Can Applying Yogurt to the Skin Improve Acne?
Maybe to Some Degree, but More Research Is Necessary Before We Can Recommend It
Yogurt is a probiotic, which means it contains beneficial bacteria that could potentially improve skin health. Yogurt also contains lactic acid, an ingredient found in many skin care products, including acne care products. Some research indicates that these beneficial components in yogurt might improve acne, but the available evidence is mostly indirect. No clinical studies have tested topical yogurt treatments on people with acne. Therefore, it is too early to say whether applying yogurt to the skin can improve acne.
Many standard acne treatments come with unfortunate side effects, making acne sufferers eager for alternative home remedies. Yogurt masks are one such remedy, and while the idea shows some promise, there is currently not enough scientific evidence to definitively say that yogurt works against acne.
Yogurt is a fermented milk product made by adding bacteria called yogurt cultures to milk.
Yogurt shows some promise as an acne treatment because it contains two medicinal components.
- Beneficial bacteria: Much of the bacteria that produces yogurt is beneficial to human health. Its presence in the human body can limit the growth of harmful bacteria that causes disease, perhaps including P. acnes, the bacteria that worsens acne. Yogurt that contains beneficial bacteria is considered a "probiotic" product.1
- Lactic acid: The bacteria in yogurt produces lactic acid, which is an alpha hydroxy acid (AHA) often included in skin care products and in chemical peels. Like other AHAs, lactic acid helps to remove corneocytes (dead cells) from the outermost layer of skin and can in turn reduce the clogging of skin pores, which contributes to acne.
Evidence That Topical Yogurt May Improve Acne
Unfortunately, the evidence that applying yogurt to the skin might improve acne is limited and indirect. Researchers have tried applying beneficial bacteria and applying lactic acid separately to the skin of people with acne with some promising results, but are not yet sure whether yogurt itself could give the same benefits.
Evidence that applying beneficial bacteria to the skin may improve acne
One clinical trial has looked at applying beneficial bacteria, but not the same bacteria that is found in yogurt, to the skin of acne patients. The clinical trial, which was published in the Journal of Microbiology in 2009, tested a topical treatment on 70 participants with mild-to-moderate facial acne. The researchers assigned half of the participants to group 1. The people in this group applied a thin layer of lotion containing a species of beneficial bacteria called Enterococcus faecalis SL-5 to the face twice a day. The other half of the participants, assigned to group 2, applied a placebo lotion (a similar lotion which did not contain any beneficial bacteria) also twice a day. After eight weeks of treatment:
- The participants in group 1 experienced a 20% reduction in the total number of comedones (clogged pores) and a 70% reduction in the number of pustules/"pimples"
- The participants in group 2, on the other hand, saw no change in the number of comedones and only a 5% decrease in the number of pustules2
The researchers noted that the side effects of this topical treatment were rare and minor, such as mild and temporary skin stinging and redness.2
The results of this study suggest that a topical treatment containing beneficial bacteria can potentially improve acne. The researchers wrote, "Our results indicate that…[the application of beneficial bacteria] has [a] potential role [in] the treatment of acne as an alternative to topical antibiotics."2 However, it is important to remember that the bacteria used in this clinical trial is not the same bacteria found in yogurt, so we still do not know whether the bacteria in yogurt would have the same effect.
Evidence that applying lactic acid to the skin may improve acne
One clinical trial has looked at applying lactic acid, but in skin care products rather than from yogurt, to the skin of people with acne. The clinical trial, which was published in International Journal of Cosmetic Science in 2004, tested a skin care regimen containing lactic acid on 90 patients with mild acne. The patients applied a cleansing gel, a facial tonic containing 2% lactic acid, and a cream gel containing 2% lactic acid to the face twice a day for six weeks. At the end of the study, the patients experienced a 56% decrease in the number of comedones.3
The results of this study suggest that a topical treatment containing lactic acid may potentially improve acne. However, it is impossible to say whether applying yogurt to the skin would have the same effect.
