Research has been done on the effect of creams containing niacinamide in rosacea. The facial skin of people with rosacea is often hyper sensitive compared to the skin of people without rosacea. (See also general tips for skin care). Niacinamide would in theory be able to somewhat recover the skin barrier. I found an article about niacinamide cream and rosacea dated in 2004 in which the effects of niacinamide on symptoms were examined and described. For the research, the products of Olay used:

an ordinary face cream (without niacinamide): (Olay ® Active Hydrating Beauty Fluid - Sensitive Skin) face wash (Olay Foaming Face Wash - Sensitive Skin), and Olay Sensitive Skin Beauty Bar.

After two weeks, with some facial cream replaced by a cream containing 2% niacinamide Olay Total Effects 7 Visible Anti-Aging Vitamin Complex Fragrance Free)

50 women participated, two of them did not complete the study due to irritation by the products. Irritation did not improve after a few weeks. The other women in the treatment group that tolerated the well.

The results were good. After two weeks  79.2% of women saw improvement, after 4 weeks  95.7% of the women saw improvement. The skin was better hydrated and the symptoms of rosacea improved. Especially the erythema was better after 4 weeks of treatment, but also inflammation and dryness improved. The only symptom that did not improve were the broken blood vessels, but this was expected.

If you want to try it then it is good to know that not  many commercially available creams contain that much niacinamide. A good rule is: The earlier it is listed on the ingredients list, the more is in there.  Note also the other ingredients. If they irritate your skin then they certainly do not help.

A commercially available cream with a high percentage of niacinamide can be found here.

Rosacea info