Quick answer
Engine oil technically always contains some additives from the manufacturer. If you avoid aftermarket products, you rely solely on the oil’s built-in detergents, anti-wear agents, and friction reducers.
Detailed answer
Any conventional or synthetic engine oil on store shelves comes with an internal additive package—zinc compounds for wear, calcium for detergency, etc. These are essential for lubrication longevity and cleanliness. “No additives” would mean zero aftermarket supplements. For many cars, that’s perfectly fine. As long as you select an oil that meets your engine’s specs, you should have adequate protection. Extra additives only matter if you face specific problems or want to push boundaries (extreme towing, high mileage, racing). You can maintain a healthy engine simply by using a good oil and following regular change intervals.