Evidence that eating or drinking yogurt may improve acne
Much of the research on the benefit of probiotics for the skin has centered on the gut-brain-skin theory. Briefly, the theory states that the health of the intestines affects the health of the skin. Absence of "friendly" organisms allows for multiplication of "unfriendly" organisms which enter the bloodstream and can cause problems anywhere in the body, including in the skin. The composition of the healthy bacteria in the gut can be altered by drinking of probiotics. Alteration of gut microorganisms alters the health of the skin and may predispose one to acne formation.
Although no studies have tested topical yogurt treatments on patients with acne, some researchers have investigated whether eating or drinking yogurt might improve acne. Generally speaking, oral medications sometimes produce similar results when applied topically.
Expand to read details of studies
A study published in the journal Nutrition in 2010 tested the effects of consuming a drinkable yogurt-like beverage containing the beneficial bacteria Lactobacillus on 56 people with acne. The researchers found that consuming the yogurt drink for 12 weeks significantly reduced the total number of inflammatory acne lesions.4
Two other studies, one conducted in Italy and the other in Russia, tested oral supplements containing yogurt cultures on people with acne. Both studies found that taking these supplements in addition to standard acne treatments helped improve acne.5
All these studies make us cautiously optimistic that applying yogurt to the skin might potentially improve acne. However, as this treatment has not been tested on patients, it is too early to say how effective it might be. Even if topical yogurt turns out to improve acne, at this point we cannot say how well, what type of yogurt, or in what quantities a person with acne should apply it to the skin to see improvement.
Curious to know exactly how yogurt might improve acne? Then read on as we delve deeper into the science behind this potential treatment.
How Might Topical Yogurt Improve Acne?
To understand why some scientists think yogurt might improve acne, we first need to take a look at how acne develops.
Acne begins when skin pores become clogged with corneocytes and excess sebum (skin oil). Scientists now believe that four main factors contribute to this clogging of skin pores.
- Excessive production of sebum
- Excessive production of a skin protein called keratin
- Increased amount of the bacteria P. acnes in skin pores
- Inflammation (redness, swelling, and soreness) of the skin pores6
In addition to these four factors, another factor that likely contributes to acne is the buildup of oxidants or free radicals. These are harmful substances that naturally form in the body and can damage the skin if they accumulate.
The medicinal components of yogurt (beneficial bacteria and lactic acid) can counteract some of the factors that contribute to acne by:
- Limiting the growth of P. acnes: The beneficial bacteria in yogurt can prevent the overgrowth of P. acnes
- Reducing inflammation: Both beneficial bacteria and lactic acid may help reduce inflammation
- Removing oxidants: Beneficial bacteria and lactic acid remove oxidants, preventing them from damaging the skin
- Helping acne lesions to heal: The beneficial bacteria in yogurt can speed up the healing of small wounds like acne lesions
Let's take a closer look at each of these medicinal properties of yogurt.
Antibacterial properties of yogurt
Yogurt owes its antibacterial properties to beneficial bacteria. At first, this idea may seem contradictory, but beneficial bacteria can hinder the growth of harmful bacteria by:
- Competing for resources: Beneficial bacteria competes with harmful bacteria for space and nutrients, preventing the overgrowth of harmful bacteria in or on the body
- Directly killing harmful bacteria: Some beneficial bacteria produces substances that are toxic to harmful bacteria
- Triggering the body to kill harmful bacteria: Some beneficial bacteria causes the skin to produce substances that are toxic to harmful bacteria
Expand to read details of study
We know that some beneficial bacteria can specifically kill P. acnes. For example, the bacteria Enterococcus faecalis SL-5, a beneficial bacterium we looked at earlier, produces a substance called bacteriocin. According to a study published in 2009 in the Journal of Microbiology, this bacteriocin kills 99% of the P. acnes in a petri dish in just one hour.2 Although this particular bacterium is not found in yogurt, this study shows that at least some beneficial bacteria can be effective against P. acnes. There is some limited evidence that the beneficial bacteria found in yogurt might hinder the growth of P. acnes specifically.2
Some beneficial bacteria can trigger the skin to produce a fat called ceramide. This fat inhibits the growth of P. acnes.7 However, scientists have not tested whether the beneficial bacteria found in yogurt can trigger the skin to produce ceramide.
