The Physics: Henry’s Law and Oxygen Dissolution

Under normal atmospheric conditions, haemoglobin carries approximately 97% of oxygen in the blood. Plasma carries the remainder — approximately 0.3ml O² per 100ml blood — a physiologically insignificant quantity. Henry’s Law states that the concentration of a dissolved gas in a liquid is proportional to the partial pressure of that gas above the liquid.

At 1.35 ATA — the upper end of our therapeutic range — plasma oxygen concentration increases meaningfully above baseline. Crucially, this dissolved oxygen is independent of haemoglobin and diffuses directly through plasma into tissues based on concentration gradients. Any tissue with compromised circulation — from inflammation, injury, swelling, or vascular insufficiency — receives significantly improved oxygen delivery even at these gentle pressures.

Hard-shell chambers operating at 1.1–1.35 ATA initiate the same biological responses as higher-pressure clinical chambers — angiogenesis, mitochondrial restoration, anti-inflammatory modulation, stem cell mobilisation — and the evidence base for wellness-range pressures is growing independently of the higher-pressure clinical literature.

Oxygen’s Downstream Mechanisms

Angiogenesis

Hyperbaric oxygen stimulates vascular endothelial growth factor (VEGF) and related angiogenic factors, promoting new blood vessel formation in hypoxic tissue. This effect persists after therapy — the vasculature remains, permanently improving oxygen delivery. Angiogenesis is central to HBOT’s efficacy in chronic wounds, radiation injury, and post-surgical healing.

Mitochondrial Function and Cellular Energy

Cellular energy production via oxidative phosphorylation is directly oxygen-dependent. In hypoxic or metabolically compromised states, mitochondrial function is impaired and ATP production falls. Hyperbaric oxygen restores mitochondrial substrate availability, increases ATP synthesis, reduces reactive oxygen species accumulation, and upregulates mitochondrial biogenesis markers. This mitochondrial restoration is central to documented benefits in chronic fatigue, post-viral illness, and cognitive decline — conditions addressed in our REBUILD programme.

Stem Cell Mobilisation

A course of hyperbaric sessions produces a significant increase in circulating CD34+ stem cells — progenitor cells capable of differentiating into new tissue, vascular, and neural cells. The mechanism involves hyperbaric-mediated nitric oxide production in bone marrow, which mobilises these cells into circulation. Stem cell mobilisation provides a mechanistic basis for HBOT’s observed benefits in tissue regeneration and neurological recovery.

Immune Modulation

Hyperbaric oxygen restores the oxidative burst capacity of neutrophils and macrophages in hypoxic tissue, where immune function is impaired. Simultaneously, hyperoxia modulates inflammatory cytokine production, reducing TNF-α, IL-1β, and IL-6 in chronic inflammatory states without suppressing the acute immune responses the body still requires.

Hydrogen: Selective Antioxidant Activity

Molecular hydrogen (H²) is the smallest molecule in biology. Its extreme membrane permeability allows it to cross the blood-brain barrier, penetrate mitochondrial membranes, and enter cell nuclei — compartments that most therapeutic agents cannot access.

Selective Neutralisation of Harmful ROS

The body’s reactive oxygen species (ROS) are not uniformly harmful — many serve essential signalling functions that must be preserved. Hydrogen is chemically selective: it reacts readily with the hydroxyl radical (·OH) and peroxynitrite (ONOO−) — the two most cytotoxic reactive species, responsible for direct DNA damage, lipid peroxidation, and protein oxidation — while leaving other ROS largely intact.

In plain terms: hydrogen acts as a precise clean-up tool. It neutralises the specific reactive molecules that cause cellular damage, without interfering with the reactive molecules the body needs for normal signalling. This selectivity is what distinguishes hydrogen from broad-spectrum antioxidants, which can disrupt normal cellular chemistry.

Anti-Inflammatory Signalling

Hydrogen modulates multiple inflammatory pathways independently of its antioxidant effects. It suppresses NF-κB activation — the master regulator of inflammatory gene expression — reduces NLRP3 inflammasome activation, and downregulates pro-inflammatory cytokine production including TNF-α, IL-1β, IL-6, and IL-12. These effects have been demonstrated across neurological, metabolic, cardiovascular, and musculoskeletal conditions.

The Complementary Rationale

Oxygen and hydrogen address opposite sides of the same cellular environment. Oxygen drives repair but generates oxidative byproducts at high concentrations — specifically, the hydroxyl radical (·OH) and peroxynitrite (ONOO−) are produced in greater quantities as oxygen delivery increases. Without intervention, these species cause the very cellular damage that therapy aims to prevent, placing a ceiling on the therapeutic benefit that can be safely achieved through oxygen alone.

Hydrogen neutralises these two specific species in real time, removing the limiting factor and allowing the full repair-driving, angiogenic, and mitochondrial benefits of hyperbaric oxygen to be realised without the oxidative cost. The combined protocol is therefore not simply two therapies delivered simultaneously — it is a protocol in which each gas actively enables the other to work more effectively.

Clinical Evidence by Condition

Post-Viral Illness and Chronic Fatigue

A 2022 double-blind RCT published in Nature found that a 40-session HBOT protocol in long COVID patients produced significant improvements in cognitive function, fatigue, sleep quality, and pain compared to placebo. Functional MRI showed increased perfusion in previously hypoxic brain regions. The proposed mechanisms — mitochondrial restoration, cerebral oxygenation, and neuroinflammation reduction — align with the established pathophysiology of post-viral illness and chronic fatigue syndrome. This application sits at the centre of our RESET and REBUILD programmes.

