Lemon juice for acne: no trial, and a sun risk

No trial has tested lemon juice on acne, so no source shows that it helps. The best documented fact about lemon juice on skin is a risk. The American Academy of Dermatology (AAD) says: "When citrus juice gets on your skin, it can react with sunlight and can cause a blistering rash or painful swelling." This page is part of Skinli's guide to home remedies for acne.

Skinli gives general education and is not a doctor. For the studies below, Skinli read the published summaries (abstracts), and one full paper on the acidity of drinks. No source read for this guide gives a way to use lemon juice on acne, so this page gives none.

No study has tested lemon juice on acne

The searches run for this guide found no study of lemon juice on acne in people. The NHS acne page and the NICE acne guideline for England do not mention lemon.

Many people still use it. A 2022 survey asked 1,571 acne patients at clinics in Turkey about complementary and alternative medicine (CAM), which means remedies outside standard medical care. It found: "As a CAM method, 66.37% of the patients reported having used lemon juice." People most often tried such remedies before they saw a doctor. The survey recorded what people used, and it measured no result for any remedy.

One laboratory study put ten essential oils in a dish with the acne bacterium, and lemon essential oil was one of the ten. Its summary names thyme, cinnamon and rose as the most active oils. An essential oil is a concentrated oil taken from a plant, so it is a different product from the juice, and no person was treated.

Citrus juice and sunlight can blister the skin

Two AAD pages warn about citrus and sun, and both name lemons. One is quoted at the top of this page. The other says:

• "Lemons, limes, clementines, oranges, and grapefruit all contain light-sensitizing chemicals that can cause a rash."
• "combined exposure to citrus fruit and sunlight should be avoided."

Doctors call this reaction phytophotodermatitis: a skin reaction that needs both a plant chemical and sunlight. A 2009 report in the journal Military Medicine explains it: "Sun-sensitizing compounds, known as furocoumarins, are found in many plants (limes, celery, and natural grasses) and are excited by ultraviolet A (UVA) irradiation." UVA is one part of sunlight.

The published reports add these points:

• What it looks like. The 2009 report lists redness that comes late, darker patches of skin and blisters.
• Where it shows. "Hyperpigmented lesions typically appear on the hands or around the mouth." Hyperpigmented means darker than the skin around it.
• It can look like a burn. A 2019 case report describes a man aged 26 after contact with lime and then sunlight. It says the reaction "is often confused with skin burns due to the blistering nature of its lesions."
• It needs no allergy. A 2024 review calls it "a non-immunologic skin reaction triggered by certain plants followed by exposure to ultraviolet radiation emitted by sunlight." In plain words, it can happen to a person who has no allergy to citrus.
• Any skin colour. The 2009 report says "there appears to be no predilection for race, although typically more easily recognized in the fair skinned." In plain words, it happens on every skin colour and is easier to see on light skin.

The case reports name limes and "citrus fruit", and the AAD pages name lemons. The FDA says the same about citrus oils in products: "Certain citrus oils used safely in food can also be harmful in cosmetics, particularly when applied to skin exposed to the sun."

No source read for this guide gives a safe length of time between lemon juice on the skin and sun.

How acid lemon juice is, compared with skin

pH is the scale used to measure acid. A lower number means more acid.

What was measured	pH	Source
A bottled lemon juice	2.25	A 2016 study of 380 drinks bought in Birmingham, Alabama, in the Journal of the American Dental Association
The 51 juices in that study	2.25 to 4.69	The same study. Lemon juice was the most acid of the 51
The pH limit used for acid cosmetics sold to the public	3.5 or greater	An FDA page, which reports the limit that a cosmetics industry panel set for glycolic acid and lactic acid products
The surface of healthy skin	4.7 on average	A 2006 study of 330 people, measured on the inner forearm

Each figure has a limit. The drinks study was about teeth, and it says nothing about skin. The skin figure comes from the forearm, and its first author worked at a maker of soap and body care products. The FDA page does not name lemon juice.

The link between lemons and acid cosmetics is citric acid. The FDA page on alpha hydroxy acids (AHAs), a family of acids used in cosmetics, says: "The most common AHAs in cosmetic products are glycolic acid and lactic acid. Among others are citric acid, hydroxycaprylic acid, and hydroxycapric acid." The same page says AHA products "may increase your skin's sensitivity to the sun and particularly the possibility of sunburn."

