Free Shipping on all UK Orders!

Benzoyl Peroxide is probably the most widely used acne treatment in the world and can be found in everything from face washes to moisturisers. Why? Benzoyl Peroxide kills the bacteria (P.acnes) that is an important part of the acne forming process. There is plenty of clinical evidence behind the ability of Benzoyl Peroxide to eliminate skin bacteria.

So it may come as some surprise that Benzoyl Peroxide is bad.

Bad, bad, bad.


Benzoyl Peroxide doesn’t cure acne.

Acne is the end result of a long sequence of events. Our genetical make-up and lifestyle choices (diet and stress) affect certain hormone levels in our body. These hormone levels affect the production rate of skin oil (sebum). Over produced sebum binds to sloughed skin cells which leads to clogged pores. Clogged pores become oxygen deprived and the perfect breeding ground for Propionibacterium acnes (P. acnes) bacteria. The activity of P.acnes causes an inflammatory response and the whole sequence results in the symptoms of acne. Red, painful inflamed pimples.

P.acnes bacteria is only one part of the whole acne forming process. Elimination of P.acnes results in a decrease in acne symptoms but will not prevent breakouts in the long term. You can use it to eliminate the p. acne bacteria on your face, but if you don’t tackle the other parts of the acne formation process your pores will continue to be blocked and bacteria will continue to have the perfect conditions to thrive. Benzoyl Peroxide is at best only a hygiene treatment, and a hygiene alone cannot cure acne.

But that’s not our only reason.

Benzoyl Peroxide can cause an increase in acne.

Eliminating P.Acnes will reduce acne in the short term – without the presence of this bacteria the bodies inflammatory response is reduced and symptoms will improve. However, within weeks or even days, the acne may return.

The reason is because of sebum, the skins natural oil that lubricates and waterproofs the skin.

Benzoyl Peroxide kills bacteria by breaking down and forming oxygen. P.acnes requires a low oxygen environment to survive and so the influx of oxygen from Benzoyl Peroxide destroys them. Oxygen however is highly reactive, and it binds with the sebum on your face to form a substance called Squalene Peroxide. Squalene peroxide is known to be highly comedogenic – it blocks pores. Animal studies have shown that applying Squalene Peroxide to rabbit ears causes acne.

Benzoyl Peroxide is essentially a very strong hygiene treatment, like a very effective soap. Regular application is needed to control P.acnes (the bacteria will always return after treatment). Unfortunately regular use of Benzoyl Peroxide also leads to an increase in the number of blocked pores which provide the breeding ground for more bacteria. A viscous cycle is entered into – Benzoyl Peroxide is used and the level of P.acnes reduces but Squalane Peroxide levels increase leading to an increase in the number of blocked pores. This in turn leads to an increase in the opportunity for more bacteria to grow resulting in more widespread inflammation.

You have to continually treat the skin to kill the bacteria but you can never fully fix your acne problem for the simple reason that it doesn’t affect any of the root causes behind it.

Benzoyl Peroxide supporters often claim it decreases sebum production – in part because it can significantly reduce skin oiliness. However, there is clinical evidence to the contrary (here & here) and the internet is awash (no pun) with Benzoyl Peroxide stories of oily skin returning after a period of time.

Benzoyl Peroxide disrupts your skins natural balance of good-bad bacteria

Benzoyl peroxide doesn’t just target P.acnes. It is a powerful bactericide and, like a bacterial-bomb, kills almost all of the bacteria it encounters. The surface of your skin has its own ecosystem — composed of living biological and physical components occupying diverse habitats and there is a delicate balance between host and microorganism. Disruptions in the balance on either side of the equation can result in skin disorders or infections.

Normal (non-acne) levels of P.acnes is believed to contribute to skin health, preventing the colonization of opportunistic pathogens via its ability to convert sebum to free fatty acids and to maintain an acidic skin pH. There is currently concern in the scientific community that by reducing skin bacteria, you create a void in the ecosystem and risk allowing the growth of dangerous pathogens like Staphlyococcus aureus.


Benzoyl Peroxide has some nasty side effects

Firstly, let’s cut through any hype. Like other common acne treatments, there are a lot of horror stories surrounding the use of Benzoyl Peroxide which aren’t true.

Although Benzoyl Peroxide is a known tumour promoter in certain laboratory obtained circumstances, there are no proven scientific links between Benzoyl Peroxide and cancer in humans. Topical Benzoyl peroxide has been used in the treatment of acne for over 60 years, with no reports of adverse effects that could be related to skin carcinogenesis.

The scientific community is still in undecided whether Benzoyl Peroxide can cause premature ageing and unfortunately there are few studies in this area. Benzoyl Peroxide can cause oxidative damage to your cells when it meets the skin and oxidative damage is linked to skin ageing. However, the scientific community is still unsure whether the free radicals produced by Benzoyl Peroxide travel far enough to cause enough damage to cause irreversible skin ageing. The jury is still out.

Aside from the above horror stories there are known side effects. Benzoyl Peroxide is commonly reported to cause skin dryness and sensitive skin can become red and irritated.

Of course, many people use Benzoyl Peroxide and get great results, but we think using Benzoyl Peroxide is unnecessary given the abundance of equally effective alternatives in treating this part of the acne formation process.

One approach to eliminating acne without the side effects of benzyl Peroxide is light therapy. Specific wavelengths of blue light at sufficient intensity and duration have been clinically shown to destroy P.acnes bacteria.

P. acnes bacteria produce a molecule called Coproporphyrin III. When Coproporphyrin III absorbs light at a certain blue wavelength it breaks down to produce oxygen (a free radical) which in turn damages and kills the bacteria. In this respect, the action is identical to Benzoyl Peroxide.

The difference however is that, unlike Benzoyl Peroxide, the free radical damage occurs within the bacteria rather than flooding the pore. The result is a targeted elimination of P.acnes without the side effects of Benzoyl Peroxide. In fact, blue light therapy has been clinically shown to be as effective as Benzoyl Peroxide.

Destroying P.Acnes is not a cure for acne however (it is only one link in the chain) and using blue light alone will perform no better than Benzoyl Peroxide in the long term. Both are hygiene treatments. For long term change the source of acne must be tackled and this requires a change to diet, lifestyle and your skin care routine.


About 28 Day Skin

28 Day Skin tackles the source of acne as well as the symptoms by treating every part of the acne formation process – not just eliminating bacteria. Using a unique combination of proprietary technology, active dermatological ingredients and nutritional supplements.

Image sources

James Heilman, MD – Own work, CC BY-SA 3.0,


WordPress Video Lightbox Plugin