What the sunlight studies measured

Researchers have published 803 studies on sunlight and the body, and only 98 of them stood anyone in real, unfiltered sun. The rest reached for a lamp, a proxy, or never said where the light came from. The map below shows all of it, including the cells that are empty.

Studies: 803
Under direct sun: 98
Years covered: 1922–2026
With our translation: 720

The corpus on one screen

Eight reviewed facets, each bar against its own largest segment. Skin dominates outcomes, simulators dominate origins, controlled doses dominate measurement, and the unclear column stays visible everywhere instead of hiding.

Skin outcomes606 of 784 carry the skin label
Simulator origins405 of 784 lit a simulator
Controlled doses555 of 784 set the dose on a dial
Route never said561 of 784 name no body route
People studied484 of 784 ran in participants
Design unclear412 of 784 resist a design label
Intent unclear351 of 784 declare no intent
Broad spectrum287 of 784 test broad-spectrum light

Where the light came from, by health topic

Read it like a map. Each row is a light source, each column a health topic, and each number is how many studies sit at that crossing. The empty crossings are the point: they are the questions nobody has asked yet. Select any cell to read its studies below.

Choose a cell in the table to list its studies here.

Who the light fell on

A study in a dish can show a mechanism. It cannot show what happens to a person who walks outside. Under the reviewed labels, 484 of 784 studies ran in people,104 in human cells, and 48 resisted a model label.

PeopleVolunteers and patients studied as whole humans484484 studies: Volunteers and patients studied as whole humans
Human cellsCell lines and cultured cells in dishes104104 studies: Cell lines and cultured cells in dishes
Mixed modelsMore than one model in a single study7373 studies: More than one model in a single study
Animals with a human inferenceAnimal work the authors tie explicitly to people5050 studies: Animal work the authors tie explicitly to people
Human tissueSkin and other tissue kept alive outside the body2525 studies: Skin and other tissue kept alive outside the body
UnclearThe reviewers could not resolve a model4848 studies: The reviewers could not resolve a model

How much of the corpus touches skin

Skin is the organ the light meets first, and the numbers show it: 660 of 803 studies touch skin at all, and 192 study skin alone. Everything else the sun might do to a body shares the remaining room.

Which light the studies tested

The export records where the light came from for every study. Simulators dominate, real sun is rare, and 25 studies never pinned the source down. Those sit in the bottom row of the map rather than being quietly dropped. The reviewed spectrum labels add which light: broad-spectrum work leads, UVB and UVA follow close, and red light has 5 studies to UVB’s 200.

Broad spectrumThe full lamp output, not split by band287287 studies tested Broad spectrum.
UVBThe burning band, 280 to 315 nanometers200200 studies tested UVB.
UVAThe aging band, 315 to 400 nanometers181181 studies tested UVA.
Solar spectrum, unspecifiedSun-like light with the band never named8989 studies tested Solar spectrum, unspecified.
VisibleLight the eye can see3131 studies tested Visible.
InfraredHeat past the red edge2020 studies tested Infrared.
RedA narrow red band near 630 to 660 nanometers55 studies tested Red.
Not reportedThe paper never named a band112112 studies tested Not reported.

Who measured the light on the person

Almost nobody did. 555 studies set the dose on a lamp dial and 174 never said how the light was fixed at all. Three strapped a dosimeter to a person, three more recorded time outdoors, and two read it from a satellite. The rest assigned exposure by place, job, record, or recall.

Controlled doseThe team set the lamp and timed it555555 studies: The team set the lamp and timed it.
Never saidNo measurement or delivery on record174174 studies: No measurement or delivery on record.
Place on a mapLatitude, season, or climate standing in for light6060 studies: Latitude, season, or climate standing in for light.
People recalling sunQuestionnaires and self-reported exposure2323 studies: Questionnaires and self-reported exposure.
Treatment or tanning recordA lamp session logged for another reason2222 studies: A lamp session logged for another reason.
Worn dosimeterA meter on the body catching real light33 studies: A meter on the body catching real light.
Time outdoorsHours outside written down, no meter33 studies: Hours outside written down, no meter.

When the studies were published

Publication peaks in the 2000s. The drift below splits each decade into lamp work against real sun. The 1990s turn is the hinge: simulators jump from 19 to 70 while direct sun inches from 13 to 17.

1920s11 studies published in the 1920s
1930s00 studies published in the 1930s
1940s00 studies published in the 1940s
1950s22 studies published in the 1950s
1960s11 studies published in the 1960s
1970s1212 studies published in the 1970s
1980s6666 studies published in the 1980s
1990s117117 studies published in the 1990s
2000s261261 studies published in the 2000s
2010s216216 studies published in the 2010s
2020s127127 studies published in the 2020s

1920s0 lamp · 1 real sun · 1 totalIn the 1920s: 0 lamp studies, 1 real-sun studies, 1 total.
1950s0 lamp · 1 real sun · 2 totalIn the 1950s: 0 lamp studies, 1 real-sun studies, 2 total.
1960s0 lamp · 1 real sun · 1 totalIn the 1960s: 0 lamp studies, 1 real-sun studies, 1 total.
1970s3 lamp · 6 real sun · 12 totalIn the 1970s: 3 lamp studies, 6 real-sun studies, 12 total.
1980s36 lamp · 13 real sun · 66 totalIn the 1980s: 36 lamp studies, 13 real-sun studies, 66 total.
1990s95 lamp · 17 real sun · 117 totalIn the 1990s: 95 lamp studies, 17 real-sun studies, 117 total.
2000s225 lamp · 19 real sun · 261 totalIn the 2000s: 225 lamp studies, 19 real-sun studies, 261 total.
2010s143 lamp · 31 real sun · 216 totalIn the 2010s: 143 lamp studies, 31 real-sun studies, 216 total.
2020s86 lamp · 27 real sun · 127 totalIn the 2020s: 86 lamp studies, 27 real-sun studies, 127 total.

