I give my 9 months old mix up pups cod liver oil, evening of primrose, garlic and omega 3 capsules you know those gel type ones that humans take to keep them healthy

Cod liver oil - joints
Evening of primrose - coat conditioner
Garlic- flea prevention
Omega 3 - joints and brain booster

The vet recommend them certainly but I often wonder if he meant the expensive types sold in pet stores and by him could the human versions harm them I have noticed most of the animal versions are in liquid form. I have been giving it to them since they were around 4/5 months with no ill effects so far. They certainly seem healthy enough and are well behaved other than the normal puppy play I have no faults whatsoever from them. Any advice would be great

Thet also get some occasional cooked veg and raw carrots to chew on rather than fattening treats

Vets disagree on things. Many of them would disagree with yours, including the ones on the staff of the large dog guide school I raise puppies for. They have incredibly more data to base their opinions on than most vets and every incentive to give the people raising puppies for them the straight story. They forbid giving supplements. They also suggest the modern monthly flea treatments. I have no faith in garlic. That your dogs don't have fleas with it doesn't prove that they would without it. A healthy dog in poor flea habitat may not have fleas even without any treatment. Not seeing fleas isn't enough. You have to pull back the hair at the base of the tail and look for dark, reddish specks.

You can find some good discussion at Woodhaven Labradors Training-Nutrition Articles

Save your money and skip the supplements. If you are feeding a quality chow, it already has everything your dog needs.