Using Niacinamide in an acidic formulation
I have been having an interesting discussion with one of my clients this week about formulations containing Niacinamide and AHA’s. Niacinamide is also known as Vitamin B3 and it is a great skin care ingredient as it has scientific evidence behind it to back up claims ranging from improving skin tone and down-regulating sebum production to acne control and barrier repair. I use it quite a bit in my skin care formulations. While Niacinamide is very stable it can break down when it is in extreme acid or alkaline environments. In fact it breaks down to release Ammonia (NH3) which is a rather stinky gas that you wouldn’t want tainting your skin care formulations, leaving Niacin behind. Niacin is also a member of the Vitamin B3 family but unlike Niacinamide which is usually (and I say USUALLY and not always) well tolerated, Niacin can cause facial flushing which isn’t something many people want from an ingredient. Because of this Niacinamide + Acid = Niacin (and facial flushing) THING many people have decided that Niacinamide and AHA’s can’t play together which is a shame as it probably isn’t true!
There haven’t been that many studies into the stability of Niacinamide over various pH’s but one study I did find looked at this very thing by heating up Niacinamide solutions with acid and measuring what happened – how much Niacin was produced. The conversion from Niacinamide to Niacin is called NON ENZYMATIC HYDROLYSIS. Basically that means splitting a molecule up to release water without using a biological enzyme to cleave the molecule. This type of hydrolysis reaction is quite common in organic chemistry.
The paper that I am referring to is called “Rate Studies on the Hydrolysis of Niacinamide” and they were using hydrochloric acid to perform the experiment in the acid region (which is all we care about here). This is a significant detail as hydrochloric acid is a strong acid whereas AHA’s are weak acids. Acid strength is not just about how much you put in a formula – 10%, 20%, 2% etc – it is also about how readily the acid let’s go of its hydrogen ion – its dissociation constant. Strong acids completely dissociate in water meaning that even at low % concentrations the acid is quite potent. Weak acids have only a tiny part of themselves raring to go meaning that even at high concentrations they won’t be quite so aggressive. The above study found that a 10% Niacinamide solution heated to around 89C and then taken to a pH of below 4.5 with a STRONG acid did start to hydrolyse and form Niacin and that this conversion was a first order reaction which basically means it went from Niacinamide to Niacin without turning into anything else first. The study found that between pH 4.5-6 very little of this crazy game of shape shifting occurred. In fact at pH 4.5 – 6 the half-life of the solution was found to be 1000 days which probably means that the average cosmetic formulator has little to worry about.
I’ve noticed several blogs and web-based publications cautioning people about using Niacinamide with Acids because of this hydrolysis reaction and even noted that the manufacturer technical data sheet includes the warning about pH too which was interesting as it seems like many people have taken a quick look at the above paper (which was written in 1962 and is available to read online for just $6 US) and jumped to the conclusion that acids and Niacinamide don’t go. To that I’d say ‘it pays to be fascinated, to really try to understand what is being said and to think wider and deeper than what is in front of you’.
That said it doesn’t mean that a formula containing Niacinamide and AHA’s will suit everybody.
Niacinamide may well be a darling ingredient but several in-vivo studies have reported skin reactions from itching to burning from simple serums using the ingredient (one study recorded negative outcomes for 4 out of 38 trial members. That is 10% which is highly significant although the study reported this as ‘minor’ as the dermatological review at the end of the study found that the negative outcomes were temporary and not serious (not likely to cause allergic reactions or ongoing discomfort or damage). This particular study used 4% Niacinamide.
So if a relatively simple Niacinamide formula can cause a burning or tingling sensation in some people it stands to reason that a formula containing AHA’s and Niacinamide could do the same given that some people are just sensitive to AHA formulations without adding anything else in.
But if we step back for a moment and think about this don’t many things that work cause a little irritation at times? AHA’s, Retinol products, High strength Vitamin C products and now Niacinamide serums and creams?
It also pays to step back and review what we are trying to do here. Niacinamide has many anti-ageing benefits as well as benefits for acne prone skin and ditto AHA’s although they tackle the problems in a different way. Most high-tech cosmaceuticals use a bevy of complimentary ingredients to ensure the product delivers results and so it is easy to see why combining these two actives sounds attractive especially when targeting premature ageing or acne – both of which require more than one dysfunction to be addressed. What this does highlight for me is the need to use these high-strength, multi-faceted active-skincare products under guidance from a trained professional who can monitor how the skin reacts to treatment and modify the treatment regimen accordingly.
The bottom line from me is that I feel it is unlikely that non-enzymatic hydrolysis will occur under when Niacinamide and AHA’s are used together in a typical cosmetic formulation. I feel that anyone using AHA’s in their formulations needs to be mindful of their power and needs to have a good grasp on the safety and chemistry of their products before they go to market and ditto for people using other highly potent cosmetic actives such as Niacinamide and Retinol.