According to Gram Research analysis of 384 older adults in Iran, doctor recommendations are the strongest influence on supplement choices, followed by price, supplement form, ingredients, and country of origin. A 2026 discrete choice experiment found that physician endorsement significantly increased the likelihood of supplement selection, while higher monthly costs reduced it—with vitamin-mineral combinations preferred over herbal-only products.
A Gram Research analysis of 384 Iranian adults over 65 reveals what really influences their supplement choices. Researchers asked older adults to imagine choosing between different supplements with varying features—like price, form, and ingredients. The results were clear: doctor recommendations matter most, followed by how much the supplement costs, what form it comes in (pill vs. liquid), and where it’s made. Surprisingly, people’s income or education level didn’t change their preferences much. These findings help doctors, supplement makers, and health officials understand what older adults actually want when picking supplements.
Key Statistics
A 2026 discrete choice experiment of 384 Iranian adults aged 65+ found that physician recommendation was the most influential factor in supplement selection, significantly outweighing other considerations like price and product form.
Among 384 older adults studied in 2026, higher monthly supplement costs substantially reduced the likelihood of selection, demonstrating strong price sensitivity in this age group.
A 2026 study of 384 older adults found that vitamin-mineral combination supplements were preferred over herbal-only products, suggesting older adults perceive formulated combinations as more trustworthy.
Research of 384 Iranian adults aged 65+ in 2026 showed that foreign-licensed supplements were favored over domestically-produced ones, indicating country of manufacture influences perceived quality among older supplement users.
The Quick Take
- What they studied: What factors influence older adults’ choices when selecting dietary supplements?
- Who participated: 384 adults aged 65 and older (average age 73.7 years, about half women) from pharmacies in two Iranian cities: Tehran and Karaj
- Key finding: Doctor recommendations were the strongest influence on supplement choices, with price, supplement form, ingredients, and country of origin also playing important roles
- What it means for you: If you’re an older adult choosing supplements, your doctor’s recommendation should carry the most weight. Price matters too—more expensive supplements are less likely to be chosen. Vitamin-mineral combinations are preferred over herbal-only products, and products made in foreign countries were favored over domestic ones.
The Research Details
Researchers used a special research method called a discrete choice experiment (DCE). Think of it like a survey where participants make choices between different options. The 384 older adults were shown different supplement scenarios and asked which they would choose. Each scenario varied by five key features: whether a doctor recommended it, the monthly cost, the form (tablet, capsule, or liquid), the ingredients (vitamins-minerals versus herbs), and where it was made (foreign-licensed versus domestic). By analyzing thousands of these choices, researchers could figure out which features mattered most.
The study took place in pharmacies in Tehran and Karaj, Iran, between 2024 and 2025. Participants were recruited directly from pharmacy customers. Researchers used statistical analysis (multinomial logit modeling) to determine which factors had the strongest influence on people’s choices. This method is more realistic than simply asking people what they think matters, because it shows what they actually choose when faced with real trade-offs.
This research approach is valuable because it reveals what older adults actually prefer, not just what they say they prefer. When people make real choices—especially when they have to trade off between features like price and quality—their true priorities become clear. Understanding these preferences helps doctors give better advice, helps supplement companies design products that older adults actually want, and helps governments create policies that serve this population well.
The study included a good-sized sample of 384 participants, which provides reliable results. The researchers recruited participants from actual pharmacy settings, making the findings relevant to real-world supplement shopping. However, the study was conducted only in Iran, so results may not apply equally to older adults in other countries with different healthcare systems, cultures, and supplement markets. The study did not track whether participants actually bought supplements based on their stated preferences, so there’s a gap between what people say they’d choose and what they actually purchase.
What the Results Show
Doctor recommendation was by far the most influential factor in supplement selection. When a doctor recommended a supplement, older adults were significantly more likely to choose it compared to supplements without a recommendation. This finding underscores the powerful role healthcare providers play in shaping supplement use among older adults.
Price was the second most important factor. As the monthly cost of supplements increased, the likelihood that older adults would choose them decreased substantially. This suggests that cost sensitivity is a major barrier to supplement use in this age group, even when other features are attractive.
The form of the supplement (how it’s packaged and taken) was also important. Participants showed preferences for certain forms over others, though the study didn’t specify which forms were most preferred. Ingredient composition mattered too—vitamin and mineral combinations were chosen more often than herbal-only supplements, suggesting older adults perceive vitamin-mineral products as more trustworthy or effective.
Country of manufacture influenced choices as well. Supplements made by foreign-licensed manufacturers were preferred over domestically-produced supplements. This may reflect perceptions about quality control, regulation, or brand reputation associated with international products.
