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Evaluating Nutritional Supplements

The world of nutritional supplements is a lot like the old wild west, with minimal regulations. In fact, prior to hitting the shelves, there are not technically any specific qualifications a supplement needs to meet.

This means that the products could contain unwanted substances (or sometimes even banned ingredients for NCAA and professional athletes). There could also be changes in the amounts of specific ingredients — which could affect the supplement’s desired outcome or how much it affects your body. This has actually been demonstrated in a research study looking at pre-workout supplements. The study demonstrated that the supplements they tested actually contained a different amount of caffeine from what was listed on the supplement panel (more or less). Some of the supplements even contained banned stimulants1,2.


When you are purchasing a nutritional supplement, you should ask yourself 4 questions:


1.) Is it safe?

2.) Is it effective?

3.) Is it worth it? (Can you afford it?)

4.) Is it legal?


And when you are asking yourself those 4 questions, be on alert for these 3 major red flags to help evaluate the nutritional supplement:


Proprietary blends

These are a company’s signature group of ingredients — sometimes they use a fancy trademark name too. This is a red flag because they do not tell you the specific amount of each ingredient in the product and/or if it is present at all! Additionally, this is an area where a company can slip in banned substances. For example, a company could have a branded blend called “CNS Muscle Excite Pump” (this is a made up name). The label would show that the supplement contains 2247 mg of “CNS Muscle Excite Pump” with the listed ingredients of L-Citrulline, Caffeine, Arginine, Beta Alanine, and HMB, (but the measurements of those specific ingredients would not be listed).


Herbal Ingredients

This can also be an area of concern as herbal ingredients may be at a higher risk for contamination (depending which country they are coming from). Another thing to consider is that herbal ingredients have minimal research to support their use and can often interact with medications and other foods.


No third-party evaluation

If the label does not show evidence that the product has been evaluated by a third-party organization, then it hasn’t been evaluated. This is like a co-worker saying they are in attendance while on a zoom call but will not make themselves visible (hint, hint — they’re not there). Each organization that evaluates supplements looks at different aspects of the supplements’ quality. Here are 3 examples of these third-party organizations:

informed choice, we test, you trust logo

Informed Choice — tests to ensure there are no banned substances.

USP logo, dietary supplement verified

USP — confirms that the label is accurate regarding the ingredients in the product.

NSF certified sport

NSF — confirms that there are no banned substances and checks for label accuracy.


It should be noted that just because one product from a supplement company is evaluated by a third party, it does NOT mean that all products from the company meet the regulation criteria. The certification must be on the product AND be visible on the company’s website to ensure that all products are safe. Additionally, if a company produces a product that contains a banned substance, and there’s been no third-party evaluation, there is a high risk of contamination to other products.


In conclusion, a product with a laundry list of benefits certainly seems appealing, but it could be giving false hope for the athlete. If you want to take nutritional supplements, working with a Sports Dietitian is the best way to accurately navigate the effectiveness of supplement claims and safety.




Desbrow, B, Hall, S, O’Connor, H, Slater, G, Barnes, K, Grant, G. Caffeine content of pre-workout supplements commonly used by Australian consumers. Drug Test Anal. 2019; 11: 523– 529. https://doi.org/10.1002/dta.2501

da Costa BRB, El Haddad LP, Freitas BT, Marinho PA, De Martinis BS. Pre-workout supplements marketed in Brazil: Caffeine quantification and caffeine daily intake assessment. Drug Test Anal. 2021 Apr 9. doi: 10.1002/dta.3043. Epub ahead of print. PMID: 33835708.