Does Hydrogen Peroxide Kill Mold?

Killing Mold With Hydrogen Peroxide

Table of Contents

Basements are filled with a musty and stale odor.  More often than not, this odor is caused by mold outgrowth.

A simple water leak coupled with poor ventilation can quickly lead to a buildup of nasty microbes known as molds. Other favorite sites of these nasty molds are the ceiling and walls of poorly ventilated bathrooms.

Apart from being hideous and smelly, the molds can be somewhat dangerous. Hypersensitivity reactions like asthma, rashes, nausea are some of the common manifestations of inhaling mold spores.

However, like bacteria and viruses, molds are also pathogenic. And when it comes to eliminating pathogens, there is no greater force than hydrogen peroxide!

So the question arises, how effective is hydrogen peroxide killing in molds? And if so, how can you clean mold and mold stains from your house using hydrogen peroxide?

So without further ado, let’s begin!

Hydrogen Peroxide’s Antifungal Properties to Kill Mold

Hydrogen peroxide has established itself as one of the most potent disinfecting agents known to humanity.

The disinfecting properties of hydrogen peroxide can be attributed to the loose oxygen atom bound to its structure.

This loose oxygen atom makes hydrogen peroxide an amazing oxidizing agent, and disinfecting properties are just a consequence of that.

Oxygen is one of the best therapeutic tools for antimicrobial activity. That’s because it is able to react with and eliminate all kinds of pathogens without any discrimination.

They include highly virulent bacteria like staph aureus—viruses like COVID-19 and molds, which are a type of fungi. In the subsequent headings, we will look into other antifungal properties of hydrogen peroxide in depth in the subsequent headings!

Fungicide Action of Hydrogen Peroxide

The most important factor of fungal growth, which is targeted by hydrogen peroxide, is its tendency to grow in damp and poorly oxygenated places.

Most fungi are anaerobes (do not require oxygen for growth) and either die when high amounts of oxygen are given or stop their growth.

And if you know the chemistry of hydrogen peroxide, you can easily predict how this chemical can effectively react with the anaerobic fungi and create a toxic environment for fungi through its oxygen.

An article published in Springers points out how hydrogen peroxide induces death in box molds and makes them aseptic.

Another factor contributing to the amazing antifungal action of hydrogen peroxide is its tendency to react with the carbohydrate cell wall.

The fungal cell wall predominantly comprises chitin and other similar complex carbohydrates.

When oxygen stress is given to these compounds via hydrogen peroxide, they change their composition, and the fungal cell undergoes death (apoptosis).

This phenomenon is beautifully illustrated in a ScienceDirect article. The paper shows how hydrogen peroxide is able to inactivate Neosartorya fischeri and Paecilomyces variotti, two of the common paper box molds.

Therefore, it is evident from research and theory how hydrogen peroxide can be amazing against fungi, especially household molds.

Why Hydrogen Peroxide?

Though hydrogen peroxide effectively removes fungi and molds, so are a dozen other disinfecting agents. So why do we choose hydrogen peroxide above all?

One of the factors is indeed the research evidence pointing towards the efficacy of hydrogen peroxide against common molds and fungi.

The second and more important thing about hydrogen peroxide is its non-toxic byproducts.

Where disinfecting agents like bleach and ammonia are strong agents to clear molds (may even be stronger than certain concentrations of hydrogen peroxide), they release harmful byproducts like chlorine and nitrates.

These are not only harmful to the surface you are using it on but also to the human body.

On the other hand, hydrogen peroxide liberates water and oxygen after it has reacted with the substrate.

The reactive oxygen liberated either undergoes a reaction with the substrate (in our case, fungal cell wall) or joins another oxygen to form free molecular oxygen.

Therefore, for procedures that are particular to homes, in our case, cleaning mold infestation, you’d want to pick a disinfecting agent that is completely safe and sound. And hydrogen peroxide is a strong candidate!

Using Hydrogen Peroxide to Kill Mold

Now that we know some of the amazing properties hydrogen peroxides have against nasty molds, we can move on to discussing the steps on how to perform the procedure for yourself as well.

Hydrogen peroxide is the king of household chemicals. Not only is it highly effective, but the ways you can use it in procedures are also simple and easy to follow.

