Glycolic acid in skin care
Glycolic acid (GA) is an alpha hydroxy acid (AHA) used primarily as an exfoliating ingredient in cleansers, toners, and over the counter cosmetics. It is also used in at home and medical chemical peels.
Glycolic acid is great for removing dead skin from the face, arms and body as well as stimulating collagen production and playing a role in hyperpigmentation treatments.
Not all skin types react the same to hydroxy acids, and GA is not suited for some sensitive skin types such as stinging skin, post procedure skin, and rosacea.
Although AHA works for oily skin types, it is not lipophilic so salicylic acid is a better choice for oily skin types.
Table of contents
What is glycolic acid
It is in the chemical family of carboxylic acids, specifically, it is a monocarboxylic acid.
Glycolic acid is the most commonly used chemical peel ingredient because it is fast acting, easy to use, inexpensive, and relatively safe.
It is an effective exfoliator, useful in treatments of various kinds of hyperpigmentation, acne treatments, small bumps on the face such as keratosis pilaris, and sun damaged skin.
It is important not to over-exfoliate, so do not use more than 3 exfoliating ingredients in your skin care routine unless you are one of these resistant Baumann Skin Types : 9,10,11,12,13,14, 15 or 16.
How does it work
The potent acidity of GA breaks apart intercellular connections, which helps dead skin cells release themselves from your body. (13)
Low pH environments are also inhospitable to many kinds of bacteria, meaning acne causing bacteria is eliminated by GA.
When your skin is exfoliated, it responds by producing new cells to replace the old ones. This mechanism is part of how GA works in skin lightening treatments.
The new cells generated after exfoliating results in more collagen in the skin,(14) which is why glycolic acid is often found in anti-aging products. (17)
Because it is hydrophilic, Glycolic acid sucks water into itself, meaning it is a humectant.
Glycolic acid dissolves in water, unlike salicylic acid which dissolves in fats. For this reason, glycolic acid is not great for use on oily skin; it does not easily get through the sebum on skin. (4)
Glycolic acid has many benefits in skin care such as exfoliating, smoothing, skin lightening, cleansing, and hydrating properties.
GA also stimulates fibroblast cells in the skin, resulting in an increased production of collagen in the skin (14-16)
It is commonly used in chemical peels because it is great at removing dead cells from the skin and works quickly.
As a strong acid, it eliminates acne-causing and other bacteria on the face, which is why it is so common in acne treatment cleansers.
The main side effects of glycolic acid are stinging, peeling and skin irritation. You can also burn your skin with GA.
Side effects are more likely to occur if:
- It is a formulated at a low pH
- You do not neutralize it (Not all GA products need to be neutralized but peels usually do)
- You leave it on too long
- You use it with other exfoliators
- You apply it to skin that had recently been exposed to friction or shearing forces such as kissing someone with a rough beard.
Glycolic acid peels should be avoided if you are beginning a retinoid topically or orally.
The risk of retinoid dermatitis and side effects are increased when using retinol and glycolic acid together.
Using a retinoid and glycolic acid together can result in over-exfoliation, inflammation, and damage to the skin barrier.
Also glycolic acid is not considered an allergen, I have seen patients that believe they are allergic to it because they get a rash every time they use it.
It is possible to experience contact dermatitis, or significant irritation and redness, after exposure to glycolic acid, especially when used with the wrong products in your skin care routine.
Is it safe?
Glycolic acid is considered safe. It is one of the first antiaging skin care ingredients on the market and one of the most studied ingredients to treat wrinkles and dry skin.
In 1998 the CIR reviewed glycolic acid and other AHAs and stated that GA was safe for use on the skin. (23)
The EWG rates glycolic acid as a 1-4. The predominant safety concern is that it will thin the top layer of your skin called the stratum corneum and make skin susceptible to sun damage. This is why most glycolic acid containing products have a warning label to use sunscreen.
Glycolic acid may a low pH, depending upon the formulation. You can find a list of the pH of various glycolic face cleansers here.
The lower the pH is, the more likely stinging, exfoliating, and irritation will occur.
- Always use SPF
- Limit sun exposure
- Do not use with more than 2 other exfoliators unless advised by your doctor
- Avoid when beginning a retinoid
- Avoid when increasing the strength of your retinoid
- Do not use with other acids in your skin care routine (except ascorbic acid and hyaluronic acid)
- Do not use after friction on the face like cold wind from skiing, kissing someone with rough facial hair, using a facial scrub
- Do not use after microneedling
How to use glycolic acid in your skin care routine
The most common uses for glycolic acid in skin care is in cleansers, toners, creams and serums.
Depending on your skin type and custom skin care regimen, there are various types of products that should be paired with glycolic acid.
The best advice is to take the quiz and find your skin type and get a custom skin care routine because it is impossible to describe all the possibilities here.
Here are some tips- but they are not correct for all 16 Baumann Skin Types:
- Use a glycolic cleanser before vitamin C to speed absorption.
- Use a glycolic toner before expensive serums (but not with serums with exosomes).
