Potassium Azeloyl Diglycinate: What the Trials Show
A close reading of the published data on Potassium Azeloyl Diglycinate, the azelaic acid derivative known as PAD. The dosages, the co-actives, and what was measured on human skin.
Skin that looks uneven usually looks that way on three fronts at once, and PAD has published work pointed at all three. Sun exposure leaves patches of pigment that settle in and stay. Persistent flushing leaves visible redness across the cheeks, nose and chin. And oil-gland overdrive, which runs higher in men, leaves pores that clog and a T-zone that shines by mid-afternoon. Most ingredients pick one of the three and leave you to solve the other two.
The usual answers each cost you something. High-strength azelaic acid (15 to 20%) has the longest record of the lot on the look of tone and redness, but at a pH of 4.0 to 5.0 it can leave the surface of the skin worse for wear and destabilise anything pH-sensitive sitting next to it in the jar, retinol included. Retinoids bring flaking and sun sensitivity of their own. Benzoyl peroxide leaves skin dry. In a single-step night cream, every one of those is a trade you would be passing straight on to the person using it.
Potassium Azeloyl Diglycinate changes that equation. The molecule is azelaic acid’s nine-carbon backbone bonded to two molecules of glycine and neutralized with potassium. That single structural change transforms the compound from a lipophilic, insoluble irritant into a water-soluble, pH-neutral amphiphile that crosses the stratum corneum at a fraction of the concentration. As a derivative of azelaic acid, PAD is expected to behave like the parent molecule: helping to even the look of tone, calm the look of redness, mop up free radicals and ease oil-gland overdrive. The bonded glycine additionally deposits free glycine into the Natural Moisturizing Factor of corneocytes. Critically, PAD’s neutral working pH makes it fully compatible with encapsulated retinol, a combination that traditional azelaic acid’s acidic pH makes inherently unstable. The published trials described below measured what changed on the skin; the reasons why were not measured directly at the 5% dose.
PAD is azelaic acid rebuilt for something you leave on overnight. It is expected to carry over the useful behaviour of the parent ingredient on the look of tone, redness and oiliness, while its neutral pH and water solubility drop the barrier disruption and the formulating headaches that come with the acid form. That is what makes it the one version of this chemistry you can put in the same bottle as retinol. In the published trials it did that at roughly a quarter of the concentration azelaic acid is normally used at, with tolerability that came back level with placebo.
Forty-two adults with persistent facial redness were randomized to receive either a 5% PAD + 1% hydroxypropyl chitosan (HPCH) cream or a matched placebo, applied twice daily for 28 days with a 2-week follow-up. Redness was measured objectively using a Mexameter, not self-reporting. The results were decisive.
The composite redness index dropped significantly at every facial site measured: forehead down 37.0 points (p=0.009), right cheek down 36.1 (p=0.010), left cheek down 38.8 (p=0.002), and chin down 53.3 (p=0.002). At the study’s final follow-up, graders working from a 4-point scale recorded no visible redness in 95% of the subjects using the active cream.
| Forehead redness reduction | p = 0.009 |
| Right cheek reduction | p = 0.010 |
| Left cheek reduction | p = 0.002 |
| Chin reduction | p = 0.002 |
| Hydration increase (forehead, study day 14) | p = 0.030 |
| Hydration increase (forehead, study day 28) | p = 0.020 |
The tolerability profile was clean: exactly zero adverse reactions were documented across the entire trial in both groups.
For context, standard 15% azelaic acid can cause transient stinging and burning on application during the first weeks of use. This PAD + HPCH formulation moved the redness readings at one-third the concentration without that trade-off.
Sixty-seven Thai adults with epidermal pigmentation were randomized to receive either a PAD + niacinamide + tranexamic acid emulsion or an emulsion-based control, applied twice daily for 8 weeks with mandatory SPF 30. This was a multi-active formulation, and the individual contribution of each ingredient cannot be isolated from the combined results.
The Relative Melanin Value (the absolute melanin gap between darkened and normal skin) showed a statistically significant reduction versus control by week 6 (p=0.005 ITT, p=0.006 on-treatment). MASI scores, the standard index for uneven facial pigmentation, improved significantly versus control at week 4 in the on-treatment population (p=0.005) and at week 8 in the primary intent-to-treat population (p=0.027).
| Relative Melanin Value (ITT, week 6) | p = 0.005 |
| Relative Melanin Value (OT, week 6) | p = 0.006 |
| MASI score improvement (OT, week 4) | p = 0.005 |
| MASI score improvement (ITT, week 8) | p = 0.027 |
The tolerability data is what separates this trial from hydroquinone and high-dose azelaic acid studies. Adverse events (mild redness, minor flaking) occurred in 12% of the active group versus 15% of the emulsion-based control group. The difference was not statistically significant, meaning the active formulation’s irritation profile was comparable to its control vehicle.
