Hyperbaric Oxygen Therapy and Cancer: Why Timing Matters With Vitamin C and Artemisinin

​Introduction

One of the first things you learn when you start looking into integrative oncology is that timing is crucial.

It’s not just about when you take your supplements or how you fast before chemotherapy. The order in which therapies are used can determine whether they work together or cancel each other out.

Take hyperbaric oxygen therapy (HBOT). Depending on who you talk to, it may come first or last in a treatment plan. Some clinics place patients in the chamber before an infusion, while others do so afterward. Both arguments have merit. However, when you introduce high-dose vitamin C (IVC), and compounds like artemisinin, the order isn’t just a matter of preference. It’s grounded in chemistry.

Here’s how I apply it, why the sequence is important, and what the research shows.

Vitamin C: Antioxidant or Pro-oxidant?

Vitamin C is well-known as an antioxidant. At low doses – oral tablets, liposomal sachets, or even small IV doses – it scavenges reactive oxygen species (ROS). This is the basis for most common advice: “Take your vitamin C after HBOT to quench the oxidative burst.”

However, at high doses (≥75-80g+ IV), vitamin C changes its role completely. Instead of neutralising ROS, it produces them. At these pharmacologic levels, ascorbate (the chemical name for Vitamin C) interacts with catalytic metals, generating extracellular hydrogen peroxide (H₂O₂).

Tumour cells are particularly sensitive to this change. Many cancers have low levels of catalase and glutathione peroxidase (GPx), making it hard for them to break down H₂O₂. The peroxide seeps into the tumour, overwhelms its defences, and induces oxidative stress that can harm or kill cancer cells.

In other words, at oxidative doses, vitamin C shifts from being a protective shield to a potent weapon.

Adding Artemisinin to the Mix

Artemisinin – a compound from sweet wormwood – also has an oxidative effect. It has a peroxide bridge that, when exposed to iron (which tumour cells accumulate), breaks apart and releases free radicals.

This creates another wave of oxidative damage, especially effective in iron-rich tumor environments.

When combined with high-dose IVC, the idea is to prep tumour cells with oxidative stress, then unleash artemisinin as a second surge of redox disruption.

Here’s where I get mine: Artemisinin – not an affiliate link

Where HBOT Comes In

Hyperbaric oxygen therapy (HBOT) involves saturation. By breathing near 100% oxygen at pressures of 1.5–3 atmospheres, you can dissolve much more oxygen into your blood plasma than usual. This oxygen infiltrates tissues, even poorly supplied tumour areas, at concentrations up to 20 times higher than normal.

On its own, HBOT improves oxygen delivery and boosts immune function while decreasing hypoxia – one of cancer’s advantages for survival.

But when used after IVC and artemisinin, HBOT becomes a powerful enhancer.
The sequence is as follows:

1. IVC first (≥80 g): plasma vitamin C peaks, peroxide starts to flow.
2. Artemisinin second: adds oxidative free radicals within iron-rich tumour cells.
3. HBOT last: floods tissues with oxygen, deepening and extending the ROS surge, pushing H₂O₂ further into already stressed tumour cells.

The result?
A powerful oxidative storm aimed at exploiting cancer’s weak antioxidant defences.

Why Not HBOT First?

Some proponents of HBOT argue for “HBOT first, then IVC.” This is reasonable if you use vitamin C at antioxidant doses. In that case, IVC would neutralise HBOT-induced ROS.

However, if you aim for oxidative stress rather than antioxidant support, the order reverses. You want the vitamin C’s pro-oxidant effect already in progress when oxygen is administered.

In simple terms:

• Antioxidant dosing: HBOT then vitamin C.
• Oxidative (pharmacologic) dosing: Vitamin C then artemisinin then HBOT.

Evidence So Far

This isn’t merely theoretical. Several studies and clinical protocols have examined the sequence:

• Monti DA et al. (2012): A pilot study of HBOT combined with high-dose vitamin C in advanced cancer showed it was feasible and safe.
• Verrax & Calderon (2009): Reviewed pharmacologic ascorbate as a pro-oxidant in cancer.
• Mikirova et al. (2016): Found that combining high-dose vitamin C and HBOT enhanced cancer cell line killing in the lab.
• Riordan Clinic Protocol (2018): Clinical experience supports IVC as an oxidative therapy, with timing adjusted for synergy.

Case reports and small trials suggest the IVC-first sequence is safe if two precautions are observed:

1. The infusion site must be closed before pressurisation (at least 5–10 minutes).
2. Avoid contraindicated chemotherapy drugs (bleomycin, doxorubicin, cisplatin) due to sensitivity to oxygen.

Practical Points

From my own experiences and what the literature suggests:

• Wait time matters: Allow 30–60 minutes after infusion for plasma ascorbate to peak and for peroxide production to start.
• Keep antioxidants away: Don’t take oral or liposomal vitamin C or other antioxidants around HBOT, as they can reduce the ROS effect.
• Stacking with artemisinin: Timing artemisinin between IVC and HBOT appears to provide an additional boost in oxidative activity.
• Protocol consistency: Repetition is essential. One-time sessions do not produce the same metabolic change.

My Personal Protocol

Here’s how I apply it in practice:

• IV Vitamin C: an above 80g dose
• Artemisinin: taken after IVC, before entering the chamber.
• Hyperbaric oxygen therapy: 90 minutes at 1.5–2.0 ATA, once the infusion has peaked.

The sequence now feels clinical, almost ritualistic. I sit through the IV drip, take the artemisinin, and step into the chamber. Pressure builds, my ears pop, and I visualise oxygen flowing through my tissues, fuelling an unseen storm inside the tumour.

It’s not glamorous – or maybe it is now Brian Johnson (the longevity bio-hacker) is on the band-wagon. It probably won’t look great on social media. But it feels like I finally have chemistry on my side.

Beyond Cancer: HBOT’s Other Benefits

Even outside of cancer treatment, HBOT is used for:

• Radiation damage repair
• Wounds that won’t heal
• Neurological recovery (stroke, TBI)
• Reducing inflammation
• Improving mitochondrial function

For me, those extra benefits – quicker recovery and less fatigue – make the demands of HBOT sessions more manageable.

Conclusion

Cancer thrives in low oxygen and low pH conditions. Hyperbaric oxygen therapy is one method to change that. But when it’s used after high-dose vitamin C and artemisinin, it becomes more than just oxygen delivery; it becomes part of a well-timed redox strategy.

The sequence is crucial: IVC then artemisinin then HBOT. Timing is everything when you’re using chemistry effectively.

It’s not a cure. It’s not a miracle. But it is one more way to improve your chances. And in the stage IV world, improving your chances is what matters most.