Ouai St. Barts Detangling and Frizz Fighting Leave in Conditioner

Editor's Take

A heavy dose of Cyclopentasiloxane drives the highly effective slip in this formula, sealing the cuticle for instant gratification while completely ignoring clean and sustainability standards.

Four-pillar formula scores

• Efficacy: 8.4 / 10
• Modern Tech: 7.8 / 10
• Clean Beauty: 1.0 / 10
• Sustainability: 0.0 / 10

The Verdict

The blend achieves its highly effective detangling claims by leaning heavily on Cyclopentasiloxane to coat the cuticle and instantly reduce friction. While that initial slip relies on throwback drugstore chemistry, the addition of biomimetic pea proteins and heat-activated polymers pushes the formula into modern territory. It excels at exactly what it promises by sealing the strand and fighting frizz, but abandons green chemistry entirely to get there. A credible pick for heavy-duty smoothing, provided you accept the environmental trade-off.

Full INCI list

Aqua/Water/Eau, Cyclopentasiloxane, Cetearyl Alcohol, Parfum/Fragrance, Quaternium-91, Phenoxyethanol, Brassica Campestris/Aleurites Fordi Oil Copolymer, Cetrimonium Chloride, Dipropylene Glycol, Glycerin, Myristyl Myristate, Polysilicone-29, Behentrimonium Chloride, Benzyl Salicylate, Silicone Quaternium-16, Limonene, Linalool, Undeceth-11, Coumarin, Hydroxycitronellal, Guar Hydroxypropyltrimonium Chloride, Butyloctanol, Undeceth-5, 3-O-Ethyl Ascorbic Acid, Adansonia Digitata Seed Oil, Argania Spinosa Kernel Oil, Disodium EDTA, Oenothera Biennis Oil, Tocopheryl Acetate, Citric Acid, Glycolic Acid, Leuconostoc/Radish Root Ferment Filtrate, Panthenol, Butylene Glycol, Sodium Hydroxide, Tamarindus Indica Extract, Sodium PCA, Sodium Lactate, Acetic Acid, Arginine, Cetearamidoethyldiethonium Succinoyl Hydrolyzed Pea Protein, Aspartic Acid, Tocopherol, PCA, BHT, Iodopropynyl Butylcarbamate, Isopropyl Alcohol, Glycine, Alanine, Sodium Hyaluronate, Serine, Valine, Hydrolyzed Rhodophyceae Extract, Isoleucine, Proline, Threonine, Histidine, Phenylalanine