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What is the Difference Between Medical-Grade Supplements and Over-the-Counter Supplements?

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What is the Difference Between Medical-Grade Supplements and Over-the-Counter Supplements?

The dietary supplement industry is a booming one within the healthcare field. According to the 2021 CRN Consumer Survey on Dietary Supplements, 80% of U.S. adults take dietary supplements to improve energy, support the immune system, fill nutrient gaps, encourage healthy aging, and prevent heart disease. The most commonly purchased dietary supplements include multivitamins, vitamin D, and vitamin C. (7)

Dietary supplements cannot be marketed for the treatment and prevention of disease, but they are often taken to address symptoms and improve overall health and function. The safety of dietary supplements is a valid concern, with one study estimating an average of 23,000 emergency department visits resulting annually from supplement usage. Dietary supplements can be safe and effective interventions to achieve health goals, but they must be thoughtfully purchased and appropriately administered. Functional medicine doctors are knowledgeable about the safety and usage of medical-grade dietary supplements.


What is a Dietary Supplement?

Dietary supplements are health products intended to supplement the diet to provide a health benefit. Common supplements include vitamins, minerals, botanical herbs and compounds, amino acids, and probiotics. (1)

Dietary supplements are defined by the Dietary Supplement Health and Education Act (DSHEA) of 1994. To qualify as a dietary supplement, a product must meet the following criteria:

  • Intended to supplement the diet
  • Intended to take orally as a pill, capsule, tablet, liquid, powder, etc.
  • Contains one or more dietary ingredients, including vitamins and minerals; herbs and other botanicals; amino acids; "dietary substances" that are part of the food supply, such as enzymes and probiotics; and concentrates, metabolites, constituents, extracts, or combinations of any dietary ingredient
  • Labeled as a dietary supplement

Efficacy of Dietary Supplements

Dietary supplements can help you to achieve and maintain optimal health by helping to meet daily requirements for essential nutrients, supporting natural body functions, and acting as alternatives to pharmaceutical medications to achieve health goals. It should be remembered that dietary supplements are most effective when they supplement, not replace, a healthy whole-food diet and lifestyle practices. A dietary supplement must be administered at a safe and therapeutic dose for its intended purpose to be effective. (2)

There are a vast number of dietary supplement options on the market. The benefits of some supplements are well established, while there is no or mixed evidence to support the use of others. Examples of strongly backed, safe, and effective dietary supplements include folic acid to prevent birth defects, curcumin to decrease inflammation, vitamin D in the treatment of osteoporosis, omega-3 fatty acids to support heart health, and lavender to reduce anxiety.

Risks Associated with Dietary Supplements

Like all medications, dietary supplements are associated with potential health risks if not taken appropriately. You are most likely to have side effects from dietary supplements if taken at high doses or combined with multiple other supplements or prescribed medications. Discussing the safety and need for a supplement with your doctor before taking it is always recommended. (2)

Poor quality supplements pose serious health risks. Because of this, the FDA has established current good manufacturing practices (cGMPs), a framework to control dietary supplement production, that companies must adhere to to ensure the purity and composition of dietary supplements. Unfortunately, not all companies comply with these regulations, which is largely why dietary supplement safety is a concern. Between October 2018 and September 2019, the FDA audited 598 dietary supplement companies globally. 52% of American and 42% of international companies received GMP non-compliance letters. Manufacturing compliance issues include ingredient safety, adulteration of ingredients, the number of listed ingredients, failure to test products appropriately, and failure to keep adequate/accurate testing records. (2, 3)

Dietary supplements most commonly linked to health and safety concerns include those marketed for sexual enhancement, weight loss, and muscle building. These supplements have the highest risk for ingredient adulteration with one or more unapproved ingredients. (4)

Patients experiencing an adverse reaction from a dietary supplement should contact their healthcare provider. Adverse events, including serious side effects, hospitalizations, birth defects, and death, due to a dietary supplement should be reported to the FDA. Consumers can directly report their experiences to the FDA by contacting their local Consumer Complaint Coordinator or completing this online form.

What is the Difference Between Medical-Grade Supplements and Over-the-Counter Supplements?

