A bottle count is a useful starting point, but it is a poor shortcut for value. Two bottles can contain different numbers of capsules, require different servings and disclose very different amounts of their featured ingredients. Write those differences down before choosing by price.
1. Count servings, not just capsules.
Look at both “serving size” and “servings per container.” FDA explains that supplement serving sizes are set by the manufacturer; they are not a universal standard across competing products. Source: FDA supplement questions and answers.
Example: 120 capsules at four capsules per labeled serving is 30 servings. A 90-capsule bottle at three per serving also contains 30 servings. The first bottle’s larger capsule count does not, by itself, buy more servings.
2. Compare the ingredient amounts.
Record the exact ingredient name, its form and its amount per labeled serving. FDA’s labeling explanation distinguishes dietary ingredients from “other ingredients” and notes that proprietary blends do not have to disclose each ingredient’s individual amount. An undisclosed amount is a missing comparison point—not something to estimate from the blend’s total weight. Read the labeling explanation.
Keep units consistent: 1,000 milligrams equals 1 gram. For example, a product listing 500 mg is not the same amount as one listing 5 g. That arithmetic says nothing about which amount you should take; it simply prevents an unfair shopping comparison.
3. Divide the full price by the servings.
Cost per labeled serving = final package cost ÷ total labeled servings. Include shipping and tax when known. If a discount requires a subscription, compare its continuing price as well as the first order.
- Package A: $24 delivered ÷ 30 servings = $0.80 per serving.
- Package B: $36 delivered ÷ 60 servings = $0.60 per serving.
- B is 25% cheaper per serving: ($0.80 − $0.60) ÷ $0.80. It still requires $12 more upfront.
These are fictional packages, not product recommendations. Cost per serving is useful only alongside comparable ingredients and amounts. A larger order may be poor value if you won’t use it, dislike it or cannot return the remainder.
4. Separate an ingredient from a finished product.
A study on one ingredient does not automatically establish the benefit of a blend containing it. NIH’s exercise-supplement guide warns that combinations are often not studied together. Check what was actually tested, in whom and in what amount before applying a headline to a bottle. Source: NIH Office of Dietary Supplements.
Our price calculations do not rate effectiveness. For a concrete shopping example, see our creatine comparison guide.
5. Check what you are committing to.
Before paying, check the final total, whether the charge recurs, cancellation steps and return conditions. For a guarantee, look for when its clock starts, whether opened bottles qualify, who pays return shipping and what you must send back. Save the terms shown with your order.
A buying guide cannot tell you whether a supplement is appropriate for you. Discuss that decision with a qualified healthcare professional, especially if you take medication. We have not tested products or independently analyzed their contents.