What Is Lactic Acid and Is It Safe for Sensitive Skin?

Chemical exfoliation is no longer a secret trend for healthy skin. But for those whose skin type is sensitive, using any exfoliator is a big challenge. A slight mistake can damage the skin barrier, and result in Erythema, Irritation or severe Breakouts. So will people with sensitive skin never get the real benefits of exfoliation? The scientific solution to this problem is Lactic Acid.

In today’s comprehensive guide, we’ll discuss what Lactic Acid actually is, how it works on our epidermis, and why it’s known as the safest AHA or Alpha Hydroxy Acid for Sensitive Skin. In addition, a step-by-step guideline is shared on how to properly incorporate Lactic Acid into your skincare routine.

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What is Lactic Acid? (The Science Behind It)

Lactic Acid is an Alpha Hydroxy Acid (AHA), which is basically water-soluble. Although historically derived from sour milk, in the modern skincare industry it is synthetically produced in laboratories, stable for the skin.

Lactic Acid gently exfoliates the dead skin or Corneocytes that accumulate in the Stratum Corneum or the outermost layer of our skin. It breaks down the Desmosomes (which hold dead skin cells together) on the skin surface. As a result, new and healthy skin cells rise up, which we call Cellular Turnover.

But the key feature of Lactic Acid is that it is not only an exfoliator but also a humectant. It helps to increase the Natural Moisturizing Factors (NMF) in the skin, thereby exfoliating the skin and keeping it hydrated.

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Lactic Acid vs. Other AHAs: The Importance of Molecular Size

Many people ask, why choose Lactic Acid over Glycolic Acid? The scientific answer is hidden in their molecular weight or molecular size. The matter is easily explained through the table below:

As seen from the table, since the molecular size of Glycolic Acid is only 76 Da, it penetrates deep into the epidermis quickly. Due to this rapid penetration or absorption, sensitive skin can easily experience itching or redness. On the other hand, the molecular size of Lactic Acid is 90 Da. Being large in size, it penetrates the skin in a gentler manner. As a result it works without disturbing the skin barrier.

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Is Lactic Acid Really Safe for Sensitive Skin?

The answer in one word is: Yes, Lactic Acid is safe, provided it is used in the right concentration and pH level. According to dermatologists, there are several scientific reasons why it is a standard ingredient for sensitive skin:

• Dual Action (Exfoliation + Hydration): Skin becomes dry after using other acids. But Lactic Acid stimulates Ceramide Synthesis by going into the skin. As a result, the barrier is strengthened and Trans-Epidermal Water Loss (TEWL) is reduced.
• Physiological Match: The pH of our skin’s natural Acid Mantle is usually between 4.5 and 5.5. As Lactic Acid is a natural metabolite, it adapts well to the skin’s biology.
• Gentle Action on Melanocytes: For those with sensitive skin, post-inflammatory hyperpigmentation (PIH) may occur with a little scrubbing or strong acid use. Lactic Acid gently inhibits the melanin-producing enzyme Tyrosinase, thereby eliminating Hyperpigmentation and Melasma gently.

But remember, there are some important points to keep in mind while using Lactic Acid for Sensitive Skin. First, Concentration. Most dermatologists recommend using 5% to 10% lactic acid for sensitive skin. If more than this concentration is used, there is a possibility of skin irritation. Second, pH Level. The ideal pH level should be between 3.5 and 4.5. A pH lower than this can be harmful to the skin.

Also, a few precautions should be taken while using Lactic Acid. For example:

• Patch Test: You must patch test before using any new skincare product. In this case, you have to wait 24 hours by applying the product containing Lactic Acid to the fold of the elbow or behind the ear. If any irritation or redness occurs, then the product should not be used.
• Frequency of Use: Frequency of use of Lactic Acid for sensitive skin should be 1-2 times a week initially. If the skin can tolerate it over time, the frequency can be increased. But it should never be used daily.
• Sun Protection: Skin becomes more sensitive after using Lactic Acid. So SPF 30 or higher must be used during the day. Otherwise, there is a possibility of sun damage to the skin.

Lactic Acid vs. Glycolic Acid: Which Is Better for Sensitive Skin?

Many people think Glycolic Acid is not suitable for sensitive skin. But actually there is a difference between the two acids. The following table compares:

From this table it is seen that Lactic Acid is more suitable for sensitive skin as it is gentler. But if Glycolic Acid is used in low concentration and high pH level, then it can also be useful for sensitive skin.

For whom is Lactic Acid not ideal?

Although lactic acid is safe for most sensitive skin, it should not be used in some cases. For example:

• Eczema or Rosacea: People with severe Eczema or Rosacea should not use Lactic Acid. Because the use of acid in such skin conditions is likely to cause irritation and flare-up.
• Open Wounds or Cuts: If there are any kind of Open Wounds or Cuts on the skin, then Lactic Acid should not be used. Because it has the possibility of pain and irritation.
• Allergic Reaction: If one is allergic to Lactic Acid, then it should not be used. Redness, Itching, Swelling etc. may appear as symptoms of allergy.

Also, if one’s skin is very sensitive and irritation occurs after using other skincare products, one should consult a dermatologist before using Lactic Acid.

Conclusion

Lactic Acid is a versatile skincare ingredient that is safe and effective even for sensitive skin. Its main feature is that it can simultaneously exfoliate and hydrate the skin. As a result, the barrier function of the skin becomes stronger and the skin remains healthy. However, some important points should be kept in mind when using Lactic Acid, such as proper concentration, pH level, patch test, frequency and sun protection.

Furthermore, comparing Lactic Acid with Glycolic Acid, it can be seen that Lactic Acid is more gentle and more suitable for sensitive skin. But if Glycolic Acid is used properly, it can be useful for other skin types as well.

Finally, if you have sensitive skin, be sure to consult a dermatologist before using lactic acid. Because everyone’s skin is different, and only an expert can tell you what is best for your skin.

Lactic Acid can be your companion to keep your skin healthy and restore its natural glow. But remember, patience and regular care is the key to keeping the skin beautiful. So start slowly, observe the skin’s reaction, and take care as needed.