Supplements for Active Adults: Creatine, Protein and What Can Wait

October 20, 2026By VitOptics Staff

Short answer: If you train most days, food, fluids and steady training do most of the work. NIH's summary says sports-medicine experts agree creatine can help with short, hard efforts like sprinting and lifting, protein usually comes from meals, and most other workout supplements have limited or mixed evidence. The NIH Office of Dietary Supplements (ODS) says performance supplements "cannot substitute for a healthy diet, but some of them may have value, depending on the type and intensity of your activity."

Food, fluids and training come first

ODS puts it plainly: you "will perform at your best and recover most quickly when you eat a nutritionally adequate diet, drink enough fluids, are physically fit, and are properly trained." It adds that only a few supplements have enough evidence to improve certain types of exercise, and that athletes might use them "if they already eat a good diet, train properly, and obtain guidance from a health care provider or sports-medicine expert."

Protein is a good example. ODS says protein "helps to build, maintain, and repair your muscles" and that, if you are an athlete, "you can probably eat enough foods that contain protein to meet your needs for protein." If needed, ODS says, protein supplements and protein-fortified foods and drinks can help you get enough protein. They are a convenience, not a requirement.

ODS also notes that many studies are small and short, and much of the work is in young, healthy men.

Creatine: for short, hard efforts

Creatine is a compound your muscles store for energy. Your body makes some and beef and salmon add more, but ODS says the larger amounts in supplements might improve certain types of performance:

Where it helps. Creatine "enhances performance during repeated short bursts of intense, intermittent activity (lasting up to about 2.5 minutes at a time), such as sprinting and weightlifting."
Where it doesn't. It "seems to have little value for endurance activities, such as distance running, cycling, or swimming."
The form. "Creatine monohydrate is the most widely used and studied form of creatine in supplements."
What to expect. ODS says creatine "usually causes some weight gain because it increases water retention." Rare reactions include muscle stiffness, cramps and stomach upset.

ODS describes the maintenance amount used in studies as 3 to 5 grams a day. That is a description of research, not a recommendation for you. ODS says talking to an expert is important if you have any medical conditions, and that it's also important to find out whether medicines you take might interact with a performance supplement.

Why capsules are a small way to take creatine

The creatine capsule in our catalog holds 750 mg of creatine monohydrate, so the 3 to 5 grams a day used in studies works out to 4 to 7 capsules. A VitOptics pouch holds up to 8 capsules a day, so creatine alone would fill half or more of it.

That is why VitOptics only puts creatine in a pack when you ask for it by name. If you already take creatine and ask us to move your current supplements into your pack, we leave creatine out and your result says: "Keep taking your creatine as you do now. Studies use 3 to 5 g a day, which is 4 to 7 of our capsules, so powder is the simpler way. Tell us if you'd rather have it in your pouch."

One more practical point: creatine and blood work. Creatinine is a waste product made when you use your muscles, and a creatinine test is one way doctors check kidney health. MedlinePlus notes that people make different amounts of creatinine depending on how much muscle they have, the foods they eat, their age and how active they are, and that "certain medicines and supplements can affect your test results." If you take creatine, include it when you tell your provider everything you take before kidney blood work.

Vitamin D, iron and magnesium: only with a reason

Training doesn't automatically mean you need more of a vitamin or mineral. Each of these is worth adding only when there is a reason.

Iron. ODS says iron deficiency, especially with anemia, "limits your ability to exercise and be active." But "if you get enough iron from your diet, taking extra iron won't help," and a health care provider "should diagnose this condition before you start taking iron supplements." Teenage girls and premenopausal women have the greatest risk of not getting enough iron from food.
Vitamin D. A vitamin D blood test measures the level in your blood; ask your clinician whether one makes sense rather than guessing.
Magnesium. MedlinePlus says magnesium "helps to maintain normal nerve and muscle function" and that most dietary magnesium comes from dark green, leafy vegetables, with nuts, beans, seeds and whole grains also good sources.

An electrolyte mix, a fortified protein powder and a multivitamin can all repeat the same nutrients. Our guide shows how to check for duplicate supplement ingredients across labels.

BCAAs, citrulline and the rest: limited evidence

The ODS table of performance ingredients is a useful reality check. For several popular ones, its bottom line is short:

BCAAs (leucine, isoleucine and valine): not much scientific evidence for supplements, and eating foods containing protein "automatically increases your intake of BCAAs."
Citrulline: the research is limited, and a few studies find it might help, hinder or have no effect.
Arginine: little scientific evidence for strength, performance or recovery.
Glutamine: either no effect or only a small benefit in the few studies done.

ODS adds that most ingredient combinations haven't been studied. VitOptics puts BCAAs, citrulline, arginine or glutamine in a pack only when you name them. If room is left after the research-backed picks, a pack may also hold a popular product with limited research for a goal you chose; its card is labelled "Popular choice."

Caffeine and pre-workouts: add up the totals

Caffeine is the other ingredient ODS says sports-medicine experts agree can help: it can help you exercise at the same intensity level for longer and reduce feelings of fatigue. ODS says it is most likely to help with endurance activities and sports with on-and-off effort, like soccer and tennis, and that it "doesn't help with short, intense exercise like sprinting or weightlifting."

The bigger issue is usually the total. Coffee, energy drinks, pre-workout powders and some supplements all add caffeine. For most adults, the FDA "has cited 400 milligrams a day — that's about two to three 12-fluid-ounce cups of coffee — as an amount not generally associated with negative effects," while noting wide variation in how sensitive people are. If you have a condition or take a medication that may make you more sensitive, or you are pregnant or breastfeeding, the FDA suggests talking to your health care provider.

"Bodybuilding" products and hidden ingredients

NCCIH warns that some products marketed as dietary supplements, "promoted mainly for weight loss, sexual enhancement, and bodybuilding," may contain prescription drugs or ingredients not listed on the label. The FDA has found bodybuilding products that illegally contain steroids or steroid-like substances, and it is aware of reports of serious liver injury.

The FDA says products used for "stacking" (two or more bodybuilding products at once) should be a red flag, especially when they come from the same seller, and recommends talking to your health care professional about any bodybuilding products you have taken. If you compete in tested sport, ODS notes that some sellers have products certified by outside programs. Before adding anything new, our checklist of what to review before starting a new supplement is a good place to start.

How VitOptics fits a training goal

The free assessment lets you choose "Training & recovery" as one of up to three goals. It also asks about exercise, how much caffeine you have on a typical day, and which supplements you take now, so you can tell us what you already take before anything is added. A separate question asks, "Any supplements you already know you want in your pack?" That is where you name creatine if you want it in your pouch.

Automated checks review the recommendation; some profiles need additional review by a person on our team. A second automated check reads the whole pack before release. The safety screen asks about kidney disease or reduced kidney function, and answers like that go to a person on our team rather than an automatic result. Your result lists every formula, the amount of each ingredient and the reason it is there, so you can compare it with your protein powder, pre-workout or sports drink. If you are deciding between a pack and a single bottle, see personalized supplement packs vs. a multivitamin.

Personalized vitamin packs from $59 a month, priced by what’s in your pack and the same every month · free standard U.S. shipping · 30-day first-pack guarantee · pause or cancel online · U.S. only

Start my free assessment.

Read more in the VitOptics learning hub.

Sources

This article is for educational purposes and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.

Prepared with AI assistance using the sources linked in this article.

Last updated: October 2026

Back to Learn

VitOptics builds personalized vitamin packs, with a written reason for every pick. Take the free assessment to see your recommendation and its price before you subscribe.