Same reason why High dosing Vit C works for colds.

The body uses Vit C to make its own safe Hydrogen Peroxide and then it uses it to burn pathogens.

There are persons who cured cancer by high dosing Vit C via and IV, 50,000 grams a session, 1-3 sessions.

If you research it, sites are vague about why it works. Now you know. Your body makes a customized brand of Hydrogen Peroxide that it can handle high levels of. Pharmaceutical grade at the same dose would never be tolerated by the body.

Look into it if ever needed, many Functional Medicine Doctors and Alternative Health Clinics offer Vitamin IVs. I personally know people who did this along with some light fasting/green juices and colonics and the cancer was gone.