Weight loss supplements: What you should know before choosing one

Perhaps you’ve tried lifestyle changes like diet and exercise, but haven’t had much success in losing weight. Now, you’re researching weight loss supplements to see what options exist and how they might support your weight loss journey. With so many products on the market, it can be difficult to navigate your options.

This article explores how weight loss supplements work, whether they’re effective and safe, and how you can access them in Canada.

What are weight loss supplements?

Weight loss supplements are a broad category of products designed to help people lose or manage weight. They can come in many different forms: powders, pills, drinks, liquids, gummies and even tea. 

They contain a range of ingredients – like vitamins, minerals, herbs, fibre, caffeine and other bioactive compounds – that aim to reduce appetite, stimulate metabolism, burn fat or limit fat absorption, or improve digestion. Some may also claim to improve mood, energy levels or focus, which can indirectly affect eating behaviour and motivation to exercise.

Here, it’s important to note the distinction between weight loss supplements and prescription weight loss medications like Wegovy and Mounjaro. Weight loss supplements are typically sold over-the-counter and are natural health products that claim to help you lose weight. Prescription weight reduction medications are only available with a prescription from your doctor and are strictly regulated in Canada.

How do weight loss supplements work?

Because there’s such a variety of weight loss supplements available, they work in very different ways. However, they typically fall into the following categories:

• Appetite suppressants: These supplements specifically target hunger, reducing your appetite and sometimes cravings for certain foods
• Metabolic boosters: Dietary metabolic boosters are designed to stimulate your metabolism, helping to increase calorie burning
• Fat burners: Also known as thermogenics, these supplements raise your body temperature slightly to boost calorie burn
• Fat blockers and absorption inhibitors: Some fibre-based supplements aim to stop your body from absorbing the fat in your food, instead causing it to go straight through your digestive system
• Carb blockers: In a similar vein, carb blockers stop your body from converting the carbs in your food to glucose. Eventually, unused glucose can turn into fat and cause weight gain
• Fat oxidation enhancers: These supplements claim to support your body’s ability to use fat as fuel rather than store it
• Blood sugar regulators: These are designed to stabilize blood sugar levels, which may reduce cravings and prevent fat storage
• Digestion improvers: Many fibre-based supplements claim to promote fullness and better digestion, which could support weight management
• Protein boosters: These provide your body with additional protein to help build lean muscle mass

Common types of weight loss supplements in Canada

A wide variety of weight loss supplements are available in Canada, including:

• Appetite suppressants and satiety enhancers: Garcinia cambogia, glucomannan (konjac root), African mango (Irvingia gabonensis), hoodia, 5-HTP, saffron extract
• Metabolic boosters and thermogenics: Caffeine, green tea extract, guarana, yerba maté, capsaicin (from chilli peppers), synephrine (bitter orange), yohimbine
• Fat burners and fat oxidation enhancers: L-carnitine, conjugated linoleic acid (CLA), green coffee bean extract, raspberry ketones, fucoxanthin, forskolin (Coleus forskohlii)
• Fat blockers and absorption inhibitors: Chitosan, oolong tea extract
• Carbohydrate and starch blockers: White kidney bean extract (phaseolamin), alpha-amylase inhibitors, Salacia reticulata extract
• Blood sugar and insulin regulators: Chromium picolinate, berberine, alpha-lipoic acid, cinnamon extract, gymnema sylvestre, fenugreek
• Fibre-based and gut-health aids: Psyllium husk, inulin, beta-glucans, guar gum, probiotics (Lactobacillus gasseri, Bifidobacterium breve)
• Hormone or neurotransmitter modulators: 5-HTP (increases serotonin and may reduce cravings), melatonin (may support sleep and weight regulation)
• Micronutrient or metabolic support supplements: Vitamin D, calcium, magnesium, zinc, coenzyme Q10
• Herbal and plant extracts with mixed mechanisms: Green coffee bean, turmeric/curcumin, ashwagandha, ginseng, cayenne pepper, apple cider vinegar
• Meal replacement and protein-based supplements: Whey protein, casein, soy protein, plant-based protein blends, fibre-rich shakes and bars

How effective are weight loss supplements?

While weight loss supplements tend to make bold claims about their effectiveness, the science behind many is still fairly lacking, especially when it comes to dietary supplements. Plus, the research that does exist shows fairly modest results.

Ingredients like green tea extract, caffeine and CLA have been heavily researched, with some evidence that they can slightly increase energy expenditure or reduce appetite. However, results from these trials showed that the amount of body weight lost was small and often not clinically significant [1][2][3].

