DIN and NPN: the eight-digit numbers that show Health Canada reviewed a product

Turn over a tube of sunscreen, a bottle of dandruff shampoo or a jar of vitamin D and you’ll find a small line of text: “DIN” or “NPN” followed by eight digits. Most people never read it. But it’s the clearest signal on a Canadian label that a government reviewer looked at the product before it reached the shelf. Here’s what each number means, what it doesn’t, and how to look one up.

What is a DIN?

DIN stands for Drug Identification Number. Health Canada describes it as a computer-generated eight-digit number assigned to a drug product before it can be marketed in Canada. It appears on the label of prescription and over-the-counter drugs that have been evaluated and authorized for sale.

The number is tied to a specific combination of six things: the manufacturer, the product name, the active ingredients (the ingredients that do the medical work), their strengths, the pharmaceutical form (cream, tablet, liquid) and the route of administration (on the skin, by mouth).

According to Health Canada, a DIN tells you the product has undergone and passed a review of its formulation, labelling and instructions for use. The digits themselves are random. And the rule is strict: a product that meets the legal definition of a drug and is sold without a DIN is not in compliance with Canadian law.

For drugs with little market history in Canada, Health Canada says the review is more stringent and the product also needs a Notice of Compliance, a separate authorization, before it can be marketed.

Why would a skin product have a DIN?

Because in Canada, the word “drug” is broader than most people expect. Under the Food and Drugs Act, anything sold to treat or prevent a disease or symptom, or to modify how the body works, is a drug, wherever it sits in the store.

Sunscreen is the everyday example. Health Canada classifies chemical UV filters such as avobenzone and octocrylene as drug ingredients, so a sunscreen containing any of them carries a DIN. Other skin products that make therapeutic claims, such as acne treatments, medicated dandruff shampoos and some diaper rash creams, also go through the drug route. That’s why a tub of moisturizer next to them has no number: it’s a cosmetic, which follows different rules.

What is an NPN?

NPN stands for Natural Product Number. It’s the licence number for a natural health product, a category Health Canada created in 2004 with its own set of rules, the Natural Health Products Regulations. These regulations are separate from the ones for prescription drugs and are designed for what Health Canada calls the lower-risk nature of these products.

The category is wider than the name suggests. It includes vitamins and minerals, herbal remedies, probiotics, traditional Chinese and Ayurvedic medicines, essential fatty acids and homeopathic medicines. It also includes everyday products you wouldn’t think of as “natural health”: Health Canada lists certain toothpastes, antiperspirants, shampoos, facial products and mouthwashes. Sunscreens that use only mineral filters, zinc oxide and titanium dioxide, get an NPN rather than a DIN.

To get an NPN, a company applies for a product licence with details on the medicinal ingredients, their source and potency, the non-medicinal ingredients and the recommended use. Once Health Canada assesses the application and grants market authorization, the label carries an eight-digit number preceded by the letters NPN. Health Canada says that number assures you the product has been reviewed and approved for safety and efficacy, and that it is safe and effective when used according to the label.

Companies that make or import these products must also hold a site licence and follow good manufacturing practices, the quality rules for clean, correct production.

What about DIN-HM?

Homeopathic products are a type of natural health product, and they get their own prefix: DIN-HM, for Homeopathic Medicine number. The review is different. Health Canada checks that these products are safe and that their claims are supported by references used in the practice of homeopathy, such as homeopathic pharmacopoeias, rather than by the scientific evidence required for a non-prescription drug.

That matters at the pharmacy, where Health Canada notes homeopathic products are often placed right next to non-prescription drugs and can be picked up by mistake. Its advice is to look at the prefix, and at the words “homeopathic medicine”, “remedy” or “preparation” on the label.

How to look up a number

Both numbers can be checked for free.

• Drug Product Database. Health Canada’s database of drugs authorized for sale. It’s updated nightly, shows whether a product is available in Canada, and links to the product monograph, the document describing what the product is for and how to use it. You can search by DIN, product name or active ingredient.
• Licensed Natural Health Products Database. The equivalent for NPN and DIN-HM products. For each licensed product it shows the licence holder, the medicinal and non-medicinal ingredients, the dosage form, the recommended use or purpose (which is the health claim Health Canada accepted) and the risk information: cautions, warnings, contraindications and known adverse reactions.

If a product makes drug-like claims (“treats”, “prevents”, “relieves”) and has no number at all, that’s a red flag.

What the number doesn’t guarantee

This is the part worth remembering. A DIN or NPN means a reviewer checked the product against Canadian rules. It doesn’t mean:

• It will work for you. The review confirms the claim is supported for the product as labelled, not that every user will see the result.
• You won’t react to it. Health Canada lists allergic reactions among the risks of licensed natural health products, and notes that sunscreen side effects, though rare, can come from UV filters, fragrances or preservatives. The number covers the medicinal ingredients; it doesn’t make the fragrance or preservative in the base any less likely to bother sensitive skin.
• It won’t interact with something else. Interactions with prescription drugs or other natural health products are on Health Canada’s risk list too.
• Everything on the market is perfectly monitored. A 2021 audit by the Commissioner of the Environment and Sustainable Development found the natural health product program needed more oversight of product quality, better monitoring of labels and advertising, and a risk-based inspection program. Health Canada accepted all the recommendations and has been rolling out changes.

Health Canada also reports that 12% of Canadians who use natural health products say they have experienced an unwanted side effect, and only 41% of those reported it. So the number is a floor, not a ceiling. Read the cautions, and if you’re pregnant, breastfeeding, giving a product to a child or managing a medical condition, ask a pharmacist or doctor first.

Reading the label like a pro

Put it together and a Canadian label tells a story. No number: it’s a cosmetic, and the ingredient list is your main tool. DIN: it’s a drug, with a specific active ingredient, strength and directions that were reviewed. NPN: it’s a natural health product with an accepted health claim you can read in the database. DIN-HM: it’s homeopathic, reviewed against homeopathic references.

Whatever the number, the same habits apply: follow the directions, respect the warnings, stop if you react, and see your doctor or pharmacist if a problem doesn’t settle. You can also report side effects to Health Canada.

The short version: DIN and NPN are Health Canada’s stamps that a product was reviewed and authorized, the first as a drug and the second as a natural health product, with DIN-HM for homeopathic products. Look them up in the Drug Product Database or the Licensed Natural Health Products Database. Treat the number as proof of review, not as a promise that the product will suit your skin.