Although the FDA regulates dietary supplements, the FDA is not authorized to review and approve them for safety and effectiveness before they are available to the market. This means that not all supplements are created equal and that many over-the-counter supplements may not contain what they claim on the label. Medical-grade supplements are high-quality supplements distinguished by the strict safety standards their manufacturers have in place, including adherence to cGMPs, third-party certification, routine supplement testing, and transparency of company audits.

cGMPs are FDA guidelines developed to establish consistent, safe, and quality supplement manufacturing. To adhere to cGMPs, manufacturers must meet standards regarding the location, people, processes, and products involved in the manufacturing process of dietary supplements. Medical-grade supplement manufacturers follow cGMPs, ensuring supplements do not contain unsafe ingredients, are produced without contamination, are packaged safely, and are labeled accurately. (5)

Medical-grade supplement companies routinely test and audit their products and production lineup to confirm the supplements contain nothing more or less than what is printed on the nutritional label and that company practices remain in accordance with federal regulations.

Third-party certification companies are independent programs that inspect and test manufacturing sites, materials, and goods to provide unbiased verification of dietary supplements' quality and label claims. A third-party certification seal on a product indicates that it has passed that company's standards; it is another checkpoint that helps guarantee the exclusion of unsafe ingredients in supplemental formulas and accurate supplement labeling. (6)

Functional Medicine Labs That Can Help Determine the Appropriate Dietary Supplements For You

Functional medicine labs act as tools to screen for health imbalances and disease processes, indicating the need for medical interventions. Dietary supplements are one such medical intervention that functional medicine providers often include as part of their treatment protocols. The decision to order functional medicine labs will depend on the patient's health history, physical exam, and health goals. Below are routinely ordered labs by functional medicine doctors that can help personalize treatment and supplement recommendations.

General Health Screening

Annual lab work can provide a great deal of information on health status and body system function. A complete blood count (CBC), comprehensive metabolic panel (CMP), thyroid panel, iron panel, and hemoglobin A1c (HbA1c) are standard labs recommended annually for the healthy population. Results outside of functional and standard reference ranges may indicate the need for supplemental support in addition to lifestyle modifications.

Nutritional Assessment

A functional and comprehensive nutritional assessment can be ordered for healthy patients looking to optimize health, enhance performance, and prevent disease or for symptomatic patients with health conditions that increase the risk of nutrient deficiencies. Organic acid and micronutrient panels measure essential nutrients and their metabolic byproducts to directly and functionally assess for deficiencies. Results can guide appropriate supplemental recommendations per the cellular needs of the body.

Comprehensive Stool Analysis

Functional medicine providers are notorious for looking to gut health for the underlying reasons of health concerns. A comprehensive stool test can screen for gastrointestinal (GI) imbalances contributing to maldigestion, malabsorption, and nutrient deficiencies. This type of test measures many biomarkers related to GI tract health and function. The results can clarify the reasoning behind malabsorption or other extraintestinal signs, symptoms, and health conditions. Comprehensive stool analysis, therefore, is a valuable tool for creating holistic treatment plans.



With so many available supplements being marketed as safe, natural alternatives to their pharmaceutical counterparts, it can feel overwhelming to know what you should or shouldn't be taking to support overall health. Choosing high-quality supplements is essential to safe, effective medicine because FDA dietary supplement regulations differ from over-the-counter and prescription drugs. When looking for a high-quality supplement, you should ask yourself the following questions: does the manufacturer adhere to cGMPs, is the supplement third-party certified, and does the manufacturer provide the results of routine testing of their products?

Because functional medicine doctors routinely rely on dietary supplements as an integral aspect of their treatment protocols, they are well-informed in dietary supplement safety. Consult with your functional medicine doctor to discuss if you should be taking a dietary supplement, which brand to buy, and how to take it for best health outcomes.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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Lab Tests in This Article

1. FDA. (2022, June 2). FDA 101: Dietary Supplements. U.S. Food And Drug Administration.

2. National Institutes of Health. (2023, January 4). Dietary Supplements: What You Need to Know. Office of Dietary Supplements.

3. Postmarketing Drug Safety Compliance: 2019 Inspection Findings. (2020, April 29). U.S. Food And Drug Administration.

4. Tucker, J., Fischer, T., Upjohn, L., et al. (2018). Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With US Food and Drug Administration Warnings. JAMA Network Open, 1(6), e183337.

5. What is GMP? International Society for Pharmaceutical Engineering.

6. Dan, L. (2023, February 27). What You Need to Know About Third-party Certification Supplements. Fullscript.

7. 2019 CRN Consumer Survey on Dietary Supplements. Council for Responsible Nutrition.

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