Price: "Buffet" is half the price of "Buffet" + Copper Peptides 1% pH level: "Buffet" ist 4.5-5.5 whereas "Buffet" + Copper Peptides 1% is 6.0-7.0 Aesthetics: "Buffet" is clear liquid serum, "Buffet" + Copper Peptides 1% has a blue tint. "Buffet" is not an oil-free formula, whereas "Buffet" + Copper Peptides 1% is oil-free. The Ordinary claims that the addition of Pure Copper Peptides further encourages collagen production, but I think jury is out on this. Personally I think regular "Buffet" suffices and does the job. Lastly, "Buffet" comes in 2 sizes (30ml and 60ml), whereas "Buffet" + Copper Peptides 1% only comes in 30ml size.