- Don't start any glycolic serums or creams until you are adjusted to the strongest retinoid strength
- Choose glycolic acid when you have dry skin and salicylic acid when you have oily skin
- Dry skin types should combine with an occlusive moisturizer in the routine.
After exfoliating your skin, it can be more sensitive to sunlight and radiation damage. To avoid sun damage, use a good broad spectrum sunscreen after your GA treatments.
The get the best glycolic product advice for your skin type; take our quiz and see which dermatologist-recommended products are right for your skin type!
Can glycolic acid be used together with other ingredients?
It can be used with the following:
Glycolic Acid Chemical peels
The most common use of glycolic acid is as a part of chemical peel treatments.
Studies have found that beyond simply smoothing and making skin radiant, alpha hydroxy acid peels are effective for treating photoaging. (5)
These peel treatments improve wrinkled skin by stimulating skin stems cells to make more cells and fibroblast to make more collagen in the skin. (6)
How vigorously you prep the skin will affect how strong the peel will be so use care with strong foaming cleansers before a GA peel.
In peels, the concentrations of glycolic acid can be as high as 70% or more in some cases, so use caution because you can easily burn your skin with these stronger peels.
We recommend seeing a medical aesthetician for stronger peels.
The initial effects of a GA peel happen very quickly, within an hour, but the skin may peel for days after a GA peel.
How long you will peel depends upon:
- How skin was prepped
- What pH the peel is
- What other ingredients were placed on the skin
- the condition of the skin's stratum corneum and skin barrier prior to the peel
Unlike most anti-aging products which take between weeks and months to show improvements, hydroxy acids show results almost immediately by smoothing the skin's surface and making skin glow in the light. Consistent use of AHAS will improve the look of aged skin.
That being said, overuse of any hydroxy acid, including GA on the skin can result in significant irritation and sensitivity on the skin.
Some Baumann Skin Types should not use glycolic acid, while others should use it infrequently to avoid side-effects.
Glycolic acid is a great ingredient for face cleansers because its low pH creates a deadly environment for bacteria and it removes dead skin from the face.
The acidity of GA breaks apart the connective membranes between cells, allowing other active compounds in cleansers to penetrate deeper into the skin. (19,20)
This process of removing dead cells and stimulating the production of new cells is called exfoliating.
GA cleansers are best for dry skin types suffering from acne, dark spots or wrinkles because they also hydrate the skin with their humectant properties.
Glycolic acid is most effective in formulations with other ingredients that do not raise it's pH.
Because glycolic acid has so many beneficial applications, it can be found in many product types including:
Based on the purpose of each product, glycolic acid may be present in higher or lower concentrations; some products need more acidity to work, and some need to be less acidic.
Glycolic acid has been shown in multiple studies to play a beneficial role in hyperpigmentation treatments. (15,18)
Under normal conditions, the melanocytes in your skin produce pigment that goes into other structures called keratinocytes. These keratinocytes slowly work their way up to the surface of your skin, loaded with whatever amount of melanin was deposited into it. When these keratinocytes reach the surface of the skin, their pigmented color results in what we call dark spots, or hyperpigmentation.
When you exfoliate with a glycolic acid product, these pigmented keratinocytes flake off with the rest of your surface level skin.
This is to say that GA helps remove dark spots, but it does not prevent them. Under the surface of the skin, pigment is still being put into keratinocytes that will eventually surface as more dark spots.
PAR-2 blockers and tyrosinase inhibitors stop melanin production, which means keratinocytes will start to appear clear and eventually surface as regularly pigmented skin.
Because it takes a while for keratinocytes to replace each other, these kinds of hyperpigmentation treatments can take 8-12 weeks to get results.
For dry skin types
GA is safe for dry skin because alpha hydroxy acids are hydrophilic humectants: they pull water into themselves.
Unlike salicylic acid, glycolic acid does not strip oils from the skin and is not as effective at clearing clogged pores.
This means, in simple terms, where GA goes, water follows. If you have dry skin and acne, or otherwise need a chemical peel, GA is a good choice because it will not dry your skin.
(The dryness you see after a peel is really a layer of dead skin cells. Underneath the skin is very hydrated.)
Using a barrier repair moisturizer is always important for dry skin types. These can contain glycolic acid or be used with a glycolic acid containing product.
Glycolic acid is a common and good ingredient in acne treatments for dry skin types because the low pH helps eliminate bacteria.
Unlike salicylic acid which directly penetrates oily clogged pores and shrinks them from the inside, glycolic acid simply assists in the body's natural desquamation processes by removing surface level clogs in pores.
Glycolic acid is also a great choice for alleviating "acne scars," the red bumps that can remain on your skin after a pimple is gone. It simply exfoliates the spots. If you have these red acne scars, consider choosing salicylic acid instead because it exfoliates and has anti-inflammatory abilities.
Hydroxy acid chemical peels like GA or salicylic acid are good for acne because they eliminate the causes of acne while also treating the symptoms.
Here are some of the best references on glycolic acid in skin care:
- Yu R, Van Scott E. Bioavailability of alpha-hydroxyacids in topical formulations Cosmet Dermatol. 1996;9:54.
