Supplements Worth Taking (and Ones That Aren't)

Walk into any health store and you’ll find walls of bottles promising better energy, faster recovery, stronger joints, and clearer skin. The supplement industry pulls in tens of billions annually, and most of that money goes toward products with weak or nonexistent evidence behind them.

That said, a handful of supplements are genuinely useful. The trick is knowing which ones sit in each category and being honest about whether your diet already covers the gap.

The ones worth taking

Three supplements have substantial research behind them, but they earn their place for different reasons: one improves training performance directly, and the other two matter mainly when your diet or circumstances leave a genuine gap.

Creatine monohydrate is the most studied sports supplement in existence. It works by increasing phosphocreatine stores in muscle, which helps regenerate ATP during short, intense efforts. That translates to a few more reps, slightly more power output, and over time, greater training stimulus. The effect is modest per session but compounds across months of consistent training.

The dose is simple: 3-5g daily. No loading phase required. No cycling on and off. Just take it consistently and let tissue saturation build over a few weeks. It’s cheap, well tolerated at recommended doses in healthy adults, and has evidence across a wide range of adult ages — though how much you get out of it depends on your training, diet, and starting point. The one caveat: it can cause a small increase in water retention within muscle cells, which may bump scale weight by a kilogram or two. That’s not fat gain.

Creatine is also being studied for cognitive benefits, particularly under sleep deprivation or high mental workload. The brain uses ATP too, and creatine supports that energy system in neural tissue just as it does in muscle. But the research here is early, and the doses used in some studies are far higher than the standard 3-5g — treat this as a promising area to watch, not a settled benefit.

Vitamin D is technically a hormone precursor. True clinical deficiency is less common than the supplement industry suggests, but low levels are a real risk for people who live at northern latitudes, work indoors, or have darker skin. Low vitamin D is associated with impaired immune function, poorer bone health, and reduced muscle function.

Getting your levels tested is the ideal approach, since the right dose depends on where you’re starting from — your doctor can tell you whether you need to supplement at all. For context, doses in the 1000-2000 IU daily range are commonly used for people without regular sun exposure. It’s not a performance enhancer, but correcting a deficiency removes a drag on your body’s basic functions. Think of it less as gaining an edge and more as removing a hidden handicap.

Low vitamin D and low mood are associated in observational studies, though supplementation hasn’t consistently improved mood in clinical trials. If your motivation for training drops every winter, that’s worth raising with your doctor rather than self-treating with vitamin D alone.

Omega-3 fatty acids (EPA and DHA) influence inflammatory signaling and play a role in cardiovascular health, though supplement trials have produced more mixed results than eating fish itself. Fatty fish a couple of times a week is the better-supported route. If you rarely eat seafood and realistically won’t start, a supplement providing 1-2g combined EPA/DHA daily is worth considering. Talk to your doctor first if you manage any chronic conditions.

Quality matters here more than with most supplements. Fish oil can oxidize if poorly manufactured or stored, and rancid oil may do more harm than good. Look for products that list third-party testing for purity and freshness. Algae-based omega-3 supplements are a solid alternative for people who don’t eat fish or prefer a plant-sourced option.

The “it depends” tier

Some supplements have real evidence behind them but only matter in specific contexts.

Caffeine genuinely improves endurance and power output. But most people already consume it through coffee or tea. If you already drink coffee before training, a caffeine pill isn’t giving you anything extra. Research typically finds performance effects at 3-6mg per kilogram of body weight taken 30-60 minutes before exercise, though lower doses around 1-3mg/kg often work too. For a 75kg person, the full range is roughly 225-450mg — and since higher doses add jitters and sleep disruption faster than they add benefit, starting at the low end (about two strong cups of coffee) is the sensible move.

One thing people overlook is caffeine’s half-life. It sits around 5-6 hours in most adults, which means an afternoon training session fueled by 200mg of caffeine can absolutely interfere with sleep quality that night. And poor sleep does more damage to recovery than caffeine provides in performance benefit. If you train in the evening, consider whether that pre-workout is costing you more than it gives. Our article on sleep and performance covers why this tradeoff matters more than most people realize.

