How 'SPF Boosters' Actually Work in a Formula
The hidden ingredients that raise a sunscreen's number.
Antioxidant vitamin C + E pairing has been shown to roughly quadruple photoprotection in some measures.
If a vitamin C + E pairing can roughly quadruple photoprotection, boosters prove a sunscreen's SPF is shaped by the whole formula, not just its UV filters.
Frequently asked questions
Do antioxidants in sunscreen actually work?
Antioxidants such as vitamins C and E don't filter UV, but they can neutralize some of the free radicals UV generates, adding a complementary layer of defense. They support — never replace — sunscreen. A studied vitamin C+E combination showed measurable added photoprotection.
Why are some UV filters more photostable?
A photostable filter keeps absorbing UV without breaking down in sunlight. Older filters like avobenzone can lose protection within an hour unless paired with stabilizers such as octocrylene. Next-generation filters are engineered to stay chemically stable, so protection lasts longer — though reapplication is still advised.
What is the difference between nano and non-nano zinc?
Nano zinc has smaller particles, so it rubs in more clearly with less white cast; non-nano uses larger particles that scatter more visible light but are preferred by some for environmental or personal reasons. Current evidence indicates nanoparticles in sunscreen don't penetrate healthy skin.
r/SkincareAddiction: 'Why is avobenzone always with octocrylene?'
Sources & citations
- Bernstein EF et al., 'Iron oxides in novel skin care formulations attenuate blue light,' J Cosmet Dermatol 2021, doi:10.1111/jocd.13803
- onlinelibrary.wiley.com ↗