If any irritation, rash or other unexpected reaction occurs, stop using the product immediately and consult a healthcare professional for advice.
Comedogenic Rating
Rating: 1/5. Solvent Yellow 33 is used in very low concentrations, is oil soluble yet lightweight, and does not leave a film that traps dead cells or sebum. Because it sits on the surface for color only and is usually blended into non-occlusive bases, it has little chance of clogging pores. Suitable for acne-prone or breakout-prone skin in most cases.
Only if a formula containing the dye is also packed with heavy waxes or butters could pore congestion become an indirect issue, so always consider the full ingredient list.
Summary
Solvent Yellow 33 functions mainly as a yellow colorant and a direct hair dye, delivering a vivid warm tone that stays bright under light and heat. Its oil solubility lets it disperse evenly through creams, oils, sprays and hair color without fading.
The dye has a niche but steady presence in cosmetics, more common in lipsticks, nail polish and specialty hair tints than in mainstream skincare. Formulators appreciate its stability but often turn to iron oxides or plant pigments when a softer yellow is desired, keeping Solvent Yellow 33 somewhat under the radar.
Current safety reviews rate it as low risk when used at approved levels, with irritation or allergy remaining rare. Still, skin is personal, so patch test any new product containing this ingredient to make sure it agrees with you.