How much omega-3 is in fish oil supplements?

We analyzed the available evidence on omega-3 content in fish oil supplements and found that the amount varies widely between products. Some supplements contain as little as 33% omega-3 fatty acids by weight, while others have as much as 79% [1]. This means the concentration of omega-3s isn’t the same across brands or even within the same brand over time. The variation comes from differences in how the oil is processed, what type of fish it’s sourced from, and whether additional ingredients are added. Because of this, you can’t assume one fish oil pill will give you the same amount of omega-3 as another, even if they look identical on the shelf. What we’ve found so far suggests that checking the label for specific omega-3 amounts — not just the total fish oil content — is important if you’re trying to get a certain dose. There’s no standard, and the product you choose could make a real difference in what you’re actually consuming.