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Some Chemicals in Lemon Juice May Help
The Essential Info
Applying lemon juice topically to acne-prone areas of the skin is a popular at-home remedy. However, since scientists have not performed clinical trials to study the effect of lemon juice on acne, we must rely on studies that have investigated specific chemicals that are in lemon juice, like alpha hydroxy acids (AHA), and extrapolate from there.
This research suggests that certain chemicals in lemon juice, as well as chemicals in lemon peels, may have the potential to help modestly reduce acne symptoms through reducing:
- Bacteria growth
- Skin oil production
- Inflammation
- Free radicals
Warning: Leaving lemon juice on the skin for a prolonged period and going out in the sun while lemon juice is still on the skin can lead to severe burns. Stay indoors while treating your skin with lemon juice, and be sure to rinse it off after about 10 minutes.
The Bottom Line: While it is possible that applying lemon juice to the skin might help reduce acne to some degree, it is unlikely that lemon juice alone will clear acne. Keep your expectations realistic, and if you are aiming for dramatic improvement in your acne, consider proven treatments instead of, or in addition to, lemon juice.
The Science
- Skip Down to How to Use Lemons for Acne
- Chemical Composition of Lemons
- Potential Benefits of Lemons on Acne
- Side Effects of Applying Lemon Topically
Numerous online anecdotal reports suggest that lemon juice helps reduce acne, while others report no benefit.
Scientists have not performed any studies investigating the effect of lemon juice directly on people with acne. However, lemon juice as well as the oils in lemon peels contain certain chemicals that may help suppress the factors involved in acne.
Chemical Composition of Lemons
Lemons are composed of:
- A juice-filled pulp
- A fiber-rich white area called albedo
- A peel called flavedo
Lemon juice: Lemon juice is extracted from the pulp and consists of 60% water, 5 – 8% citric acid, and a mixture of other chemicals, including malic acid, ascorbic acid (vitamin C), glucose, and minerals like potassium and magnesium. Citric acid and malic acid are alpha-hydroxy acids (AHAs), which are commonly used in skincare products for the treatment of acne.1,2 This gives us a hint that lemon juice may in fact help reduce acne in a similar way to AHAs.
Lemon peel: Most people using lemons to treat acne only use lemon juice and discard the peel. However, the lemon peel contains a high concentration of a fatty acid called linoleic acid. Acne-prone skin tends to be deficient in linoleic acid. Whether the oils from a lemon peel can be topically applied and help increase linoleic acid levels, and in turn treat acne, is still unknown.1
Potential Benefits of Lemons on Acne
Several studies investigating the effect of lemon juice and lemon peels on acne have found that chemicals in lemons may help:
- Reduce the growth of acne bacteria
- Decrease skin oil production
- Reduce inflammation
- Provide antioxidants
All of these could theoretically help reduce acne. Let’s have a look one by one.
Reducing the growth of acne bacteria
Acne bacteria, called C. acnes, is a common type of bacteria that lives in the skin of people both with and without acne, but can worsen acne when it begins overgrowing.
Four studies have found that lemon juice itself, or certain chemicals found in lemon juice, may possess antibacterial properties, which would potentially suppress C. acnes growth.
Expand to see details of these 4 studies
A 2013 study published in the International Journal of Science Inventions Today found that lemon juice inhibited the growth of C. acnes. To perform this study, scientists collected pus from human acne lesions and grew the bacteria in the pus before treating it with different concentrations of lemon juice. The scientists found that all concentrations of lemon juice tested were able to inhibit the growth of C. acnes, even the lowest 20% concentration.3
A 2008 study published in the journal of Bioscience, Biotechnology, and Biochemistry found that citrus oils were able to inhibit C. acnes growth. To perform this study, the researchers obtained two citrus fruits that were not lemons, but were instead fruits common to the island on which the study was performed. They found that the two most common oils in these citrus fruits were limonene and terpinene, which also make up 88% of the oils in lemons. After isolating the oils, the researchers added them to laboratory-grown C. acnes samples and measured bacterial growth. Both oils showed properties that interfered with the C. acnes.4
A 2016 study published in the International Journal of Cosmetic Science found that a combination of zinc oxide and citric acid displayed antimicrobial activity against C. acnes. To perform this study, scientists grew C. acnes in a laboratory before treating it with different concentrations of zinc oxide and citric acid, sometimes using more zinc oxide than citric acid and vice versa. The researchers found that an equal concentration of zinc oxide and citric acid, rather than either substance alone, showed the highest antibacterial activity.5
A 2019 study published in the journal Heliyon found that citrus oils can effectively inhibit the growth of C. acnes. In this study, the researchers used a citrus plant that grows in China, where the study was performed. They found that the essential citrus oil of this plant, which is mainly composed of limonene, can reduce the growth of C. acnes as effectively as some common antibiotics like erythromycin, clindamycin, and tetracycline.6 As we have already seen, limonene is also a key component of lemon juice. Like the other studies, this study was performed in a lab and not on real people with acne, but it gives us additional evidence that lemon juice may fight acne bacteria.
