Guide 4 min read
Can you use vitamin C and niacinamide together?
Yes. The warning that vitamin C and niacinamide cancel each other out comes from test-tube chemistry, not from skin. Both have human trial data on their own: 5% niacinamide improved fine lines, spots and blotchiness in a 12-week split-face trial of 50 women (Dermatologic Surgery, 2005). Apply the vitamin C first, wait a minute, then the niacinamide.
Where did the warning come from?
Two places, neither of them a skin trial. The first is solution chemistry: in water, with heat, ascorbic acid and niacinamide can interact, which is a fact about a beaker and not about a face. The second is flushing. Low-grade niacinamide can carry traces of nicotinic acid, and nicotinic acid makes skin flush. People who flushed after using niacinamide alongside vitamin C blamed the combination, when the more likely culprit was the grade of the raw material.
What is missing from the warning is a study showing the two ingredients cancelling each other on skin. We could not find one, and we looked, because we sell both.
What does niacinamide do?
Niacinamide is vitamin B3 in its amide form: water soluble, stable, cheap and backed by more human trial data than most ingredients three times its price. It is a precursor to NAD and NADP, the cofactors epidermal cells run their energy and repair chemistry on. Downstream it is associated with increased production of stratum corneum lipids and keratin, and with reduced transfer of pigment from melanocytes to the surrounding skin cells. Better barrier, more even tone.
The trial everyone cites is Bissett, Oblong and Berge, 2005, in Dermatologic Surgery. Fifty women with clinical signs of facial photoaging applied 5% niacinamide to one side of the face and the vehicle to the other, twice daily for 12 weeks. The niacinamide side showed significant reductions in fine lines and wrinkles, hyperpigmented spots, red blotchiness and sallowness, plus improved elasticity by cutometry. Five percent is the studied level and the level Mixed Signals uses.
What does vitamin C do?
L-ascorbic acid donates electrons, which lets it quench the free radicals ultraviolet light generates in skin. It is also a required cofactor for the two enzymes that hydroxylate proline and lysine during collagen synthesis, which is the mechanistic link between vitamin C and the dermis. It needs a low pH, roughly 3.5 or below, to be in the form that crosses the stratum corneum. At 15% with vitamin E and ferulic acid it has photoprotection data on human skin (Journal of the American Academy of Dermatology, 2008).
How do you layer vitamin C and niacinamide?
Vitamin C first, because it is the one with the pH requirement. Let it absorb for a minute. Then niacinamide, which is happy at almost any pH cosmetics run at and is one of the least fussy actives in the category. In our routine that is Bright Side, a minute, then Mixed Signals, every morning, with Baby's Bottom and sunscreen on top.
If you would rather not think about it at all, put the vitamin C in the morning and the niacinamide at night. Nothing is lost either way.
- Bright Side onto clean, dry skin. Wait a minute.
- Mixed Signals on top. Wait a minute.
- Baby's Bottom, then sunscreen.
Does mixing them cause redness or flushing?
A minority of people flush or tingle from niacinamide on its own, more often at higher percentages, and the grade of the raw material is a known factor. The tingle from a pH 3 vitamin C serum is separate and brief. If you get real redness, the fix is to separate the two by time of day and see which one your skin is objecting to. Above roughly 5% niacinamide the added benefit is not documented and flushing complaints go up, which is one more reason we stopped at five.
What we made with it
Bright Side is the vitamin C: 15% L-ascorbic acid with 1% vitamin E and 0.5% ferulic acid. Mixed Signals is the niacinamide: 5%, with copper tripeptide-1 and palmitoyl pentapeptide-4 doing the interesting signalling work alongside it. They are steps two and three of the morning routine, in that order.
Related questions
Which goes first, vitamin C or niacinamide?
Vitamin C. It needs a low pH to get into the skin, so it goes onto clean, dry skin first. Give it a minute, then apply the niacinamide, which does not care about pH. Thinnest to thickest is the general rule; here the pH rule points the same way.
Is 10% niacinamide better than 5%?
Not in the published work. The 12-week split-face trial used 5%, and above roughly that level the extra benefit is not documented while flushing complaints go up. Five percent is the level with the data, which is why Mixed Signals uses it.
Can I use vitamin C and niacinamide with retinal at night?
Use the vitamin C in the morning and keep retinal at night. Niacinamide can go either time; at night it sits before the retinal. Splitting vitamin C and retinal across the day avoids stacking a pH 3 serum and a retinoid on the same skin in one sitting.
Sources
- Bissett DL, Oblong JE, Berge CA. Niacinamide: a B vitamin that improves aging facial skin appearance. Dermatol Surg 2005;31:860-866. PMID 16029679
- Murray JC, et al. A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation. J Am Acad Dermatol 2008;59:418-425. PMID 18603326