Should you use niacinamide with hyaluronic acid and vitamin C?

In theory, yes, all three are excellent skincare ingredients. But the problem, as with so many ingredients that do well in studies carried out in a lab, is how to get the ingredients in to the right layer of the skin, in a beneficial concentration, for long enough to do some good. Skin contains all three of these and they all play a part in keeping skin healthy. The difficulty that faces formulators is how to get them where they need to be. If you are particularly interested in how this happens, Fick’s Law of Diffusion is where we start - below if you really want to know… These all tend to start in watery environments (vitamin C comes in several forms now, but l-ascorbic acid is the most common and has been tested most thoroughly). The water makes it reasonably simple to get it into a product and onto your skin. It’s the next bit that proves tricky… in order for it to be absorbed deeper, the ‘active’ needs to get there in as concentrated a form as possible - so if it is in something that will evaporate quickly on the skin, like water or alcohol, the active must be in a reasonable concentration. Whatever it is, it will need to get into the natural lipids that surround each skin cell. They form a protective layer and tend to be more hydrophilic. There has been a very nice study conducted by Dr Majella Lane recently on the optimal delivery of both niacinamide and an l-ascorbic acid ester. In brief, she demonstrated that both work better when in a carefully combined solution of two or three vehicles. It wasn’t an exhaustive trial, but she found the vitamin C ester was absorbed best (deepest), in a combination of propylene glycol, propylene glycol myristate and hexelene glycol with fatty acid esters. This allows the vitamin to be absorbed into the skin lipids successfully. Niacinamide worked best in a solution of propylene glycol and a combination of linoleic and oleic fatty acids (these are found in a variety of fruit and nut oils). Hyaluronic acid tends to be a large molecule and there is research to suggest that it is actually more useful sitting on the top of the skin if it is mixed with the smaller molecule, sodium hyaluronate, which can penetrate deeper (whenever I put hyaluronic acid in a formulation, I also add the salt, sodium hyaluronate to take care of this) - the moisture is then delivered both superficially and more deeply. This is an additional stage to optimise delivery to those detailed here for niacinamide and vitamin C. So - the vitamin must be protected and stable before it gets to your skin and must be formulated with ingredients that evaporate at skin temperature, leaving a maximum amount of the vitamin behind. They should also be in a combination of hydrophilic and lipophilic solutions that allow it to be optimally absorbed into the lipids in order to get down to a layer where the body can use it effectively.

Just incase you were wondering…

Fick’s Law (Adolf Fick - 1829 - 1901)

He was a German physiologist, from Kassel, who came up with a principle in physics and physiology that describes the diffusion of particles through a particular medium.

The general form of Fick's law is as follows:

J = -D * (∂C/∂x)

where:

J represents the diffusion flux, which is the amount of particles diffusing per unit area per unit time.

D is the diffusion coefficient, which is a property of the material through which diffusion occurs and is related to the mobility of the particles.

∂C/∂x is the concentration gradient, representing the rate of change of concentration with respect to distance.

This equation states that the diffusion flux is proportional to the concentration gradient and is inversely proportional to the diffusion coefficient.

Simply - the diffusion rate is higher when the gradient of the concentration is steeper and the diffusion coefficient larger.