Your Skin Care Secret Weapon

Skincare acids have been used in skincare since Cleopatra’s time. The queen is said to have bathed in sour milk containing lactic acid. I know what you’re thinking: Why do I need to use an acid?

Acids are the miracle tools to fight acne, wrinkles, age spots, scarring, and uneven skin tone.

I get it. I was just like you a few months ago. But now I’m here to tell you why acids are so great and why they should be in your skincare routine.

Acids are used to exfoliate the skin.

There are three primary categories of acids in skincare: alpha-hydroxy acids (AHAs), beta-hydroxy acids (BHAs), and poly-hydroxy acids (PHAs). All three types of skincare acids work as chemical exfoliants, weakening the bonds between dead skin cells.

All groups release the fluid that links skin cells, revealing a smoother, brighter surface. As the acid dissolves skin cell bonds, thousands fall off simultaneously. Depending on the acid’s strength, this shedding can be seen. Skin flakes after a peel? Dead cells, indeed.

But with so many acids on the market, it can seem overwhelming to remember which to use — and for what — and which products to buy. Before all that, you have to know where to start.

So let’s start at the beginning: What is an acid?

An acid is a substance that has a low pH (less than 7 on a scale of 1–14). When applied topically (on your face), it causes a chemical reaction that results in the exfoliation of dead skin cells and other debris from your pores. This creates smoother-looking skin by removing dead cells that make your complexion look dull or uneven. Acid also has another side effect: It increases collagen production in your skin by as much as 50%! Collagen keeps your skin looking plump and youthful; when you don’t have enough, lines and wrinkles develop.

AHAs: Alpha hydroxy acids (AHA) work best on thin, sun-damaged, or wrinkled skin.

AHAs are water-soluble exfoliants that work mainly on the skin to promote cell turnover and smooth fine lines and wrinkles. Glycolic acid is perhaps the most well-known AHA because it’s the only one approved by the FDA for treating signs of aging on the face. It’s also found in many over-the-counter products designed for acne treatment because it helps remove excess skin oil without irritating, as benzoyl peroxide does. They’re also suitable for treating acne and hyperpigmentation because they increase cell turnover and exfoliate dead skin cells from the surface of your face. A few examples include glycolic acid (found in glycolic peels), lactic acid (lactic acid peels), mandelic acid (mandelic peels), and malic acid (malic acid peels).

Glycolic acid is the most popular skin-care acid (AHA).

It is made from sugar cane and is the smallest AHA; it penetrates the skin best. Glycolic acid is a powerful anti-aging agent; it exfoliates the skin, reduces fine wrinkles, prevents acne, fades dark spots, thickens skin, and evens skin tone and texture. Unsurprisingly, it’s in anti-aging skin care products, but usually below 10%.

Mandelic acid comes from bitter almonds. It’s an exfoliating agent that prevents acne, treats UV damage, and evens pigmentation. Its more extensive molecular structure makes it less irritating to the skin than glycolic acid. It’s advised in peels instead of glycolic acid, especially for ethnic skin prone to rebound pigmentation. Overuse of a drug causes rebound pigmentation.

Azelaic acid is a prescription-only therapy for mild acne that has been used for three decades. It decreases irritation and keeps pores free. It’s found in 15 to 20% concentrations in the morning and nighttime face creams. Azelaic acid can cause stinging, peeling, and redness in persons with sensitive skin.

Kojic acid is made from several different types of fungi. It’s also a byproduct when certain foods ferment, like sake. Its brightening and anti-aging qualities make it a popular Asian skincare component. Kojic’s primary use — and benefit — is to lighten visible sun damage, age spots, or scars. This can result in an anti-aging effect on the skin.

Ascorbic is a water-soluble type of vitamin C used in anti-aging skin care. It’s also used to treat melasma instead of hydroquinone.

Linoleic and oleic acids in skin care are oils, not actual acids. In oils, fatty acids lose acid groups to produce triglycerides. Oils with higher linoleic acid are drier and better for oily skin, whereas oleic acid oils are richer and better for dry skin. Linoleic acid has pigmentation-lightening effects, but since it’s prevalent in oils, you’ll need a product without it to obtain the same result. Oleic acid alone can assist medications in penetrating the skin’s barrier.

