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Well, you may have heard the saying that what we eat has a lot to do with what is manifested, skin-wise. This can be true for lactic acid, which is found in the human body and can be found largely in fermented foods, such as cheese, yoghurt, kombucha, and tomato juice as well as in sour milk.

Lactic acid is part of the Alpha Hydroxy Acids (AHAs) family. AHAs are organic acids and include such acids as glycolic, malic, tartic and citric acid (Tang and Yang, 2018). AHAs are prized acids due to their facial peeling capabilities as well as their ability to improve the appearance of keratosis and acne (Tang and Yang, 2018).  To this extent, these acids are usually noted in the lineup of topical skincare treatments, particularly as it relates to skin discolourations, acne and the enhancement of the surface of the skin.  

In this article, we are going to look at some of the main benefits of including lactic acid in your skincare regimen, not only for gentle exfoliation but also for that firm, plumped-looking skin most of us desire. Let’s discuss!

You can read more about AHAs in these articles:

• Glycolic acid, the Sting of Beauty!
• Aging like a Boss!
• Mandelic acid for Acne and Wrinkles – Does it Work?

The Discussion

Lactic acid is an organic acid of low molecular weight (Ata et al. 2015). The acid is formed due to the fermentation of the lactic acid bacteria or synthetically (Ata et al. 2015).  While the ingredient is used in the food industry, it is now commonly used in the pharmaceutical and cosmetic industries due to its purported skincare benefits which include exfoliating the skin, improving skin texture, cleansing the skin as well as just improving the overall look and feel of the skin.

some time.   It is reported to have been discovered in the 1780s by the Swedish Chemist – Carl Scheele (Ata et al. 2015).  However, it is said that industrial-scale production of the ingredients started around 1895 by the Pharmaceutical Company – Boehringer Ingelheim (Alsaheb et. al. 2015).  In food, the acid plays a huge role in the preparation of fermented dairy products, winemaking, sausages, meats as well as the curing of fish (Alsaheb et.. al. 2015).  

However, its use in the meat and fish industries is usually for flavour enhancement (Naveena et. al. 2005; Saha and Nakamura, 2003).  On the other hand, it is used in the cosmetic industry as a moisturizer, PH regulator and humectant. It is also used for the development of products geared at acne management, and lightening of the skin, particularly as it relates to hyper-pigmentation and the overall rejuvenation of the skin (Wee et. al. 2006).

In this article, we will be discussing five (5) benefits of lactic acid as it relates to the skin. These include its benefits for photodamaged skin, gentle peeling and exfoliation of the skin, how it can help those suffering from melasma, and acne as well as its possible effects in firming the skin. We will also look at any reported side effects of using this acid as well as some of the best concentrations for overall skin care.

You can read more about skin and skincare in general in these in-depth articles:

• Love the skin you’re in.
• Clay is for beauty.
• Aging like a Boss!
• Hyaluronic Acid – Antiaging Hero or Fad?

Five(5) ‘Must know’ skincare benefits of Lactic Acid:

• It may help with photodamaged skin.
• Excellent for gentle exfoliating or peeling of the skin.
• Melasma.
• Managing acne.
• Firming of the skin.

Lactic Acid and Photodamaged Skin

Photodamaged skin is described as the gradual changes in the skin which can make one seem older than they usually are, or what is called premature aging. Some of the signs of photodamaged skin include premature wrinkling of the skin, spots, lack of elasticity etc.  The condition is usually said to be caused by prolonged sun exposure to the skin.  

Photodamaged skin is usually very challenging to treat and requires a careful assessment before a treatment plan is introduced. Nonetheless, several ingredients have been touted as being effective in helping to reduce or eliminate some of the effects of this condition, one such being lactic acid and other AHAs in general.

Lactic acid benefits for photodamaged skin were observed in a Twenty-two (22) week, double-blinded, randomized clinical trial assessments by Stiller et al (1996).  Seventy-four (74) women, ages Forty to Seventy (40-70) years of age, participated in the study.  These women suffered from moderate to severe photodamaged facial skin. Two (2) AHAs were used in the study, namely glycolic and lactic acid. The percentage concentration for each was 8% (glycolic acid) and 8% (lactic acid).  The glycolic and lactic acid creams were added two (2) times daily to the face as well as the outer part of the forearms. 

Participants of both the glycolic acid and the lactic acid reported improvement in the overall severity of photodamaged to the skin (at least a 1-grade improvement).  It was stated that the lactic acid was proven a bit superior in reducing the severity of photodamaged skin, hyper-pigmentation as well as the natural complexion of the skin than the glycolic acid, which was also very impactful.

The study concluded that both acids were very useful in reducing some of the chronic signs of photodamaged skin. In addition, the concentration was mostly well tolerated by all the participants except one (1) person who withdrew due to skin irritation issues

Lactic Acid and Skin Peeling and Exfoliating

Skin peeling is a procedure that aims to speed up the process of skin exfoliation (Prestes et al. 2013).  As such, it usually involves the use of chemical or caustic agents to cause superficial destruction to the skin (Prestes et al. 2013).

