Hello and thanks for researching this very important question!

Your question was listed under the Cat Category, but I am qualified to address Dog Questions as well...you can see my Profile by clicking my name in the upper left corner!

As you know, Denosyl is the veterinary brand name for the dietary supplement: S-adenosylmethionine (SAMe). When looking at human equivalents, there are differences: the human dietary supplement business is largely unregulated to date.

I recommend you ask your pharmacist for a referral to a product that customers buy more than once or twice...if a product does not have repeat business, it is probably ineffective!

Also discuss using a substitute with your dog's vet so that it can be noted in the record for testing purposes...any decreased effectiveness should bring you back to the Nutramax product (Nutramax pricing includes testing and ingredients that are human-grade!). The chain-of-custody from the Nutramax warehouse to your veterinarian's office is climate-controlled and guaranteed for quality.

http://www.petplace.com/drug-library/s-adenosylmethionine-same/page1.aspx

Ursodiol is a prescription medication sold under the human brand name Actigall...to price-shop you have to look for online pharmacy listings. Your vet would need to provide you with a written prescription:

http://www.petplace.com/drug-library/ursodiol-actigall-urso/page1.aspx

http://www.drugdelivery.ca/s320-s-ACTIGALL.aspx

http://www.shopping.com/xDN-nutrition--progressiverx_com~V-grid