Hi There
The answer is a little Shaky. Overall there is no Test Procedure for general Cosmetic Products. But there are several tests that are Performed to Determine if the product, tested under special circumstances, is biologically degradable.
Singel Raw material Testing is possible depending on the claim I would say but it is very expensive.
the OECD 301D is originally designed for Volotail Chemical Substances. Depends on your Cosmetic Formulation if it is a test you want to go for.
As I said for a Cosmetic Product, there is no standard test to perform (sadly). Most Companys will Performe the OECD 302B at least in Europe because it will Determine the Aerobe Biological Degradability and you Propoply will get the best results for Emulsions with that.
If you have a Shampoo or Wash Product like a cleanser you can Perform the Standadiest Test for the Biological degradability of Surfactants. not sure about the Number but a Test institute that performs the other test will probably know.
In the end, your Customer can communicate that the Product is Readily bio-degradable tested with test method XXX.
Hope that helps.
Tobias