My partner says she loves this serum and has noticed a difference in about a month of using it.
Very small amount is needed and it seems to go a long way.
Thank god to be fair because the price of this is pretty astonishing. I don't know how they justify these kinds of prices but she says you can't argue with the results.

I've been using this Blue Lagoon serum morning and night for about 2.5 weeks now. Given how expensive it is, I wanted to try and give it a really good go to see if I could discern some miraculous reason for it being priced at £716.67 /100 ml (at the time of writing).
The positives: 
– It contains the powerhouse ingredients of hyaluronic acid and vitamin  C
– It comes in a dark tinted bottle with an integrated pipette which works well to dispense the recommended 4-5 drops
– There is no perceptible fragrance
– A little goes a long way – this bottle will last a while even with using 10 drops a day
– My skin felt softer and looked more hydrated and more fresh
– My skin did not have any sensitive reactions to this product
What I wasn't so keen on:
– It massages over skin easily, but doesn't absorb fully. Whilst it doesn't look shiny after application, there is definitely a residual tackiness which is annoying if applying further products like sunscreen and makeup (I really had to powder and blot!)
– The price! You're definitely paying a premium for the branding here.
In conclusion – if you have money to spend and want to try this out, you will probably appreciate the results. Personally, I feel that whilst my skin did look nicer, there is no way I could justify the hefty price tag!

Ok so let's start with thr price, yes its quite expensive but it is worth the money. I would heavily suggest thatyou pair this with a retinol to see results quicker. I kind you not the night after I added this within my routine my skin felt so much better. At first I was skeptical but then I saw the results and they do not lie. Again use with a retinol or some type of chemical exfoliate to see the best results.

I knew this was expensive and advertised as 30ml but nevertheless when received you see just how small the bottle is and how little you get for your money. I am however hoping that what little is there is packed full of goodness and I will see a difference over time. The listing says it works over time so I will have to take that at face value and persevere with it.
Some of the ingredients can be found in other products that perhaps offer better value but this one is formulated without a lot of the other additives you may find elsewhere. The instructions say 4-6 drops but I've found myself using 4, probably because I don't want to use more than needed given the cost so I'm making sure those 4 drops go far. It dries relatively quickly and applying a moisturiser afterwards is fine.
I haven't used anything similar before so only time will tell if it is effective or not and whether I notice a difference but fingers crossed. I went for 4 stars as I can at the moment only assume I will see the long term benefits it says but the cost is a bit off putting.