Smell, memory & sensory clarity

Why smell, taste, memory, and attention can feel so connected

A scent can bring back a vivid emotional memory in an instant. That is not a small thing: smell sits close to the brain systems involved in memory, emotion, flavour, and attention.

The entorhinal cortex is especially important here: it is a gateway into the hippocampus, the brain system central to forming and retrieving memories. Human neuroimaging research also finds stronger resting functional connectivity between primary olfactory cortex and hippocampal networks than between the hippocampus and several other sensory systems.

So smell tests are not merely testing the nose. Tasks such as identifying an odour also require the brain to recognize, retrieve, name, and connect that scent to previous experience.

Smell and cognitive decline

In ageing research, poorer smell—especially difficulty identifying odours—has repeatedly been associated with later cognitive impairment and with neurodegenerative diseases such as Parkinson’s and Alzheimer’s. It is considered a potential early marker, not a diagnosis on its own.

A likely reason is that the olfactory and memory systems overlap anatomically. If a process affects the olfactory bulb, entorhinal cortex, hippocampus, inflammation, small-vessel circulation, or broader neural networks, it may show up as both weaker smell and weaker memory or attention.

Why COVID made this obvious

COVID made this connection easier to notice. Loss or distortion of smell was one of its most recognizable symptoms, while many people also described brain fog, memory slips, slowed thinking, fatigue, and difficulty concentrating.

A 2023 review of 17 studies found that 12 studies reported significantly poorer cognitive performance in people with COVID-related olfactory dysfunction; four found no association, so the overall finding is meaningful but not absolute.

More recent studies have strengthened the pattern:

• In a post-COVID cohort, people with reduced smell performed worse cognitively than healthy controls, and olfactory impairment was associated with cognitive performance, fatigue, and general health. Read the study
• A longitudinal study of people with persistent COVID-related smell dysfunction found impaired cognitive performance in the early long-COVID phase compared with people whose smell had returned. Read the study
• MRI and behavioural research in people recovering from COVID found differences in decision-making-related brain activity, white-matter integrity, and cortical thickness in people who had experienced anosmia. Read the study

What that does—and does not—mean

It does not mean every person who temporarily loses smell has brain damage or will develop cognitive decline. Most acute COVID smell loss improves, and cognitive symptoms can occur with or without smell loss. Read more

But persistent smell loss may be a useful clue that the olfactory system—and possibly related brain networks—has not fully recovered. In that sense, smell can function as a visible, everyday marker of something deeply connected to memory, emotion, attention, and the wider sensory network.

This is also why an ozone/MCI paper can be interesting: a change in smell and a change in a cognitive screen moving together is biologically plausible because those systems are not separate—they are closely linked. It still does not establish a treatment mechanism, but the pairing itself is not random or far-fetched.

How this relates to ozone therapy + my patches

Smell seems simple, yet it sits at an intersection of memory, emotion, flavour, attention, and broader brain function. Observing sharper smell or richer taste can therefore feel meaningful—not only because a scent is easier to detect, but because of how the brain is receiving and interpreting sensory information.

Popular ozone therapies

MAH + EBOO

MAH is a small-batch draw–mix–return procedure. EBOO is a continuous, machine-assisted blood circuit—closer in setup to dialysis—that aims to expose a larger cumulative volume of blood to ozone/oxygen during one session.

Practical differences

MAH / 10-pass: This approach uses repeated draw–mix–return cycles. It generally uses less machinery and has fewer circuit-related demands. Standard MAH treats a smaller blood volume, while 10-pass repeats the process for greater cumulative exposure.

EBOO: This is a continuous blood circuit through a machine. It processes a larger cumulative blood volume in an uninterrupted run and typically involves two IVs, anticoagulation, a pump/membrane circuit, and close monitoring.

Budgeting for MAH

Clinics commonly suggest a series rather than one session. One Vancouver provider describes a typical MAH course as six to ten treatments, often once or twice weekly.

• 6 sessions: approximately CAD 1,050–1,500 at CAD 175–250 per session
• 10 sessions: approximately CAD 1,750–2,500 at CAD 175–250 per session

Provincial health insurance generally does not cover these services. Some extended plans may reimburse part of an IV or naturopathic service, depending on the practitioner and plan. EBOO is often listed around CAD 1,250–1,450 per treatment.