Neurological Rehabilitation

HBOT has an established evidence base in traumatic brain injury, stroke rehabilitation, and post-concussion syndrome. A series of studies from the Sagol Center in Israel demonstrated significant cognitive and neurological improvements in TBI patients years after injury, when conventional medicine considered recovery plateaued. The mechanisms — angiogenesis in the perilesional penumbra, neuroinflammation reduction, mitochondrial restoration in neural tissue — are well-characterised. Hydrogen’s blood-brain barrier penetration extends the therapeutic reach into cellular compartments HBOT alone does not fully address.

Cancer — Supportive Care and the Hypoxia Hypothesis

Hyperbaric oxygen has an established clinical role supporting cancer patients through treatment and recovery. For patients undergoing radiotherapy, it accelerates healing of radiation-damaged tissue — an approved indication in multiple jurisdictions. For those on chemotherapy, it helps mitigate oxidative side effects and supports tissue integrity during treatment.

The more significant area of emerging research concerns tumour hypoxia. Most solid tumours develop in oxygen-depleted microenvironments. This hypoxia is not incidental — it is actively exploited by tumours to resist treatment. Radiation therapy and several chemotherapy agents are significantly less effective in low-oxygen environments. Tumour cells adapted to hypoxia also upregulate pathways that promote invasion and metastasis.

The hypothesis that hyperbaric oxygen can disrupt this protective hypoxic environment — making tumours more vulnerable to radiotherapy and certain chemotherapy agents while being hostile to the conditions tumour cells prefer — is supported by a growing body of preclinical and early clinical evidence. Several trials are ongoing.

Hydrogen’s role in an oncological context is primarily protective — reducing the oxidative and inflammatory burden of cancer treatment, supporting quality of life, and potentially reducing treatment side effects. Research in hydrogen-rich water and hydrogen gas inhalation in cancer patients is ongoing across multiple centres.

Wound Healing and Post-Surgical Recovery

This represents HBOT’s most extensively documented application, with regulatory approval in multiple jurisdictions for conditions including diabetic foot ulcers, radiation injury, necrotising fasciitis, and compromised grafts. Recovery from surgery, cosmetic surgery recovery, and post-surgical wound care all benefit from the same mechanisms: angiogenesis into hypoxic wound tissue, enhanced collagen synthesis, improved neutrophil function, and stem cell mobilisation. Meta-analyses consistently show improved healing rates and reduced complication rates.

Chronic Pain, Fibromyalgia and Endometriosis

Tissue hypoxia is increasingly recognised as a driver of chronic pain. A randomised controlled trial in fibromyalgia patients showed significant reductions in pain scores following HBOT, with functional brain imaging showing normalisation of abnormal pain-processing patterns. Hydrogen’s suppression of central and peripheral inflammatory mediators provides a complementary anti-nociceptive mechanism.

Endometriosis — a condition of chronic pelvic inflammation, oxidative stress, and immune dysregulation — sits within the same mechanistic framework. Endometrial lesions thrive in hypoxic, high-inflammation environments; hyperbaric oxygen disrupts this environment while hydrogen suppresses the NF-κB and cytokine pathways implicated in lesion growth and pain sensitisation.

Skin Health — Eczema and Inflammatory Dermatological Conditions

Inflammatory skin conditions including eczema, psoriasis, and atopic dermatitis share core mechanisms with the conditions HBOT addresses systemically: dysregulated inflammation, impaired epidermal barrier function, oxidative stress, and reduced tissue oxygenation. Hyperbaric oxygen improves dermal and subdermal oxygenation, accelerates epidermal repair, and stimulates the angiogenic and growth factor responses that support skin regeneration.

Hydrogen’s selective neutralisation of hydroxyl radicals — which are elevated in inflamed skin tissue and contribute directly to barrier disruption and keratinocyte damage — provides a complementary intracellular mechanism. The anti-inflammatory cytokine modulation common to both gases directly addresses the inflammatory mediators that drive eczematous flare cycles.

Biological Ageing — Telomeres and Senescence

A landmark 2020 study (Hachmo et al., Aging) demonstrated that a protocol of 60 hyperbaric oxygen sessions produced mean telomere lengthening of 20–38% across immune cell populations, alongside a 10–37% reduction in senescent cells — the first non-pharmacological, non-genetic intervention to demonstrate simultaneous reversal of both measurable biological ageing markers in humans. Hydrogen’s role in protecting telomeric DNA from oxidative damage and reducing the SASP (senescence-associated secretory phenotype) extends this longevity application.

Clinical Evidence Summary

In Summary

Hyperbaric oxygen and hydrogen therapy works through two primary and complementary mechanisms. Hyperbaric pressure dissolves oxygen directly into plasma, bypassing circulation to reach hypoxic tissues and triggering angiogenesis, stem cell mobilisation, mitochondrial restoration, and immune modulation. Molecular hydrogen crosses every biological membrane to selectively neutralise the most damaging reactive oxygen species while modulating inflammatory gene expression throughout the body.

The clinical evidence spans wound healing, neurological rehabilitation, post-viral illness, chronic pain, cancer supportive care, and measurable reversal of biological ageing markers. The emerging research into tumour hypoxia disruption adds a further dimension that is scientifically compelling and actively being investigated.

At 1.1–1.35 ATA in a hard-shell chamber, sessions of 30–90 minutes are well-tolerated, non-invasive, and accessible — with the same fundamental mechanisms as higher-pressure clinical protocols and a growing independent evidence base at wellness pressure ranges.