Electrolyte supplements matter when you’re sweating heavily for extended periods. A 30-minute gym session doesn’t create meaningful electrolyte depletion. A two-hour run in summer heat does. Context determines whether you need them or whether regular food and water cover you just fine. If you’re interested in the broader picture of fluid intake and exercise, our piece on how nutrition affects your training recovery goes deeper on timing and practical strategies.

Magnesium falls into this tier as well. Many people eat less magnesium than recommended, especially those with limited dietary variety — though low intake isn’t the same as clinical deficiency. Magnesium supports muscle function, sleep quality, and hundreds of enzymatic reactions. Leg cramps and shallow sleep have many possible causes and don’t prove you’re low on magnesium, but if your diet is light on magnesium-rich foods, a modest dose of glycinate or citrate before bed is a low-risk experiment for most healthy adults. Keep supplemental doses under the 350mg/day upper limit, check with your doctor first if you manage any ongoing health conditions, and mention persistent cramps or sleep problems to them too, since those can signal other issues.

Iron is critical for oxygen transport and energy metabolism. But supplementing without knowing your levels is a bad idea. Excess iron is toxic and can cause organ damage over time. Get tested, and let your doctor decide whether supplementing makes sense for you since risk varies a lot with diet, training volume, and individual factors they’re best placed to weigh.

The overhyped category

This is where most supplement spending goes.

BCAAs (branched-chain amino acids) were once a staple in gym bags everywhere. The logic seemed sound: leucine triggers muscle protein synthesis, so isolated BCAAs should help recovery. The problem is that if you’re already eating adequate protein, BCAAs provide no additional benefit. They’re just expensive, flavored amino acids you’d already be getting from chicken, eggs, or whey. The research consistently shows no advantage over simply hitting your daily protein target.

Testosterone boosters based on herbal extracts (tribulus, fenugreek, ashwagandha for this purpose) show minimal to no meaningful effect on testosterone levels in controlled trials. The studies that do show small increases tend to be funded by supplement companies and measure changes within normal physiological ranges that don’t translate to noticeable performance or body composition differences.

Fat burners are typically caffeine plus a grab bag of plant extracts with no meaningful thermogenic effect beyond what the caffeine alone provides. You’re paying a premium for a caffeine pill dressed up with marketing language.

Glutamine supplementation for muscle recovery has largely been debunked for people eating adequate protein. Your body synthesizes plenty of glutamine on its own, and dietary protein provides more. It may have a role in gut health for specific clinical populations, but for general recovery in healthy active people, it’s unnecessary.

Collagen supplements are the newest entrant into this space. Marketing claims around joint health and skin elasticity are everywhere. The research is mixed at best. Your body breaks collagen peptides into a mixture of free amino acids and small peptides during digestion, some of which (like hydroxyproline-containing dipeptides) are absorbed intact and detectable in blood. Whether these peptides preferentially stimulate collagen tissue rebuilding in a meaningful way is not well established. Some small studies show modest benefits for joint pain in athletes, but the effect sizes are tiny and the study quality is often low. Gelatin with vitamin C before targeted connective tissue work is a more evidence-backed approach if joint health is your concern, and even that protocol is still being studied.

How the supplement industry keeps you spending

Understanding why so many people buy ineffective supplements helps you avoid the same traps.

The industry relies heavily on a few psychological patterns. First, there’s the “marginal gains” narrative. You hear that elite athletes use a particular supplement, so you assume it must be helping. What you don’t see is that those athletes also sleep nine hours, eat perfectly timed meals prepared by a chef, and have their recovery monitored daily by a sports science team. The supplement is a rounding error in their results.

Second, there’s the nocebo-placebo loop. You start taking something new, and you feel different. Maybe more energetic, maybe your workout was better. But you also just spent money on it, you’re paying attention to your body, and you showed up to train with slightly more intention. That’s placebo, and it’s powerful. It doesn’t mean the supplement is working at a physiological level.

Third, proprietary blends hide the ball. When a label lists a “performance matrix” of twelve ingredients without specifying individual doses, you have no way to know whether any single ingredient is present at an effective amount. Often it isn’t. The most expensive ingredients appear in trace amounts while cheap fillers make up the bulk.