Peeling can be superficial, medium or deep.  Superficial peeling occurs when only the epidermis is targeted, medium peeling when the papillary dermis is affected and deep when the reticular dermis is destroyed (Prestes et al. 2013). Generally, though, lactic acid can be used as any of the types of peeling described as the degree of peeling will be dependent on the concentration of the ingredient as well as the amount of time it is left on the skin.  

Nonetheless, studies purport that AHAs are commonly used as agents for superficial peeling (Bagatin et al. 2009; Funasaka et. al. 2001).  To this extent, peeling, in general, can cause the epidermis to thicken, increase collagen, as well as increase the dermal volume of the skin (Bagatin et al. 2009).  Hence it’s highly prized and used in the beauty industry.

In a study conducted by Prestes et al. (2013), it was found that lactic acid peel was effective in reducing the appearance of fine lines and wrinkles around the eyes.  In this study, nine (9) participants with varying wrinkle depths were provided with lactic acid or glycolic acid solution and sunscreen to treat the skin.  The participants were divided into three (3) groups and ranged in years from Thirty to Sixty (30-60) years. One group received an Eighty-five (85%) percent lactic acid product, a Seventy (70%) percent glycolic acid solution or a sunscreen only.  It must be noted, that both the lactic acid and glycolic acid groups were also provided with sunscreen to use after application. This is because AHAs can make the skin more sensitive to the sun.

The study lasted for three (3) months with the mixture added once per month (or every 30 days).  The acid treatments were applied on the skin for three (3) minutes which makes it a superficial peeling procedure.  Both the lactic and glycolic acid groups experienced a significant reduction in wrinkles with the lactic acid, after the second application and glycolic acid after the third application. 

The sunscreen-only group did not present any significant differences in the skin. As such, the researchers concluded that sunscreen alone is not enough to reduce fine lines and wrinkles.  Additionally, lactic acid used at the reported concentration only saw participants reporting mild reactions such as redness and burning.

Lactic Acid and Melasma

Melasma is a common disorder of the pigment of the skin.  It is said to mostly affect women of child-bearing years, particularly those of both Asian and Hispanic descent (McDonald and Georgouras, 1992; Jimbow and Jimbow, 1989). The condition is usually described as a convergent of grey-brown patches on areas of the face that have been mostly exposed to the sun. These areas usually include the forehead, cheeks, nose and chin (Newcomer et. al. 1962).

According to (Raka and Brahmbhatt, 2019), melasma occurs due to the hyperactivity of the melanocytes of the epidermis layer of the skin.  Several noted factors have been suggested as risk factors for the development of the condition such as one’s genetic predisposition, pregnancy, excessive exposure to ultraviolet lights, certain foods as well as particular medications/drugs among other stressors of the skin (Taylor, 2003; Bonilla et. al. 2002; Hexsel et. al. 2006).

While there is no easy fix for this condition, recent studies have been indicating the role of chemical peeling (Kalla et. al. 2001).  One such was a randomized, open-label, single-blinded, single-centre, comparative study with Fifty (50) melasma patients. The study was conducted from 2010 through 2011 by Raka and Brahmbhatt (Raka and Brahmbhatt, 2019). The study was conducted with participants ranging in age from Twelve to Fifty (12-50) years for Twelve (12) weeks. 

The participants were divided into two (2) groups. One group was administered a Fifty (50%) percent glycolic acid peel and the next, a Ninety-two (92%) percent lactic acid peeling solution.  The patients were advised to use the peeling solutions two (2) times per week. Before each peel, the volunteers’ faces were cleansed with a mild cleanser and degreased with pure acetone.  

The peel was neutralized with a baking soda (sodium bicarbonate) solution of Ten to Fifteen (10-15%) percent concentrations.  The peeling solution was left on the skin from as low as one (1) minute to Thirty (30) seconds or Five (5) minutes (glycolic) and up to Thirty (30) minutes for the lactic acid peel.

The study showed significant improvement in their melasma.  As such, it was shown that lactic acid was equally effective as glycolic acid peel, but with fewer side effects. Additionally, let’s take into consideration that the glycolic acid solution was lower than the lactic acid and remained on the skin for a shorter period, as it is more potent than the lactic acid which is considered a gentler solution, even with a concentration that was presented in this study.  

Nonetheless, another study by Sharquie et al. (2005), reported patients experiencing more improvement in their melasma with a similar lactic acid solution of 92% of PH 3.5. This solution was applied every Three to five (3-5) weeks until the patients experienced their desired goal but did not go beyond Six (6) weeks.

Some of the side effects reported by participants were burning, and skin rash. Some patients of the glycolic acid group experienced post-inflammatory hyper-pigmentation as well as milia. On the other hand, minimal side effects were experienced by the lactic acid group. 

Lactic Acid and Acne

Acne vulgaris is a common skin disorder of the pilosebaceous or structural follicle and is said to affect about Ninety-eight (98%) percent of adolescents (Chan and Rohr, 2000).  However, adults also suffer from acne, which can be caused by multiple factors including hormonal changes, the food we eat as well as environmental factors. What makes the situation a more concerning one, is the aftermath of acne – lesions and scars which can affect one’s self-esteem (Lee et. al. 2003).  As such, chemical peeling can be a welcoming alternative in the fight for the management of acne as well as scars.

