The relation between sun protection factor and amount of suncreen applied in vivo

  title={The relation between sun protection factor and amount of suncreen applied in vivo},
  author={Annesofie Faurschou and Hans Christian Wulf},
  journal={British Journal of Dermatology},
Background  The declared sun protection factor (SPF) is based on the use of a sunscreen layer of 2 mg cm−2. However, only around a quarter (0·5 mg cm−2) of this amount is applied by sunbathers. Theoretical calculations have suggested that the effective SPF is related to sunscreen quantity in an exponential way but this was not confirmed in vitro and has not been studied in vivo. 
The influence of the amount of sunscreen applied and its sun protection factor (SPF): evaluation of two sunscreens including the same ingredients at different concentrations
The objective of the present study was to estimate the influence of the quantity of sunscreen applied in the determination of SPF, according to the FDA methodology.
Relationship between sun‐protection factor and application thickness in high‐performance sunscreen: double application of sunscreen is recommended
The sun‐protection factor (SPF), which indicates the efficacy of UV protection, is determined using a prescribed sunscreen application thickness of 2.0 mg/cm2; in most cases, however, users apply insufficient amounts of sunscreen.
The meaning and implication of sun protection factor
The Sun Protection Factor (SPF) was introduced in 1962 and has become a worldwide standard for measuring efficacy of sunscreen products in shielding the sun’s ultraviolet radiation (UVR) and thereby
The relation between the amount of sunscreen applied and the sun protection factor in Asian skin.
It is concluded that to get the expected SPF value, it is important to apply the UV protective sunscreen precisely in the amount of 2.0 mg/cm(2) on Asian skin as recommended by the Food and Drug Administration.
Sun protection factor: meaning and controversies.
There are controversies in literature about the method for determining the SPF and the implications of the real conditions of use in the protection achieved in practice by users.
Influence of the quantity of sunscreen applied on the ability to protect against ultraviolet‐induced polymorphous light eruption
The aim of this study was to compare the ability of sunscreens to protect against UV‐induced polymorphous light eruption (PLE) when applied at 2 mg/cm2 and 1‪cm2.
Accumulation of sunscreen in human skin after daily applications: a study of sunscreens with different ultraviolet radiation filters
The consequences of accumulation for SPF are investigated in women using sunscreen for consecutive days with high sun protection factor (SPF) after 8 h.
Sunburn protection as a function of sunscreen application thickness differs between high and low SPFs
The objective of the present study was to determine the actual sun(burn) protection given by a range of sunscreen application thickness levels for both low and high SPF formulas.
Sunscreen applied at ≥ 2 mg cm−2 during a sunny holiday prevents erythema, a biomarker of ultraviolet radiation‐induced DNA damage and suppression of acquired immunity
People typically apply around 0·8 mg cm−2 and use sunscreen daily for holidays and such use results in erythema, which is a risk factor for skin cancer.
Application of sunscreen preparations: a need to change the regulations
This study assesses whether a detailed instruction can improve the use of sunscreens by showing that people usually applied much less than the recommended dose.


Sunbathers' application of sunscreen is probably inadequate to obtain the sun protection factor assigned to the preparation.
A large number of volunteers on a beach applied their own sunscreen all over the body and the amount of the applied sunscreen was on average 0.5 mg/cm2, indicating that the labelled SPF is probably considerably higher than the obtained degree of protection against sunburn.
How well are sunscreen users protected?
  • R. Stokes, B. Diffey
  • Chemistry, Medicine
    Photodermatology, photoimmunology & photomedicine
  • 1997
It was found that application thickness had a significant effect on the sun protection factor (SPF), with most users probably achieving a mean SPF of between 20–50% of that expected from the product label.
Quantity of sunscreen used by European students
Background The ability of sunscreen products to delay sun‐induced skin erythema is indicated by the sun protection factor (SPF), which is measured using an internationally agreed sunscreen thickness
Sunscreens used at the beach do not protect against erythema: A new definition of SPF is proposed
It is demonstrated that more sunscreen users than non‐users reported to be red the day after sun exposure, 42 and 34%, respectively, and theoretical calculations support this finding and show a drastic reduction in the achieved photoprotection if a thinner layer than in the test situation is used.
Sunscreen isn't enough.
  • B. Diffey
  • Business, Medicine
    Journal of photochemistry and photobiology. B, Biology
  • 2001
That the protection achieved is often less than that expected depends upon a number of factors: application thickness and technique; type of sunscreen applied; resistance to water immersion and sand abrasion; and when, where and how often sunscreen is re-applied.
Reduction of solar keratoses by regular sunscreen use.
Regular use of sunscreens prevents the development of solar keratoses and, by implication, possibly reduces the risk of skin cancer in the long-term.
High sun protection factor sunscreens in the suppression of actinic neoplasia.
The regular use of sunscreens can significantly reduce cutaneous neoplasia, as indicated by its suppression of precancerous lesions.
Sunscreens for delay of ultraviolet induction of skin tumors.
Long-term investigations seem to be necessary to unveil the specific SPF value, in sunscreens, that should be recommended to the public for prevention or delay of actinic damage and/or cancer development.
Sun exposure and sunscreen use among sunbathers in Denmark.
This study indicates that sunscreen users may not increase their exposure to the sun, and the sun exposure time was not significantly different in the group of subjects using sunscreens, compared to thegroup of subjects not using sun screens.
The validity and practicality of sun-reactive skin types I through VI.
It was decided that a brief personal interview regarding the history of the person's unburn and suntan experience was one approach to estirnate the skin tolerance to uitraviolet radiation (UVR) exposure.