By: Lisa Toma, dietetic-student volunteer studying at the University of Guelph, reviewed by Natalie Walsh, RD, and the JM Nutrition Team
Supplements are everywhere. Pharmacies, grocery stores, even gas stations stock shelves of vitamins, protein powders, and herbal blends promising better health.
Social media has made it significantly worse. Influencers promote various supplements for many different reasons. They could have experienced a personal benefit from taking a product, or they could be getting paid to talk about it. Some of their claims have merit. Others do not.
The supplement industry is booming, and it shows no signs of slowing down. In Canada alone, the dietary supplement market was valued at over 27 billion CAD in 2025, and is expected to more than double by 2035. With that kind of money on the table, it is no surprise that marketing can often overshadow science.
In this post we take a closer look at some of the most popular supplements available today. We separate supplements fact from fiction, outline what the research actually supports, and highlight when supplementation may or may not be worth your time and money.
Common Myths About Supplements
Before looking at specific products, it helps to address some widespread beliefs that shape how people think about supplements. Specifically, let’s take a closer look at myths about supplements.
“Natural Means Safe”
Many people assume that because a product comes from a natural source, it cannot cause harm. This is not always the case. According to the Mayo Clinic, even natural products can be harmful if mixed with other medications or taken at the wrong dosage.
Fat-soluble vitamins like A, D, E, and K can build up in the body and reach harmful levels at high doses. Certain herbal supplements can also interact with prescription medications in ways that many people do not expect.
A good example is St. John’s wort, a popular herbal supplement often taken for depression and anxiety. The problem is that St. John’s wort can make other medications less effective, or in some cases, increase their effects and lead to more side effects. Affected medications include birth control pills, blood thinners, and antidepressants.
The takeaway? Just because a supplement product is natural, it does not automatically mean it is risk-free. Therefore, the claim is fiction.
“More Is Better”
If a small dose of supplements is good, a larger dose must be better. This is a common assumption. It is incorrect. It is fiction.
For most nutrients, exceeding the recommended upper limit offers no additional benefit and can cause side effects.
For example, high-dose vitamin D taken in large, infrequent amounts has been linked to an increased risk of falls in older adults. More is not always better, and in many cases, it can do more harm than good.
“Everyone Needs Supplements”
For the average adult eating a balanced diet, most nutrient needs can be met through food.
Supplements become most useful when there is a specific gap to fill, such as a diagnosed deficiency, a higher need during pregnancy, or a dietary pattern (like being vegan or vegetarian) that can limit certain nutrients.
Related: nutrition tips for pregnancy
Taking supplements “just in case” without understanding your actual needs is usually not necessary, and can sometimes give a false sense of security about the quality of your overall diet.
“Supplements Can Replace a Balanced Diet”
No pill or powder can replicate the complex interactions between vitamins, minerals, fibre, and other compounds found in whole foods.
Nutrients in food work together in ways that supplements simply cannot reproduce. Vitamin C helps your body absorb iron. Dietary fats improve the absorption of vitamins A, D, E, and K. These interactions happen naturally when you eat a balanced meal.
As the name suggests, supplements are meant to supplement your diet, not replace it. Therefore, the claim that supplements can replace a balanced diet is fiction.
Popular Supplements on the Market
Now that we’ve debunked those common misconceptions, let’s take a closer look at some of the most popular supplements on the market.
1. Vitamin D
Vitamin D is often called the “sunshine vitamin” and is widely promoted for everything from stronger bones to better immunity to chronic disease prevention. Some sources suggest that nearly everyone should be supplementing with high doses year-round. But how much of that is actually supported by research?
What Science Says
Vitamin D does play a well-established role in calcium absorption and bone health, and deficiency is a genuine concern in Canada. According to Statistics Canada, about 32% of Canadians have vitamin D levels below what is considered adequate for bone health. When you factor in long winters and limited sunlight, the concern is justified.
The 2024 Endocrine Society Clinical Practice Guideline recommended vitamin D supplementation for several specific groups: children and adolescents, adults over 75, pregnant women, and adults with pre-diabetes.
The claims, however, go further than the evidence does. For healthy adults between the ages of 19 and 74 who already have adequate vitamin D levels, the evidence for supplementation to prevent chronic disease is weak. The same guideline found no significant benefit for this group.
What’s more, most clinical guidelines suggest a daily intake of 400 to 1,000 IU for populations at risk, though individual needs can vary depending on factors like age, skin tone, and geographic location.
The Verdict
Vitamin D supplementation makes sense for people who are deficient or at high risk of deficiency. This includes many Canadians, particularly during winter. However, mega-dosing without medical guidance is not supported by the evidence and may carry risks.
2. Fish Oil (Omega-3 Fatty Acids)
Fish oil capsules have been a medicine cabinet staple for years, promoted for everything from heart health to sharper thinking. Despite this fact, the evidence behind them is more complicated than most people think.
