Supplement Basics
Three things that work beat twelve that don't.
I take supplements. I also think most of the supplement aisle is a very profitable placebo. Both of these things are true, and the difference is evidence, which is what this page sorts.
Rule zero: supplements are barely regulated, and nobody checks that what's on the label is in the bottle. Only buy brands with third-party testing, look for NSF or USP seals. That one habit filters out most of the junk regardless of what you're buying.
The short list with real evidence
Vitamin D3 + K2 Test first, then decide
Deficiency is genuinely common and this is the rare supplement where a lab value should make the decision. The pairing logic: D3 helps you absorb calcium, K2 helps direct it into bones instead of arteries. Delivery and address on the same label.
My take: test, correct to a sensible level, retest in a few months. This is the top of my own stack.
Creatine Cheapest, most studied thing on the shelf
The most studied sports supplement in existence, with consistent strength benefits alongside resistance training. The newer story is the brain: cognitive function, mental fatigue, performance under stress and short sleep, with especially interesting research for women around the menopause transition.
My take: creatine has a bro-shaker image problem that keeps out the people who'd benefit most. Plain monohydrate, nothing with a lightning bolt on the label.
Magnesium If your sleep is broken, try this first
A real share of people don't get enough from food, and the sleep evidence is most convincing in people who were low. Form matters: citrate sends you to the bathroom, glycinate mostly doesn't, and that difference explains a lot of one-star reviews.
My take: the personal one. 240mg of glycinate nightly ended my 3am wake-ups, and since sleep is the foundation everything else is built on, a supplement that protects a full night punches way above its price. You'll know within two weeks if yours noticed.
Omega-3s Food first, capsule as insurance
Strong support for triglycerides, and low levels are common because almost nobody hits the real goal: fatty fish twice a week. Salmon, sardines, mackerel.
My take: food is the plan, the supplement is the insurance, and a third-party tested fish oil is cheap insurance for the weeks the fish schedule doesn't cooperate.
Psyllium husk The fiber your doctor already means
When a physician says "take a fiber supplement," this is the one they're talking about. Psyllium forms a gel in your gut that keeps you regular, helps lower LDL cholesterol, steadies blood sugar, and keeps you full between meals. Most people eat about half the fiber they should, which is why this earns a spot on the short list. The famous orange canister is psyllium too, just buried under flavoring and sweeteners you don't need.
The catch is quality. Psyllium is a crop, and independent testing has found lead in every psyllium product tested, some far above safe daily limits. This is rule zero with the stakes visible: buy plain, unflavored psyllium from a company that publishes heavy metal testing, and skip everything else.
My take: Yerba Prima, whose psyllium came through independent lead testing best in class. Start with a half teaspoon in a big glass of water, drink it before it turns to gel, and work up slowly over a couple of weeks. Keep it two hours away from medications and other supplements, since the same gel that lowers cholesterol can also blunt absorption of whatever you take with it.
The situational ones
Iron Only with a tested deficiency
Fatigue plus low ferritin is a great reason to supplement (see Lab Values Decoded). But iron builds up, excess is harmful, and guessing gets it wrong in both directions. Test, then decide.
B12 Real for specific groups
Worth it if you're vegan or vegetarian, over 60, or on metformin or long-term acid reducers, all of which interfere with absorption. For everyone else with normal levels, extra B12 mostly produces expensive urine.
Zinc A tool, not a subscription
Reasonable evidence for shortening colds when started at the first sign of symptoms. As a daily forever-supplement on a decent diet, the case is thin, and long-term high doses interfere with copper.
Protein powder Convenient food, compliment intended
Not really a supplement. If you struggle to eat enough protein, especially with age or strength training, a third-party tested powder is one of the most legitimately useful things in the store. It just doesn't need magic words on the label to work.
The overhyped shelf
Greens powders Not a vegetable at any price
Dried plant dust with a beautiful Instagram presence. The fiber, water, and food matrix are most of what makes vegetables work, and none of them survive the powdering. Fine as a garnish on an already decent diet.
Collagen Marketing outruns the data
Some evidence for skin elasticity and joint comfort, with real debate over whether that's collagen being special or just amino acids you'd get from protein anyway. Not snake oil, low risk if you love it, but solid protein intake gets you most of the same building blocks.
Detoxes, cleanses & IV drips Your liver already does this, free
Your liver and kidneys are the detox, running continuously, never improved on by juice. On drips, the inside view from someone who worked that world: most of what you feel afterward is the fluids. Your call, no side-eye, just know what you're buying.
The standing rule: I'm a nurse giving you education, not your nurse giving you medical advice. Supplements interact with medications and conditions, so run your list past someone who knows yours.