OUAI Fine Hair Biotin Thickening Shampoo – 32 oz Refill, Volumizing & Color-Safe with Keratin

OUAI Fine Hair Shampoo is a lightweight, biotin-enriched thickening shampoo formulated to add volume, strengthen fragile strands, and cleanse without stripping color-treated hair.

Designed specifically for flat, thin hair, this sulfate-free, refill-sized shampoo uses biotin, hydrolyzed keratin, and chia seed oil to gently build body while maintaining a soft, manageable finish. The formula is free of sulfates, parabens, phthalates, and gluten, making it suitable for chemically-treated and color-treated hair that needs lift without heavy residue. The fragrance leans fresh and sophisticated—Mercer Street—so your wash routine leaves hair smelling like Italian lemon, iris, and white musk.

How does this shampoo create noticeable volume for fine hair?

The shampoo targets the hair fiber with ingredients that thicken and lift at the root while delivering a gentle cleanse that won’t weigh hair down. Biotin helps support strand resilience, and chia seed oil adds slip and body so hair feels fuller after rinsing.

• Biotin reinforces fragile cuticles to reduce breakage and maintain lift.
• Hydrolyzed keratin smooths and increases shine without heaviness.
• Chia seed oil provides light conditioning and texture for natural volume.
• Sulfate-free surfactants clean without stripping color or moisture.

Will this shampoo work with color-treated or chemically processed hair?

Yes — the formulation is color-safe and free of harsh sulfates that can fade dyes more quickly. It is also compatible with keratin treatments and other chemical services, helping preserve tone and surface integrity while improving body.

• Sulfate-free base reduces aggressive color stripping.
• Gentle cleansing maintains salon-treated finishes and shine.
• Hydrolyzed keratin supports treated fibers for smoother appearance.

How should I use OUAI Fine Hair Shampoo for best results?

Apply a quarter- to palm-sized amount to wet hair, focusing on the scalp and roots, then work through to the ends to distribute the active ingredients. Rinse thoroughly, and follow with OUAI Fine Conditioner and optionally OUAI Thickening Spray for amplified lift and sustained shape.

• Massage into wet scalp to boost circulation and root lift.
• Rinse well to avoid build-up that can flatten fine hair.
• Pair with matching conditioner and styling products for long-lasting volume.

What does the scent and packaging offer for daily use?

The Mercer Street fragrance blends citrus, floral, and musk for an elevated daily routine that smells fresh without overpowering. The 32 oz refill size reduces waste and keeps a generous supply on hand for frequent washing or multi-person households.

• Mercer Street scent: Italian lemon, iris, white musk – clean and refined.
• Large refill format supports sustainability and value.
• Lightweight lather that rinses clean, leaving hair soft yet voluminous.

Who is this for: OUAI Fine Hair Shampoo is aimed at people with fine, limp, or thinning-looking hair who want a lightweight, color-safe option to increase body and reduce breakage. It works well for anyone seeking a gentle everyday cleanser that adds lift—suitable for both women and men, and for those who have color, keratin, or other chemical treatments. If you prefer non-heavy, fragrance-forward products and value refill packaging, this formula is designed to fit into that routine.

Ingredients

Water/Aqua/Eau, Sodium C14-16 Olefin Sulfonate, Cocamidopropyl Betaine, Sodium Methyl Cocoyl Taurate, Peg-200 Hydrogenated Glyceryl Palmate, Cocamide Mipa, Fragrance / Parfum, Panthenol, Cocoglucosides Hydroxypropyltrimonium Chloride, Hydrolyzed Keratin, Biotin, Salvia Hispanica Seed Oil, Cetrimonium Chloride (Anti-Static Agent/Agent Antistatique), Hydroxypropyl Guar Hydroxypropyltrimonium Chloride, Glycerin, Sodium Lauroyl Glycinate, Peg-150 Distearate, Propoxytetramethyl Piperidinyl Dimethicone, Trideceth-6, C11-15 Pareth-7, Peg-7 Glyceryl Cocoate, Sodium Chloride, Polyquaternium-7, Disodium Edta, Citric Acid, Sodium Hydroxide, Tetrasodium Edta, Potassium Sorbate, Sodium Benzoate, Phenoxyethanol, Benzyl Alcohol, Acetic Acid, Sodium Acetate, Benzyl Salicylate, Limonene, Hexyl Cinnamal