What is the sun protection factor (SPF) of Nicomenthyl?

Nicomenthyl is not a sunscreen (i.e. does not absorb or reflect some of the sun's ultraviolet (UV) radiation) and therefore does not have a sun protection factor.
Its protection against UVA and UVB rays is of purely biochemical and biological nature, i.e. due to its release of Vitamin B3 into the skin. Vitamin B3 is currently considered more effective than sunscreens in protecting against skin cancer caused by excessive exposure to sun rays. (RF: Niacin The Real Story by Abram Hoffer, MD., Ph.D – Andrew W. Saul, Ph.D, and Harold D. Foster, Ph.D. Publisher Basic Health Publications INC)