Hi,
A few things to consider: How long have you been selling the product you want to patent? Under US patent law you have only one (1) year to get your patent filed after your first sale or first public use or public disclosure. So in your case a patent may not be possible if its been after the one year point.
Also, in general, things like recipes and food supplements that are simply a combination of already known and used food ingredients are generally not patented and instead are protected as trade secrets. There are a few reasons for this:
(a) once you file a patent on the idea everyone around the world will be able to read your published patent application online and see exactly what your "secret sauce is" and in what proportions. So if everyone starts copying you, do you have the ability and resources to keep track of this and test in a lab all of your competitors products to see if they are copying you exactly? Most companies don't have those resources making a trade secret more attractive. Remember, patents are not "self enforcing" so it would be up to you to go out and prove people are copying you and take legal action against each party (sometimes costing millions).
https://patentfile.org/you-have-a-patent-so-what/(b) in general the US Patent Office see combinations of already known and used food ingredients as being an "obvious" type invention and therefore will reject it as being obvious even though you may be the first person to combine those items in this particular way. The exception to this would be a new type of chemical formulation such as an artificial sweetener etc. as those type of items would be less obvious.
*This is not legal advice. I don't know your particular situation or invention.