Let’s talk acids, the true heroes in acne formulations. I remember when I first started working with these actives. The possibilities felt endless, but I also knew I had to approach them with precision and respect. Over the years, I’ve come to love four in particular: Salicylic Acid, Glycolic Acid, Azelaic Acid, and Lactic Acid. Each one works uniquely, and if you’re formulating for acne-prone skin, you’ll want to know exactly how to incorporate them safely and effectively.
Salicylic Acid:
When we talk about formulating for acne-prone or oily skin, salicylic acid is one of the first actives that comes to mind and for good reason. It’s a beta hydroxy acid (BHA), and unlike AHAs that work only on the skin’s surface, salicylic acid is oil-soluble, which allows it to penetrate into the pores, breaking down excess sebum and dead skin cells. This makes it a must-have for addressing blackheads, whiteheads, active breakouts, and even preventing future congestion.
From a formulator’s perspective, it’s incredibly effective but only when handled correctly.
Usage Levels in Formulations
In over-the-counter skincare, salicylic acid is typically used at 0.5% to 2%.
- 0.5% is suitable for daily use products like cleansers or gentle toners.
- 2% is more potent and ideal for leave-on treatments like gels or spot correctors.
This is also the maximum allowed concentration in many regulatory frameworks such as the US FDA for OTC acne products. Anything higher moves into professional or clinical-grade formulations, which require neutralization and strict safety protocols.
Solubility & Compatibility
One of the biggest formulation challenges with salicylic acid is its solubility. It’s not water-soluble, which means simply adding it to a water-based serum or toner won’t work—you’ll end up with gritty, unstable results.
Instead, salicylic acid needs to be dissolved in an appropriate solvent before being added to your formulation. Some of the best options include:
- Propanediol (natural and skin-safe)
- Ethanol or Alcohol Denat (commonly used in toners or peels)
- Butylene glycol or Propylene glycol (synthetic, effective, but less “clean”)
When working on natural or “green” formulations, I personally prefer using propanediol, which not only solubilizes salicylic acid effectively but also improves the skin’s hydration level offsetting any potential dryness.
pH Matters
Salicylic acid is most active and effective at a pH between 3 and 4. If the pH creeps higher, the exfoliating power diminishes. However, going too low (below pH 3) can increase irritation, especially in sensitive skin.
That means your preservative system must be acid-compatible. I recommend using preservatives like Geogard Ultra, Gluconolactone & Sodium Benzoate, or Optiphen, all of which function well in low-pH environments.
Product Types You Can Create
Salicylic acid can be incorporated into a wide range of professional skincare products:
- Clarifying Cleansers – at 0.5–1%, paired with gentle surfactants and soothing botanicals.
- Exfoliating Toners – at 1–2%, combined with witch hazel or green tea hydrosols.
- Leave-on Gels – at 2%, formulated with propanediol and panthenol for hydration.
- Acne Spot Treatments – targeted formulas with 2% salicylic acid, niacinamide, and tea tree oil.
- Pore-Refining Serums – with salicylic acid and zinc PCA for oily skin control.
Pro Tips from My Lab
- Avoid pairing with strong AHAs in the same formula unless it’s a wash-off product. The risk of over-exfoliation and barrier damage is real.
- Combine with soothing agents like allantoin, panthenol, aloe vera, or calendula extract to minimize irritation.
- If you’re formulating for sensitive skin, consider using encapsulated salicylic acid—this offers controlled release and is gentler on the skin barrier.
Watch Outs
- Salicylic acid can cause dryness or peeling if overused. Always communicate this clearly on product labels and usage guides.
- Some users may be allergic to salicylates, especially those with aspirin sensitivity. Include a caution in your product documentation.
- Regulatory compliance is essential—maximum concentration limits vary by region, so always double-check local regulations when exporting.
So, if you’re aiming to create a professional-grade acne product line, salicylic acid is non-negotiable. It’s powerful, science-backed, and versatile but only when used with precision.
Formulating with it is a balance between effectiveness, skin compatibility, and elegance in the final product. And once you master it, your clients will notice the difference almost immediately.
Next up is
Glycolic Acid:
If you’ve ever formulated for dull, textured, or acne-scarred skin, you’ve probably reached for glycolic acid at some point. It’s an absolute game-changer when it comes to improving skin clarity, smoothness, and overall radiance.