What Science Says
Omega-3 fatty acids, particularly EPA and DHA, are found in fatty fish and play a genuine role in brain function, cell membrane health, and the regulation of inflammation.
For people with existing heart disease, there is moderate evidence that omega-3 supplementation can reduce cardiovascular events and mortality. The benefit appears strongest with higher-dose, purified EPA formulations used under medical supervision. That said, omega-3 supplementation has also been associated with an increased risk of atrial fibrillation and potential bleeding complications, so the decision is not straightforward.
For the general population without heart disease, the story changes. A Cochrane review found that long-chain omega-3 supplements likely have little or no effect on heart health or mortality in otherwise healthy people.
On the brain health front, a 2025 review of 58 trials found some improvements in attention, processing speed, and memory with omega-3 supplementation. The certainty of this evidence, however, was rated low to moderate. Promising, but far from definitive.
One point that often gets overlooked: eating whole fish appears to offer stronger health benefits than taking fish oil capsules. Other nutrients in seafood, along with the broader dietary benefit of choosing fish over less nutritious options, are big contributors to this point.
The Verdict
If you have heart disease or elevated triglycerides, omega-3 supplements may be beneficial under medical guidance. For everyone else, eating fatty fish two to three times per week is the more evidence-based approach. A supplement can help if you rarely eat fish, but it is not a complete substitute for the real thing.
3. Collagen
Few supplements have had a bigger moment than collagen. Powders, capsules, drinks, even coffee creamers. The marketing promises smoother skin, stronger nails and a more youthful appearance. Collagen seems very convincing, and it is everywhere.
What Science Says
Collagen is the most abundant protein in the human body and plays a key role in the structure of skin, bones, tendons, and cartilage. Production naturally declines with age, which is one reason the supplement appeals to so many people.
Here is the problem. When you take collagen orally, your body breaks it down into individual amino acids during digestion, just like it does with any other protein. There is no guarantee that those amino acids will be directed to your skin, hair, or joints.
A 2025 meta-analysis published in The American Journal of Medicine looked at 23 studies involving over 1,400 participants. When all studies were pooled together, collagen supplements appeared to improve skin hydration, elasticity, and wrinkles. However, when the researchers separated the results by funding source, a very different picture emerged. Studies that were not funded by supplement companies showed no significant benefit. Studies funded by industry did. Similarly, higher-quality studies found no effect, while lower-quality ones did.
The researchers concluded that there is currently no strong clinical evidence to support the use of collagen supplements for preventing or treating skin aging.
The Verdict
The collagen supplement market is built largely on industry-funded research and persuasive marketing. If you want to try to support your body’s collagen production, focus on getting enough vitamin C, protein, and zinc through your diet. These are the building blocks your body uses to make its own collagen.
4. Biotin
Walk into any pharmacy and you will find biotin supplements marketed for thicker hair, glowing skin, and stronger nails. Also known as vitamin B7, biotin has become one of the most popular beauty supplements on the market. But does it actually work?
What Science Says
Biotin does play a role in cell growth and metabolism. People who are biotin-deficient can experience hair loss, skin rashes, and brittle nails. However, true biotin deficiency is rare in adults who eat a balanced diet.
A review in the Journal of Clinical and Aesthetic Dermatology put it plainly: there have been no studies demonstrating that biotin supplementation is beneficial for hair growth in healthy individuals. Every reported case of improvement involved a patient who had an underlying condition causing their hair loss in the first place.
There is also a safety concern that most people are not aware of. The U.S. FDA has issued a warning that high-dose biotin supplements can interfere with common lab tests, including tests for troponin (used to diagnose heart attacks) and thyroid hormones. This interference can lead to incorrect results and potential misdiagnoses.
The Verdict
Unless you have a diagnosed biotin deficiency, which is uncommon, there is no good evidence that biotin supplements will improve your hair, skin, or nails. The potential for lab test interference is an added reason to think twice before taking high doses.
5. Greens Powders
If you spend any time on social media, you have almost certainly seen ads for greens powders. Products like AG1 promise to deliver the equivalent of multiple servings of fruits and vegetables in a single scoop, along with benefits for energy, immunity, digestion, and overall wellness. Some cost upwards of $100 per month.
What Science Says
These products typically contain a blend of powdered vegetables, fruits, vitamins, minerals, probiotics, and herbs.
So what’s the problem?
Dietitians and independent reviewers have pointed out that there is currently not enough evidence to show that consuming powdered forms of produce offers the same health benefits as eating whole foods.
A key issue is fibre. Greens powders lack the fibre that whole fruits and vegetables provide, and fibre plays an essential role in digestion, blood sugar regulation, and feeding the beneficial bacteria in your gut. You simply cannot replicate that with a powder.
Many of these products also use proprietary blends, meaning they do not disclose the exact amounts of each ingredient. This makes it difficult to know whether you are getting a meaningful dose of anything, or just a sprinkle of everything.
