Investigation of niacin on parameters of metabolism in a physiologic dose: randomized, double-blind clinical trial with three different dosages

The effect of facial blood flow on ratings of blushing and negative affect during an embarrassing task: preliminary findings

Expecting to blush is a common source of social anxiety, and is associated with heightened perceptions of blushing and embarrassment. To assess whether sensory cues associated with heightened facial blood flow are an additional source of anxiety, the vasodilator niacin (100mg) or placebo was administered double-blind to 33 participants, and facial blood flow was investigated when they sang a children's song. Vasodilatation during singing was greater in the niacin than placebo condition, and niacin-evoked flushing and increases in pulse rate were greater in participants with high than low fear of negative evaluation. Nevertheless, ratings of embarrassment, anxiety, blushing and facial heat were similar in both drug conditions. This dissociation implies that cognitive appraisals or negative affect overrode more subtle physiological cues of blushing during embarrassment. Clarifying how judgments about blushing are made could be crucial for correcting faulty assumptions about blushing in people who are frightened of this response.

The effect of niacin on facial blood flow in people with an elevated fear of negative evaluation

The vasodilator niacin may provoke greater facial flushing and other symptoms of anxiety in patients with social anxiety disorder than in non-anxious controls. To determine whether this also applies in non-clinical samples, niacin (100mg) or placebo was administered double-blind to 33 young adults and flushing was investigated in relation to fear of negative evaluation (a cardinal feature of social anxiety). Increases in facial blood flow were greater in people with high than low fear of negative evaluation in the niacin condition, but were similar in both groups in the placebo condition. However, changes in pulse rate and ratings of embarrassment, anxiety, blushing and facial heat were similar in both groups in both drug conditions. These findings suggest that the facial vessels of people with a heightened fear of negative evaluation are particularly responsive to niacin under conditions of low anxiety and embarrassment.