For many decades iodine solutions have been successfully used as trustworthy antiseptic agents, particularly povidone-iodine solutions. They are widely used in hospitals to disinfect the skin before and after surgery. They are sold globally over the counter under a number of brand names as first aid agents to disinfect minor skin wounds.
Povidone-iodine is so well regarded for its disinfection properties that it is on the World Health Organization’s List of Essential Medicines.
For topical antiseptic purposes, povidone-iodine products are sold as a maximum 10% solution. But povidone-iodine is equally beneficial for applications in the mouth, nose, and eyes in the appropriate concentration. However, most of us are not utilizing its full potential for preventative health purposes.
What is Povidone-Iodine?
Povidone-iodine (PVP-I) is a water-soluble complex made from iodine and polyvinylpyrrolidone (PVP). The addition of a solubilizing agent, in this case PVP, allows a slow release of free iodine (iodine that is not chemically bonded to another element) from the solution, which minimizes iodine toxicity in mammalian cells. The stability of povidone-iodine in solution is greater than Lugol’s iodine or tincture of iodine.
History of Povidone-Iodine
The formulation of povidone-iodine is credited to scientists at Industrial Toxicology Laboratories in Philadelphia in 1955. In vitro tests demonstrated that the complex had notable antibacterial activity and was less toxic in mice compared to iodine tincture. Subsequent human trials confirmed that povidone-iodine was superior to other forms of iodine.
Up until the discovery of this new formula, aqueous iodine solutions were widely used to prevent and treat skin infections, but they often caused irritation at the application site. Another drawback of aqueous iodine was the greater risk of causing iodine toxicity. Povidone-iodine, however, has a very low concentration of free iodine that is released more slowly and minimizes toxicity to humans and other mammals.
Following the 1918 influenza pandemic, great interest was placed on researching the causes and treatments for the H1N1 virus. Iodine emerged as a worthy antiseptic effective against airborne viruses that caused influenza. 
How Does Povidone-Iodine Work?
The true reason why povidone-iodine works so well is credited to the release of iodine which does all the dirty work. As a member of the halogen family on the periodic table of elements, iodine’s seven valence electrons in its outermost electron shell means it’s on the hunt to acquire one more electron to be stable. This makes iodine biologically compatible and willing to grab on to structures close by to get that last electron. The eagerness to fill its outer electron shell is also what makes iodine a potent disruptor of biological activity.
PVP itself, the solubilizing agent in the complex, has no harmful effect on biological structures such as living cells and viral particles. It simply acts as the delivery vehicle for free iodine (iodine not bound to any other element). Once free iodine encounters a viral or cellular membrane, it destabilizes the membrane and then oxidizes amino acids and nucleic acids within the structure. At this point, the pathogen has been irreversibly damaged because the microbial metabolic pathways that are essential for survival have been destroyed .
Does Povidone-Iodine Kill Coronavirus?
There is no time like the present to reignite the reputation of iodine as a virucidal agent. As the COVID-19 pandemic continues to cause new infections and claim more lives, many of us have become more open to adopting protocols to keep ourselves and others virus free.
Airborne pathogens enter the body through the respiratory tract. The body is equipped with protective mucus that traps foreign matter before it can do further damage. The respiratory tract has mucous membrane linings in the sinuses, nose, mouth, throat, and lungs that trap dust, particulate pollutants, allergens, and infectious bacteria and viruses.
If you could easily and effectively disinfect your respiratory entry sites, wouldn’t you add such a protocol to your prevention routine? With specialized povidone-iodine based products, you may be one step closer to stopping respiratory infections before they start.
A recent in vitro study compared the effectiveness of povidone-iodine preparations against the virus responsible for the COVID-19 pandemic, Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2). Researchers tested four products: 10% PVP-I antiseptic solution, 1.5% PVP-I skin cleanser, 1% PVP-I gargle solution, and 0.45% PVP-I throat spray. All products achieved ≥99.99% virucidal activity against SARS-CoV-2 within 30 seconds of contact .
Broad Spectrum Antimicrobial
Think beyond COVID-19 when you consider adding povidone-iodine to your preventative health plan. Even if you practice good oral hygiene, the mouth and throat are great places for pathogenic microbes to try to unleash an attack.
Studies have shown that povidone-iodine products are also effective against other coronaviruses including the ones responsible for the SARS  and Middle Eastern Respiratory Syndrome (MERS)  epidemics in 2003 and 2012 respectively. And we can’t leave out that povidone-iodine has demonstrated inactivation of viruses that cause mumps, measles, rubella, polio, herpes, HIV, influenza and common colds .
And it’s not just viruses that are extinguished by povidone-iodine. Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginisa, and other drug-resistant bacteria can be eliminated by disinfecting the oral cavity with povidone-iodine solutions within 60 seconds .
So far, researchers have not detected any microbes resistant to iodine , while there is a growing list of antibiotic resistant bacteria. And while iodine is brutal to pathogenic bacteria, it leaves the friendly probiotic bacteria in the gut alone.
In short, povidone-iodine is effective against a wide range of gram-positive and gram-negative bacteria, bacteria spores, fungi, protozoa (single-celled parasites), and viruses.
Povidone-Iodine for Respiratory Infections
Respiratory infections are caused by a number of viral and bacterial pathogens, such as rhinovirus, influenza, coronavirus, Streptococcus, Pseudomonas, and Mycoplasma . The pathogens enter through the airways and adhere to the mucosal linings. When pathogenic colonization occurs in the oral cavity, gargling can offer a practical means of eradication.
In Japan, gargling is an accepted and recommended practice to prevent respiratory infections. Multiple studies out of Japan confirmed the effectiveness of gargling, and particularly gargling with povidone-iodine, to reduce the severity and overall risk of respiratory infections [9-11].
Povidone-iodine gargle solutions have been available for some time outside the US. Not until recently have povidone-iodine based gargles and throat sprays been available in the US, most likely due to the strict regulations placed on iodine sales because iodine can be used to manufacture illegal narcotics. Companies are now allowed to sell low concentrations, typically 0.5 to 1.25% povidone-iodine solutions for oral and nasal transmission in the US.
So unless you have an allergy to iodine, povidone-iodine based solutions should be in your medicine cabinet at all times. You never know when a flesh wound or sore throat could turn into something more sinister. Just make sure you’re using the right products with acceptable povidone-iodine concentrations for topical, oral, nasal, or ocular applications as not all solutions are formulated for the same use.