Opalescence Teeth Whitening: What It Is And Is It Legal In The UK?

Opalescence is a teeth whitening brand made by Ultradent Products, Inc., and its whitening gels are peroxide based. Is it legal in the UK? Yes, through a dental practitioner. The strengths Ultradent lists on its European site, 6% hydrogen peroxide in Opalescence Go and 10% or 16% carbamide peroxide in Opalescence PF, all sit in the band UK law reserves for dentists: above 0.1% and up to 6% hydrogen peroxide, sold only to dental practitioners, first use in each cycle by a dental practitioner or under their direct supervision, and never on anyone under 18. The brand's own European site carries this line on its product pages: "Opalescence teeth whitening products are available only at dental offices." Below: what each Opalescence product is, how carbamide peroxide relates to hydrogen peroxide, what the law says word for word, and where peroxide-free whitening at home fits.

What is Opalescence?

Opalescence is a range of whitening products from Ultradent Products, Inc., whose European site gives an address in Cologne. Its whitening gels use one of two peroxides: hydrogen peroxide, or carbamide peroxide, which breaks down to release hydrogen peroxide.

The brand explains the mechanism in its European FAQ: "The active ingredients in Opalescence teeth whitening gels pass into your teeth to oxidize the discolored molecules deep down in your teeth, removing stains and whitening your smile." The same FAQ says its formula "contains PF (potassium nitrate and fluoride) for patient comfort".

If you want the chemistry of peroxide itself, including what it does to teeth and gums, it is set out in what hydrogen peroxide does to teeth.

The Opalescence products listed in Europe

Ultradent's European site lists three products and compares them side by side. Everything in this table is taken from the brand's own European pages, and the compare page carries its own condition on all of it: "Usage may vary, always consult your dentist".

Product	What it is	Strength, as the brand states it	Wear time and frequency, as the brand states it
Opalescence Go	Prefilled, ready to wear trays using the brand's "Universal UltraFit™ Tray"	"Available in 6% hydrogen peroxide"	60 to 90 minutes, once a day "for 10 days or until desired shade"
Opalescence PF 10%	Gel worn in a custom-made tray	"10% carbamide peroxide (10% CP ~ 3% HP)"	8 to 10 hours, or overnight
Opalescence PF 16%	Gel worn in a custom-made tray	"16% carbamide peroxide (16% CP ~ 5,8% HP)"	4 to 6 hours
Opalescence Toothpaste	A daily whitening toothpaste, Original and Sensitivity Relief	Not given as a peroxide strength on the compare page	"2x day or as directed by your dentist"

Two points about the table. The PF page describes the custom tray as "A customized teeth whitening tray tailored to your smile", which means a tray made for your own teeth rather than a ready-made one. And the Go page states that its gel, like PF, "contains potassium nitrate and fluoride for patient comfort".

For how a dentist's tray course compares with the products you buy and use yourself, on cost and on what each one involves, see our guide to dentist vs home whitening.

Carbamide peroxide and hydrogen peroxide: why the conversion matters

Opalescence PF is labelled in carbamide peroxide, while UK law is written in hydrogen peroxide. The two are not the same number, and the brand gives the conversion itself on its PF page: 10% carbamide peroxide is shown as about 3% hydrogen peroxide, and 16% carbamide peroxide as about 5.8% hydrogen peroxide. (The page writes it "5,8%", with a continental decimal comma.)

That conversion matters because the UK limits apply to hydrogen peroxide "present or released", so a carbamide gel is judged by the hydrogen peroxide it releases, not by the larger number on the label. On the brand's own figures, a 16% carbamide gel releases about 5.8% hydrogen peroxide, which is close to the 6% ceiling, and a 10% carbamide gel releases about 3%.

Opalescence Go is labelled in hydrogen peroxide directly, at 6%, which is the top of the dentist-only band.

Is Opalescence legal in the UK?

