6 Common Acids and How They Work on Different Skin Types

6 Common Acids and How They Work on Different Skin Types



To date, Alpha Hydroxy Acids are some of the most beloved skincare ingredients. AHAs are a group of acids that include ingredients like glycolic acid, citric acid, mandelic acid, and lactic acid. Many of us who love skincare use glycolic because they reduce natural wrinkles and reverse sun damage.


As life goes on and as we are exposed to more sun, aged skin cells are replaced by newer ones at a slower rate. While aged and sun-damaged cells gradually get replaced at a slower rate, Alpha-hydroxy acids encourage them to shed at a faster rate. This process is known as “anti-aging.”


Many anti-aging products work by loosening the lipids or glue-like substances that hold the surface skin cells to each other. Once AHAs loosen the lipids binding the older or dead skin cells together, the cells can peel off gently. Then, voila! The skin underneath has a fresher, healthier look with a more even color and texture. With high concentration and long-term use, alpha hydroxy acids may also affect the deeper layers of our skin. This deep penetration aids in collagen, elastin (connective tissue that tightens skin) regeneration, and the softening of fine lines.


That’s what AHA product descriptions mean when they say “more supple-looking” skin can be attained by using it. However, there are some cons to consider. Some AHAs used in high concentrations can cause irritation and hyperpigmentation in people with Fitzpatrick phototype levels 4-6. While both mandelic and lactic acids are AHAs too, they are often considered gentler choices for hyperpigmentation and sensitive skin types. Depending on how sensitive the person’s skin is, glycolic acid can be irritating and lead to further hyperpigmentation.



Ascorbic Acid (Vitamin C).

Ascorbic acid is the antioxidant component in many skincare products. Antioxidants prevent UV damage or decrease UV damage by fighting free radicals, and likewise, they can help protect your skin’s collagen.  However, the higher concentration of ascorbic acid, the higher the probability of irritation.  The pH of ascorbic is between 2 and 3.5 while your skin’s pH is around 5.5. Therefore, if you have sensitive skin, using vitamin C as the last step of your skincare routine in the morning might be helpful. The products that you have already applied to your skin form a barrier and using vitamin C in the morning provides a fresh barrier against free radicals and pollution.


Ascorbic acid works for combination, oil, and dry as well as all Fitzpatrick phototypes. The thing to be most conscious about is the concentration of the acid.


The Ordinary Vitamin C Suspension 30%



Retinoic Acid
Retinoic acids are fierce molecules that decrease oil production in cystic acne, papulopustular acne, cystic acne, blackheads, and whiteheads. Retinoids decrease sebum, and they decrease inflammation. They also regulate cell turnover within the hair follicle and decrease congested skin. It is also antibacterial which means it kills p acnes bacteria (the type of acne implicated in acne). As retinoic acid is very potent, it is the active ingredient in tretinoin. And given that, retinoic acid can be very irritating, almost abrasive. When you use it, it is normal to have sensitivity. Retinoic acid can cause burning, stinging, irritation, and dryness. However, a gentler form of retinoic acid is retinol. It’s more gentle because retinol goes through bioconversion in the skin in order to form retinoic acid. More simply, retinol turns into retinoic acid within the skin whereas retinoids do not. They are a pure form which means your skin absorbs in its raw form. Retinoids that have higher side effects like photosensitivity (sensitivity to sunlight and making the skin burn more easily). Although this is less common with OTC retinols, they can still cause irritation.


To avoid this, you can dilute retinols with ingredients like hyaluronic acid. Whether you’re using a retinol or retinoid, you should put on a moisturizer and sunscreen afterward. As another skincare tip, AHAs increase the permeability (help them absorb better) of retinols, but dry skin types or those with skin sensitivity should proceed with caution when combining these two.


All in all, retinoids and retinols work well on oily, combination, and dry skin. However, when retinol is applied to sensitive skin, there can be irritation.



The Ordinary Granactive Retinoid 5% (Very Potent) 





Kojic Acid
Kojic Acid is a naturally derived acid, but the kojic acid we buy is chemically formed. Kojic acid inhibits tyrosinase (the production of melanin). So, while it can prevent hyperpigmentation, it can cause irritation. It is normally used in addition to other ingredients within a formula. Used alone, the ingredient is not that potent. It’s a strong ingredient, so

It’s a strong ingredient, so it’s better to increase it with time.


Versed Weekend Daily Glow Solution



BHAs are oil-soluble meaning they can dig deep into the pores to remove dead skin cells and to dissolve excess sebum. The BHA used for skincare and dermatology is known as salicylic acid. Salicylic acid unclogs pores and improves pore size by penetrating sebum. BHAs are also humectants which means they work to keep skin moisturized by pulling water from the air into the upper layer of your skin. BHAs are particularly suitable for people with normal to oily skin,

congested pores, and acne-prone skin.


Pacifica Clean shot BHA/AHA 25% Peel Solution