We will start by discussing how you can use hydrogen peroxide for the removal of active molds, the notorious pathogen responsible for infecting hundreds of homes.

1. Killing Active Mold

As we have discussed above, common household molds are vulnerable to hydrogen peroxide and vinegar damage. In addition, the acidic environment vinegar provides increases the effectiveness of hydrogen peroxide, which reacts with the fungal cell wall and organelles, rendering it useless.

White vinegar and hydrogen peroxide together can kill well over 80% of common mold species.

Material You Need:

The procedure is fairly simple, and the ingredients are available in almost all homes:


Now that we have gathered our equipment and put on our gloves, it’s time to get on with the cleaning!

  • Start by opening doors and windows, which will allow fresh air to breeze inside the room.
  • Take a spray bottle and pour half a cup of 3% hydrogen peroxide
  • Then dilute the solution using ⅓ cups water
  • Add in a few tablespoons of white vinegar and close the bottle
  • Spray this solution wherever mold is detected
  • You will start to notice the “sizzling” action of hydrogen peroxide
  • Wait until the reaction stops and start scrubbing the surface after 10 minutes
  • Make sure to get all of the residue and spores of mold as you are wiping away hydrogen peroxide
  • Repeat the procedure as needed

And that’s it! With hydrogen peroxide, cleaning molds is as easy as cleaning windows.

Take Care of the Following:

Though hydrogen peroxide is an astoundingly safe and effective chemical, you should be careful during the procedure nonetheless.

Some of the precautions are:

  • The extent of mold spread, make sure to check the air ducts as well
  • The surface you are applying the solution on shouldn’t be brittle or prone to discoloration.
  • Make sure to avoid direct contact with the chemical or mold
  • Keep a safe distance between you and mold
  • Give hydrogen peroxide adequate time to react (about 20-30 minutes) before moving on to the next step.

2. Removing the Nasty Mold Stains

You have successfully neutralized all of the active molds in your house. What’s next?

Unfortunately, in addition to being nasty pathogens, molds release some kind of pigments as well. These pigments cause characteristic yellowing/darkening of the walls.

The pigments are organic and cling to walls very firmly. Therefore, you can’t remove them with regular acid/water and cloth.

Fortunately for hydrogen peroxide enthusiasts, this problem is treated by the said chemical as well!

Stuff You Need:

The ingredients for this procedure are very similar to the previous one. However, you don’t particularly need vinegar to remove stains. Hydrogen peroxide is a potent bleaching agent itself.

  • 3% hydrogen peroxide
  • Spray bottle
  • Water


Removing mold stains from walls using hydrogen peroxide is as easy as cleaning windows!

What you have to do is:

  • Take a spray bottle and pour half a cup of 3% hydrogen peroxide
  • Then dilute the solution using ⅓ cups water
  • Spray this solution wherever mold stains are seen
  • You will start to notice the “sizzling” action of hydrogen peroxide
  • Wait until the reaction stops and start scrubbing the surface after 10 minutes
  • Make sure to wipe the surface thoroughly and clean hydrogen peroxide off
  • Repeat the procedure as needed

And voila! The amazing bleaching properties of hydrogen peroxide make your job just that much easier!

Take Care of the Following:

Hydrogen peroxide is a strong bleaching agent in addition to being a disinfecting agent. And with great power comes great responsibility!

While using hydrogen peroxide, be mindful of the surface you are using it over. Many surfaces are prone to discoloration and react with hydrogen peroxide.

Moreover, make sure to keep a distance from reacting hydrogen peroxide on molds. The liberated particles can go inside your lungs and lead to various hypersensitive reactions.

3. Getting Rid of Black Mold

Black molds are even more stubborn and hideous when it comes to infesting your homes.

Not only are they more apparent, but they are much more difficult to clean.

And did we mention, black molds are known to cause many respiratory diseases and eye irritations? Making your home a difficult place to live in!

But worry not! For hydrogen peroxide comes once again to your rescue.

The amazing oxidizing and disinfecting properties can even neutralize even the most stubborn of pathogens, black molds being one of them.

