First: you don't need any
Every plan on this site works without a single supplement. If you're eating enough protein, sleeping 7 to 9 hours, and training consistently, you already have 95% of the results. Supplements are the last few percent, and only a few have strong research behind them.
Check with your doctor or a registered dietitian first, especially if you take any medication, have a health condition (for example kidney, heart, or blood pressure problems), or are pregnant or breastfeeding. This guide is general information for healthy adults, not medical advice.
Worth considering
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Good evidence
Protein powder
It's just food in a convenient form. It helps if you struggle to reach your daily protein from meals. Research finds extra protein helps muscle growth up to about 1.6 g per kg of bodyweight a day in total, from food and powder combined.
How people use it: one scoop (usually 20 to 30 g of protein) when meals fall short. Whey, or a plant blend if you avoid dairy.
Research: Morton et al., 2018 review of 49 studies. Find your target with the calorie and protein tool.
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Strong evidence
Creatine monohydrate
The most researched sports supplement. It helps you do a rep or two more on hard sets, which adds up to more strength and muscle over time. Studies in healthy adults find it safe at normal doses.
How people use it: 3 to 5 g a day, any time of day, every day. No "loading" needed. Your scale weight may go up a little at first from water stored in your muscles; that's normal, not fat. Plain creatine monohydrate is all you need.
Research: International Society of Sports Nutrition position stand, 2017. Skip it and ask your doctor if you have kidney problems.
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Good evidence, use with care
Caffeine
A coffee before training can make hard sets feel a bit easier. Pre-workout powders are mostly caffeine, often a lot of it, so check the label and count your other coffee and energy drinks too.
Keep it sensible: the FDA says up to 400 mg a day is generally not linked to problems for most adults (about 2 to 3 cups of coffee). Avoid it late in the day if it hurts your sleep, and never use pure caffeine powder.
Sources: ISSN position stand on caffeine, 2021; FDA: how much caffeine is too much?
Usually skip
- Fat burners. Mostly high-dose stimulants. They don't replace eating a little less, and they can raise your heart rate and blood pressure.
- Testosterone boosters. Herbal blends with little good evidence for muscle gain in healthy people.
- BCAAs. If you get enough total protein, research shows they add nothing extra.
- SARMs, prohormones, and "research chemicals." These aren't supplements. They're unapproved drugs with real health risks, and they're banned in sport and the military.
- "Proprietary blends." If a label won't tell you how much of each ingredient is inside, you can't know what you're taking.
How to buy safely
Look for a third-party seal
The FDA doesn't approve supplements before they're sold; the company is responsible for their safety and labels. Independent testing checks that what's on the label is in the tub, and nothing banned is. Two common seals: NSF Certified for Sport and Informed Sport. Both let you search certified products.
In the military?
Check every product with Operation Supplement Safety (OPSS), the Department of Defense's supplement resource. Search its DoD Prohibited Dietary Supplement Ingredients list before you buy, and use its scorecard if you're unsure.
Where to buy
These are plain links to the stores' own pages. We don't earn anything from them and we're not affiliated with either store. Compare price per serving, and pick products with a third-party seal.