BHAs: Beta hydroxy acids (BHA) work best on oily skin prone to breakouts and blackheads.

They’re also effective at unclogging pores and keeping oil production under control — if you have oily or blemish-prone skin, you should use a BHA daily. Beta hydroxy acids bind to sebum — that’s oil. BHAs are also great for treating hyperpigmentation because they have exfoliating properties that slough off dead skin cells from the surface of your face, revealing fresh new cells underneath. Salicylic acid (like benzoyl peroxide) is a common BHA used in acne products and treatments.BHAs are also great for treating hyperpigmentation because they have exfoliating properties that slough off dead skin cells from the surface of your face, revealing fresh new cells underneath. BHAs are also oil-soluble, which means they can penetrate deep into the pores and help unclog them from the inside out. This makes them a good choice for treating acne or other skin conditions that affect the surface of your face (like blackheads).

Salicylic acid exfoliates the skin and keeps pores clear, reducing acne. Salicylic acid is used in dermatology offices to treat acne scars, melasma, sun damage, and age spots. It’s also used in wart and corn removal products, although it’s suitable for pigmentation-prone dark skin.

Hyaluronic acid is a natural acid in our skin that helps keep our bodies hydrated. As we age, the amount of this acid in our bodies decreases and causes our complexion to become dehydrated; research shows we lose 50% of hyaluronic acid from our skin and joints by the mid-40s. This water retention allows the plumping of the tissue and prevents moisture from escaping the skin, which can help soften the appearance of wrinkles. This hydrating formula can be used for the face, neck, and hands.

Polyhydroxy acids — PHAs are chemical exfoliants similar to AHA’s (considered their next-generation cousins); they work by exfoliating dead skin cells on the surface, evening skin tone and texture.

So how are PHA’s any different from AHA’s and BHA’s? Well… their main difference is down to their molecular structure.

The molecules in PHA’s are much larger, therefore, cannot penetrate as deeply, working exclusively on the surface without disturbing the deeper delicate layers. This means they work harder to resurface those top layers of the skin, acting as a humectant to strengthen your skin’s barrier while being suitable for those of you who are more sensitive, offering less irritation.

• Gluconolactone: The most popular of the PHAs, gluconolactone not only works to exfoliate your skin but also hydrates and may offer some antioxidant benefits.
• Lactobionic acid: An oxidized form of milk, it works as both an exfoliator and a humectant, meaning it helps your skin retain moisture.
• Galactose: This PHA may sound familiar to you because it’s the sugar found in milk. This one is a bit less common than the other two, but it works to exfoliate your skin just as gently.

General guidelines:

For acne-prone skin: azelaic acid, salicylic acid, glycolic acid, lactic acid, mandelic acid
For mature skin: glycolic acid, lactic acid, ascorbic acid, ferulic acid
For fading pigmentation: kojic acid, azelaic acid, glycolic acid, lactic acid, linoleic acid, ascorbic acid, ferulic acid

• Test the formula on your inner arm and wait 24 to 48 hours to determine if you react. If you’re safe, put acid on your face.
• Don’t neglect your neck. Apply AHA face cream to a blotchy chest.
• Use a salicylic acid body wash to clear back acne or an acid product on the backs of your hands to reduce aging.
• Always wear SPF, especially in the morning, no matter what location you’re treating or what acid you’re using. Even if you use acids at night, your skin is extra-sensitive in the morning.
• Start gradually and try a few different products until you find the one that works best for you.
• If you’ve never used exfoliating acids in your skin care regimen, the key is to start slowly.
• Follow the manufacturer’s directions when applying any acids.

Some face acids shouldn’t be mixed.

Never combine salicylic acid with another acid. Mixing causes skin discomfort.
When using niacinamide, avoid salicylic acid.
Never combine glycolic or lactic acid with ascorbic acid (vitamin C). This will prevent ascorbic acid from working.
Avoid retinol-containing AHAs.

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