Stuff You Need:

The ingredients for cleaning a black mold infestation are quite similar to the regular mold. However, we will not dilute hydrogen peroxide with water in this procedure.

  • Vinegar
  • Spraying bottle
  • 3% Hydrogen Peroxide


  • Make sure to equip yourself with gloves and safety glasses before beginning the procedure
  • Open windows and doors to allow fresh air to come in
  • Now, take a spray bottle and pour half a cup of 3% hydrogen peroxide
  • Add in a few tablespoons of white vinegar and close the bottle
  • Spray this solution wherever mold is detected
  • You will start to notice the “sizzling” action of hydrogen peroxide
  • Wait until the reaction stops and start scrubbing the surface after 10 minutes
  • Make sure to get all of the residue and spores of mold as you are wiping away hydrogen peroxide
  • Repeat the procedure as needed

Take Care of the Following:

Although it is improbable that hydrogen peroxide will cause any serious side effects if used at lower concentrations like 3%.

However, with vinegar, you have to be careful as it reacts with vinegar to form peracetic acid (which is toxic to the body if inhaled in higher amounts)

So make sure to keep a distance between you and the reaction, as black mold particles can also lodge inside your airway tract.

4. Dealing With the Odor

Pungent odors are one of the worst (yet beneficial) features of mold growth.

Although the odors are very harsh and difficult to withstand, they are the ones that can help you find mold growth in the first place.

Once you have successfully decontaminated your house from molds, the next step is to remove the lingering odors associated with a mold infestation.

Fortunately for us, hydrogen peroxide can also act as a deodorant agent. This is because the oxygen inside the chemical reacts with most of the compounds responsible for the smell.

So after you are done with cleaning using hydrogen peroxide, a significant decrease in moldy smell will be observed.

However, you can follow this procedure to put the final nail in the coffin!

Stuff You Need:

  • Bowl
  • Vinegar
  • Lemon
  • Saltwater


  • Take a regular bowl and pour some vinegar in
  • Cut a fresh lemon in half and place it inside the vinegar solution
  • Take another bowl and pour some saltwater in
  • Place a few of such bowls around the previously contaminated room
  • The lemon zest, acidic vinegar, and salt absorb the pungent odors in the room
  • In about a few days or so, your room will be free from all smell

With this simple household procedure, you can effectively free your room with the pungent moldy smell!

Take Care of the Following:

The salt, lemon, and vinegar that you used in this procedure will absorb smell-causing bacteria.

Therefore, they should not be used in food or drinking, and make sure to discard them as soon as the smell is gone.

Rinse the water and vinegar inside the sink and discard lemons in a trash can outside.

Sometimes, the mold growth in the house can be extensive and requires an expert for complete treatment.

Is It Safe to Use Hydrogen Peroxide on Mold?

Molds are one of the nastiest house pests you can face. Their high reproductive rate and difficulty in neutralizing make it essential to take immediate action.

Hydrogen peroxide is one of the most common and effective disinfecting agents we have at our homes. But the question of the hour is whether it is safe to use?

When it comes to disinfecting agents, hydrogen peroxide is as safe as they get. Agents like bleach, though effective, are highly toxic.

They contain chemicals like chlorine which are detrimental to human skin and health.

Hydrogen peroxide, on the other hand, is a mild and relatively safe chemical. In addition, unlike other disinfecting agents, the byproducts liberated by hydrogen peroxide are water and oxygen.

Water, as we know, is the chemical of life, and oxygen is essential for breathing!

However, there are certain risk factors associated with a higher concentration of hydrogen peroxide as well.

Inhalation of hydrogen peroxide vapors may lead to irritation of sensitive mucous membranes. Ingestion can lead to inner burns.

Though these risk factors are associated with higher hydrogen peroxide concentrations, the 3% hydrogen peroxide we use in our procedure seldom causes any side effects.

What Concentration of Hydrogen Peroxide is Best for Killing Mold?

Hydrogen peroxide is one of the most versatile chemicals we have on the market. Therefore, industries have produced various concentrations of hydrogen peroxide, which directly relate to their tasks.

The spectrum ranges from the mild 0.5% hydrogen peroxide concentration to the strong 90% hydrogen peroxide. As the concentration of hydrogen peroxide increases, the tasks at hand get severe. Food grade hydrogen peroxide, which is 35%, is used in the packaging and canning of food products.