Lactic acid has been proven effective in the treatment and management of acne in many research. One such was that of Sayed and Abdel-Motaleb (2012), which was conducted with Forty (40) participants with facial acne.  In the study, Twenty (20) of the patients suffered from mild acne while the other Twenty (20), had moderate acne.  The patients were given two (2) solutions, of twenty (20%) percent salicylic acid which was applied to the right side of the face and an Eighty-five (85%) percent lactic acid solution applied to the left side of the face.  

The solutions were added once per week over a Two (2) month period. All the patients experienced significant results with the application of both treatments.  As such, the researchers concluded that there were no significant differences between the two (2) methods.  However, the salicylic acid solution had a bit more improvement than the lactic acid over that duration, which was to be expected, seeing that it is usually an acid prescribed for acne treatment. Nonetheless, lactic acid, which is a milder acid, had similar results and would be more beneficial for persons with sensitive skin types.  Additionally, lactic acid has been proven useful in the treatment of acne scarring.

Lactic acid acne scaring benefits were also proven in a study by Sachdevo (2010) with women of Indian descent.  In the study, a lactic acid solution of Ninety-two (92%) with a PH of 2.0 was used. The lactic acid was applied over two (2) weeks with a maximum of four (4) peels.  The patients were followed every month after the application of the peel. This was done for Three (3) months. The results showed that they experienced significant clearance of lesions (up to 75%) as well as scaring.

Lactic Acid and Skin Firming

Lactic acid was also proven effective in the firming of the skin due to its effect on both the epidermal and dermal layers of the skin.  This was observed in a study by Smith (1996).  In this study, participants were treated with either a Twelve (12%) percent or Five (5%) percent lactic acid solution twice daily over 3 months.  The study found that twelve (12%) percent lactic acid solution increased both epidermal and dermal firmness and thickness.  

It was also observed that the participants experienced an overall improvement in skin smoothness as well as in the appearance of both fine lines and wrinkles.  No dermal changes were observed for patients who had applied the lactic acid solution of five (5%).  However, similar epidermal and clinical changes were reported.

Are there any side effects of using Lactic Acid on the Skin?

While lactic acid is a milder acid in the family of AHAs, it still does carry some level of side effects especially as it relates to post-inflammatory hyper-pigmentation due to its peeling effects on the skin.  Other reported side effects include scarring, allergic reactions, milia as well as changes in the texture of the skin (Tang and Yang, 2018).

Additionally, studies have indicated that peeling can increase the sensitivity of the skin to ultraviolet (UV) light which can lead to serious damage to the skin (Kaidbey et. al. 2003).  As such, a sunscreen with a sun protection factor (SPF) of Thirty (30) or higher is usually recommended for use.  Sunscreen becomes, even more, paramount the higher the concentration of the AHAs. This is due to the potential of UV-induced phototoxicity (Tang and Yang, 2018).

What is the best Lactic Acid Concentration for Skincare?

Generally, lactic acid is considered a milder AHA and as such, it may require greater percentages to experience the best results.  However, for regular use, research usually recommends a low concentration of Five (5%) percent to Eight (8%) percent.  This is because a percentage of this range, even as low as Five (5%) percent can modulate the surface of the skin as well as the dermis.  

However, solutions of Ten (10%) percent and Twelve (12%) percent may be able to influence both the epidermis and dermis over a Three (3) month period.  Higher percentages are usually not recommended for regular use and are suggested to be administered by a trained professional.

Therefore, concentrations of Five (5%) percent, Ten (10%) percent and Twelve (12%) percent can be proven effective in mildly exfoliating the skin, firming it, reducing fine lines and wrinkles, and scarring and hyperpigmentation of the skin.

Illustrative Summary

Here is a summary of the Five (5) of LACTIC ACID for Skincare.

Let’s Sum Up!

Lactic acid is a member of the Alpha Hydroxy Acids (AHAs) family, which are organic acids largely used for superficial peeling of the skin. Other AHAs include glycolic acid, malic acid, tartaric acid and citric acid. However, of the list of acids, lactic acid is considered one of the milder of the bunch.  

As such, it is usually recommended for all skin types, especially those with sensitive skin types.  Lactic acid has proven to be beneficial to the skin as it has been proven to be effective in improving photodamaged skin, helping with the management of acne and scars, melasma and the firming of the skin.

But, which solution is best? Well, research indicates that a Five (5%) percent concentration can serve to only impact the dermis of the skin while higher concentrations can be more profound by influencing several layers of the skin.  Therefore, it would be an excellent addition to any skincare regimen, especially for those with sensitive skin or those who want to manage the signs of skin aging.  Have you ever used lactic acid before? How was it? Share it nuh!  So, with all that was said…Are you Skintimate Yet?

For further guides for skincare, check out these other posts:

• • 5 Natural Oils to seriously consider for your skincare arsenal – Grape seed is one of them!
  • Glycolic Acid – the sting of beauty!
  • Clay is for Beauty!
  • Aging like a Boss!

Editor’s Note: Article was updated on July 10, 2024.

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