What people commonly report after 10-pass

Online patient anecdotes are not clinical evidence, but the recurring themes include:

• Clearer thinking or reduced brain fog: sometimes during treatment, sometimes after several sessions
• More energy or stamina: some people describe fatigue first, followed by a noticeable lift
• Improved mood or a calmer nervous system: feeling lighter, more positive, or less overwhelmed
• Less pain, stiffness, or heaviness
• Better sleep
• Stronger sensory awareness, including sharper smell or richer taste
• A temporary reset, with some people noticing benefit for several days

Prolozone

Prolozone is a localized injection treatment for a particular painful joint, tendon, ligament, or soft-tissue area. Unlike MAH and EBOO, it is not a blood-based systemic procedure.

It is commonly marketed for knee, shoulder, hip, tendon, ligament, plantar fascia, bursitis, and some neck or back pain concerns. A clinician injects small volumes of an oxygen–ozone gas mixture—often with local anaesthetic and/or other solutions—into or around the target area.

A realistic Canadian planning range is approximately CAD 200–400 for one straightforward area per visit, plus possible consultation, imaging/ultrasound, and supply fees. Multi-site or spine-focused care can cost more. Ask for the expected all-in cost of a recommended series, not only the price of one appointment.

Ozone: antibacterial, antifungal + antimicrobial

Ozone is antimicrobial because it can damage or inactivate bacteria, fungi/yeasts, viruses, and some protozoa through oxidation, particularly when used directly on surfaces, wounds, water, or other local applications. This is why ozone is used as a disinfectant and why alternative-health practitioners often describe it as antibacterial and antifungal.

Ozone’s direct antimicrobial action is generally described as oxidative damage to microbial membranes, proteins, and genetic material. It is important not to treat that broad property as a guarantee that a systemic ozone procedure will resolve a particular internal infection.

Ozone + mycotoxins

At a chemistry level, ozone can oxidize and transform many mycotoxin molecules on direct contact. From a holistic ozone-therapy perspective, however, ozone is often framed less as something that “chases down” mycotoxins directly and more as a system-wide support tool that may help the body cope with the stress of mold exposure and support its own clearing processes.

The holistic framework

Practitioners commonly describe mold/mycotoxin burden as involving several overlapping layers:

• Ongoing exposure or re-exposure
• A taxed immune and nervous system
• Inflammation and oxidative stress
• Slower bile flow, lymph movement, bowel clearance, or cellular energy production
• Biofilm, sinus, gut, or dental factors that may make recovery feel stalled

Within this framework, MAH, 10-pass, or EBOO may be used with the intention of supporting circulation, immune regulation, oxygen use, and resilience—rather than as a literal internal disinfectant or a direct chemical “mycotoxin eraser.”

How ozone is said to help

• Cellular energy and oxygen utilization, sometimes felt as clearer thinking or a lift in energy
• Immune recalibration, particularly when someone feels reactive or chronically inflamed
• Circulation and microcirculation, associated with delivery of nutrients and removal of metabolic waste
• Lymphatic and drainage support, often paired with hydration, movement, sauna if tolerated, bowel regularity, or massage
• Inflammatory balance, with the aim of easing a wired, tired, puffy, brain-foggy state
• Microbial terrain, particularly when sinus, gut, dental, or wound-related imbalance is also suspected

How people say it feels

Anecdotally, people pursuing ozone for mold-related concerns may report a clearer head, improved energy, better mood, or deeper sleep. Others report a short-lived increase in fatigue, headache, nausea, body aches, anxiety, brain fog, or temporary sensitivity to smells and chemicals.

Some holistic clinics call the difficult response a detox or healing response. A more useful approach is to treat it as feedback about dose and tolerance: severe or escalating symptoms are not something to push through.

Smell, taste + mold concerns

From a holistic mold-illness perspective, practitioners commonly view cognitive symptoms, smell changes, and taste changes as potentially connected, especially after time in a damp or mold-affected environment. The framework often includes the nervous system, sinuses and olfactory pathway, inflammation, sleep, stress response, and gut–brain influences.

People may describe diminished or distorted smell and taste, stronger sensitivity to fragrances or musty odours, food aversions, brain fog, forgetfulness, word-finding difficulty, reduced focus, and slower processing. In this perspective, the symptoms can fluctuate together rather than appearing as isolated problems.