If I had $100 for supplements, I would keep it simple

First decide what is actually missing

Write down what you eat, what you train for, and what you are trying to improve. A powder is useful when it solves a specific problem: convenient protein at work, or a well-supported aid for repeated high-intensity effort. It is less useful when the goal is vague reassurance that you are “doing everything.”

Supplements do not replace sufficient energy, hydration, suitable training and recovery. The NIH Office of Dietary Supplements reviews evidence ingredient by ingredient; benefits depend on the activity, dose and person, and many products have limited supporting evidence.^[1]

Priority one: plain creatine monohydrate

Creatine can improve performance in repeated short, intense efforts and support training-related gains. Monohydrate is the most studied form; a premium-sounding alternative is not automatically better. A common maintenance intake is 3–5 grams a day, and loading is optional rather than necessary.^[2]

Daily consistency is more important than finding a magical minute to take it. Some early scale gain reflects water retained with creatine rather than fat. It is not a fat burner, and you still need progressive training. Start with a simple product and compare cost per gram, not tub size.

If you have kidney disease, are pregnant, take medicines affecting kidney function or have another relevant health condition, get individual advice before using it. A healthy-adult sports recommendation cannot be transferred automatically to every medical situation.

Priority two: protein only if food leaves a gap

Protein supplementation can help resistance-training outcomes when it raises an otherwise insufficient total intake. More is not indefinitely better. A large meta-analysis found diminishing average benefit as daily intake approached roughly 1.6 grams per kilogram; individual needs and dieting conditions vary.^[3]

A whey, soy or suitable blended plant powder can be convenient, but it is not inherently more anabolic than a well-planned diet. Check protein per serving, allergens, how many servings you actually get and the cost per 25 grams of protein. If ordinary food already meets your needs, keep this money for groceries.

Older adults may find a convenient protein food helpful when appetite is low, but the priority is also enough total food and appropriate resistance training. A shake should make meals easier to complete, not displace every meal or promise to reverse age-related muscle loss by itself.

Caffeine and vitamin D are conditional choices

Caffeine can improve some exercise performance, but response and side effects vary. Coffee may already do the job. More stimulant is not better if it causes anxiety, palpitations or poorer sleep. Skip concentrated caffeine powders and do not stack energy drinks with pre-workouts without checking the combined dose.^[1]

Vitamin D is important, but “important” does not mean everyone needs a high-dose supplement. Requirements depend on age, diet, clinical context and national guidance. Avoid megadoses. A clinician or pharmacist can help when deficiency risk, medication or a specific recommendation makes supplementation appropriate.^[4]

An example $100 allocation

Use these as ceilings and adjust to local prices. If a suitable product exceeds the cap, you can buy a smaller amount or leave it out. A budget should remain a budget.

What I would leave on the shelf

I would not make BCAAs, fat burners or testosterone boosters a default purchase. Nor would I choose a proprietary blend that hides individual doses. A long ingredient list can make it harder to evaluate both evidence and safety.

Choose transparent labels and reputable independent testing where available. Certification can reduce contamination risk; it does not prove that a product works. Competitive athletes should check sport-specific certification and anti-doping requirements. In Canada, look for the appropriate product licence where applicable, while recognising that authorisation is not a guarantee of a muscle-building result.^[5]

My rule is to buy the simplest product that solves a real problem, then reassess. If you can meet the same need with affordable food or a better routine, that is a successful supplement decision—even when the purchase is nothing.