When it comes to acne, you want to do two things
1. Clean out your pores from dead skin cells, bacteria and sebum and
2. Kill the acne-causing bacteria to stop it from returning.
Two ingredients will do that.
Benzoyl Peroxide vs Salicylic Acid.
Benzoyl Peroxide (BPO) is an ingredient that is very commonly used for treating acne. BPO has keratolytic properties. It also prevents new acne from forming by killing acne-causing bacteria. Salicylic acid is a BHA which means it exfoliates. In acne treatment, salicylic acid is used to exfoliate the top layer of skin and clean out blocked pores.
When it comes to pimples, you may need one or the other or both together. Let’s take a look under the hood of these two acne treatment warriors.
What is Benzoyl Peroxide?
Benzoyl Peroxide is a chemical compound. It doesn’t occur naturally in nature, and it has to be manufactured in a lab.
We have P. acnes bacteria on our skin all the time, but not everyone develops acne. Researchers discovered that when P.acnes gets trapped in an airless environment that contains sebum. It turns into a fatty acid that activates inflammation in nearby cells. This causes the redness and inflammation associated with acne.
What’s great about BPO is that it has an antibacterial effect which means it kills bacteria, and unlike antibiotics, you don’t build up a resistance to it.
It’s also bleach and used commercially to lighten flour, clothing and hair and clean products in much larger doses than you would ever put on your skin.
It can bleach your dark coloured clothing and towels, so be careful if using it as a face wash.
What is it Good For?
When dealing with breakouts, benzoyl peroxide is one of the most effective and powerful treatments.
It can treat mild to moderate pimples or a major breakout situation and reach your goal for a clear, healthy complexion.
Its ability to remove dead cells, reduce excess oil, and fight acne-causing bacteria makes it ideal if you’re dealing with inflammatory acne (painful infected pimples and blemishes).
The results it can give you can be quite impressive, but there are also some limitations to using it.
Before you start searching for benzoyl peroxide products, it’s important to know if it’s beneficial to your skin type, its side effects, and how to use it.
Who can use Benzoyl Peroxide?
This medication can be used by most adults and children above the age of 12.
Before using benzoyl peroxide you should consult your dermatologist or doctor.
Especially if you:
- Are allergic to it or other medicines
- Have broken skin around the area where you need to use the treatment
- Have severe acne with nodules and cysts. These have to be treated by a specialist to avoid a rare but hard to treat a side effect of benzoyl peroxide, post-inflammatory hyperpigmentation.
- Post-inflammatory hyperpigmentation is when acne scars or any inflamed areas leave dark spots after healing.
Benzoyl peroxide can make your skin sensitive to sunlight.
Always apply oil-free sunscreen (SPF) 30 or above daily.
It works quickly to help reduce acne within 5 days once you see improvements keeping using it for 4 – 6 weeks to prevent acne from coming back.
Side Effects
Like any other medication, benzoyl peroxide can cause side effects to some people, such as:
- Skin dryness
- Red or peeling skin
- Irritation (stinging or burning)
- Post-inflammatory hyperpigmentation
These are the most common symptoms that may affect people, but some serious side effects might occur rarely but require immediate medical attention:
- Swollen skin
- Blisters
- Rash
- Throat tightness
- Difficulty breathing
If you experience any of those symptoms, you should seek medical help at once.
What is Salicylic Acid?
Salicylic acid can be made from willow bark and used to make a drug used by millions of people every day called aspirin. Aspirin is acetylsalicylic acid and used for everything from blood-thinning to joint pain and headaches.
Salicyclic acid is also a beta hydroxy acid or BHA. This means it has an exfoliating effect and in high concentration can cause peeling and dryness. It gets down deep into the skin and clears out pores of sebum, bacteria and debris.
Salicylic acid products are best suited to oily, congested and acne-prone skin. They are not recommended for rosacea as they are too stripping and irritating. It is excellent for use cystic and blind pimples.
Salicylic Acid can be soothing in the correct amounts, and most OTC products for the treatment acne do not contain enough to cause an issue with irritation.
