Supplements: What Are You Taking, and Why?

There's an enormous amount of information about supplements, and it can be difficult to know what to believe. Which supplements are good for you? Should everyone take a multivitamin? Can supplements help us live longer? Which brands can you trust? It's a confusing space, made worse by the amount of money involved. Companies and influencers promote products with compelling claims, but some claims have solid evidence behind them and others rest on preliminary research, plausible theories, or very little data. Before adding another supplement to your routine, here are a few things worth understanding.

Supplements are regulated differently than medications

One common misconception is that supplements undergo the same evaluation as prescription medications. They don't. Dietary supplements are FDA-regulated, but generally do not require FDA approval for safety and effectiveness before being sold. Manufacturers still have legal obligations for safety, accurate labeling, and manufacturing quality. The FDA can act against products that violate the law, but it doesn't approve every supplement's clinical effectiveness before it reaches consumers.

Why does this matter? Without trustworthy controls, you can't always be certain a product contains what's on the label or is free of unacceptable contaminants. A supplement advertising five grams of creatine per serving should actually contain that amount. Independent certifications such as NSF and USP can evaluate ingredient identity, labeled quantities and quality. This doesn't prove the supplement works; it offers greater confidence about what you're taking.

A supplement can sound scientific without improving your health

You may hear claims that a compound reduces inflammation, supports mitochondria, increases cellular energy, or influences a biological pathway linked with aging. Those mechanisms may sound impressive, and some may be scientifically plausible. But that doesn't establish that taking the product improves health. Depending on the compound, it needs to survive digestion, become biologically available, reach its target and produce an effect. Most nutrient absorption occurs in the small intestine, and different ingredients work through different pathways.

Even when a supplement changes a marker or cellular process, the critical question remains: does it meaningfully improve symptoms, prevent disease, enhance performance or extend life? Animal studies, laboratory findings and small human studies don't always translate into clinical benefits. Some supplements do have good evidence for specific purposes. Creatine monohydrate can improve aspects of exercise performance and strength, particularly with resistance training. Treating a documented nutrient deficiency can also provide genuine benefits. Other products are promoted on much weaker evidence. Lack of proof doesn't automatically mean a supplement is useless, but it isn't proof that it works.

Supplements can have side effects

People may assume that "natural" or "over the counter" means safe, but supplements contain biologically active substances. Dose, medical conditions and medication interactions matter. Iron can cause nausea or constipation, and excessive iron can be dangerous. Prolonged high-dose zinc intake can impair copper absorption. St. John's wort interacts with many prescription medications. Certain high-dose omega-3 formulations have been linked with increased atrial fibrillation risk in some populations. Even a supplement with legitimate uses can be inappropriate in a particular situation.

That isn't a reason to fear supplements. It's a reason to assess them with the same care given to medications. Understand the intended benefit, dosage, side effects and interactions. Tell your healthcare professional what you're taking, particularly if you have medical conditions or take prescriptions.

Multivitamins may not do everything you think they do

Multivitamins are an appealing entry point: one or two pills, and you hope you've covered your nutritional needs. But formulations and quantities vary considerably. Some contain many essential nutrients yet only modest amounts of minerals such as magnesium. A multivitamin may help fill dietary gaps without meeting all your nutritional requirements or treating a true deficiency.

There can be interactions between nutrients: calcium may decrease iron absorption under certain circumstances, and long-term high-dose zinc can reduce copper absorption. That doesn't mean ingredients in a multivitamin cancel each other out; dose and formulation matter. Someone with a documented iron or other nutrient deficiency may need targeted replacement at an appropriate dose, as well as investigation into the cause.

What about longevity? Evidence doesn't convincingly show that daily multivitamins help generally healthy adults live longer. A large NIH-supported observational analysis of nearly 400,000 adults found no reduced mortality associated with daily use. Some trials suggest modest cognitive benefits among older adults, but that doesn't mean multivitamins extend lifespan. They may be useful for specific diets, medical conditions or life stages, but don't replace a healthy diet.

How should you approach supplements?

Start by asking what you're trying to accomplish. Correcting a deficiency? Improving training performance? Addressing a medical condition? Or hoping to live longer because of a marketing claim? Look for meaningful evidence from human research, not only mechanisms or animal studies. Evaluate the dose, formulation, independent testing, side effects and medication interactions.

Then ask whether a better-supported approach exists. For cardiovascular health, nutrition, regular exercise, blood pressure management and appropriate lipid treatment may be more important. For sleep, start with the sleep schedule, habits, and possible underlying disorders. For performance, look at training, nutrition and recovery. Supplements have a place, but they rarely replace these foundations.

The bigger picture

This is not meant to discourage supplements across the board. Some have excellent evidence for a specific purpose. Instead, approach them with curiosity and appropriate skepticism. Know what you're taking, why you're taking it, and what it realistically can and cannot do. The goal isn't to take more supplements. It's to make better decisions about your health.