05/06/2026
(Coat Health Part 3)
🐾 Why you should never use human shampoo on your dog 🧴
It’s one of the most common things people do without thinking — they’ve run out of dog shampoo, the baby shampoo is right there, and it seems harmless enough. But there are some really important reasons why human shampoo — even the gentlest versions — genuinely isn’t suitable for dogs.
It starts with skin structure
Human skin has 10 to 15 layers in the outer protective layer of skin. Dog skin typically has only 3 to 5 layers. This structural difference that affects everything. Thinner skin means ingredients — helpful or harmful — pe*****te far more easily and deeply. Dogs also have much higher hair follicle density than humans, creating more pathways for chemicals to pe*****te the skin.  What sits on the surface of a dog’s coat doesn’t just stay there — it can get in.
💥 The pH problem
Dog skin is naturally neutral to slightly alkaline, sitting at a pH of around 6.2 to 7.4. Human skin sits at around 4.5 to 5.5 — meaningfully more acidic.  Shampoos are formulated to match the pH of the skin they’re designed for, which means human shampoo is significantly more acidic than a dogs skin requires.
When you use a product with a significantly different pH, the protective layer ontop of the skin is damaged — leaving the skin exposed to bacteria, viruses, and yeasts that the natural barrier would normally keep in check.  Do this repeatedly, and you start to break down one of your dog’s most important lines of defence.
When you use an acidic human shampoo on a dog’s neutral skin, it disrupts the natural bacterial balance — potentially leading to overgrowth of harmful bacteria and fungi.  That’s how a seemingly harmless bath can contribute to recurring skin infections over time.
* What it does to the coat itself
Human hair has 7 to 10 protective cuticle layers wrapped around each strand. Dog hair has just 3 to 5 — making it more permeable to both beneficial and potentially problematic ingredients, and more vulnerable to damage from aggressive cleansers. 
Humans produce significantly more natural skin oil than dogs. Human shampoos are designed to remove this heavier oil production. When used on dogs, they over-cleanse and strip away the minimal natural oils dogs actually need to maintain a healthy coat and skin barrier. 
A good dog shampoo should promote the proper production of natural oils in the skin and allow these to flow freely across the skin to keep it moist and elastic— and close up the scales on each individual hair shaft so it reflects light and stays clean.  Human shampoo actively works against all of this.
What you’ll see if you keep using it
The effects aren’t always immediate, which is why people assume it must be fine. But over time, the signs build up — dry, flaky skin, persistent itching, a dull and brittle coat, and in some cases recurring bacterial or yeast infections as the skin’s natural balance continues to be disrupted. The distressed skin barrier also leads to increased water loss from the skin — resulting in dry, flakey, itchy skin.
What about baby shampoo?
It’s the one people reach for most often, because it feels mild and gentle. But mild for a human infant is still formulated for human skin — and human skin, as we’ve covered, is fundamentally different in structure and pH to a dog’s. Even baby shampoos are designed for the very different requirements of human skin and don’t account for the needs of a dog’s coat and skin at all.  Gentle doesn’t mean suitable.
The right shampoo makes a real difference
A properly formulated dog shampoo isn’t just a safer option — it actively supports the health of your dog’s skin and coat. At The Dog Retreat Spa we select shampoos specifically matched to each dog’s coat type and skin condition — because what goes on in the bath is the foundation of everything that follows during the rest of the grooming process. Get it right, and the results speak for themselves. 🐾✂️