- Ahn HH, Kim IH. Whitening effect of salicylic acid peels in Asian patients. Dermatol Surg. 2006;32:372.
- Davies M, Marks R. Studies on the effect of salicylic acid on normal skin. Br J Dermatol. 1976;95:187.
- Fabbrocini G, Padova M, Tosti A. Superficial to Medium-Depth Peels: A Personal Experience. In: Tung R, Rubin M, editors. Procedures in Cosmetic Dermatology Series: Chemical Peels. 2nd ed. London: Elsevier Health Sciences; 2010. pp. 7–16.
- Ditre CM, Griffin TD, Murphy GF, et al. Effects of alpha-hydroxy acids on photoaged skin: a pilot clinical, histologic, and ultrastructural study. J Am Acad Dermatol. 1996;34:187.
- Kim SJ, Park JH, Kim DH, et al. Increased in vivo collagen synthesis and in vitro cell proliferative effect of glycolic acid. Dermatol Surg. 1998;24:1054.
- Sharad J. Combination of microneedling and glycolic acid peels for the treatment of acne scars in dark skin. J Cosmet Dermatol. 2011 Dec;10(4):317-23.
- . Usuki A, Ohashi A, Sato H, Ochiai Y, Ichihashi M, Funasaka Y. The inhibitory effect of glycolic acid and lactic acid on melanin synthesis in melanoma cells. Exp Dermatol. 2003;12 Suppl 2:43-50. doi: 10.1034/j.1600-0625.12.s2.7.x. PMID: 14756523.
- Sharquie KE, Al-Dhalimi MA, Noaimi AA, Al-Sultany HA. Lactic Acid as a new therapeutic peeling agent in the treatment of lifa disease (frictional dermal melanosis). Indian J Dermatol. 2012;57(6):444-448.
- Sharquie KE, Al-Tikreety MM, Al-Mashhadani SA. Lactic acid as a new therapeutic peeling agent in melasma. Dermatol Surg. 2005 Feb;31(2):149-54.
- Dayal S, Sahu P, Jain VK, Khetri S. Clinical efficacy and safety of 20% glycolic peel, 15% lactic peel, and topical 20% vitamin C in constitutional type of periorbital melanosis: a comparative study. J Cosmet Dermatol. 2016 Dec;15(4):367-373.
- Dainichi T, Ueda S, Imayama S, Furue M. Excellent clinical results with a new preparation for chemical peeling in acne: 30% salicylic acid in polyethylene glycol vehicle. Dermatol Surg. 2008;34:891-899.
- Newman N, Newman A, Moy LS, Babapour R, Harris AG, Moy RL. Clinical improvement of photoaged skin with 50% glycolic acid. A double-blind vehicle-controlled study. Dermatol Surg. 1996;22(5):455–60.
- Smith WP. Epidermal and dermal effects of topical lactic acid. J Am Acad Dermatol. 1996;35(3 Pt 1):388–91.
- Ditre CM, Griffin TD, Murphy GF, Sueki H, Telegan B, Johnson WC, et al. Effects of alpha-hydroxy acids on photoaged skin: a pilot clinical, histologic, and ultrastructural study. J Am Acad Dermatol. 1996;34(2 Pt 1):187-95.
- Bernstein EF, Lee J, Brown DB, Yu R, Van Scott E. Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin. Dermatol Surg. 2001;27(5):429-33.
- Ramos-e-Silva M, Celem LR, Ramos-e-Silva S, Fucci-da-Costa AP. Anti-aging cosmetics: facts and controversies. Clin Dermatol. 2013;31(6):750–8.
- Baumann L, Saghari S. Chemical Peels, in Cosmetic Dermatology: Principles and Practice, 2nd edition. L Baumann, S Saghari, E Weisberg, eds. New York: McGraw-Hill, 2009, pp. 148–162.
- Van Scott EJ, Yu RJ. Control of keratinization with alpha-hydroxy acids and related compounds. I. Topical treatment of ichthyotic disorders. Arch Dermatol. 1974;110(4):586-90.
- Van Scott EJ, Yu RJ. Hyperkeratinization, corneocyte cohesion, and alpha hydroxy acids. J Am Acad Dermatol. 1984;11(5 Pt 1):867-79.
- Thompson BC, Halliday GM, Damian DL. Nicotinamide enhances repair of arsenic and ultraviolet radiation-induced DNA damage in HaCaT keratinocytes and ex vivo human skin. PLoS One. 2015;10(2):e0117491.
- Surjana D, Halliday GM, Damian DL. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in human keratinocytes and ex vivo skin. Carcinogenesis. 2013;34(5):1144-9.
- Andersen, F. E. (1998). Final report on the safety assessment of glycolic acid, ammonium, calcium, potassium, and sodium glycolates, methyl, ethyl, propyl, and butyl glycolates, and lactic acid, ammonium, calcium, potassium, sodium, and TEA-lactates, methyl, ethyl, isopropyl, and butyl lactates, and lauryl, myristyl, and cetyl lactates. International Journal of Toxicology, 17(1_suppl), 1-241.