Dogs handle medicine their own way, and the record on that is thin

Approval is granted one species at a time

The FDA clears an animal drug for one stated use in one stated species. The company has to show the drug works and does no undue harm in that species. Approval for cats does not carry over to dogs, and approval for people carries over to neither.

The FDA has a special list, called the Index, that lets some medicines be sold for small-market animals such as ferrets and pet birds without full approval. Dogs are among its seven major species, so that list cannot give a dog medicine permission to be sold.

One medicine, a separate dog version

Cyclosporine shows the pattern. Dogs get it as capsules for allergic skin disease, cats get a liquid for their own skin condition, and one is not a stand-in for the other.

An insulin approved for both animals still ships with its own dog leaflet, and its label sets different blood-sugar goals for dogs than for cats.

The disease itself runs differently too. A cat with diabetes may stop needing insulin for a time; that is called remission. Diabetes in dogs usually lasts for life.

A dog's own insulin

Insulin is built slightly differently in different animals. Pig insulin matches the dog's version. In a study of dogs with diabetes, cow insulin more often caused the body's defenses to make substances against it, called antibodies. Dogs given pig insulin had antibody results much like dogs given no insulin. That comparison was about antibodies, not whether treatment helped their diabetes.

The lesson reaches past insulin: the exact build of a peptide matters to the dog that gets it. The study authors called the importance of those antibodies unclear.

Lab rats do not stand in for dogs

In one laboratory study, the share of BPC-157 that reached the blood after a shot into muscle was about 14 to 19% in rats and 45 to 51% in beagles. That gap is why rodent results cannot simply be copied over to dogs, and the figures are no guide to any amount for a pet.

Ordinary human products that harm dogs

Xylitol is a sweetener used in sugar-free gum and in some brands of peanut butter. In a dog it can drive blood sugar dangerously low within 10 to 60 minutes.

The FDA also warns that pain relievers made for people may not suit pets and can even do harm. A person's medicine, or a person's amount, is not a dog's.

Where the record goes quiet

The research behind this map holds nothing specific about puppies and peptides. It holds nothing about how small breeds, giant breeds or very old dogs handle the peptides sold online.

Beyond one lab study of BPC-157 in beagles, no source describes how a dog's body handles TB-500, GHK-Cu or KPV.

For a puppy, a very small or large dog, or an older dog, a useful question for the vet is whether any evidence fits that dog's age, size and health.