Why Lactic Acid Belongs in Your Skincare Routine (Especially in Dry Climates)
If you've been curious about lactic acid but aren't sure it's right for you — whether it's too strong, too much, or just unnecessary — this is for you.
Lactic acid has a reputation that often precedes it. People hear "acid" and picture aggressive treatments, red skin, a week of peeling. But lactic acid is genuinely one of the gentler exfoliants available, and when you're living in a dry climate or at altitude, it may be the one ingredient that finally changes how your skin feels.
Here's what it actually does, how to use it — and why where you live matters more than you might think.
The Short Answers
Is lactic acid good for dry skin? Yes. It's one of the best exfoliants for dry skin because it removes dull, rough buildup while also helping skin hold onto moisture.
Is lactic acid a humectant? Yes. Lactic acid is part of the skin's own natural moisturizing factor, and it draws water into the skin as it exfoliates. That's why it tends to leave skin smoother and more hydrated, not tight.
When should you use lactic acid in your routine? In the evening, two or three times a week, after cleansing and before serum and moisturizer. Wear SPF the next morning.
What Lactic Acid Actually Is
Lactic acid is an alpha hydroxy acid, or AHA. Unlike scrubs or physical exfoliants that buff away dead skin, lactic acid works chemically — it dissolves the bonds that hold dead skin cells together at the surface, allowing them to shed naturally.
It's one of the oldest cosmetic ingredients in existence. Milk baths, Cleopatra, all of it — lactic acid is why. Fermented dairy is naturally rich in it.
What makes lactic acid different from other AHAs like glycolic acid is its molecular size. Lactic acid molecules are larger, which means they penetrate more slowly and more gently. That's not a weakness — for most skin types, it's exactly what you want. You get real exfoliation without the irritation that can come from more aggressive acids.
It also has a secondary benefit that most people don't know about: lactic acid is a humectant. It draws moisture into the skin as it works. So unlike some exfoliants that leave skin feeling tight or stripped, lactic acid tends to leave skin feeling smoother and more hydrated.
Why Dry Climates and High Altitude Change Everything
If you live somewhere with low humidity, thin air, or significant elevation, your skin is dealing with conditions that most skincare advice wasn't written for.
At altitude, the air is drier and UV radiation is more intense. Wind accelerates moisture loss. Your skin's barrier is working harder just to maintain basic hydration — and when that barrier is compromised, everything else is compromised too. Moisturizers don't absorb as well. Serums sit on top instead of sinking in. Skin looks dull even when it's well-cared-for.
A lot of that dullness has a simple explanation: dead skin cell buildup.
In drier climates, skin doesn't shed as naturally as it does in humid environments. The natural turnover process slows, and the result is a layer of dry, rough, lackluster skin sitting on top of the healthier skin underneath. No amount of moisturizer fully compensates for this — it's like watering a plant through a tarp.
Exfoliation removes that barrier. And lactic acid, specifically, does it while simultaneously pulling in hydration — which makes it particularly well-suited to dry, high-altitude skin that can't afford to lose more moisture in the process.
Who Lactic Acid Is For
Lactic acid is often recommended as the AHA to start with if you're new to exfoliating acids, or if your skin tends toward sensitivity. But it's also genuinely effective for skin that has used other exfoliants before. It's not a beginner's consolation prize — it's a smart choice at any stage.
It works well for:
- Dry or dehydrated skin that looks dull or rough
- Skin that feels congested or uneven in texture
- Anyone living in low-humidity or high-altitude environments
- Sensitive skin that has reacted to glycolic acid or physical scrubs
- Skin that has been relying only on moisturizer and not seeing the results it expected
It requires a little caution if you're pregnant, or if you're using other active ingredients like retinol — not because you can't use it, but because layering actives takes some care. When in doubt, use lactic acid on its own to start, introduce other actives gradually, and check with your doctor during pregnancy.
How to Use Lactic Acid
Less is more, especially at first. A few times a week in the evening is a good starting point — your skin has a chance to turn over overnight, and you avoid the sun exposure that can make freshly exfoliated skin more reactive.
If you're using a leave-on lactic acid serum or toner, apply it to clean, dry skin and give it a minute before layering anything on top. Applying acids to damp skin can increase how deeply they penetrate, which raises the chance of stinging.
If you're using a lactic acid wash, like ours, massage it onto damp skin and leave it on for about 10 minutes, like a mask, then rinse. That gives the lactic acid time to work while keeping it off your skin overnight.
Either way, follow with your serum and moisturizer, and wear SPF the next morning. This isn't optional. Freshly exfoliated skin is more vulnerable to UV damage, and at altitude, UV exposure is already elevated. Sunscreen is always part of an acid routine.
You don't need to use it every day for it to work. Two or three evenings a week is often enough to see a real difference in texture and brightness within a few weeks.
A Note on Concentration
Lactic acid comes in a range of concentrations, typically from around 5% up to 15% or higher. Lower concentrations are gentler and better for introducing the ingredient to your routine. Higher concentrations work more efficiently but require more careful use — and at 15%, you're getting a genuinely effective treatment without crossing into professional-only territory.
The key is finding a formula that's balanced: the right concentration, the right pH, and ideally other ingredients that support the skin while the lactic acid works. A good lactic acid product shouldn't feel harsh. If it stings significantly or leaves your skin red for hours, something's off.
What You'll Notice
In the first week or two, you'll likely notice smoother texture — the rough, slightly sandpapery feeling that dry climates cause tends to ease quickly. Over the following weeks, skin usually looks brighter, more even, and more receptive to everything else in your routine. Moisturizers absorb better. Serums go further. The skin just functions better.
For high-altitude and dry climate skin, this is often the missing piece. Not a new moisturizer. Not a richer oil. Just the simple act of clearing the surface so everything underneath can actually work.
Lactic Acid: Common Questions
Do you use lactic acid before or after moisturizer?
Before. Lactic acid goes on clean skin, right after cleansing. Serum and moisturizer come after, to replenish and seal in hydration.
Does lactic acid dry out skin?
Not usually. Because lactic acid is also a humectant, it tends to leave skin more hydrated than other exfoliants. Overuse can cause dryness or irritation, so start with two or three times a week.
Does lactic acid make your skin more sensitive to the sun?
Yes. Like all AHAs, lactic acid can increase sun sensitivity for a while after use. Use it in the evening and wear SPF every day, especially at high altitude.
Can you use lactic acid every day?
Some people can, but most dry or sensitive skin does best with two or three times a week. Watch how your skin responds and adjust from there.
Is lactic acid good for sensitive skin?
It's one of the gentlest AHAs, which makes it a good choice for sensitive skin. Start slowly, and stop if you notice lasting redness or stinging.
Our Lactic Acid 15%
We formulated our Lactic Acid 15% exfoliating wash for skin that lives in challenging conditions — dry air, high elevation, the kind of environment that asks more of your skin than most products are designed for.
At 15% concentration, it's effective without being aggressive. We pair it with ingredients that support the skin's barrier rather than leaving it exposed after exfoliation, so it works with the rest of your routine rather than against it.
If you've been curious about whether lactic acid is right for you, this is a good place to start.
Made in small batches in Colorado.