Two supplements can list almost the same ingredients and still be completely different products. The difference is in the details on the label. Here is how to read one in two minutes.
1. Find the Supplement Facts panel
In the United States, every dietary supplement must have a Supplement Facts panel. It lists the serving size, the number of servings per container, and each ingredient with its amount per serving.
Check the serving size first. A product might list 600 mg of an herb, but if the serving is four capsules, you are taking four capsules to get it, and the bottle may last half as long as you thought.
2. Watch out for proprietary blends
A proprietary blend lists a total weight for a group of ingredients without saying how much of each one is inside. For example: “Performance Blend 800 mg: fenugreek, ashwagandha, tribulus, maca.”
The law allows this, but it means you can’t tell whether the product contains a meaningful dose of the ingredient you care about or just a sprinkle. Ingredients are listed in descending order by weight, so the last few in a blend are often present in very small amounts.
Our rule: full disclosure of every dose is a sign of a confident brand.
3. Compare doses with the research
When a product says an ingredient is “clinically studied,” check the dose. A few examples of amounts commonly used in studies:
| Ingredient | Amount often used in studies |
|---|---|
| Ashwagandha root extract | 300–600 mg per day |
| Fenugreek seed extract | 500–600 mg per day |
| Creatine monohydrate | 3–5 g per day |
| Korean red ginseng | 600–1,000 mg, up to three times per day |
| Tongkat ali extract | 200–400 mg per day |
If the product delivers a fraction of these amounts, the research probably doesn’t apply to it.
4. Check the form of each nutrient
Forms matter. Magnesium oxide is poorly absorbed compared with glycinate or citrate. Vitamin D3 raises blood levels more effectively than D2. Standardized extracts, which list their active compound percentage, are more consistent than plain powders.
5. Look for third-party testing
Supplements are not approved by the FDA before sale. Independent testing programs check that products contain what the label says and are free of certain contaminants. Seals to look for include NSF Certified for Sport, USP Verified and Informed Sport. Not having a seal doesn’t mean a product is bad, but having one is a meaningful plus.
6. Read the claims carefully
Supplements may make “structure/function” claims, such as “supports healthy testosterone levels,” but may not claim to treat or cure disease. Products that claim to treat erectile dysfunction, cure prostate problems or replace prescription medication are breaking the rules, which tells you something about the seller.
7. Calculate cost per day
Divide the price by the number of days a bottle lasts at the recommended dose. Multi-bottle packages often cut the per-day cost substantially. Check the money-back guarantee too: the best ones cover opened bottles and give you at least 60 days.
Put this into practice with our comparison guides.