Yes, through a dental practitioner, at the strengths the brand lists in Europe. The rule that decides it is the hydrogen peroxide entry, number 12, in Annex III of the cosmetic products regulation as it stands in UK law: the limits that The Cosmetic Products (Safety) (Amendment) Regulations 2012 brought in. It sets two tiers for whitening.

• Oral products, including tooth whitening or bleaching products, at 0.1% hydrogen peroxide or less, present or released. This is the level that can be sold to the public.
• Tooth whitening or bleaching products above 0.1% and up to 6% hydrogen peroxide, present or released. The regulation's conditions, in its own words: "To be only sold to dental practitioners. For each cycle of use, the first use to be only done by dental practitioners or under their direct supervision if an equivalent level of safety is ensured. Afterwards to be provided to the consumer to complete the cycle of use." And: "Not to be used on a person under 18 years of age."

Every strength on the brand's European product pages falls in that second tier: 6% hydrogen peroxide for Go, from the Go page, and about 3% and about 5.8% hydrogen peroxide for the two PF gels, from the PF page. So the UK answer is that these products are lawful when they come through a dental practitioner, the first use in each cycle is done by the practitioner or under their direct supervision, and the patient is 18 or over. The law sets no tier above 6% for tooth whitening products.

The brand's European FAQ describes its own route: "Opalescence teeth whitening is available from dental professionals." It adds that after a routine exam "to ensure you are a good candidate for teeth whitening, your dentist will provide you with the right Opalescence teeth whitening product".

Who may carry out whitening on another person is a separate question, and our post on the UK whitening rules in full covers both together, including what a carbamide label means for a shop-bought kit.

What about other Opalescence strengths you may see online?

The brand's US site, opalescence.com, is a different market with its own range. It sells directly to consumers in the United States, including Opalescence Go at 10% and 15%, Go Advanced at 15%, whitening strips, and "Whitening Gel Refills" at 10%, 15%, 20% and 35% carbamide peroxide, with 45% listed as "Available from a dentist".

Those are American products sold under American rules, and none of that is a statement about what is sold in the UK. We have not verified which of them, if any, are sold here, so we are not going to guess. For any carbamide product, the UK limit applies to the hydrogen peroxide it releases.

Your dentist can tell you which Opalescence product, if any, suits your teeth.

How long does Opalescence take?

On the brand's European compare page, Opalescence Go is worn for 60 to 90 minutes once a day "for 10 days or until desired shade", and the PF gels once a day, also "for 10 days or until desired shade", for 8 to 10 hours or overnight at 10%, or 4 to 6 hours at 16%. The brand puts its own condition on every one of those figures: "Usage may vary, always consult your dentist". Its FAQ says your dentist will provide the right product for your needs, and the law requires the first use of each cycle to be done by a dental practitioner or under their direct supervision.

How long a whitened shade then holds depends on the person, and the general picture from the NHS, Bupa and the Oral Health Foundation is set out in our UK guide to your teeth whitening options, alongside costs for each route.

Why we wrote this

I am Daniel Smith, and I started Pure Glow. Before that I spent fifteen years at Jaguar Land Rover, six of them in health and safety. That is not dental regulation and I am not going to pretend it is, but it is part of why I care what goes into a product people put on their teeth. When I started Pure Glow I bought every whitening strip I could get hold of and catalogued every fault. This post quotes the regulation and the brand's own pages directly, so you can check them yourself.

Questions like "is Opalescence legal in the UK" come down to exactly that: one regulation, two tiers and a conversion. We would rather you had the rule in its own words and could check any product against it, including ours.

Where peroxide-free whitening at home fits

If what you want is to whiten at home without a dentist supplying the product, the 0.1% limit decides how much peroxide a product sold to you directly can contain. A peroxide whitening product sold to you directly in the UK is capped at 0.1% hydrogen peroxide, present or released, which is a fraction of the strengths in the table above.

Peroxide-free whitening uses a different chemistry, so that cap is written for something it does not contain. Our PAP teeth whitening strips use PAP, phthalimidoperoxycaproic acid, and the ingredients on our box contain no hydrogen peroxide or carbamide peroxide.