The Verdict
For the same $3 to $4 per serving, you could buy a significant amount of fresh or frozen vegetables and fruits that deliver more fibre, more nutrients, and more variety. Greens powders are not a replacement for eating vegetables. They may offer some convenience, but your money is almost always better spent at the grocery store.
Final Thoughts on Supplements Fact vs. Fiction
During the course of the research we found that many of the most popular products on the market are backed more by marketing than by research.
Some of the most widely sold supplements have surprisingly little independent research behind them. The popularity of a supplement does not equal the strength of its evidence.
That is not to say supplements are never useful. They absolutely can be, when they are filling a real gap. But there is a big difference between supplementing based on an actual need and supplementing based on an Instagram ad.
The supplement aisle will always be full of promises. Your job is to look past the packaging and ask what the research actually says, and most importantly, discuss with a health professional.
Conclusion
We hope this Supplements Facts vs. Fiction post helped clarify some of the common misconceptions around supplements and their use and provided a clearer picture of what the evidence actually supports.
Should you feel you require personalized sessions for guidance around supplements or other matters, book a free consultation or contact us for an appointment. As always, if you have comments or questions, we encourage you to let us know.
References
1. Market E. Canada Dietary Supplements Market Size, Growth 2024-2032. Expertmarketresearch.com. Published 2024. https://www.expertmarketresearch.com/reports/canada-dietary-supplements-market
2. Natural vs. safe: Why the two aren’t the same. Mayo Clinic. Published 2025. https://www.mayoclinic.org/tests-procedures/complementary-alternative-medicine/in-depth/natural-vs-safe-health-remedies/art-20587690
3. Marie S. 12 Medications That Interact With St. John’s Wort. GoodRx. Published August 11, 2022. Accessed April 20, 2026. https://www.goodrx.com/well-being/supplements-herbs/st-johns-wort-interactions?srsltid=AfmBOorvEPsjW4FgtE53VStgs5m5DtTU4Wx8DMNOFhKoV0mLKJJwTI-7
4. Vishal Paresh Shah, Tarek Nayfeh, Yahya Alsawaf, et al. A Systematic Review Supporting the Endocrine Society Clinical Practice Guidelines on Vitamin D. The Journal of clinical endocrinology and metabolism/Journal of clinical endocrinology & metabolism. Published online June 3, 2024. doi:https://doi.org/10.1210/clinem/dgae312
5. Vitamin D blood levels of Canadians. Statcan.gc.ca. Published January 10, 2013. Accessed April 20, 2026. https://www150.statcan.gc.ca/n1/pub/82-624-x/2013001/article/11727-eng.htm#archived
6. Zemp J, Erol C, Kaiser E, Aubert CE, Rodondi N, Elisavet Moutzouri. A systematic review of evidence-based clinical guidelines for vitamin D screening and supplementation over the last decade. Archives of Public Health. 2025;83(1). doi:https://doi.org/10.1186/s13690-025-01709-x
7. Yan J, Liu M, Yang D, Zhang Y, An F. Efficacy and Safety of Omega-3 Fatty Acids in the Prevention of Cardiovascular Disease: A Systematic Review and Meta-analysis. Cardiovascular Drugs and Therapy. Published online September 14, 2022. doi:https://doi.org/10.1007/s10557-022-07379-z
8. Abdelhamid AS, Brown TJ, Brainard JS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews. Published online July 18, 2018. doi:https://doi.org/10.1002/14651858.cd003177.pub3
9. Shahinfar H, Yazdian Z, Avini NA, Torabinasab K, Shab-Bidar S. A systematic review and dose response meta analysis of Omega 3 supplementation on cognitive function. Scientific Reports. 2025;15(1). doi:https://doi.org/10.1038/s41598-025-16129-8
10. Myung SK, Park Y. Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-analysis of Randomized Controlled Trials. The American Journal of Medicine. Published online May 2025. doi:https://doi.org/10.1016/j.amjmed.2025.04.034
11. Patel DP, Swink SM, Castelo-Soccio L. A Review of the Use of Biotin for Hair Loss. Skin Appendage Disorders. 2017;3(3):166-169. doi:https://doi.org/10.1159/000462981
12. JCAD Online Editor. Biotin for Hair Loss: Teasing Out the Evidence | JCAD | The Journal of Clinical and Aesthetic Dermatology. JCAD | The Journal of Clinical and Aesthetic Dermatology. Published August 2024. https://jcadonline.com/biotin-for-hair-loss-evidence/
13. National Institute of Health. Office of Dietary Supplements – Biotin. Nih.gov. Published January 10, 2022. https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/
14. Kunik K. AG1 2023 Review: Pros, Cons, Science, and More. Healthline. Published April 28, 2023. https://www.healthline.com/nutrition/athletic-greens-review
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About Author:
Natalie Walsh is a registered dietitian in North York who focuses her practice on weight management counselling, menopause support of a dietitian, digestive health, hearth health and more. Natalie is registered with the College of Dietitians of Ontario.
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