Weight Loss Supplements: Are They Recommended?

by Melinda D. Maryniuk, MEd, RD, CDE 

People have long been searching for a magic bullet that works for weight loss… and nearly 50% of women on weight loss diets have tried some kind of supplement. While most are heavily advertised and widely available, there is very little research that any are effective. Many are expensive and have some side effects.

Our goal is to help you be an informed consumer so you know the benefits & risks, and help you make smart choices. The important thing to understand here is that no supplement or vitamin has strong data to show that they work for weight management. If you still want to take a supplement, ask yourself the questions below.

  • Is my focus still on nutritious eating, staying active, and keeping a good connection with my doctor?
  • Does this fit my budget?
  • Can I find neutral, unbiased information about it on the web?
  • Am I aware of possible side effects?
  • Have I told my doctor?
  • Do I feel better when I take it?

As you think about the answers, read below about each of the most popular supplements. This information summarizes popular supplements in two different categories:

  • Pills – or tablets that you can buy without a prescription
  • Foods – or ingredients in common foods that are commonly linked to weight loss

Note: This article does not address “meal replacements” sometimes referred to as “supplements”. These specially-formulated shakes or protein bars to be eaten instead of a meal have been used in several large research studies involving weight loss, and are linked with better outcomes for weight loss and weight maintenance.


  1. Conjugated Linoleic Acid (CLA)
    1. What is it? A fatty acid found naturally in beef and dairy products. The supplement is made by chemically altering the linoleic acid from sunflower or safflower oils.
    2. What’s it supposed to do? While some research shows links with weight loss (by decreasing food intake and increasing fat break-down), studies are not consistent. Many studies show no effect. High doses are linked with increased levels of fat in the liver, inflammation, increased insulin resistance, diarrhea and stomach upset.
    3. Bottom line: Skip it. Get a variety of healthy fats (which help you feel full) from foods like avocado, nuts, seeds, and fish.
  2. Garcinia Cambogia
    1. What is it? Extract from the fruit Malabar Tamarind.
    2. What’s it supposed to do? May help decrease hunger and block an enzyme linked with producing adipose tissue. One study showed those who took it lost 2 pounds more than those who didn’t… not a big deal. And, it’s costly: $50 for a one-month supply.
    3. Bottom line: Put that money into buying more fresh fruits and veggies!
  3. Glucomannan
    1. What is it? A water soluble dietary fiber.
    2. What’s it supposed to do? As with other dietary fibers, this is linked with increased feelings of fullness and slower stomach emptying. It’s important to take with plenty of water shortly before eating as it can increase bloating, gas, and diarrhea.
    3. Bottom line: Eat more food sources of soluble fiber instead of taking this! Oats, barley, beans, and apples are all good sources.
  4. Raspberry Ketones
    1. What is it? A synthetic substance modeled after the aromatic flavor in raspberries.
    2. What’s it supposed to do? Stimulate the break-down of fat, and increase levels of adiponectin, a hormone that regulates metabolism. While early studies show some promise in rats, there have been no good studies in humans showing that this is effective.
    3. Bottom line: Enjoy raspberries as a fresh fruit, but there seems to be no benefit to this supplement for weight loss.
  5. Orlistat
    1. What is it? An over-the-counter medicine (Alli) or a prescription medicine (Orlistat). Supposed to be used alongside a low-calorie meal plan.
    2. What’s it supposed to do? This medicine works by inhibiting the breakdown of fat in the stomach so that it passes through, undigested, thus limiting the calories absorbed. Must be taken shortly before a meal containing fat. Can lead to some unpleasant side effects including oily stools and increased urgency of bowel movements or diarrhea. Take a multi-vitamin with fat-soluble vitamins.
    3. Bottom line: If you try it, follow instructions carefully. Be sure to talk to your doctor about it.


  1. Apple Cider Vinegar (ACV)
    1. What is it? The kind you find along with other vinegars in the supermarket.
    2. What’s it supposed to do? The mild acetic acid found in this vinegar is associated with increased feelings of fullness, delayed stomach emptying, and improved blood glucose and insulin response. This has been highly touted as the new wonder food, however, evidence is weak that this actually decreases weight. Large amounts of vinegar can hurt you – acid can erode teeth and cause stomach upset.
    3. Bottom line: There’s no harm in consuming a few tablespoons a day. If you want to try it, add more ACV to salads, veggies or even as a beverage mixed with water, but it won’t necessarily help you reach a better weight.
  2. Caffeine
    1. Where is it found? Coffee beans, tea, cacao/chocolate, and caffeine pills.
    2. What’s it supposed to do? While caffeine is known to decrease appetite and increase metabolism, it does not appear to be useful as a supplement for weight loss. Too much (more than about 400 mg/day) can cause many negative side effects (accelerated heart rate, tremors, excessive urination, insomnia), as well as a dependence.
    3. Bottom line: Enjoy your morning cup of coffee or tea, but avoid excessive caffeine intake because of the side effects listed above.
  3. Green Tea
    1. What kind? Any variety – from common store brands to exotic.
    2. What’s it supposed to do? While there is some caffeine in green tea, the health benefits reportedly come from the high levels of antioxidants – linked with decrease of adipose tissue and boosting metabolism.
    3. Bottom line: If you like it, enjoy a cup or two of green tea each day. It’s a delicious, antioxidant-filled drink.

Diet and exercise alone aren’t enough to help many people reach a healthier weight. Medical treatments are needed to address the biological changes happening in our bodies that can drive weight regain. To find a physician in Canada near you who specializes in weight management, click here.

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This article was sponsored by Novo Nordisk Canada. All content is created independently by My Weight – What To Know with no influence from Novo Nordisk.

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