Yes, the predominant (like 90%) form of cholesterol in our blood
is what we make ourselves, NOT from
what we eat.
The drug companies have been very disengenuous about this.
Cholesterol shares a pathway in its synthesis with a necessary element called Co-Q-10. As we age our body makes less Co-Q-10, but if the levels fall significantly many tissues fail to fucntion correctly. As you block the synthesis of cholesterol, you block the needed synthesis of Co-Q-10.