It takes longer to affect acne and is more gentle than benzoyl peroxide. Salicylic acid doesn’t kill bacteria; it cleans out pores and can soothe the skin.
How To Use Salicylic Acid?
If you have pimples on your arms, chest or back, then a salicylic body wash or soap is a great idea for helping to clear it up. In this case a 0.5% up to 5% is recommended.
Because it cleans and clears pores so efficiently if enlarged pores are an issue for you, you can use a gentle face wash containing, your salicylic acid. I would recommend using it as the second step of a double cleanse.
Side Effects of Salicyclic Acid
If you’re pregnant or breastfeeding:
There is evidence that ingested salicylic acid (such as aspirin) can harm a foetus. Topical use of has not been shown to cause harm during pregnancy or breastfeeding.
But as no company is willing to test the theory and no mothers willing to take the risk, there is no conclusive proof. So I will always recommend caution when pregnant or breastfeeding and don’t use any skincare product that has even the potential to harm you or your baby.
If you have rosacea:
While salicylic is a prevalent ingredient in treating most acne types, it is not good for treating rosacea. Although rosacea can look like common acne (Acne Vulgaris ) it is very different, and you should avoid products salicylic acid and retinols.
If you are taking Accutane:
Stop using salicylic and BPO products when taking Accutane they are too drying.
Other cautions
It can cause dryness, peeling and irritation if this occurs stop using the product for a few days and see if the irritation resolves. You may need to use the product to spot treat active areas of concern every second day.
Which One For Mild Acne
Even though benzoyl peroxide can effectively treat inflammatory acne, it’s probably not the best ingredient if you only have just a few whiteheads and blackheads.
Noninflammatory pimples can easily be treated with salicylic acid, an exfoliant acid that doesn’t dry your skin.
Both benzoyl peroxide and salicylic acid help remove dead skin cells, reduce oil production and unclog pores.
The difference between the two is that benzoyl peroxide has antibacterial properties, while salicylic acid doesn’t.
Benzoyl peroxide may also have more side effects and in some cases cause allergic reactions as well as post-inflammatory hyperpigmentation. It is rare for it to cause PIH and allergic reactions, but they do happen, so it is important to be aware. It should be used with caution, and according to the product’s instructions.
If you have inflammatory acne and an oily, less sensitive skin type, then benzoyl peroxide might be the better option.
Should I Use Benzoyl Peroxide or Salicylic Acid?
If you have inflamed acne issues, use a benzoyl peroxide product that doesn’t contain salicylic acid.
Otherwise, if you can tolerate BPO, it’s often a great idea to use a product that contains both because these two ingredients are drying to the skin. It is recommended using a product that also contains moisturizing and hydration properties.
If you cannot tolerate benzoyl peroxide, then you might be able to use a salicylic acid without it irritating. When introducing a new ingredient into your skincare routine, it’s important to go slowly and only introduce one new ingredient at a time.
If you need to change your skincare routine drastically, I would recommend starting from the beginning rather than add drastically in more than one ingredient.
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Changing your skincare routine drastically?
Start from the beginning and stop all your skincare regimen apart from cleansing, moisturizing and sunscreen. Once your skin adjusts to one new product without reacting badly for at least one week, then start adding in the next product.
AM: Use a gentle type of cleanser that contains either salicylic acid or benzoyl peroxide. Then apply your usual moisturizer and sunscreen.
PM: Double cleanse and use your new cleanser as the second step. Then moisturize with your normal night moisturizer.
Continue doing this for a week if there is no reaction and add in another new ingredient.
Always start slowly breakouts can make your skin sensitive so treat it gently.

The Bottom Line
Benzoyl peroxide treats and prevents acne by targeting bacteria underneath the skin, removing dead skin cells trapped within pores, and reducing excess sebum – the oily substance found on the skin.
It can help with reducing inflammatory breakouts- red bumps with pustules, cysts, and nodules.
Also, it helps with cystic acne, the most serious form of acne, and It the most difficult to treat.
It’s also most helpful when paired with other treatments like topical retinoids and salicylic acid for treating acne vulgaris.
And always make sure to consult your doctor or dermatologist if OTC products aren’t working out for you, or if you get an allergic reaction.