It’s worth mentioning, too, that no supplement is a magic bullet for weight loss – no matter what its claims are. It should always be used alongside healthy lifestyle strategies like a balanced diet, exercise and other lifestyle changes to support meaningful weight loss. And even then, results may not be that noticeable, or they could be difficult to maintain long-term.

Are there any safety concerns

The safety of weight loss supplements really comes down to the individual product. Some are considered safe and with a low risk of side effects (such as fibre-based or probiotic supplements), while others can pose a serious risk to your health. 

Some are also believed to include illegal additives (such as diuretics, which make you lose water weight temporarily) to enhance the product’s weight loss effects.

Generally speaking, most health experts do not recommend over-the-counter weight loss supplements, given the lack of evidence that they work and the fact that they carry potential health risks [4][5]. Before choosing an over-the-counter weight loss supplement, always consult your healthcare provider.

Risks and side effects to watch for

If you do end up taking an over-the-counter weight loss supplement, there are a few common side effects [6] to keep an eye on, such as:

• Nervousness, jitteriness, anxiety or insomnia
• Headache, dizziness or nausea
• Elevated heart rate (tachycardia) and increased blood pressure
• Gastrointestinal symptoms such as bloating, flatulence, constipation, diarrhea, indigestion or abdominal cramps
• Heartburn or nausea after use
• Gas or bloating
• Dizziness, weakness or fatigue
• Changes in blood lipids or glucose levels
• Increased urination or dehydration
• Allergic reactions, rash or hives 

Some risks are more severe and require immediate medical attention. Stop taking the supplement, call 911 or head to your emergency department if you experience:

• Liver injury or elevated liver enzymes
• Kidney stones or high calcium levels
• Severe allergic reactions or anaphylaxis
• High blood pressure, heart arrhythmia, heart attack or stroke

Cost and availability of supplements for weight loss in Canada

Once again, the cost of weight loss supplements varies widely, given the broad range of brands on the market and the variety of places you can buy them from. You might pay anywhere from CA$20 to CA$100 for a single product, or sometimes even more.

You can generally purchase over-the-counter weight loss supplements from pharmacies, health food and supplement stores, online, and sometimes even at the supermarket.

Canadian regulations and healthcare guidance on dietary supplements

Here in Canada, we have very strict regulations for natural health products, including weight loss supplements. Health Canada introduced the Natural Health Products Regulations in 2004 and has regularly updated the framework since then [7].

The regulations are designed to make products safer and to ensure manufacturers can substantiate their claims. From January 2026, any natural health product sold in Canada must  have a label showing [8]:

• The type of supplemental ingredient added to the product, and how much
• A Natural Product Number (NPN) or Homeopathic Medicine Number (DIN-HM). This shows that Health Canada has reviewed it for safety, quality and at least some evidence of efficacy for its stated use
• All the product’s ingredients and potential risks, including whether it has a high caffeine content
• Who should and shouldn’t use the product
• A warning about limiting the number of daily serves
• A warning about not taking the supplement alongside other foods or supplements with the same supplemental ingredients

Despite the stricter labelling requirements, it’s always a good idea to consult a healthcare professional before choosing a supplement. They can advise whether it’s suitable for your health and goals, and suggest other treatments or lifestyle changes if it’s not.

Also note that some supplements sold online may not adhere to Health Canada’s regulations. Always check if the product has an NPN before purchasing.

Alternatives to supplements

Given the limited effectiveness of weight loss supplements, you might be thinking about alternatives.

Prescription medications like Wegovy and Mounjaro have proven effectiveness when it comes to weight loss (studies show that they can support body fat loss of up to 15% when combined with diet and exercise) [9], and are only available with a prescription. This means they’re administered under much stricter guidance and monitoring from a medical professional. Currently, they're available to those with a body mass index (BMI) of at least 27.

If you’re looking to get started with a prescription weight loss medication, you can do so with Juniper. We offer a range of medications, including Wegovy and Mounjaro, which we recommend alongside lifestyle changes to help you lose weight.

Juniper’s expert care team includes health coaches and doctors, who provide you with personalized guidance and ongoing support throughout your journey. You’ll get an exercise and healthy eating plan tailored to your goals and lifestyle, and ongoing check-ins to ensure you stay on track.

Plus, you’ll have access to Juniper’s dedicated app, where you can manage your medication, track your progress towards your goals and contact your team whenever you need.

Ready to see if Juniper is right for you? You can check your eligibility here. 

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