- No supplement causes major weight loss on its own. The best evidence shows small effects at most.
- Check for a Natural Product Number (NPN) and look it up in Health Canada’s database.
- Some products sold as weight loss aids have been found to contain hidden drugs; Health Canada publishes advisories.
- Avoid DNP and unauthorized hCG products, which Health Canada has warned about.
Weight loss supplements are everywhere, from pharmacy shelves to social media ads. Most don’t do much; a few are dangerous. This guide shows how to check a product in Canada and what the evidence supports.
How to check a supplement in Canada
- Look for an eight-digit NPN (Natural Product Number) on the label
- Search it in Health Canada’s Licensed Natural Health Products Database to confirm the product, ingredients and approved claims
- Check Health Canada’s Recalls and Safety Alerts site for advisories
- Be wary of products sold only online with no NPN, dramatic claims or before-and-after photos
Ingredients with some evidence
| Ingredient | Evidence | Notes |
|---|---|---|
| Caffeine | Small increase in energy use; helps exercise | Keep under 400 mg a day |
| Psyllium and glucomannan (fibre) | Can increase fullness | Take with plenty of water |
| Protein powders | Help hit protein targets | A food, not a fat burner |
| Green tea extract | Small effect at most | Concentrated extracts linked to rare liver injury |
Little or no evidence
- Garcinia cambogia
- Raspberry ketones
- Apple cider vinegar gummies
- Most “detox” teas, which work as laxatives or diuretics
Dangerous products
- DNP (2,4-dinitrophenol): an industrial chemical sold as a fat burner; overdoses have been fatal, and Health Canada has warned against it
- Unauthorized hCG products: Health Canada has warned that hCG isn’t authorized for weight loss
- Products with hidden drugs such as sibutramine (withdrawn for heart risk) or laxatives
Stop and seek care for a racing heart, high temperature, severe sweating or chest pain after taking a weight loss product.
What actually works
A moderate calorie deficit, enough protein and fibre, strength training, daily walking and sleep. For people with obesity, prescription medicines like semaglutide have strong evidence; see our weight loss clinics guide.
Frequently asked questions
Do weight loss supplements work?
Most have small or no effects. Caffeine and fibre have modest evidence.
How do I know if a supplement is approved in Canada?
Check for an NPN and search it in Health Canada’s Licensed Natural Health Products Database.
Is DNP legal in Canada?
It isn’t authorized for human use, and Health Canada has warned about serious and fatal harm.
Are detox teas good for weight loss?
They mostly cause water and stool loss, not fat loss.
This article is general information for adults in Canada, not medical advice. Talk to a doctor or pharmacist before using any prescription drug, anabolic steroid or research compound, and get bloodwork done. If you’re in crisis, call or text 9-8-8 (Suicide Crisis Helpline) any time.