The highest available concentration of hydrogen peroxide is 90% which is used in rocket fuel! However, the ideal concentration of hydrogen peroxide is 3% concentrated.

At this concentration, hydrogen peroxide is strong enough to perform disinfectant and bleaching tasks effectively, as well as prevent any harmful side effects. The 3% hydrogen peroxide is, hands down, the best concentration you can use for cleaning mold infestations and various other household procedures!

Take All The Necessary Precautions While Using Hydrogen Peroxide!

One of the most important aspects while using hydrogen peroxide and vinegar or similar chemicals for cleaning molds is the surface you are using them over.

Many experts recommend against using vinegar to clean marble or granite surfaces. That’s because they are made up of brittle chemicals that contain compounds like calcium carbonate. The brittle surfaces of granite or marble can react with the acidic vinegar and decompose. Acidic chemicals like vinegar are known to “eat away” the surfaces as well as cause discoloration. To clean fragile surfaces like marble or granite, the use of rubbing alcohol or vodka with water can provide an alternative.

A similar problem is faced while using hydrogen peroxide too. Apart from being an amazing disinfecting agent, it is also a bleaching one.

Whenever hydrogen peroxide is applied over a dark surface prone to discoloration, it will smudge and dim the color. So make sure to check the surface you are using these chemicals over before applying.

Another precaution, or rather, a tip you should consider, is to make a fresh batch of hydrogen peroxide and vinegar for every procedure. Hydrogen peroxide is a volatile chemical, and it can quickly dissociate into its constituent elements if exposed to light to air. Hydrogen peroxide along with vinegar can make peracetic acid, which is toxic to the body if ingested in larger amounts.  So it is not ideal for storing this solution, especially if you have children at home.

One last thing you should be mindful of while using hydrogen peroxide to clean mold infestation from your house is that the hydrogen peroxide you are using is fresh. Though hydrogen peroxide is an amazing disinfecting agent, it is a fragile chemical. The same reactive oxygen that is responsible for its oxidizing properties makes it a vulnerable chemical.

The reactive oxygen is so loosely bound to the structure of hydrogen peroxide that a slight exposure to the atmosphere makes it lose oxygen atoms and change into water. Therefore, always make a fresh batch of hydrogen peroxide. Even more so with vinegar which increases its reactivity!

Can You Kill All Types of Mold With Hydrogen Peroxide – When To Call for Help?

Although hydrogen peroxide does give people some leverage by being a potent mold-killing agent, it is sometimes hard to get rid of all the mold. Molds are one of the fastest-growing house-pests. They love to grow inside narrow grooves which are dark and damp, making their appearance hidden.

If you or someone at your house saw a mold growth into the main lounge or around the well-lit areas, chances are the mold has deeply infested the house. In such a scenario, trying to remove all of the molds can not only be ineffective but harmful too if you do not know the proper procedures.

Molds are known to cause hypersensitive reactions if they get inside your airway. Some of them include mold-induced asthma, allergic sinusitis, or even pneumonitis.  A closer contact during the cleaning of mold may cause some of the particles to shrivel inside your airway and trigger the reaction.

Moreover, there are some species of molds that cannot be killed by acidic and disinfecting agents of hydrogen peroxide. This is most likely due to their tough apical covering with complex molecules. It is ideal to call a disinfecting company or an expert for help in such cases. They are proficient in detecting mold spread and can thoroughly treat growths.

The Takeaway

Hydrogen peroxide is one of the best antimicrobial tools we all have in our homes. The trusty brown bottle has shown itself effective in countless household procedures, with the list keep increasing.

Eliminating household molds is another feature of hydrogen peroxide as well.  Due to its indiscriminate killing of microbes, it is able to kill all kinds of fungi, including molds. And the best part about hydrogen peroxide is that it is easily available, simple to use, and does not liberate any harmful byproducts.

All of these factors contribute to making hydrogen peroxide a potent agent against fungal growth at homes.  So if you or someone you know is suffering from mold infestation, order a set of hydrogen peroxide bottles today!

Faizan Khan
Faizan Khan
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