Figure 4.

Blue light induces skin reddening. (a) Blue light irradiation a* values as measured on day 3. ***P < 0.001 vs day 0 for all groups. Compared to placebo, these values were significantly lower for niacinamide (*P < 0.05 niacinamide vs placebo). (b) Mean delta a* values show non‐significantly lower a* values for the algal extract and niacinamide compared to the placebo at days 3 to 10. (c) Volunteer #13 with lighter skin using the placebo formulation on one arm and the algal extract formulation on the other arm is shown here. The difference in skin reddening between the two formulations can be seen from day 3 to day 10. (d) Volunteer #16 with lighter skin using the placebo formulation on one arm and the niacinamide formulation on the other arm is shown here. The difference in skin reddening between the two formulations can be seen from day 3 to day 10.