Decreasing skin oil production
Skin oil, called sebum, is a contributing factor to acne. Generally speaking, the more sebum a person has, the more likely he or she will develop acne.
One study has found that citrus peel components may decrease the production of sebum.
Expand to see details of study
A 2007 study published in the Journal of Investigative Dermatology found that nobiletin, a chemical found within citrus peels, decreased the amount of sebum produced in hamster skin. Additionally, application of nobiletin also decreased the size and number of the sebaceous glands.7
Reducing inflammation
Acne is at its root an inflammatory disease, so anything that can reduce inflammation could hypothetically reduce acne symptoms. Furthermore, when inflammation in acne lesions does not go away in a timely manner, it can lead to acne scarring.
Three studies have found that chemicals in lemons may decrease inflammation by inhibiting a variety of specific inflammatory proteins.
Expand to see details of these three studies
A 2010 literature review published in the journal Clinical, Cosmetic, and Investigational Dermatology reported that citric acid and ascorbic acid can prevent inflammation by inhibiting inflammatory proteins called NFkB and TNF-alpha.8
Mentioned previously, the 2007 study published in the Journal of Investigative Dermatology also found that the nobiletin found in citrus peels can suppress the release of inflammatory proteins called IL-1 and IL-6.7
Also mentioned previously, the 2008 study published in Bioscience, Biotechnology, and Biochemistry found that the citrus oils limonene and terpinene reduced the secretion of TNF-alpha and another inflammatory protein called IL-8.4
Providing antioxidants
Antioxidants are compounds that fight free radicals. Free radicals are toxins that our skin naturally produces and that can build up, contributing to inflammation. Since inflammation is a major component of acne, using antioxidants to reduce free radicals in the skin might help with acne. One study found that lemon juice might possess antioxidant activity.9
Expand to read details of study
A 2016 study published in the journal Food Chemistry tested the antioxidant properties of a citrus juice made from citrus fruit species grown in Korea. The researchers found that the juice was able to reduce free radicals in human skin cells grown in the lab. The scientists also exposed hairless mice in the lab to UV light, which caused free radicals to form in the skin of the mice, and then gave the mice the citrus juice to drink. The researchers found that the citrus juice reduced signs of free radical damage, such as wrinkling, in the skin of the mice. This suggests that Korean citrus fruits, and perhaps lemon as well, might possess antioxidant properties that might theoretically help with acne.9
Side Effects of Applying Lemon Topically
Applying lemon to the skin can sometimes cause side effects. Certain substances in citrus fruits like lemon are phototoxic, which means that when exposed to the sun’s rays, they can react to produce harmful chemicals. These chemicals can produce a strong burning reaction in the skin known as phototoxic dermatitis.
One case report published in the journal Wounds in 2017 described a 7-year-old girl who squeezed a lemon, rubbed it on her skin, and then continued to play in the Arizona sun. Within 24 hours, the girl experienced severe burning and blistering, with multiple first- and second-degree burns on her skin. The cause of this injury was furocoumarin, a chemical found in lemon that had reacted under the sun’s rays.10
This case underscores the importance of avoiding sun exposure while lemon juice is on the skin and also rinsing the lemon juice off after about 10 minutes.
How to Use Lemons for Acne:
- Very gently wash your skin with only your bare hands, using a cleanser designed for sensitive facial skin.
- Rinse thoroughly with warm (not hot) water.
- Cut a lemon in half and squeeze out the juice into a bowl. Tip: Use a citrus juicer to get all the juice out.