PAP is an oxidising agent. It lifts surface stain, and it also works on the coloured compounds inside the tooth, just by a gentler route than peroxide takes. That chemistry is explained properly in how PAP whitening works, and why we left peroxide out is explained on our page about peroxide-free teeth whitening.

How they are used is simple. The course is one strip a day for 14 days: brush, dry your teeth with a towel, and wear the strips for a minimum of 30 minutes. A sip of water while they are on is fine. The strips are dry-fit with a no-slip grip, so they stay where you put them, and clean removal leaves no messy residue behind. On the box, the result is up to 6 shades whiter in 14 days, depending on where you start.

The formula is clinically tested for zero sensitivity, dentist approved and enamel safe, and sensitivity has its own page on whitening strips for sensitive teeth. It also carries hydroxyapatite, which supports the enamel surface, and xylitol; what the hydroxyapatite does is covered in whitening strips with hydroxyapatite.

They are not suitable for children under 12. They will not change the base colour of a crown, veneer or filling, though they can lift staining that has built up on top of one. And the 14-Day Two-Shade Guarantee applies: if you are not at least two shades whiter, you get a full refund.

None of this is a comparison with Opalescence. A dentist-supplied peroxide course and a peroxide-free strip you buy yourself are different routes under different rules, and which suits you is your call, ideally with your dentist if you have any dental work or concerns.

Frequently asked questions

Is Opalescence legal in the UK?
Yes, through a dental practitioner. The strengths on the brand's European site are 6% hydrogen peroxide for Go and about 3% or about 5.8% released hydrogen peroxide for the two PF gels, all inside the UK tier that is "To be only sold to dental practitioners", with the first use in each cycle by a dental practitioner or under their direct supervision, and not for anyone under 18.

Can I buy Opalescence without going to a dentist?
The brand's European site says its whitening products "are available only at dental offices", and UK law reserves products above 0.1% hydrogen peroxide for dental practitioners. Its US site sells a separate range directly to American consumers, which is a US matter.

Is Opalescence peroxide based?
Yes. Opalescence Go is listed at 6% hydrogen peroxide and Opalescence PF at 10% or 16% carbamide peroxide, which breaks down to release hydrogen peroxide.

What is the difference between Opalescence Go and Opalescence PF?
On the brand's European pages, Go is a prefilled, ready to wear tray at 6% hydrogen peroxide, worn 60 to 90 minutes a day. PF is a gel worn in a custom-made tray, at 10% or 16% carbamide peroxide, worn for hours or overnight.

How does Opalescence whiten teeth?
The brand says its gels "pass into your teeth to oxidize the discolored molecules deep down in your teeth". We do not comment on how well another brand's product works; your dentist, who supplies it, is the right person to ask about the result you can expect.

Can under 18s use Opalescence in the UK?
For tooth whitening products above 0.1% and up to 6% hydrogen peroxide, present or released, the law says: "Not to be used on a person under 18 years of age."

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Related reading:

• Crest Whitestrips and UK rules
• PAP versus peroxide whitening
• Is PAP right for you?
• How long whitening results last

Sources:

• Opalescence (Ultradent Products, Inc.), European site, Compare, read October 2026. For the products, strengths and wear times, and the site's banner stating the products are available only at dental offices.
• Opalescence European site, Opalescence Go, read October 2026. For the 6% hydrogen peroxide strength and the gel.
• Opalescence European site, Opalescence PF, read October 2026. For the two strengths, the brand's own hydrogen peroxide equivalents and the custom tray.
• Opalescence European site, FAQ, read October 2026. For the mechanism, the potassium nitrate and fluoride note, and how the brand is supplied.
• Opalescence (Ultradent Products, Inc.), US site, opalescence.com, read October 2026. For the US range only.
• Regulation (EC) No 1223/2009 on cosmetic products, Annex III, entry 12, legislation.gov.uk. For the hydrogen peroxide tiers, conditions and warnings as they stand in UK law.
• The Cosmetic Products (Safety) (Amendment) Regulations 2012, legislation.gov.uk. For when the limits came into UK law.