What Is Solvent Green 7?
Solvent Green 7, also known as Trisodium 8-hydroxypyrene-1,3,6-trisulphonate or CI 59040, is a synthetic green dye made by sulfonating a hydroxypyrene base and then neutralizing it with sodium ions. This gives it three sulfonate groups that help it dissolve in water and stay stable in many kinds of cosmetic formulas.
The colorant first appeared in industrial dyes during the mid-20th century when brighter, longer-lasting pigments were needed for fabrics and plastics. Its strong shade and good light stability soon caught the eye of cosmetic chemists who wanted vivid green hues that would not fade on hair or skin. Over time safety tests showed it could be used at low levels in personal care products, which led to its listing on the Color Index as CI 59040.
Production starts with a hydroxypyrene core that is treated with sulfuric acid to add sulfonate groups. Controlled temperatures keep side reactions low. The acid form is then neutralized with sodium hydroxide to create the final trisodium salt, which is purified, dried and milled into a fine powder or turned into a liquid concentrate for easier dosing.
You will most often find Solvent Green 7 in semi-permanent and temporary hair dyes, color-depositing shampoos, colored styling gels, bath bombs, face masks and novelty makeup like body paints. Its water solubility makes it easy to rinse off skin while still giving rich green tones in hair products.
Solvent Green 7’s Cosmetic Benefits/Uses
In beauty formulas Solvent Green 7 serves two main jobs that add value for both brands and users.
- Colorant: It delivers a bright green shade that stays clear and even, letting formulators create products with eye-catching color. This can boost shelf appeal, help users see where a mask or gel has been applied and allow brand signature hues.
- Hair dyeing agent: When used in semi-permanent or wash-out dyes the molecule binds lightly to the hair surface, giving a vivid green tint without harsh oxidation. It mixes well with other dyes to create custom shades and fades gradually with shampooing so users can change looks without long commitment.
Who Can Use Solvent Green 7
Because Solvent Green 7 is a water-soluble synthetic dye that sits on the surface of skin and hair, it is generally suitable for normal, dry, oily and combination skin types. People with very sensitive skin or a known allergy to synthetic dyes should use caution since even low-level colorants can sometimes trigger irritation.
The ingredient is produced entirely from petrochemical feedstocks and does not rely on animal by-products, so it is considered suitable for both vegetarians and vegans. Ethical shoppers may still want to confirm that the finished product was not tested on animals, as regulations vary by region.
No evidence shows that Solvent Green 7 is absorbed through skin in meaningful amounts or interferes with fetal or infant development. Even so, pregnant or breastfeeding users should check with a healthcare professional before trying any new cosmetic just to be safe.
The dye does not make skin more sensitive to sunlight and it has no known interactions with common UV filters, so additional sun protection beyond normal daily habits is not required. It can however stain porous surfaces like nails or bathroom grout if left in contact for long periods, so rinsing off promptly is a good habit.
Potential Side Effects/Adverse Reactions
Responses to topical Solvent Green 7 differ from person to person. The effects listed below are only potential outcomes and are unlikely for most users when the ingredient is used at the low concentrations allowed in cosmetics.
- Mild skin redness or itching, especially on sensitive areas
- Contact dermatitis in individuals allergic to synthetic dyes or sulfonates
- Eye irritation if the product accidentally gets into the eyes
- Temporary staining of skin or nails that usually washes away after several cleanses
- Scalp dryness or flaking when used in high-pigment hair dyes
If any discomfort or unexpected reaction occurs stop use immediately and seek advice from a medical professional.
Comedogenic Rating
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Solvent Green 7 is a fully water-soluble dye that contains no oily or waxy components, so it does not linger inside pores or create the kind of film that can trap sebum. Because it rinses away easily and does not interact with skin lipids, the chance of it blocking pores is extremely low.
That makes the ingredient generally suitable for people who are prone to acne or breakouts.
As with most water-soluble colorants any residue left on towels, pillowcases or applicators can transfer back to skin, so keeping accessories clean will further reduce any risk of irritation.
Summary
Solvent Green 7 is a synthetic green dye used mainly as a colorant and temporary hair-tinting agent. Its triple sulfonate structure keeps it stable in water-based formulas and allows it to deposit bright, even color on hair or skin without the need for harsh chemical developers.
While not one of the most famous cosmetic dyes on the market, it shows up in niche products like vivid hair gels, bath bombs and novelty makeup where a true green shade is needed and has a loyal following among users who enjoy bold looks without long-term commitment.
Safety data indicates a low risk of irritation at the low levels used in cosmetics and it carries virtually no comedogenic risk. Even so, skin responses vary, so it is wise to patch test any new product containing Solvent Green 7 before full use to make sure your skin agrees with it.