Nutritional Supplement Testing Standards

This topic of this page, nutritional supplement testing standards is actually a sub-topic page from my article Ingredient quality in supplements which deals with 'ingredient quality' as one of the key criteria that should be used to properly evaluate the true standard of supplements. 

That article lists several questions we need to ask of nutritional supplement companies in order to draw out often hidden information, allowing us to thoroughly evaluate competing supplement brands.

Some of those questions come from an examination of the content on this page. To view all the questions please use the link above.

Those that care and those that don't

Testing standards for supplements is a topic that interests me but probably not many other supplement users. I used to work in the industry for a supplement manufacturer so I know what goes on behind the scenes.

So the first fact you need to know is that there is a gap the size of Niagara Falls between the quality testing protocols of the supplement industry's best companies and then all the rest!

Contamination is a major concern for reputable nutritional supplement manufacturers!

The minority of supplement companies out there who can be classed as truly professional spend a lot more money to employ stringent testing protocols to ensure absolutely no contaminants end up in their supplements.

The marketplace is crowded with supplements produced by disreputable, poorly qualified and/or ineffective manufacturers who don’t give a damn about your safety!

These manufacturers only care about profit and getting the product to market as quickly and cheaply as possible. They take numerous ‘safety’ shortcuts to cut costs and this is primarily what opens the door for contaminants to enter the manufacturing process. 

“High levels of polychlorinated biphenyls (PCBs) have been identified in five brands of shark liver oil capsules that are available internationally over the counter”

High Levels of PCBs Found in Numerous Brands of Shark Oil Capsules – Medscape.

What a supplement website should tell you

The best nutritional supplement companies ensure that stringent testing is performed at various steps in the production cycle. Reputable companies with nothing to hide will include information on their websites about testing protocols for the following areas:

  • raw material farming

  • extract manufacturing

  • in-process manufacturing controls

  • finished product analysis


If you really want to dig down deep into the nitty gritty of a company’s testing specifications for the raw materials they purchase (or grow) - then request material testing information and look for specifications involving assessing, sampling, testing, cross checking and inspecting of the following factors:

  • Soil quality

  • irrigation water

  • weather

  • growing conditions

  • field rotation

  • storage

  • heavy metals

  • solvents

  • pesticide/chemical residues

  • microbiological analysis

  • potency of active ingredients

  • purity

  • appearance

  • texture

  • strength

  • consistency


Once raw ingredients arrive at a nutritional supplement company’s manufacturing plant more testing begins. 

Here’s a list of the most important routine tests that you want to see on a website!

The Quarantine Process (Pre Manufacture)

  • Full microbiological testing - includes total plate counts for bacteria, mould and yeast, coliforms, E-coli, Staph.aureus and Salmonella.

  • Potency testing, to confirm that the active ingredients are present in the amounts stated in the manufacturers COA (Certificate of Analysis).

  • Heavy metal testing. No contamination with Mercury, Lead, Arsenic or Cadmium.

Materials sensitive to room temperature must be stored in chillers at all times. 

The Tableting Process

Periodic tests - to ensure that weight, thickness and hardness are within specifications.

Finished Product Testing – Microbiological

Further microbial tests (see above) must be carried out to ensure that tablets have not picked up any contaminants during the manufacturing process. If this test is passed a COA is prepared for that batch and the product is released for bottling and labeling.

Finished Product Testing - Friability, Dissolution, Disintegration

Tablets must be tested for 

  • friability (tablet's resistance to breakage)

  • dissolution (tablet’s ability to dissolve) 

  • disintegration (the fragmentation and distribution of ingredients)

And lastly...

A reader emailed me recently to ask why supplement companies never publish finished product testing reports to confirm the correct amounts of all ingredients in a nutritional supplement. 

A very good question and here's the answer!

Only certain ingredients can be confirmed through testing for a finished multi nutrient supplement. This is because in order to do the test the tablet must be liquefied but as soon as this happens the ingredients start to react with one another. 

This causes changes in the structure /weight of certain ingredients and in some cases new substances are created so it becomes impossible to measure each and every ingredient.

The only way to confirm all ingredients are present, in the correct quantities, is through the validation of the protocols followed during the manufacturing process. There must be at least two people independently signing off for each ingredient added.

So that’s all we need to discuss on this topic. If you want to check on the tests performed on the nutritional supplement you use, to ensure its quality, check the company website first. If the information is not there then email them and request a list of their tests. If they won’t answer you they’re hiding something - CHANGE BRANDS !

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