what'S the optimal epa dha ratio for omega 3

There isn’t a universally optimal EPA-to-DHA ratio. A suggested daily target is at least 1,000 mg EPA and about 300 mg DHA; one discussion also notes that roughly 300–400 mg of DHA alongside 1,000 mg EPA is reasonable. 1

• EPA and mood: At least 1,000 mg of EPA daily is described as a threshold that may help relieve depressive symptoms and support mood. 2
• DHA and attention: Around 300 mg of DHA daily is identified as an important threshold for attentional effects; EPA also matters, and sufficient EPA intake will usually provide at least that much DHA. 3