Can Vitamin C target cancer cells?

At very high concentrations achievable only through IV infusion, Vitamin C stops acting as the antioxidant you know from supplements and becomes a pro-oxidant. Once inside cancer cells, it generates hydrogen peroxide — a reactive oxygen species that damages the cell from within. Cancer cells are defenceless because they lack sufficient catalase, the enzyme that neutralises hydrogen peroxide. Healthy cells have abundant catalase and break down hydrogen peroxide instantly, so they are largely protected. This selective toxicity is why high-dose IV Vitamin C is used in integrative practice as a targeted cancer treatment rather than a general supplement.

Is high dose Vitamin C safe during chemotherapy?

High-dose IV Vitamin C has been used in integrative oncology for decades with an excellent safety record. At CancerSA, it is part of the weekly treatment protocol alongside IPTLD low-dose chemotherapy. Before your first session, you are tested for G6PD deficiency — a rare enzyme condition that contraindicates the treatment — and kidney function is checked. The timing of IV Vitamin C relative to chemotherapy is carefully managed by Dr Pretorius. Some conventional oncologists express concern about interactions, so open communication with your full medical team is encouraged. Thousands of patients worldwide receive this combination safely.

How does insulin potentiation improve IV Vitamin C?

Insulin potentiation dramatically increases how much Vitamin C enters cancer cells. Cancer cells have extra sugar transporters on their surface, and Vitamin C competes with glucose for entry through these same doors. When insulin is given first, it lowers blood sugar temporarily, which means cancer cells become desperate for fuel and open their transporters wide. With no glucose competing, the Vitamin C floods directly into cancer cells in far greater quantities than a standard infusion would achieve. This targeted delivery means more Vitamin C reaches the cancer and less is wasted. The insulin effect is carefully monitored and blood sugar is restored after treatment.

IV Vitamin C cancer treatment at Cancer SA, Centurion, Pretoria

Insulin Potentiated · Targets Cancer · Protects Healthy Cells

Mega-Dose IV Vitamin C — Targeted by Insulin, Targeted Against Cancer

We lower your blood sugar with insulin so cancer cells open their doors wide — then flood them with Vitamin C that targets them from the inside. Healthy cells are largely protected.

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At a Glance

Insulin lowers blood sugar so cancer cells open their doors wide — then Vitamin C floods in and targets them
At IV concentrations (100x higher than tablets), Vitamin C becomes a pro-oxidant that targets cancer cells
Healthy cells are protected — they have enzymes that neutralise the effect instantly
Combined with hyperthermia (heat therapy) for even stronger results
Part of the weekly cancer protocol — Day 2, out-patient, 2–3 hours per session

This approach is part of integrative oncology, where treatments are selected based on individual patient needs and may be used alongside or in consideration of conventional medical care.

Insulin-potentiated mega-dose IV Vitamin C is an integrative cancer therapy that delivers high-dose intravenous ascorbic acid under controlled hypoglycaemia. At concentrations up to 100 times higher than oral supplements, IV Vitamin C acts as a pro-oxidant that selectively targets cancer cells while leaving healthy cells unharmed. It is used as part of a comprehensive integrative oncology protocol alongside other supportive therapies.

On This Page

Quick Facts

Session Length: 60–90 minutes
Frequency: 2–3 infusions / week
Setting: Out-patient — IV infusion
Location: Centurion, Pretoria

Why Are Cancer Cells Addicted to Sugar?

Cancer cells consume sugar (glucose) at more than double the rate of normal cells. To feed this addiction, they grow extra "doors" on their surface — called GLUT-1 transporters — to let more sugar in. At our Centurion, Pretoria clinic, we exploit this weakness with insulin-potentiated high-dose IV Vitamin C, used alongside or in consideration of conventional oncology care.

Here is the key: Vitamin C and sugar look almost identical to these doors. They compete for the same entry point into the cell.

Under normal circumstances, there is so much sugar in your blood that cancer cells absorb sugar, not Vitamin C. But what happens when we remove the sugar?

The Insulin Advantage

We Lower Blood Sugar

Insulin temporarily drops your glucose level. Cancer cells become desperate for fuel.

