A number of topical antioxidants have demonstrated the ability to improve the appearance of acne. Originally, it was thought that topical antioxidants improved acne purely by reducing inflammation, however, more recent research has suggested that it may be due to their ability to neutralize free radicals. This begs the question – “can topical antioxidants cure acne?”.
What Causes Acne?
Acne is a common inflammatory skin condition that is characterised by blocked hair follicles and oil glands that lead to lesions. It is well-established that acne is caused by a number of overlapping factors:
- An overproduction of oil
- A build-up of dead skin cells
- P-acnes bacteria
- Inflammation/Immune response
Basically, hormones cause the skin to produce more oil which then gets trapped inside the hair follicle due to a build-up of dead skin cells on the surface of the skin. A bacterium that is naturally present on our skin (the p-acnes bacteria) feeds off of this oil which allows it to rapidly multiply. When the body senses this increase in bacteria it initiates an immune response that leads to inflammation.
Related Reading: The 4 Main Causes Of Acne.
Free Radicals and Acne
In addition to the four main causes of acne, some research suggests that oxidative stress caused by free radicals may be partly involved in the cause of acne . A free radical is formed when oxygen acquires an unpaired electron and once it is formed it can produce further free radicals that result in oxidative damage and inflammation.
The skin is particularly susceptible to oxidative damage as it is continuously exposed to multiple internal and external sources of free radicals, including, but not limited to, UV radiation and environmental pollutants .
Free radical oxidation by reactive oxygen species (ROS) and lipid peroxidation (LPO) has been implicated in all four of the main causes of acne in the following ways:
- The excessive production of oil promotes the production of excess ROS leading to oxidative stress within the follicle and overwhelming the skins antioxidant system. In addition, lipid peroxidation of the fatty acids found in sebum produces ROS which alters the thickness and structure of sebum .
- The oxidants generated by lipid peroxidation are comedogenic and promote the blockage of hair follicles by dead skin cells .
- The effect of ROS and LPO on oil production and the blockage of hair follicles has an indirect effect on the p-acnes bacteria. Furthermore, oxidative stress within the hair follicle results in an environment that p-acnes bacteria is able to thrive in .
- Oxidative stress from lipid peroxidation may play a role in the inflammation of the hair follicle by inducing inflammatory responses and initiating the release of inflammatory agents .
One type of ROS that has been implicated in acne is hydrogen peroxide. Hydrogen peroxide is produced by neutrophils and causes inflammation and tissue and lipid damage . In one study, hydrogen peroxide production was 43% higher in patients with inflammatory acne than in those without, as measured by blood levels. After treatment with minocycline (a tetracycline antibiotic), hydrogen peroxide levels were reduced by 25% .
In general, individuals with acne produce 59% more sebum than those without acne. However, it appears that this increased production is almost entirely explained by a specific lipid in sebum – squalene .
Squalene is particularly sensitive to oxidation and shows enhanced comedogenicity when oxidized. In fact, multiple studies have demonstrated that squalene and its oxidized metabolites are found at much higher levels in individuals with acne than those without . Squalene peroxides (oxidized squalene) are highly comedogenic  increase inflammation , and reduce antioxidant levels in skin .
This ‘lipid peroxidation hypothesis’ of acne led to the idea that antioxidants may be an effective treatment to control the inflammation associated with acne by preventing the oxidization of lipids .
As it turns out, antioxidant levels appear to be significantly lower in individuals with acne than in those without acne . In some cases, antioxidant levels can be up to 42% lower in those with acne and appear to be the lowest in individuals with the most severe forms of acne .
One study found that vitamin A levels were 52% lower in individuals with the most severe acne, while vitamin E levels were 31% lower . Other research has also identified reduced antioxidant levels in individuals with acne (33% less vitamin A, 40% less vitamin C, 46% vitamin E, and 64% less beta-carotene) .
Antioxidants, such as vitamins A, C, E, B3, co-exist to protect the skin from free radical damage, such as that caused by UV radiation and environmental pollutants.
When the antioxidant defence system is functioning properly, they are able to prevent the production of free radicals in the hair follicles and the resulting oxidative damage of lipids and proteins that maintain the integrity of the skin.
However, when there is an excessive amount of LPO and ROS the antioxidant-oxidant balance is shifted and levels of antioxidants are reduced . This leads to higher oxidative stress and more inflammation.
The cells in the body seem to require a specific balance of both antioxidants and free radicals in order to function optimally. Some research suggests that an excessive amount of antioxidants is also bad for the skin. This is due to the fact that ROS may have some tumour supressing and anti-bacterial effects .
In theory, this means that ROS may prevent acne by preventing the growth of p-acnes bacteria. However, the research regarding these antimicrobial effects is focussed on the Salmonella enterica bacteria rather than p-acnes so this is only speculation.
Antioxidants and Acne
As mentioned earlier, minocycline treatment was able to reduce hydrogen peroxide levels in individuals with acne by 25% . Tetracycline antibiotics, such as minocycline, are known to have antioxidant effects and are particularly good at reducing LPO with a similar effectiveness to vitamin E .
