SPF
Also written as: SPF — Sun Protection Factor
Sun Protection Factor; a numerical measure of how effectively a sunscreen product protects the skin from UVB radiation, frequently cited in aesthetic post-procedural care instructions and product marketing copy.
Full Definition
SPF (Sun Protection Factor) is a standardised measure of the degree to which a sunscreen formulation extends the time skin can be exposed to UVB radiation before sunburn occurs, relative to unprotected skin. In aesthetic dermatology, high-SPF sunscreens (typically SPF 30–50+) are a cornerstone of pre- and post-treatment care to minimise pigmentation complications and photoageing. SPF appears in aftercare leaflets, prescribing notes, regulatory product information, and marketing materials. Editors should note that SPF is always formatted in capital letters as an acronym and is followed by a numeral (SPF 50), not a percentage symbol. It does not measure UVA protection, a distinction increasingly important in regulatory copy.
Usage
Usage note: Write 'SPF 50' not 'SPF-50' or '50 SPF'; the numeral follows the acronym without a hyphen. Do not imply SPF protects against UVA unless UVA coverage is separately stated.
In Context
- "All post-peel patients are instructed to apply a broad-spectrum SPF 50 sunscreen every two hours when outdoors." — Post-procedure aftercare leaflet
- "The marketing copy must not claim that SPF values measure UVA protection." — Regulatory marketing document