Anti-inflammatory properties of yogurt
Unfortunately, no clinical trials have tested yogurt to see if it reduces inflammation in people with acne. However, studies conducted in vitro (in a petri dish) show that one bacterium found in yogurt, called Lactobacillus, does possess anti-inflammatory properties. According to an article published in the journal Beneficial Microbes in 2014, "Several strains of Lactobacillus…demonstrate anti-inflammatory properties."8
Antioxidant properties of yogurt
The human body contains special substances called antioxidants, which find and remove harmful oxidants that naturally form in the body. The beneficial bacteria and lactic acid found in yogurt can also act as antioxidants, helping prevent oxidants from building up and damaging the skin.9,10
Wound-healing properties of yogurt
Medically speaking, acne lesions are small wounds. To date, no studies have tested whether applying yogurt to the skin can help acne lesions heal faster. However, research involving animals shows that topically applying beneficial bacteria like that which is found in yogurt can speed up wound healing.11
To sum up, yogurt holds some promise as a home treatment for acne because two of its components, beneficial bacteria and lactic acid, possess medicinal properties. Some preliminary studies suggest that separately applying helpful bacteria and lactic acid to the skin might improve acne. However, until scientists test topical yogurt treatments on people with acne, it is impossible to say whether this home remedy really works against acne.
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- Lourens-Hattingh, A. & Viljoen, B. C. Yogurt as probiotic carrier food. Int Dairy J 11, 1 - 17 (2001).
- Kang, B. S. et al. Antimicrobial activity of enterocins from Enterococcus faecalis SL-5 against Propionibacterium acnes, the causative agent in acne vulgaris, and its therapeutic effect. J Microbiol 47, 101 - 109 (2009).
- Scherdin, U. et al. In vivo assessment of the efficacy of an innovative face care system in subjects with mild acne vulgaris. Int J Cosmet Sci 26, 221 - 9 (2004).
- Kim, J. et al. Dietary effect of lactoferrin-enriched fermented milk on skin surface lipid and clinical improvement of acne vulgaris. Nutrition 26, 902 - 9 (2010).
- Bowe, W. P., Patel, N. B. & Logan, A. C. Acne vulgaris, probiotics and the gut-brain-skin axis: From anecdote to translational medicine. Benef Microbes 5, 185 - 199 (2014).
- Oberemok, S. S. & Shalita, A. R. Acne vulgaris, I: pathogenesis and diagnosis. Cutis 70, 101 - 105 (2002).
- Pavicic, T., Wollenweber, U., Farwick, M. & Korting, H. C. Anti-microbial and -inflammatory activity and efficacy of phytosphingosine: an in vitro and in vivo study addressing acne vulgaris. Int J Cosmet Sci 29, 181 - 90 (2007).
- Benyacoub, J. et al. Immune modulation property of Lactobacillus paracasei NCC2461 (ST11) strain and impact on skin defenses. Benef Microbes 5, 129 - 136 (2014).
- Kober, M. M. & Bowe, W. P. The effect of probiotics on immune regulation, acne, and photoaging. Int J Women's Dermatol 1, 85 - 89 (2015).
- Wang, Y. et al. Antioxidant properties of probiotic bacteria. Nutrients 9, (2017).
- Nasrabadi, H. M. Study of cutaneous wound healing in rats treated with Lactobacillus plantarum on days 1, 3, 7, 14 and 21. African J Pharm Pharmacol 5, (2011).