Well, to be fair, the commerce clause is a single line in the text of our country's constitution that simply authorizes congress to act, and serves to preempt interference by state government.
But also to be fair, literally none.
In 1787 our constitution was written. It authorized Congress, in part:
"To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;"
That text has never changed, never been amended, and never been added to.
The extent of powers that this has granted Congress, and the limitations this has placed on other entities to infringe upon this power, have been interpreted and reinterpreted countless times by our Courts over the centuries since. This interpretation and reinterpretation is not dissimilar to the way that our Courts attempt to construe statutes - The difference being that the constitution is extremely difficult to change, whereas if the Court interprets a statute in a way that is unpopular, or against the wishes of the legislature, they can often amend the statute with a simple majority vote. In my state (Grrrr) we've even had more than a few constitutional amendments to that same effect.
The Commerce Clause also does have real effect on regulation in the United States, primarily through the
"Dormant Commerce Clause."