When azelaic acid enters your skin, it interferes with the enzyme tyrosinase, slowing down melanin production and gradually evening out your skin tone. It’s a well-studied ingredient with solid results for acne, rosacea, and hyperpigmentation. But here’s the catch: azelaic acid is notoriously difficult to formulate with. It doesn’t dissolve well in water, it can sting on application, and some people find it too irritating to use consistently. That’s where its derivative, potassium azeloyl diglycinate (PAD), comes in.
How PAD Is Made (and Why It Matters)
Chemically, PAD is created by bonding azelaic acid with two molecules of glycine (an amino acid) and stabilizing it with potassium hydroxide. This process transforms the oil-soluble azelaic acid into a water-soluble salt. And that solubility change is a bigger deal than it might sound.
Water solubility means PAD can be formulated into lightweight serums, toners, and gel moisturizers without the gritty texture that pure azelaic acid products sometimes have. If you’ve ever used a 15-20% azelaic acid cream and noticed a slight graininess or pilling, that’s the azelaic acid not fully dissolving in the formula. PAD eliminates that problem entirely.
The glycine component also adds a benefit that straight azelaic acid doesn’t have. Glycine is a naturally occurring amino acid in your skin. It plays a role in collagen synthesis and has mild moisturizing properties. So PAD doesn’t just deliver azelaic acid’s benefits in a gentler package, it brings a small hydrating bonus along with it.
What PAD Does for Your Skin
PAD targets the same concerns as azelaic acid, just through a slightly different delivery system.
Brightening and pigmentation. Like its parent compound, PAD inhibits tyrosinase activity. Studies on PAD have shown it can reduce melanin production and improve the appearance of dark spots, post-inflammatory hyperpigmentation, and uneven skin tone. It won’t bleach your skin or dramatically lighten it. It works by slowing excess pigment production so that as old skin cells turn over, the new ones underneath are more evenly pigmented.
Sebum regulation. PAD helps control oil production by influencing enzymatic activity in the sebaceous glands. This is the same mechanism azelaic acid uses, and it’s one of the reasons azelaic acid is prescribed for acne. PAD offers a comparable effect without the drying or stinging that some people experience with conventional azelaic acid products.
Anti-inflammatory action. Redness, irritation, and the inflammation that drives acne and rosacea all respond to PAD. The anti-inflammatory pathway is similar to what you’d get from azelaic acid itself. For people with rosacea who find azelaic acid prescriptions too harsh for daily use, PAD can be a more sustainable option.
Mild antimicrobial effects. Azelaic acid has documented antibacterial properties against Cutibacterium acnes, the bacteria involved in inflammatory acne. PAD retains some of this activity, though research specific to PAD’s antimicrobial strength is still limited compared to the extensive data on azelaic acid itself.
PAD vs. Azelaic Acid: The Key Differences
They come from the same parent compound, but they’re not interchangeable. Here’s where they diverge.
Concentration and potency. Prescription azelaic acid typically comes in 15-20% concentrations. Over-the-counter versions usually sit around 10%. PAD is commonly used at 3-5% in cosmetic formulations. This doesn’t mean PAD is weaker per percentage point. Its improved solubility and absorption mean it delivers the active component differently. But if you have severe acne or rosacea that responds to high-concentration azelaic acid, PAD at cosmetic concentrations probably won’t be a direct replacement for prescription-strength products.
Irritation potential. This is the biggest practical difference. Azelaic acid, especially at higher percentages, commonly causes tingling, stinging, or a burning sensation on application. Some people build tolerance over a few weeks. Others never do. PAD rarely causes these sensations. If you’ve tried azelaic acid and your skin protested, PAD is the logical next step.
Formulation flexibility. Azelaic acid is difficult to dissolve, which limits what kinds of products it can go into. PAD dissolves easily in water-based formulations. This means you’ll find PAD in serums and essences with elegant, non-greasy textures, while azelaic acid usually shows up in heavier creams or suspensions.
pH requirements. Azelaic acid works best at a slightly acidic pH (around 4.0-4.9). PAD is more stable across a wider pH range, which means it plays nicely with other active ingredients in a single product. This makes it easier to layer in a routine without worrying about pH conflicts between steps.
When PAD Is the Better Choice
Not everyone needs to switch from azelaic acid to PAD. If your current azelaic acid product works fine for your skin and doesn’t cause irritation, there’s no reason to change. But PAD becomes the more practical choice in several situations.
Sensitive or reactive skin. If you have rosacea, eczema-prone skin, or a generally reactive skin type that flares up with strong actives, PAD gives you access to azelaic acid’s benefits without the irritation risk. This makes it easier to use daily rather than a few times a week.
Simplifying your routine. Because PAD works well at neutral pH and dissolves in water, it’s easier to incorporate into multi-step routines. You don’t need to worry about waiting times between application steps or avoiding certain ingredient combinations the way you sometimes do with pure azelaic acid.
When you want brightening without dryness. Azelaic acid can be drying, especially in drier climates or during winter. PAD’s glycine component adds a touch of hydration, making it less likely to contribute to moisture loss. If you’re someone who needs a well-planned active rotation to avoid overdoing it, PAD is gentler enough to slot in more frequently.
Maintenance after clearing a concern. Say you used prescription azelaic acid to get rosacea or post-acne marks under control. Switching to PAD for maintenance lets you keep the benefits going with a lower-intensity product.
How to Use PAD in Your Routine
PAD is straightforward to use. Here’s the basic approach.
Apply your PAD serum or treatment after cleansing and before heavier creams or oils. Because it’s water-soluble, it goes on early in your routine (thin-to-thick layering). Morning or evening works fine. If you’re using it for pigmentation, morning application under sunscreen gives you an added layer of protection against further darkening.
PAD pairs well with niacinamide, hyaluronic acid, peptides, and most moisturizing ingredients. It can also be used alongside retinoids if your skin tolerates the combination, though start slowly and monitor for irritation.
Avoid combining PAD with strong acids like high-concentration glycolic or salicylic acid in the same application step. Not because they react badly, but because stacking too many actives at once increases irritation risk regardless of how gentle each one is individually.
Where to Find It
PAD isn’t as mainstream as azelaic acid yet, so you won’t find it in every drugstore. It shows up more often in K-beauty and indie skincare brands. Check ingredient lists for “Potassium Azeloyl Diglycinate.” Some brands market it as a natural brightening alternative, which is a reasonable description as long as you understand that “natural” and “effective” are separate conversations.
Look for products where PAD is listed in the first third of the ingredient list. If it’s buried near the bottom, the concentration is probably too low to do much.
What the Research Says (and Doesn’t Say)
Transparency matters here. Azelaic acid has decades of clinical research behind it, including published studies on acne, rosacea, and melasma. PAD has significantly less independent research. Most of the data comes from ingredient suppliers or brand-sponsored testing, which is useful but not the same as peer-reviewed clinical trials.
That doesn’t mean PAD doesn’t work. The chemistry is sound, the mechanism of action is well-understood because it’s derived from a well-studied compound, and anecdotal reports from dermatologists and skincare professionals are generally positive. But if someone tells you PAD is “clinically proven” to do everything azelaic acid does, ask to see the specific studies. We’re not quite there yet.
What we can say with confidence: PAD is a legitimate azelaic acid derivative that delivers similar benefits with notably less irritation. For many people, especially those with sensitive skin, that trade-off is worth it. For severe dermatological conditions, prescription azelaic acid still has the stronger evidence base.