As the most commonly used Alpha Hydroxy Acid (AHA), glycolic acid has a solid scientific reputation, and as a formulator, I can tell you it earns every bit of that credibility.
What sets glycolic acid apart is its tiny molecular size. It’s the smallest of all AHAs, which means it penetrates the stratum corneum (the outer layer of the skin) more effectively than others. Once inside, it works by loosening the bonds between dead skin cells, allowing them to slough off more easily. This not only improves cellular turnover but also enhances the absorption of other actives, making it a star in multi-functional formulations.
Usage in Professional Formulations
When using glycolic acid, the percentage and pH control everything. In general:
- 5% to 8% is great for daily-use products like exfoliating cleansers or night creams.
- 10% to 15% is suitable for weekly-use masks or treatment serums, formulated with extra skin-calming ingredients.
- 20% to 30% is used for professional-grade peels, but these should be reserved for trained therapists and often require neutralization post-application.
As a formulator, I personally love using glycolic acid at 6–8% in emulsions or gel-serums it’s strong enough to give visible results but gentle enough when buffered and paired with hydrating agents.
Formulation Considerations: pH, Stability & Neutralization
Glycolic acid is highly acidic (with a pH close to 1 in its raw state), so adjusting your formulation’s pH is non-negotiable.
For safe and effective exfoliation, you want your final product to be at a pH of 3.5 to 4.0. This keeps the acid active but reduces the risk of skin irritation.
To get there, you’ll often need to neutralize part of the glycolic acid using a base like:
- Sodium Hydroxide (NaOH)
- Potassium Hydroxide (KOH)
- Triethanolamine (TEA) (used sparingly in natural formulations)
You can also buy pre-neutralized glycolic acid solutions, which are more stable and easier to use especially in natural or beginner-level formulations.
Also, glycolic acid can be corrosive to packaging materials, especially at lower pH, so always use acid-resistant packaging like HDPE or glass when dealing with high concentrations.
What to Pair It With
Now here’s where formulating gets fun. Glycolic acid can be beautifully balanced with ingredients that soothe, hydrate, or reinforce the skin barrier, such as:
- Aloe Vera Juice
- Panthenol (Provitamin B5)
- Glycerin or Sodium PCA
- Allantoin
- Oat Beta-Glucan
This is especially important because high concentrations of glycolic acid can cause tingling, dryness, or peeling in some users particularly those new to exfoliation.
You can also blend glycolic acid with other mild AHAs, like lactic or mandelic acid, for a broader range of exfoliating action without overly stressing the skin.
Ideal Product Types
Glycolic acid lends itself beautifully to a variety of product types:
- Exfoliating Cleansers – mild and low in concentration (3–5%), great for daily use
- Overnight Renewal Creams – at 6–8%, buffered and combined with nourishing actives
- Brightening Toners – at 5%, paired with antioxidants or humectants
- Peel Pads or Peeling Gels – at 10–20%, to be used weekly
- Professional Spa Peels – at 30% or higher, often neutralized post-treatment
If you’re formulating for sensitive or dry skin types, it’s best to start with 5% or less and gradually build tolerance.
Formulation Tips & Cautions
- Always conduct a final pH check and adjustment at the end of the formulation process acid pH can shift slightly over time.
- Avoid formulating glycolic acid with L-ascorbic acid, retinoids, or strong essential oils in the same phase it can lead to over-exfoliation or irritation unless well-encapsulated or time-released.
- Be mindful of regulations EU cosmetic law requires warning labels for products with more than 10% glycolic acid and below pH 3.5.
My Formulator’s Insight
What I love about glycolic acid is that it’s results-driven. If you’re creating a glow-inducing, texture-smoothing line be it for acne, dullness, or pigmentation glycolic acid will likely be one of your cornerstone ingredients.
But remember, it’s all about balance. Formulating with glycolic acid means not just understanding its strength, but learning how to cushion its power with ingredients that support and protect the skin. When done right, your product doesn’t just exfoliate it transforms the skin.
Here is one amazing acid..
Azelaic Acid:
If there’s one acid I wish more formulators would fall in love with, it’s Azelaic Acid I also call it calm clarifier.. While not as loud as glycolic or as deep-diving as salicylic, azelaic acid brings something equally valuable to the table: balance. It’s like the peaceful herb in your tea blend that doesn’t just calm you it brings harmony to the whole cup. That’s what azelaic acid does for irritated, inflamed, or acne-prone skin.
