AARP Hearing Center
Supplement Testing Methodology: How We Review Nutritional Products
Learn our process for choosing the best supplements, from probiotics to protein powder
Courtesy of iStock
As we age, our bodies become less efficient at absorbing and processing nutrients from food. But dietary supplements, such as protein, can help bridge those nutritional gaps. For older adults, the right supplements can support bone health, boost immunity, promote healthy heart and brain function and maintain muscle mass.
Quality supplements, combined with a balanced diet and exercise, can help us stay mobile and continue living an active, independent lifestyle. In our September 2026 survey of 300 adults ages 50-plus who’ve regularly taken protein supplements in the last year, 78 percent reported improved muscle strength due to their supplement. “Taking protein supplements makes me feel like I’m being proactive in maintaining my health into my late 70s,” one participant wrote.
More Ways to Benefit
- Related Benefit 1
- Related Benefit 2
- Related Benefit 3
- Related Benefit 4
- Related Benefit 5
But with so many options, how do you determine which supplement is best for you? That’s where our AARP Smart Picks team comes in. Read on to learn how we test supplements and the key factors we look for in products based on expert insights from medical professionals.
How we vet and test supplements
- Research the marketplace. We dive deep into supplement products across the industry and ask questions such as: Which companies are popular and why? What supplements are formulated specifically for older adults? Which products have positive reviews — and are they legitimate?
- Analyze insights from our 2026 survey. We conducted a September 2026 survey of 300 adults ages 50 and older who purchased a protein supplement, such as protein powder, within the past year. These findings help us pinpoint which factors matter most to older adults when selecting supplements, as well as their overall satisfaction with the products.
- Consult medical experts. For every supplement we review, we work with medical professionals to assess its formula. Experts review the nutritional information for each supplement and offer insight on the formulation, active ingredients and any unnecessary fillers or additives. These professionals also offer guidance and answer questions such as: What supplements are appropriate for certain age groups or health conditions? What ingredients should older adults avoid?
- Verify third-party certifications. Each supplement must meet certain eligibility requirements before our team considers recommending it. These include independent ingredient verification by an accepted third party, such as ConsumerLab.com, National Sanitation Foundation (NSF) International or the U.S. Pharmacopeia Convention (USP). Third-party testing helps verify the product’s safety and quality, especially since the U.S. Food and Drug Administration does not usually have to evaluate or approve supplements for safety or effectiveness before they are sold to consumers.
- Purchase and test each item. We examine each supplement, analyzing and comparing key features such as ingredients, serving size, company policies, accessibility and affordability.
- Recruit independent testers ages 50-plus. Our older adult testers prepare, evaluate and rate various aspects of each supplement, answering questions such as: How easy is it to read and follow the supplement’s instructions? How does the product taste? Have you experienced any side effects since ingesting the supplement?
- Assess the customer service experience. We analyze company policies, including manufacturing standards and regulations, returns and customer support options. We also compare pricing, shipping, discounts and subscription models to determine overall affordability. In addition, our team contacts each company to assess the quality of their customer support.
Testing metrics
Products that perform well on these metrics make it onto our list of the best protein powders
Medical expert review
- Medical professionals help us select and vet products to test. They review the nutritional information of each product and answer questions such as:
- Is the protein source suitable for older adults?
- Has the product been third-party tested to meet our quality and safety standards?
- Are there additives, preservatives or fillers that may pose health concerns?
- Does the recommended serving size meet older adults' daily protein needs?
- Are there health conditions or medications that could negatively interact with this supplement?
- How does this brand compare to other protein powders regarding digestibility and nutritional value?
Packaging and instructions
- Next, our older adult testers rate their first impressions of the packaging, noting how easy or difficult it is to open the product and whether the directions and ingredients are displayed in a clear, easy-to-read font.
- They assess the instructions and how easy they are to follow, including whether the steps clearly state how much to use, when to consume the supplement and what liquids it should be mixed with for optimal digestion.
Mixability
- Testers rate a protein powder’s solubility, or the ability to dissolve. To ensure standardization across products, testers mix each powder with water and shake the bottle for 60 seconds. They note how well the powder dissolves and whether any chunks remain. Did it require any additional mixing or shaking beyond the 60 seconds?
Taste and texture
- Our testers then try the supplement and describe the taste in as much detail as possible. They give it an overall taste rating and a separate score for sweetness. They note whether the flavors seem strong, subtle, artificial or natural.
- Texture is factored into the tester’s score. Is the resulting product smooth, creamy, foamy, chalky, gritty or clumpy? Finally, they answer: Would you drink this product again?
Side effects
- Testers assess their overall experience after ingesting the product. They address questions such as: Are you satiated or full? Are you experiencing any side effects, such as an upset stomach? Do you feel more energetic?
Affordability
- We calculate the price per serving by dividing the total cost by the number of servings in each canister. We also evaluate costs based on available subscription models.
Note: Individual health considerations, medical conditions and possible supplement interactions can vary from person to person. It’s important to consult your health care provider before starting a new supplement to ensure it's safe and suitable for your unique needs.
Have questions or feedback about our process? Email us at AARPSmartPicks@aarp.org.
AARP Membership
Join AARP for only $15 per year with automatic renewal. Get instant access to members-only products and hundreds of benefits, a free second membership, and a subscription to AARP The Magazine.
You Might Also Like
25 Great Ways to Get More Protein in Your Diet
Smart strategies to give your body this crucial nutrient you need to stay strong
Doctor, How Much Protein Do I Need?
Why people over 50 need twice as much protein as younger people
Protein Supplements: What You Need to Know
Whey powder aids muscle growth in mature adults