Skin niacin test was performed by two concentrations including 0.5 ml solutions of 0.01 M and 0.1 M diluted methyl nicotinate. The two solutions were applied for one minute to the inside of the different forearms of each individual.

Skin niacin test was performed by two concentrations including 0.5 ml solutions of 0.01 M and 0.1 M diluted methyl nicotinate. The two solutions were applied for one minute to the inside of the different forearms of each individual.

Skin niacin test was performed by two concentrations including 0.5 ml solutions of 0.01 M and 0.1 M diluted methyl nicotinate. The two solutions were applied for one minute to the inside of the different forearms of each individual.

Skin niacin test was performed by two concentrations including 0.5 ml solutions of 0.01 M and 0.1 M diluted methyl nicotinate. The two solutions were applied for one minute to the inside of the different forearms of each individual.

Two concentrations including 0.5 ml solutions of 0.01 M and 0.1 M diluted methyl nicotinate were applied for one minute to the inside of the different forearms of each individual.

Skin response was assessed by a single physician every 5 minutes for 20 minutes after removal of the substance. The outcome assessor was not blinded to the applied solution dosages. The strength of the flushing reaction was classified as 0 = no redness, 1 = faint redness, 2 = distinct redness, and 3 = extreme or maximum redness.