Cancer Cells Open Wide

Starving for sugar, cancer cells throw open all their doors — ready to absorb anything that looks like glucose.

Vitamin C Floods In

With no sugar to compete, Vitamin C rushes through the doors. The cancer cell has absorbed what becomes a pro-oxidant agent.

What Happens Inside the Cancer Cell

Most people think of Vitamin C as a gentle antioxidant — something you take to prevent a cold. At the concentrations we achieve through IV infusion, it becomes something very different: a powerful oxidant designed to target cancer cells.

Why Tablets Cannot Do This

Your gut can only absorb a limited amount of Vitamin C, no matter how many tablets you swallow. The cancer-targeting effect requires blood levels that are 100 times higher than what any oral dose can achieve. This is the difference between a supplement and a treatment.

Made Even Stronger With Heat

At Cancer SA, we administer IV Vitamin C under hyperthermia — controlled heat therapy using an infrared blanket. This is not arbitrary — a Phase II clinical trial (Ou et al., 2020) showed that combining IV Vitamin C with heat therapy significantly improved survival time in advanced lung cancer patients.

Benefits Beyond Cancer

Even outside of its cancer-targeting role, high-dose IV Vitamin C provides real benefits that patients notice.

What to Expect

Before your first session: A simple blood test checks that you can safely receive the treatment (G6PD enzyme and kidney function).

Starting dose: We begin at 15–25 grams and gradually increase to 50–75 grams over several sessions, monitoring your response.

During treatment: You recline comfortably while insulin is given first, followed by the Vitamin C drip under the hyperthermia blanket. The whole session takes about 2–3 hours. Sugar is given at the end to restore your blood glucose.

How often: Usually once per week as part of the full cancer treatment protocol (Day 2). Out-patient — you go home the same day.

Frequently Asked Questions

Why do you use insulin with IV Vitamin C? +

Insulin temporarily lowers your blood sugar, which forces cancer cells to open their "gates" wide — desperately looking for fuel. Instead of glucose, they absorb a massive dose of Vitamin C. This dramatically increases how much Vitamin C actually gets into the cancer cells compared to a standard infusion without insulin.

Does high-dose Vitamin C really target cancer cells? +

Research suggests it can. At the very high concentrations achieved through IV infusion, Vitamin C stops acting as the antioxidant you know from supplements. It becomes a pro-oxidant — it generates hydrogen peroxide inside cancer cells. Healthy cells have an enzyme called catalase that instantly neutralises this. Cancer cells do not have enough catalase, so the hydrogen peroxide targets them from the inside.

Why can't I just take Vitamin C tablets? +

Your body limits how much Vitamin C it absorbs through the gut. Even at very high oral doses, your blood levels will never reach the concentration needed for the cancer-targeting pro-oxidant effect. IV infusion bypasses the gut entirely and achieves blood levels up to 100 times higher than any pill could — that is the difference between a supplement and a treatment.

Is this painful or uncomfortable? +

Not at all. You sit comfortably in a reclining chair while the IV runs. Most patients read, rest, or use their phone. The insulin causes a temporary dip in blood sugar, which you may feel as mild lightheadedness, but this is carefully monitored and glucose is given immediately after the treatment window to restore your levels.

How many sessions will I need? +

IV Vitamin C is part of your weekly cancer treatment protocol — typically administered on Day 2 of each treatment week (after oxidation therapy and chelation on Day 2). Depending on individual patient needs, IV Methylene Blue may be combined with the Vitamin C infusion on the same day. The full protocol runs for 16–30 weeks (average 16–20) in two phases, but every patient’s protocol is different — Dr Pretorius tailors the treatment to your specific cancer, response, and needs.

Is it safe? +

IV Vitamin C has been used in integrative medicine for decades with an excellent safety record. Before your first treatment, we test for a condition called G6PD deficiency (a rare enzyme deficiency) to make sure you can safely receive the infusion. Kidney function is also checked. The temporary low blood sugar from insulin is carefully managed throughout.

Important Information

All treatments are provided within an integrative care framework and are tailored to the individual. They are not intended to replace necessary conventional medical care where required. Patients are encouraged to discuss all treatment options with their healthcare providers.

Individual results vary. The information on this website is for educational purposes and does not constitute medical advice.

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