- (Optional) Peel the lemon and cut the peel into small pieces. Put the small pieces of the lemon peel into a garlic press and squeeze out the oils and add it to the juice in the bowl.
- Soak up the juice (and oils if you added them) with a cotton ball or cotton pad.
- Very gently apply to your skin.
- Repeat steps 4 and 5 until you have covered any areas of your skin that have acne or are prone to acne.
- Allow the juice (and oils if you added them) to dry. This should take about 5-10 minutes. Note: If your skin stings too much or you experience too much discomfort, rinse it off immediately with warm water. Caution: Avoid sun exposure while the lemon juice is on your skin.
- Rinse your skin with warm water and very gently remove the lemon components from your skin. Remember: Irritation can lead to acne, so always stay extremely gentle.
- Washing your skin and applying lemon juice (and oil) will leave your skin prone to dehydration. Acne-prone skin is clearest when it is balanced. Therefore, apply a moisturizer to keep your skin balanced.
Keep your expectations realistic: Even if the alpha hydroxy acids and other chemicals in lemons and lemon peels help with acne, they likely will not help to dramatically clear the skin. Therefore, do not look for this to completely clear your skin. Expect moderate improvement only.
References
- Cupane, M. Effects of some practices of citrus postharvest management on fruits quality and aromatic fingerprint. (Universita Delgi Studi Di Palermo, 2015). https://www.ncbi.nlm.nih.gov/pubmed/28052466
- Hsiao, Y. P. et al. Triggering apoptotic death of human epidermal keratinocytes by malic acid: Involvement of endoplasmic reticulum stress- and mitochondria-dependent signaling pathways. Toxins (Basel) 7, 81 – 96 (2015). https://www.ncbi.nlm.nih.gov/pubmed/25584429
- Shinkafi, S. & Ndanusa, H. Antibacterial activity of citrus lemon on acne vulgaris (pimples). Int J Sci Interv Today 2, 397 – 409 (2013). https://pdfs.semanticscholar.org/74f3/74e7aa23dd53e4660323a31d858c97fafa39.pdf
- Kim, S. S. et al. Biological activities of Korean Citrus obovoides and Citrus natsudaidai essential oils against acne-inducing bacteria. Biosci Biotechnol Biochem 72, 2507 – 13 (2008). https://www.ncbi.nlm.nih.gov/pubmed/18838824
- Bae, J. Y. & Park, S. N. Evaluation of anti-microbial activities of ZnO, citric acid and a mixture of both against Propionibacterium acnes. Int J Cosmet Sci 38, 550-557 (2016). https://www.ncbi.nlm.nih.gov/pubmed/26940755
- Hou, H S., Bonku, E. M., Zhai, R., Zeng, R., Hou, Y. L., Yang, Z. H. & Quan, C. Extraction of essential oil from Citrus reticulate Blanco peel and its antibacterial activity against Cutibacterium acnes (formerly Propionibacterium acnes). Heliyon 5, e02947 (2019). https://pubmed.ncbi.nlm.nih.gov/31872120/
- Sato, T. et al. A citrus polymethoxy flavonoid, nobiletin inhibits sebum production and sebocyte proliferation, and augments sebum excretion in hamsters. J Invest Dermatol 127, 2740 – 8 (2007). https://www.ncbi.nlm.nih.gov/pubmed/17597820
- Kornhauser, A., Coelho, S. G. & Hearing, V. J. Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clin Cosmet Investig Dermatol 3, 135 – 142 (2010). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3047947/
- Kim, D. B., Shin, G. H., Kim, J. M., Kim, Y. H., Lee, J. H., Lee, J. S., Song, H. J., Choe, S. Y., Park, I. J., Cho, J. H. & Lee, O. H. Antioxidant and anti-ageing activities of citrus-based juice mixture. Food Chem 194, 920-927 (2016). https://pubmed.ncbi.nlm.nih.gov/26471635/
- Matthews, M. R., VanderVelde, J. C., Caruso, D. M., Foster, K. N. Lemons in the Arizona sunshine: The effects of furocoumarins leading to phytophotodermatitis and burn-like injuries. Wounds 29, E118-E124 (2017). https://www.ncbi.nlm.nih.gov/pubmed/29324427
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