The FDA also counted complaints. Between 1992 and February 2004 it received 114 reports of reactions to AHA cosmetics, including "burning (45), dermatitis or rash (35), swelling (29), pigmentary changes (15), blisters or welts (14), skin peeling (13)". Every one of those reports concerns a finished cosmetic. Lemon juice, by the table above, is more acid than the limit set for those products.

For washing the face, NICE advises people with acne to use a "non-alkaline" cleanser, with a pH that is neutral or close to the skin's own. No source has measured what a liquid at pH 2.25 does to a face with acne.

Irritation can add to acne and leave dark marks

The AAD says: "Anytime you irritate your skin, you risk getting more acne." Its tips page for acne says: "Avoid products that can irritate your skin, including astringents, toners, and exfoliants. These products can dry your skin and make acne appear worse."

Irritated skin can also darken. An AAD news release from 2023 says that "whenever there is inflammation in the skin, such as an acne bump, there is a risk for darkening of the skin (known as post-inflammatory hyperpigmentation)." It adds: "This risk is increased if you do not protect your skin from the sun." Lemon juice followed by sun can therefore darken skin in two ways: through the citrus and sun reaction, and through the mark that irritation leaves behind.

For marks left by pimples, the AAD names a tested ingredient. It says of azelaic acid: "It fights acne and can also fade the dark spots that appear when an acne spot clears." Skinli's guides on dark marks after pimples and vitamin C for dark spots cover what has been studied.

A food that is safe to eat can still harm skin. The FDA says: "many plants contain materials that are toxic, irritating, or likely to cause allergic reactions when applied to the skin." The page on garlic for acne covers a kitchen item with published burn cases.

Lemon water, and other questions no source answers

• Lemon water and lemon in food. No study read for this guide looked at lemon as a drink or a food and acne. NICE says: "Advise people that there is not enough evidence to support specific diets for treating acne." The guide does diet cause acne covers the foods that have been studied.
• A safe dilution. No source gives one.
• Lemon juice left on overnight. No study tested it for any length of time.
• Lemon mixed with honey or baking soda. No study of either mix on acne was found. The pages on honey for acne and baking soda for acne report what exists on each.

What the AAD, the NHS and the FDA rule support

These three sources name a short list of drug ingredients for acne.

• The AAD, for a deep, painful pimple: "Choose a product that contains one of these acne-fighting active ingredients: adapalene, azelaic acid, benzoyl peroxide, or salicylic acid."
• The NHS acne page: "try acne treatments you put on your skin such as salicylic acid or benzoyl peroxide".
• The FDA rule for acne drugs sold without a prescription: benzoyl peroxide at 2.5 to 10 percent, salicylic acid at 0.5 to 2 percent, sulfur at 3 to 10 percent, and sulfur combined with resorcinol.

Lemon juice and citric acid appear on none of these lists. Adapalene is a retinoid, a medicine related to vitamin A, and the AAD says acne treatment that contains it is sold online and in stores. The AAD's acne pages name a maker of prescription acne drugs as their supporter.

If lemon juice has touched your skin, and when to see a doctor

The AAD's advice for citrus on the skin is short: "Rinse your skin with lots of water immediately after touching anything with citrus and then apply sunscreen". The guide to sunscreen for acne-prone skin explains what to look for on the label.

See a doctor for blisters, painful swelling, or dark patches that appear in the days after lemon juice and sun. Tell the doctor about the juice. A 2014 case report says this reaction "may often be misdiagnosed as other skin conditions including fungal infection, cellulitis, allergic contact dermatitis, and even child abuse." Cellulitis is a bacterial infection of the skin, and allergic contact dermatitis is an allergy rash from something that touched the skin.

For the acne itself, the NHS says to see a GP, which is a family doctor, if "you've tried treating it yourself but it's not getting better", or if "you have lots of spots, or the spots are deep, painful or causing scars". The AAD says to see a dermatologist when acne causes cysts and nodules, which are deep blemishes that can leave scars, or when acne has not cleared with treatment you can buy without a prescription.