Azelaic acid is a dicarboxylic acid derived from grains like barley, wheat, and rye but don’t worry, it’s not irritating like it sounds. Quite the opposite, actually. It’s anti-inflammatory, antimicrobial, and mildly keratolytic, which means it helps gently exfoliate while calming down redness and targeting acne-causing bacteria. It also helps reduce post-inflammatory hyperpigmentation (PIH), making it ideal for treating acne in deeper skin tones, where pigmentation is a common aftermath.
Why Formulators Love It
Unlike many acids, azelaic acid is not pH-dependent in the way that glycolic or lactic acid is. It still performs well in a wider pH range (around 4 to 5.5), which gives you more freedom and less concern over extreme acidity. This is especially helpful when working on formulas for sensitive, rosacea-prone, or dry skin, where low pH might be too aggressive.
The Formulation Challenge: Solubility
Now here’s where things get a little tricky: Azelaic acid is not very water-soluble, and it doesn’t dissolve well in oils either. This means if you’re working with the pure powder form, you have two main options:
- Create a suspension – where azelaic acid sits evenly dispersed in a base like a gel or emulsion.
- Use a solubilized version or derivative – such as potassium azeloyl diglycinate (PAD), a water-soluble derivative that offers similar benefits but with better skin feel and absorption.
When formulating with the raw form, I like to use glycols (like propylene glycol or butylene glycol), or PEG-400 to dissolve it. You can also prepare emulsions using fatty alcohols or emulsifiers to suspend the acid if you’re going for a cream or lotion format.
For natural or green cosmetic brands, this does pose a limitation, as PEGs aren’t permitted in strictly clean beauty standards. In that case, you may lean on PAD or microencapsulated versions of azelaic acid to stay within natural formulating boundaries.
Effective Use Levels & pH
Azelaic acid is typically used at:
- 5% for gentle daily care or prevention-focused formulas.
- 10% for more therapeutic effects (similar to prescription-grade levels in some countries). Higher levels (15–20%) exist in pharmaceutical-grade topicals, but those aren’t typically permitted in consumer skincare.
Ideal pH range for effectiveness: 4.0–5.5
Best Product Types to Use It In
Azelaic acid shines in leave-on treatments, where it gets the time to calm inflammation and target discoloration. Some ideal formats include:
- Lightweight Gel-Cream Serums – for oily, acne-prone skin types.
- Creamy Emulsions or Lotions – perfect for dry, sensitive, or rosacea-prone skin.
- Spot Treatment Pens – for PIH and stubborn acne areas.
- Daily Barrier Repair Serums – combined with niacinamide, allantoin, or panthenol.
Pro Tip: Combine with niacinamide, zinc PCA, or green tea extract to amplify its brightening and anti-inflammatory effects. And avoid pairing with low-pH AHAs in the same product unless you’re working with stabilized derivatives and buffering systems.
Formulator Notes from My Lab
- When I make azelaic acid serums for clients, I love to add oat beta-glucan or bisabolol to create a calming matrix for skin that’s constantly irritated. It’s like a mini spa in a bottle.
- If using it in suspension, make sure to use stabilizers like xanthan gum or carbomers to prevent settling and ensure even application.
- Watch the particle size it can feel gritty if not milled fine enough or suspended properly.
- And always communicate to your customer: results are gradual but lasting azelaic acid works best over weeks, not overnight.
Why I Call It the “Calm Clarifier”
Azelaic acid isn’t the acid that burns, tingles, or gives an instant glow. It’s the steady, dependable ingredient that works quietly in the background to reset the skin’s rhythm. Whether someone is dealing with hormonal breakouts, reactive redness, or a fragile barrier post-acne, azelaic acid gently clarifies without chaos.
If you’re formulating a soothing acne treatment, a barrier-repair serum, or a pigmentation-fighting cream, this ingredient deserves a prime seat in your lab.
Note:
When using acids, there are a few non-negotiables:
Always test and adjust pH after blending
Preservative system must be compatible with low pH (like Optiphen, Geogard Ultra, etc.)
Never combine too many exfoliants in one formula especially for leave-ons
Start simple and build tolerance this applies to your consumer too!
Acids are magic but only when used with mindfulness and a solid understanding of their chemistry. Whether you’re crafting a professional-grade toner, a gentle peel, or a blemish-fighting serum, choosing the right acid and using it properly is the key to results without irritation.
