By Dr Daniel Tankard, Lead Dentist at Smilie
If you've been shopping around for a teeth whitening kit lately, you've probably come across two very different types of products. Those that use hydrogen peroxide, and those that use PAP+ (phthalimidoperoxycaproic acid). The marketing around both can be confusing, so I want to break down exactly what the science says.
What is Hydrogen Peroxide Whitening?
Hydrogen peroxide has been used in professional teeth whitening for decades. It's the same active ingredient used by dentists in in-chair whitening treatments, and it's the most extensively researched whitening agent available.
It works by penetrating the enamel and breaking down the organic compounds that cause staining, a chemical process called oxidation. The result is genuinely whiter teeth, not just surface cleaning.
In Australia, at-home whitening kits are regulated to a maximum of 6% hydrogen peroxide by the Therapeutic Goods Administration (TGA). This concentration is proven to deliver visible results while remaining safe for home use.
What is PAP+ Whitening?
PAP+ is a newer whitening agent that has been popularised by several direct-to-consumer brands as a peroxide-free alternative. The selling point is that it whitens without the sensitivity associated with peroxide.
PAP+ works differently to hydrogen peroxide. It targets chromogens (colour molecules) on the tooth surface rather than penetrating the enamel. This is why it's gentler, but it's also why the results tend to be more limited, particularly for deeper or older stains.
The research on PAP+ is still emerging. While some studies show promising surface-level whitening, the long-term data and independent clinical evidence doesn't yet match the decades of research behind hydrogen peroxide.
So Which One Actually Works Better?
For surface stains like fresh coffee, tea, or wine staining, PAP+ can deliver noticeable results. For deeper, more established stains, or for people who want a significant shade change, hydrogen peroxide consistently outperforms PAP+ in clinical comparisons.
The sensitivity argument for PAP+ is valid, but it's also somewhat outdated when applied to modern peroxide formulas. Well-formulated hydrogen peroxide kits that include Potassium Nitrate and other desensitisers have largely closed the sensitivity gap. The idea that peroxide always causes pain comes from older, poorly formulated products.
Why Smilie Uses Hydrogen Peroxide
At Smilie, we chose hydrogen peroxide because the evidence supports it. Our formula uses a clinically appropriate concentration within Australian TGA guidelines, combined with Potassium Nitrate to manage sensitivity throughout the whitening process.
We're not anti-PAP+. For some people it may be a suitable option. But when our team of 70+ dental professionals set out to develop a kit that delivers real, visible results for Australian customers, the evidence pointed clearly to hydrogen peroxide as the gold standard.
Over 2,500 verified reviews and 4.9 stars later, we're confident that decision was right.
The Bottom Line
If you want proven, significant whitening results, especially for stubborn or deep stains, a professionally developed hydrogen peroxide formula is your best option. If sensitivity has been a barrier in the past, look for a peroxide kit that includes desensitising ingredients rather than switching to PAP+ entirely.
The goal is a whiter smile without discomfort. With the right formulation, you don't have to choose between the two.
Dr Daniel Tankard is the Lead Dentist at Smilie and works alongside a team of 70+ Australian dental professionals to develop clinically effective, sensitivity-safe whitening products.