I had to see what the fuss was about with Torriden Dive-In, so I used it for a while and wrote it up. The thing I kept coming back to wasn't really the serum. It was what went on top of it.
Do you need a moisturiser over a hyaluronic acid serum?
Yes, I'd always put one on. A hyaluronic acid serum pulls water into the top layers of your skin, and a moisturiser over it helps hold that water there. Without the last step, a watery serum can leave dry skin feeling tight and a bit unfinished.
That's exactly how Dive-In felt on me. It's a light, watery gel with five types of hyaluronic acid plus panthenol, and on my dry days it felt like half a routine on its own. With a cream on top, my skin looked a little plumper and felt comfier, which is why it got 4/5 in my Torriden Dive-In serum review.
What to put on top
It depends on your skin. If you're oily, a light gel cream is plenty. If you're dry or your barrier is struggling, go richer. At night, a thick ceramide cream like Aestura Atobarrier 365 Cream (the one I reach for on dry nights) seals everything in.
My order is toner, then the serum, then the moisturiser. Dive-In sinks in fast with no sticky film, so there's no waiting around, and it doesn't pill under the next step.
If you have seb derm or fungal acne
Check both lists before you stack them. SkinSort flags one ingredient in Dive-In (30th of 36, so a tiny amount) and eight in the Aestura cream, most of them fatty acids and esters. I've got seb derm, so I'd keep that cream off my face. You can paste any ingredient list into my fungal acne and seb derm ingredient checker and see the flags yourself.
The full Torriden write-up covers who it suits, who should skip it and where to buy it.