Can I use this hyaluronic acid day créme under makeup, and will it work as a primer base?

Yes, and it performs very well in that role. The lightweight, fast-absorbing texture creates a smooth, hydrated surface that helps makeup apply more evenly and adhere better throughout the day. Apply it as the final skincare step after any serums, allow one to two minutes for full absorption, and then apply sunscreen and makeup as usual. Users in dry climates find it particularly effective at maintaining that smooth base through the day without settling into fine lines or looking dry under foundation. It can also be worn alone on low-makeup days as a standalone daytime moisturizer.