The simplest defense against all of this is asking for the specific mechanism. How does this compound work in the body? At what dose? Shown in which populations? If the answer relies on “antioxidant support” or “cellular energy optimization” without specifics, that’s marketing copy, not science.

Timing and stacking

People love to optimize when they take things, but for most of the supplements that actually work, timing barely matters.

Creatine doesn’t need to be taken pre-workout or post-workout specifically. Daily consistency is what drives tissue saturation. Take it whenever it’s easiest to remember. In your morning coffee, with lunch, mixed into a post-workout shake. It doesn’t matter.

Vitamin D is fat-soluble, so taking it with a meal that contains some dietary fat helps absorption. Taking it with your largest meal of the day is a simple habit worth building.

Fish oil with food reduces the likelihood of fishy burps. That’s the main timing consideration.

Stacking multiple supplements together is fine as long as you’re not creating interactions. Iron and calcium can compete for absorption, which is why people prescribed iron are often advised to take it away from calcium supplements. But unless you’re dealing with specific clinical deficiencies, you don’t need to overthink this. Take your supplements, eat your food, and move on.

The “food first” principle

Here’s the uncomfortable truth for the supplement industry: most of what these products offer is already available through a reasonably varied diet. Eating vegetables, fruit, quality protein sources, and some fatty fish covers the vast majority of micronutrient needs.

Supplements work best as exactly what the name suggests. They supplement a solid nutritional foundation. They don’t replace one. No pill compensates for consistently poor eating habits, inadequate sleep, or a training program that doesn’t include recovery.

The people who benefit most from supplements are those who already have their nutrition dialed in and are addressing a specific, identified gap. Everyone else is better off spending that money on groceries.

This doesn’t mean everyone needs to eat perfectly before considering a supplement. If you know you don’t eat fish and probably won’t start, omega-3s make sense now. If you live in Minnesota and work indoors, vitamin D makes sense in October regardless of what you’re eating. Pragmatism beats purism.

What about protein powder?

Protein powder is technically a supplement, but it’s probably better thought of as a food. It’s just a concentrated protein source derived from milk, eggs, plants, or other whole foods.

The question isn’t whether protein powder “works.” It’s protein. Of course it works. The question is whether you need it to hit your daily intake targets. If you consistently eat enough protein through whole foods, you don’t need powder. If you struggle to hit your target because of schedule, appetite, or convenience, protein powder solves a practical problem.

Whey protein has the most research behind it and contains a complete amino acid profile with high leucine content. Plant-based blends (pea, rice, hemp combinations) work fine too, though you may need slightly more volume to match the leucine content of whey. The difference is marginal for most people and shrinks to nothing over a full day of eating.

Don’t let anyone convince you that protein powder is essential for building muscle or recovering from training. Real food does the same job. Powder is just convenient.

A simple decision framework

Before buying any supplement, ask yourself three questions. Does it have consistent evidence from independent research (not just studies funded by the manufacturer)? Does it address a gap that your current diet doesn’t cover? And is the cost justified by the expected benefit?

Most supplements fail at least one of those questions. Creatine passes all three for most people who train regularly. Vitamin D and omega-3s pass when testing or an honest look at your diet reveals a genuine gap. Everything else deserves scrutiny before you add it to your monthly budget.

If you’re spending more on supplements each month than on fresh produce, something has gone sideways. Redirect that budget toward better food, and you’ll likely notice more difference than any capsule ever provided.

Your body doesn’t care about branding or endorsements. It cares about whether it’s getting what it needs to function, adapt, and recover. For most of us, that comes down to eating well, training consistently, sleeping enough, and maybe taking a few grams of creatine with your morning water. The rest is noise.

One last thing worth knowing: in the US, supplements aren’t reviewed by the FDA for safety or effectiveness before they’re sold, so third-party testing matters for everything you buy, not just fish oil. And nothing here is medical advice. Supplements can interact with medications and health conditions in ways a blog post can’t account for. If you take prescription medication, are pregnant, or manage a health condition, run any new supplement past your doctor or pharmacist first.