This is the best HA serum I have used. Ive tried many brands, from cheap, inexpensive brands to $300 bottles of overpriced serums with underwhelming results. This product did not irritate my skin at all, and most of them slightly tingle (Osea does this). A tiny drop of this goes a very long way. Allow the serum to dry, and then follow with your favorite oil or moisturizer. Skin stays soft and hydrated all day. I have a very dry patch of skin on my cheek which seems to look a bit less wrinkly after using this for a few days. If you've tried them all, try this one. HIGHLY RECOMMEND. IT WORKS.