How to Know if a Supplement is Worth Taking

Devin's Supplement Guide: Part 1 of 2

There are few things in fitness & nutrition more confusing than supplements. Everybody has an angle, the marketing is compelling, and it’s hard to separate real science from “bro-science”. The FDA does not regulate supplements in the US, meaning that it’s up to you to determine if a supplement is worth it or not.

Fret not, as I’ve spent dozens of hours researching supplements. This includes university coursework, research papers, reading textbooks & studies, and even researching individual ingredients. Even with all of that, sometimes it takes me a little while to determine if a supplement is worth the money.

I’m going to explain how I judge supplements and pick the best brands. I’ll talk about two great free resources for researching supplements. I’ll share my biggest red flag when it comes to evaluating supplements.

And in part 2, I’ll make my recommendations for 5 supplements for general health & fitness.

To start, there are two resources that have made supplement research far simpler.

How to Determine if a Supplement is Worth Taking

Simply put, I don’t trust anecdotal evidence (personal stories) and I don’t trust people selling Multilevel Marketing (MLM) products. MLM products are sometimes high quality, but I’d rather not pay the markup on commission.

What counts for me and my clients is cold, hard science. Luckily, there are two websites that make the science a lot easier to figure out.

1 – Labdoor (

Labdoor analyzes the content, quality, and purity of many of the most popular supplements out there. They use a FDA-registered laboratory to study each supplement. They started with fish oil and protein powder, but have expanded to cover reviews of 20 supplement types, to include: probiotics, pre-workout mixes, creatine, CoQ10, and more.

Their listings are free. You can pay to read the full analysis, but that isn’t necessary if you’re not into the nitty gritty of supplement science. The listings can be sorted by best value and by best quality.

They’ve reviewed most of the big brands, including GNC, Shakeology, Spectrum, Vega, Optimum Gold Standard, and more. Their protein ranking lists 77 brands!

They rank brands by label accuracy, product purity, nutritional value, ingredient safety, and projected efficacy. It’s a great, unbiased way to get the real story on a supplement.

Note: Labdoor makes money as a business through affiliate links when you clickthrough to buy a supplement off of their site. They’re upfront and transparent about it. (I also use affiliate links to gain commission off of brands that I recommend, same as every blogger out there).

This may limit the number of brands ranked, as they don’t seem to list brands that they can’t sell as an affiliate. But I can’t complain, as it’s still a great service with free lab testing.

2 – Examine (

Do you want to know exactly how much Vitamin C to take?

Or what the best dosage of fish oil is, and when to take it?

Do you want to find out if “raspberry ketones” really work (or if Dr. Oz is just full of it)? is where you find out. They have over 50,000 references to studies. They also have a great nutrition FAQ. Their free stack guides are still available, if a little outdated. Stacks are a combination of supplements for a specific purpose, for example, joint health. Their membership is well worth it if you’re really curious.

(Examine does offer a free 5 day supplement course at their website)

“ is an independent encyclopedia on supplementation and nutrition. We are not affiliated in any way with any supplement company and we have a team of health professionals analyzing the full body of research. is an unbiased nutrition and supplement resource. We are not influenced by commercial interests, product manufacturers, or any other organization, and we will not advertise products or brands. does not accept donations, third-party funding, or sponsorship of any kind. One hundred percent of our revenue is generated through our three products: the Research Digest, Supplement-Goals Reference, and the Supplement Stack Guides.”

I use Examine to determine if a supplement has the right amounts of each ingredient. For example, a supplement might only contain 50mg of Green Tea Extract when the recommended dosage is 200mg, 3 times a day.

How to Know if a Supplement is Safe

Another key issue is supplement safety. Labdoor does a great job, but they haven’t reviewed every brand. There are many excellent brands that they simply haven’t been able to analyze yet.

In general, I look for 2 certifications.

1 – GMP – Good Manufacturing Practices

GMP certification or a label stating that it was manufactured in a GMP-compliant facility. GMP certification can be expensive, and so many generics will label that the product was made in a GMP-compliant facility to save expense on their budget brands

GMP ensures general safety from contamination as well as product consistency.

It is not the same as a laboratory analysis of ingredient quality, purity, or amount. It simply means that there isn’t contamination from other products. For example, you wouldn’t want a multivitamin that was made in a sloppy lab that also produces hormone pills.

2 – NSF Certified for Sport

NSF certified supplements are safe to be taken at the highest levels of sport. This is why I roll my eyes – hard – when a UFC fighter blames a failed PED test on their supplements. Any athlete taking only supplements that are NSF Certified for Sport won’t fail a PED test.

They also certify for clean manufacturing and ingredient verification. Not all supplements need to be NSF Certified. In general, I look for NSF certifications for performance supplements and for use by athletes. I do prefer to recommend companies that have at least one supplement with NSF certification, as it implies a rigorous production process.

NSF also certifies for content, meaning that the ingredients on the label are guaranteed to be in the bottle. You may remember that in 2015, the New York Attorney General issued cease and desist letters to Walmart, GNC, Target, and Walgreens for selling supplements that did not contain their stated ingredients. NSF certification prevents this from occurring.

Supplement Red Flag

Many supplement companies will trick you by not listing how much of each ingredient you actually receive.

For example, Juice Plus includes Bromelain, a potent anti-inflammatory, but does NOT disclose how much Bromelain is in its product. Therefore, there is no way to know if it’s an effective dose without there being clinical studies on the proprietary blend itself for the specified outcome.

I do not recommend taking supplements that don’t disclose the amounts of the majority of ingredients.

For example, Juice Plus lists a number of effective ingredients (bromelain, papain, Lactobacilus acidophilus, lycopene) on their label:
Notice how the ingredients, even common ones like lycopene, aren't disclosed

However, the exact amounts of effective ingredients are not disclosed! There is no way to know if an effective dosage is being given, or if you’re being charged for 1mg of product when 500mg is necessary to see a benefit. Without transparency, it’s difficult to recommend a product.

As another example, THRIVE M uses similarly tricky labeling.

The proprietary blend is 526mg. However, an effective dose of glucosamine, a supplement for joint health, is 300-500mg taken 3 times per day, according to The blend includes probiotics. often measured in billions per unit, but the probiotic count is not mentioned at all here. It includes caffeine in an unknown amount, and glutamine – which is usually dosed at 5 grams (5000mg) or more. You could be paying out the nose for common caffeine.

Compare this to Greens + “Advanced Multi Wild Berry”, a superfood blend that I recommend to clients that don’t eat enough fruits & veggies. It uses blends but lists out every ingredient and its amounts. It includes probiotics, but states the total amount (2.5 billion):

This article ended up being longer than I expected! Keep an eye out for Part 2, which will include the top supplements and trusted brands that I recommend to my clients.

Do you have supplement questions?

E-mail me at and I’ll get back to you with my thoughts.

I might even turn the answer into a full article!

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-Devin Gray, CSCS

Devin Gray

Devin Gray

Personal Trainer and Nutrition Coach


NSCA-CSCS, FMSC, Pn1 Certified
B.S. in Exercise Science – Texas A&M University, Cum Laude

Devin is the owner & head coach of Optimize Fitness & Performance. He is an exercise geek, with a long list of certifications and coursework for personal training, nutrition coaching, and injury post-rehabilitation. In his personal workouts, Devin combines gymnastics drills, free weights, and kettlebell exercises to stay fit.

You can e-mail Devin at



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