This trial did not test PAD on its own. It tested three ingredients in one emulsion: PAD, niacinamide and tranexamic acid, each with its own published record on the look of uneven tone, and each measured here only as part of the mixture. The reason they could be combined at all is PAD: water-soluble and neutral in pH, it sits comfortably next to pH-sensitive company. Traditional azelaic acid’s low pH makes that harder, though careful buffering can address it in some formulations. What the trial reports is what the three did together, and we do not split the credit between them.
Thirty-seven Caucasian adults with persistent facial redness, visible capillaries and long-running burning and stinging were enrolled across multiple study sites. They applied 5% PAD + 1% hydroxypropyl chitosan cream twice daily for 12 weeks. Of the 37 enrolled, 30 (81.1%) completed the study and were considered evaluable. This was an open-label study with no control group, meaning results should be interpreted with more caution than the double-blind RCTs above.
Stinging and burning were scored on a 4-point scale at each visit. Across the evaluable group the baseline total came to 66 points (mean 2.2 per subject). By the end of the 12 weeks the total had fallen to 37 points (mean 1.2), a 56.1% reduction in reported stinging and burning.
Standard azelaic acid can bring on transient burning when you apply it, which is why people give up on it. This study measured the inverse: across 12 weeks of twice-daily use of the PAD + HPCH formulation, the investigators documented zero side effects among the evaluable subjects.
This is the study that shows how far a well-formulated PAD active can reach. The formulation did not merely avoid causing sting of its own. Over the run of the study, the sting people came in with was reported less often.
The assumption across most of skincare is simple: higher concentration equals stronger result. Azelaic acid is where that logic came from. At 10% it does little. At 15% the published results start to land. At 20% it reaches its best measured showing and takes the barrier with it. The dose-response curve is steep, narrow, and punishing.
The one data point below 5% is the manufacturer’s own evaluation of PAD at 3% (Maramaldi, 2002, published in an industry trade magazine, not a peer-reviewed journal).
The Berardesca and Veraldi studies both used 5%, in combination with hydroxypropyl chitosan: the first recorded no visible redness in 95% of subjects, the second a 56.1% drop in reported stinging and burning. No published trial has tested above 5%, so there is no evidence that going higher does more. What going higher would certainly do is add raw material cost and push the pH away from the neutral window that keeps PAD comfortable and retinol-compatible.
Concentration is not the bottleneck. How much of it actually gets into the skin is. Traditional azelaic acid needs 15 to 20% because the molecule dissolves poorly. PAD's amphiphilic structure, from the bonded glycine, improves its solubility in water and may improve how well it crosses the outer layer. No head-to-head penetration study has been published, but the published trials converge on 5% as the concentration that was actually tested. Going higher has not been shown to do more.
“PAD-based formulations moved the measured outcomes at a fraction of the concentration traditional azelaic acid needs, with a markedly better tolerability profile.”
Summary of the cited published dataSATURATE Vector ONE is the first formulation to combine Potassium Azeloyl Diglycinate with encapsulated retinol in a single product. Traditional azelaic acid’s low pH degrades retinol on contact, making co-formulation impossible without compromising one or both actives. PAD’s neutral working pH solves this entirely. The formulation carries PAD at 8%, above the 5% used in the trials cited here. No published trial has tested PAD above 5%, so 8% is our formulating decision and not a studied dose. We would rather say that than let you assume our number matches theirs. The vehicle is a lightweight oil-in-water emulsion built on a Cetearyl Olivate and Sorbitan Olivate emulsifier system, reinforced with squalane, shea butter, and hydrogenated lecithin to deliver lipid-phase actives without occluding pores.
It is a structurally distinct molecule with its own solubility and tolerability profile, paired for the first time with
[2] Berardesca E, Iorizzo M, Abril E, et al. “Clinical and instrumental assessment of the effects of a new product based on hydroxypropyl chitosan and potassium azeloyl diglycinate in the management of rosacea.” J Cosmet Dermatol, 2012; 11(1):37-41. (Double-blind RCT; includes co-authors from Sinerga and Polichem.)
[3] Viyoch J, Tengamnuay I, Phetdee K, et al. “Effects of Trans-4-(Aminomethyl) Cyclohexanecarboxylic Acid/Potassium Azeloyl Diglycinate/Niacinamide Topical Emulsion in Thai Adults With Melasma.” Curr Ther Res Clin Exp, 2010; 71(6):345-359. (Double-blind RCT; multi-active formulation.)
[4] Veraldi S, Raia DD, Schianchi R, et al. “Treatment of symptoms of erythemato-telangiectatic rosacea with topical potassium azeloyl diglycinate and hydroxypropyl chitosan.” J Dermatolog Treat, 2015; 26(2):191-192. (Sponsor-free, multicenter, open-label study; no control group.)
[5] Kostrzebska A, et al. “Synergy of Tetracyclines and Potassium Azeloyl Diglycinate (Azeloglycine) in Hydrogels: Evaluation of Stability, Antimicrobial Activity, and Physicochemical Properties.” Int J Mol Sci, 2025; 26(11):5239.
[6] Aggregate data: Maramaldi evaluations, 2002 (oil, hydration, luminance and redness measurements). (Industry data; not independently peer-reviewed.)