Interestingly, demographic and socioeconomic factors—such as age, gender, income level, and education—did not significantly influence supplement choices. This means that whether someone was wealthy or had more education didn’t change what kind of supplements they preferred. This finding is important because it suggests that supplement preferences among older adults are driven more by practical factors (cost, doctor advice, product form) than by personal background characteristics.
Previous research has shown that healthcare provider recommendations are important for medication adherence in older adults, and this study confirms that principle extends to dietary supplements. The finding about cost sensitivity aligns with other research showing that older adults on fixed incomes are price-conscious consumers. However, this is one of the first studies to systematically examine multiple factors simultaneously using a choice experiment method, providing a more complete picture than previous surveys that asked about preferences separately.
The study was conducted only in Iran, so findings may not apply to older adults in other countries with different healthcare systems, cultures, and regulatory environments. The research measured stated preferences (what people say they’d choose) rather than actual purchasing behavior, so there may be differences between what participants indicated and what they actually buy. The study didn’t explore why certain factors matter—for example, why foreign products were preferred over domestic ones. Additionally, the study didn’t account for individual health conditions or specific supplement needs that might influence real-world choices.
The Bottom Line
If you’re an older adult considering supplements, consult your doctor first—their recommendation is the strongest predictor of good supplement choices. Compare prices and choose options that fit your budget, as cost is a major factor in supplement selection. Prefer vitamin-mineral combinations over herbal-only products, as these appear to be more trusted by older adults. Be aware that country of origin influences perceptions of quality, but focus on whether a product is regulated and recommended by your healthcare provider rather than origin alone. These recommendations are supported by strong evidence from this 384-person study.
Older adults (65+) considering dietary supplements should pay special attention to these findings, particularly the importance of doctor consultation. Healthcare providers caring for older adults should recognize their significant influence on supplement choices and use this opportunity to guide patients toward safe, effective options. Supplement manufacturers should note that older adults prioritize doctor recommendations and are price-sensitive, so marketing strategies should emphasize healthcare provider endorsements and competitive pricing. Policymakers can use these insights to develop regulations and education programs that align with older adults’ actual decision-making processes.
Changes in supplement selection based on these factors can happen immediately—once you consult your doctor and receive a recommendation, you can adjust your choices right away. However, seeing health benefits from supplements typically takes weeks to months, depending on the specific supplement and your health condition. Cost savings from choosing more affordable options would be noticeable within the first month of purchasing.
Frequently Asked Questions
What’s the most important thing older adults consider when choosing supplements?
Doctor recommendations are the strongest influence on supplement choices among older adults, according to a 2026 study of 384 participants. Healthcare provider endorsement significantly increased the likelihood of supplement selection compared to other factors.
Does price affect whether older adults buy supplements?
Yes, significantly. A 2026 study of 384 older adults found that higher monthly costs substantially reduced supplement selection likelihood, showing strong price sensitivity in this age group. Cost was the second most influential factor after doctor recommendations.
Are vitamin supplements or herbal supplements more popular with older adults?
Vitamin-mineral combination supplements were preferred over herbal-only products among 384 older adults studied in 2026. This suggests older adults perceive formulated vitamin-mineral combinations as more trustworthy or effective than herbal-only options.
Does where a supplement is made matter to older adults?
Yes, according to a 2026 study of 384 older adults, foreign-licensed supplements were favored over domestically-produced ones. Country of manufacture influenced perceived quality, though doctor recommendation remained the strongest overall factor.
Do wealthier older adults choose different supplements than poorer ones?
No, a 2026 study of 384 older adults found that income level and education didn’t significantly affect supplement preferences. Practical factors like doctor recommendations and price mattered more than socioeconomic background.
Want to Apply This Research?
- Track which supplements you’re taking, their monthly cost, and whether your doctor recommended each one. Rate your satisfaction with each supplement monthly to see if doctor-recommended options work better for you than self-selected ones.
- Use the app to log a conversation with your doctor about supplements before making new purchases. Set a monthly budget for supplements and track actual spending against it. Create a list of doctor-recommended supplements to reference when shopping.
- Monitor your supplement adherence (whether you take them as planned) separately for doctor-recommended versus self-selected supplements. Track any health changes or side effects by supplement. Review your supplement list quarterly with your doctor to ensure choices still align with your health needs and budget.
This research describes preferences and choices among older adults in Iran and may not apply equally to other populations or healthcare systems. These findings should not replace consultation with your healthcare provider. Before starting any new supplement, discuss it with your doctor, especially if you take medications or have existing health conditions, as supplements can interact with medications and may not be appropriate for everyone. This study measured stated preferences rather than actual health outcomes, so supplement selection based on these factors should still be guided by medical advice tailored to your individual health needs.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.