Animology Deep Clean Shampoo

The number that matters here is 20:1. This is a concentrate, so the 5 litres in the bottle make 105 litres of shampoo once diluted, which is why a professional-sized bottle is not the extravagance it looks like — it is the cheapest way to buy shampoo per wash by a very long way.

Animology describe the action as mild but deep cleaning: it lifts dirt and odour without stripping the coat of its essential oils, and the easy-rinse formulation is designed to cut the time spent getting it back out again, which anyone who has washed a thick-coated dog will recognise as the actual work. There is a conditioner built in, along with Pro-Vitamin B5. It can be used on all coat and skin types including sensitive skin, and Animology state it suits all dogs from 6 weeks old.

• 5 litre bottle, concentrated 20:1
• Makes 105 litres of shampoo once diluted
• Built-in conditioner and Pro-Vitamin B5
• Easy-rinse formulation
• All coat and skin types, including sensitive skin
• Suitable for dogs from 6 weeks old

Dilute it, and mind what it is not. Used neat this is far stronger than a dog's skin needs, so follow the dilution rather than eyeballing it. It is also a grooming shampoo, not a treatment: it will not deal with fleas, and a dog with genuinely itchy, red, flaking or broken skin needs a vet rather than a different bottle — washing an irritated coat more often usually makes it worse, not better.

Who it's for: groomers, breeders, multi-dog households, and anyone washing a big dog often enough that bottle size has become a running cost.