So, are the improvements in acne due to tetracycline antibiotics antimicrobial or antioxidant effects?
Well, one study compared the effect of two different doses of doxycycline in the treatment of acne. One dose was high enough to have an antimicrobial effect, while the other dose was too low to have an antimicrobial effect. Low-dose (subantimicrobial) doxycycline was still able to significantly reduce papules by 84% and pustules by 90% over a 3-month period. This suggests that the anti-acne benefits of doxycycline are at least partly attributable to its antioxidant effect .
This research provides further evidence that the topical application of antioxidants may be an effective acne treatment. So, which antioxidants have scientific research to suggest that they offer benefits for acne and acne-prone skin?
Vitamin E is a lipid soluble antioxidant that is found in sebum and sebum-rich areas, such as the upper layers of facial skin at high levels . When there is an overproduction of sebum, vitamin E levels can decrease and lead to an increase of oxidative stress.
A number of studies have demonstrated that blood levels of vitamin E are lower in individuals with acne than in those without , with levels of vitamin E decreasing further the more severe the acne .
Oral vitamin E supplementation can significantly increase the levels of vitamin E in the skin, particularly in areas with a lot of sebaceous glands, however, this can take weeks . For this reason, topical application of vitamin E may be more effective and appropriate. In fact, the addition of vitamin E to a treatment regimen consisting of benzyl peroxide and salicylic acid significantly reduced the number of inflammatory and non-inflammatory acne lesions in as little as two weeks .
Vitamin C is the most abundant antioxidant in the skin and is essential for the production of collagen. Even with very high doses of oral vitamin C, only a small amount is biologically available to the skin and, for this reason, topical application of vitamin C is required to maintain sufficient skin levels of the antioxidant .
There isn’t a huge amount of research investigating the anti-acne effects of topical vitamin C, however, it does have potent anti-inflammatory and antioxidant effects . In addition, blood levels of vitamin C are lower in individuals with acne than in those without .
Some research has demonstrated that vitamin C can reduce sebum oxidation by up to 40% and may be more effective and tolerable at treating acne than benzoyl peroxide .
In one study, a vitamin C precursor (5% sodium ascorbyl phosphate) reduced inflammatory acne lesions by 49% after 8 weeks of use . In another study, topical application of a 5% sodium-L-ascorbyl-2-phosphate (a vitamin C derivative) formulation reduced the number of acne lesions in 61-71% of subjects after 12 weeks of application .
Related Reading: Does Vitamin C Serum Cause Acne?
Vitamin B3 / Niacinamide
Niacinamide is a water soluble form of vitamin B3 that can stabilise the skins barrier function and improve skin hydration . It also acts as an anti-inflammatory and can reduce sebum levels . In fact, a 2% niacinamide containing moisturiser was able to reduce the rate of sebum secretion after 2-6 weeks of use .
Topical application of a 4% niacinamide gel can lead to significant reductions in papules, pustules, and comedones when used over an 8-week period . In addition, 4% niacinamide gel was more effective at improving the appearance of acne than 1% clindamycin gel when applied twice daily for 12 weeks .
Related Reading: 3 Skin Benefits of Niacinamide.
Green Tea Polyphenols
Polyphenols are antioxidant molecules that are present in green tea and have antimicrobial and anti-inflammatory effects. The major polyphenol present in green tea is epigallocatechin-3-gallate (EGCG).
Some research has demonstrated that topical application of green tea can reduce sebum production. In fact, one study found that a topical 3% green tea formulation reduced sebum production by 60% after 8 weeks of application .
In terms of acne, topical green tea lotion can significantly reduce the number of inflammatory acne lesions in two weeks when applied twice daily . In another study, this reduction was as much as 89% for inflammatory lesions and 79% for non-inflammatory lesions .
However, topical green tea may only be effective for certain types of acne lesions. For example, when applied twice daily for 8 weeks, a green tea extract was able to reduce open comedones by 61%, pustules by 28%, but there was no significant reduction in the amount of closed comedones .
Related Reading: Green Tea Serum For Acne.
Can Topical Antioxidants Cure Acne?
As it stands, there is not enough research currently available to answer this question. However, research has demonstrated that individuals with acne have higher levels of free radicals and lower levels of antioxidants than those without.
This would indicate that the antioxidant-oxidant balance is altered individuals with acne and that correcting this balance may help improve the appearance of acne and possibly prevent further acne outbreaks.
Oxidative stress has been linked to all four of the main causes of acne, which suggests it could be an underlying factor or the primary cause. In particular, the oxidation of squalene in sebum is especially comedogenic.
Levels of squalene and its metabolites are much higher in individuals with acne than in those without acne and oxidized squalene can cause inflammation and reduce antioxidant levels in the skin.
There is some research that a number of antioxidants can improve the appearance of acne, including vitamins C, E, niacinamide, and green tea polyphenols. These effects have been largely attributed to their anti-inflammatory effects, but more and more research is suggesting that it may actually be their antioxidant effects responsible for these improvements.
So, have you had any success with antioxidants for acne?
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