What is the difference between omeprazole and omeprazole magnesium?

No difference: Omeprazole is a proton pump inhibitor (ppi). It works by decreasing the amount of acid produced in the stomach. I can find no difference in the literature between Omeprazole & Omeprazole magnesium except in the way different companies formulate it.

Humph: Omeprazole is combined with sodium esomeprozole(nexium) is combined with magnesium. Your body does not absorb either the sodium or the magnesium , it is just how they are made so your body can use the active ingredient

Omeprazole: Over-the-counter omeprazole(omeprazole-magnesium) treats frequent heartburn that occurs for more than 2 days a week. However, over-the-counter Omeprazole should not be used if you have an underlying condition or if heartburn continues after the indicated 14-day therapy.

Not much: Magnesium is the salt attached to the molecule that allows it to dissolve. Omeprazole-magnesium can be taken with food or on an empty stomach- Omeprazole with another salt should be taken before meals. Theoretically speaking.