“Proprietary blend” shows up on a lot of supplement labels. It sounds official, but it also means something specific — and something specific is missing.
A proprietary blend label names every ingredient included, listed in descending order by weight. What it doesn't disclose is how much of each individual ingredient is in the blend.
Without individual doses, you can't directly compare a product's potency to the amounts used in published research on any single ingredient. The blend could be mostly one cheaper ingredient with smaller amounts of the rest.
If dose transparency is a dealbreaker for you, a proprietary blend is a real limitation worth factoring in. If you're comfortable evaluating a formula by your own experience and a strong refund policy, it's a more manageable trade-off.