Why Five Ingredients Are Enough (and Six Might Be Too Many)

If you've spent years rotating through cleansers and moisturizers, you already know the pattern: a product works fine for two weeks, then your skin starts acting up. The instinct is to blame the formula's main ingredient — the glycerin, the niacinamide, the hyaluronic acid. But the data tells a different story.

The reaction is almost never the active ingredient. It's the preservative system. The fragrance compound (even "natural" essential oils). The emulsifier at position seven on the INCI list that you've never looked up. This is the core premise behind everything Derrin formulates: every ingredient past five statistically raises the probability of a sensitizing compound slipping in.

What's in Derrin's Barrier Cleanser — and Why

The cleanser has five ingredients: Aqua, Glycerin, Sodium Cocoyl Glycinate, Panthenol, Allantoin.

Aqua is the solvent base. Glycerin is a humectant — it draws moisture from the environment into the stratum corneum and is one of the most well-tolerated topical compounds in existence. Sodium Cocoyl Glycinate is a coconut-derived amino acid surfactant with a natural pH of 5.5–6.5, matching skin's own acid mantle — unlike sodium lauryl sulfate, which strips the barrier at pH 7+. Panthenol (provitamin B5) supports barrier repair and is used by dermatologists specifically post-procedure to accelerate healing. Allantoin calms post-cleanse sensitivity and has a decades-long safety record.

There is no fragrance. No preservative needed beyond the formula's own pH stability. No "botanical extract" that sounds reassuring but adds antigenic load.

The Moisturizer and the SPF Serum Follow the Same Logic

The Barrier Moisturizer uses Squalane instead of occlusive fats like shea butter or petrolatum — important for seborrheic dermatitis sufferers, because petrolatum and certain fatty acids (C11–C24, specifically) are known to feed Malassezia overgrowth. Squalane is phytogenic (from sugarcane), Malassezia-safe, and mimics skin's own sebum without feeding the fungal yeast that causes SD flares.

The Mineral SPF Serum uses 18% Zinc Oxide as its only UV filter — no oxybenzone, no avobenzone, no octinoxate. Chemical UV filters are among the most common triggers for photoallergic and contact-allergic reactions in sensitive skin. Zinc oxide is the only broad-spectrum (UVA + UVB) filter the FDA classifies as "generally recognized as safe."

The Rule We Use

Before any ingredient makes it into a formula, we ask one question: can we explain, in plain language, exactly what this ingredient does and why no simpler ingredient does it better? If the answer is "it's in there for texture" or "it rounds out the formula," it doesn't make the cut.

Sensitive skin isn't unusual skin. It's skin that's been trained to respond to unnecessary complexity. Fewer ingredients isn't a compromise — it's the product.