Proprietary blends hide individual ingredient doses. Why they exist, what they conceal and why WellnessChecked considers them a negative quality signal in every review.
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A proprietary blend is a combination of ingredients listed under a single group dose without disclosing individual amounts. That makes it impossible to tell whether each ingredient is present at the dose used in research, and it lets a label list popular ingredients at amounts too small to matter. We treat undisclosed doses as a negative in our reviews.
A supplement label might show: 'Testosterone Support Matrix 750mg: KSM-66 Ashwagandha, Fenugreek Seed Extract, Zinc, Vitamin D3'. You know the combined amount is 750mg — but not how much of each ingredient is present. If the product includes 600mg of ashwagandha (the upper end of the daily amount used in KSM-66 trials), there is only 150mg left for three other ingredients. If it includes 50mg of ashwagandha, there is 700mg for the others.
The stated reason is often 'protecting the formula', and a fully disclosed formula is easy to copy. But a blend also allows popular ingredients to be included at very small amounts without the buyer being able to tell. A transparent label from a confident manufacturer should show every individual ingredient amount.
If you cannot calculate whether each ingredient in a supplement is present at its clinical dose — because the amounts are hidden in a proprietary blend — you cannot judge whether it is likely to work. This is the fundamental problem with proprietary blends.