In the realm of antiseptics, hypochlorous acid (HOCl) is gaining significant wide-scale understanding and use—and for good reason. It's gentle on tissues, tough on pathogens, and even produced naturally by our own white blood cells¹. On the surface, a solution's pH can seem like a small or even trivial detail, but did you know it can have a pivotal influence on the purity, stability and effectiveness of any HOCl-based preparation?

When it comes to wound care, these attributes are of critical concern and consideration when selecting the right solution(s).

That's why we're about to take a closer look at why pH plays this critical role in HOCl formulations, and what this means for healthcare professionals exploring available solutions on the front lines of patient care.

What Is HOCl, and Why Do We Use It?

One can easily become absorbed into the vast depths of literature and knowledge about hypochlorous acid. After all, it's a truly fascinating molecule. For the sake of brevity, however, let's go over the basics.

Hypochlorous acid is a powerful antimicrobial molecule that naturally mimics the immune response of our bodies¹. In fact, our white blood cells create this molecule when required to kill bacteria, viruses, fungi, and more¹. This unique chemistry gives hypochlorous acid its remarkable ability to destroy pathogens while remaining completely safe for human tissue. 

Chemically known as HOCl, hypochlorous acid is also the active molecule in what we call super oxidizing saline—a saline solution in which pure hypochlorous acid exists in its most stable, biocompatible form. 

When formulated properly, HOCl can be used externally in wound care, surgical prep, eye care, and other sensitive clinical settings because it is both effective and well-tolerated by tissue¹⁻³. However, its safety and effectiveness depends on its environment, especially its pH¹⁻³.

The pH Sweet Spot

Simply put, the pH of a solution tells us how acidic or alkaline it is, on a scale from 0 (very acidic) to 14 (very alkaline).

A manufactured hypochlorous acid solution is most stable and effective in a slightly acidic environment; specifically between pH 3.5 and 5.5¹⁻³.

Within this range¹:

• HOCl remains the dominant chlorine species, meaning it’s in its most potent antimicrobial form.
• The solution is non-toxic to healthy tissue (i.e. non-cytotoxic). This is unlike high-pH (>5.5) solutions that can cause irritation or cytotoxicity due to the presence of increasing amounts of hypochlorite (bleach) molecules in the resulting solution.
• Stability is maintained, allowing the product to retain its effectiveness over time.

What Happens Outside the Ideal pH Range?

In healthcare, we rely on antiseptics to do two things well: kill pathogens and promote patient safety and well-being. HOCl that’s out of pH range may still contain chlorine, but not in a form that offers the same biocompatibility, stability, or clinical efficacy¹⁻³.

If the pH drifts too high, HOCl begins converting into the hypochlorite ion (OCl⁻): a weaker and more irritating chlorine species¹⁻³. This is the same compound found in household bleach and in Dakin’s solution used in some wound care settings. Hypochlorite is not only less effective than pure HOCl at killing microbes, but it can also damage healthy and healing tissues: something to be aware of and avidly avoided in wound care or ocular use¹.

On the flip side, as the pH drops too low, HOCl begins to converting into increasing amounts of a highly acidic molecule called aqueous chlorine (Cl₂) which is unstable by nature and harmful in high concentrations¹⁻³.

With these consequences of a drifting pH in mind, it should be clear why formulating (and using) HOCl at the right pH isn’t just ideal, it’s essential¹.

What to Look for as a Healthcare Professional

When selecting or recommending an HOCl product, ask these questions:

• Is the pH of the product kept between 3.5 and 5.5 throughout its shelf life?
• Does the manufacturer disclose its FAC (Free Available Chlorine) / concentration and pH stability data?
• Has it been tested by a third party under real-world and extreme conditions?

Choosing a formulation with pure, stable HOCl at the optimal pH means you’re choosing a product that works as hard, and safely, as you do.

Products like Biomiq’s PureCleanse™ HOCl Wound Solution are engineered with this in mind. Existing product studies show that the product’s formulation is kept within the optimal pH range for pure HOCl, and retains its concentration of active HOCl during it’s two year shelf-life, even under environmentally stressful conditions such as UV exposure and storage temperature fluctuations¹. Moreover, controlled studies on partially empty bottles stored beyond their labeled shelf-life have shown that PureCleanse™ maintains strong clinical efficacy even up to one year beyond its expiry date. This is thanks to a proprietary manufacturing process that leverages AI and machine learning to tightly control the pH within the optimal zone for pure HOCl to exist—all without requiring the use of additives or stabilizers during manufacturing.

The Bottom Line: From Chemistry to Patient Care, pH Matters.

pH isn't just a chemistry term; it’s a clinical one. The right pH ensures that HOCl is at its strongest, most stable, and safest form¹⁻³. In wound care, infection control, and beyond, pH is the key to unlocking the full power of this biomimetic, safe and antimicrobial molecule¹⁻³.

By critically evaluating the products available to them and choosing HOCl products formulated within the ideal 3.5-5.5 pH range, healthcare professionals can ensure they're delivering the safest, most effective care possible for their patients.