How real is real enough

Drag the threshold from direct sun down through filtered light, simulators, devices, and proxies, and watch how many studies survive. The slider below filters the grid rows above: it is a filter, not a scatter.

Keep studies at least this real

Everything including proxies: 778 of 803 studies survive.

Patch or whole body

A coin of lit skin is the commonest human setup: 134 studies lit a patch and 20 lit the whole body, with 12 on the eyes. But 561 never said where the light fell, and 63 mark route not applicable, so the figure below shades a small patch and leaves the unreported majority as its own bar.

Never saidNo body route on record561561 studies: No body route on record.
Skin patchLight on one coin of skin134134 studies: Light on one coin of skin.
Not applicableDish, proxy, or design with no body route6363 studies: Dish, proxy, or design with no body route.
Whole bodyThe full person under the light2020 studies: The full person under the light.
EyesLight aimed at or reaching the eyes1212 studies: Light aimed at or reaching the eyes.

Which questions never went outdoors

For each topic, the share of its studies that used real sun, sorted lowest first. Mortality sits at the bottom with 5 of 103. The reader sees which questions the field never took outdoors.

Death and serious disease5 of 1035 of 103 Death and serious disease studies used real sun.
Cancers beyond skin13 of 13213 of 132 Cancers beyond skin studies used real sun.
Skin78 of 66078 of 660 Skin studies used real sun.
Immune and infection21 of 17421 of 174 Immune and infection studies used real sun.
Metabolism and hormones16 of 11416 of 114 Metabolism and hormones studies used real sun.
Mind and mood17 of 11217 of 112 Mind and mood studies used real sun.
Vitamin D and bone16 of 9516 of 95 Vitamin D and bone studies used real sun.
Pain, injury and safety38 of 14838 of 148 Pain, injury and safety studies used real sun.
Other topics36 of 13936 of 139 Other topics studies used real sun.

Which topics the sun reached

For each topic, the share of its studies that used real sun. Skin leads. The gravest topics sit at the bottom of the list. The strip below is the whole real-sun literature: 116 studies, oldest first.

Death and serious disease5 of 1035 of 103 Death and serious disease studies used real sun.
Cancers beyond skin13 of 13213 of 132 Cancers beyond skin studies used real sun.
Skin78 of 66078 of 660 Skin studies used real sun.
Immune and infection21 of 17421 of 174 Immune and infection studies used real sun.
Metabolism and hormones16 of 11416 of 114 Metabolism and hormones studies used real sun.
Mind and mood17 of 11217 of 112 Mind and mood studies used real sun.
Vitamin D and bone16 of 9516 of 95 Vitamin D and bone studies used real sun.
Pain, injury and safety38 of 14838 of 148 Pain, injury and safety studies used real sun.
Other topics36 of 13936 of 139 Other topics studies used real sun.

The full outcome ranking

The grid folds twenty-two reviewed outcome domains into nine columns. The full ranking restores what folding hides: cellular intermediates second at 317, immune or inflammatory at 154, cancer beyond skin at 132, injury or safety at 117, metabolic at 114, mind at 112, mortality at 103, vitamin D at 88. Eyes hold 27, newborns 22, sleep 18, pregnancy 7.

Skin606606 studies touch Skin.
Cellular or molecular intermediate317317 studies touch Cellular or molecular intermediate.
Immune or inflammatory154154 studies touch Immune or inflammatory.
Cancer beyond skin132132 studies touch Cancer beyond skin.
Injury or safety117117 studies touch Injury or safety.
Metabolic or endocrine114114 studies touch Metabolic or endocrine.
Mind and wellbeing112112 studies touch Mind and wellbeing.
Mortality or major disease103103 studies touch Mortality or major disease.
Vitamin D8888 studies touch Vitamin D.
Infectious disease4343 studies touch Infectious disease.

What stood in for the sun

83 proxy studies never lit anyone at all. Latitude and season stand in 56 times, questionnaires 25 times, treatment or tanning records 22 times, occupation 9 times, and a single biomarker once. Each branch below names its stand-in plainly.

Latitude and seasonWhere and when standing in for how much light5656 proxy studies: Where and when standing in for how much light.
QuestionnairesPeople recalling their own sun2525 proxy studies: People recalling their own sun.
Treatment or tanning recordA lamp log reused as exposure2222 proxy studies: A lamp log reused as exposure.
OccupationA job title standing in for dose99 proxy studies: A job title standing in for dose.
One biomarkerA molecule standing in for light22 proxy studies: A molecule standing in for light.

Where the evidence stops at a dish

The second-largest outcome is not a disease at all. 317 studies stop at cellular or molecular intermediates: dimers, mutations, signals in a dish. Skin at 606 often means the same dish work wearing an organ label, so the reader should ask of every skin count how many left the dish.

What travels together

One study often touches more than one topic. These are the pairs that appear together most. Skin rides along with nearly everything.

Immune and infection with Skin157157 studies touch Immune and infection with Skin.
Pain, injury and safety with Skin134134 studies touch Pain, injury and safety with Skin.
Cancers beyond skin with Skin123123 studies touch Cancers beyond skin with Skin.
Mind and mood with Skin9292 studies touch Mind and mood with Skin.
Death and serious disease with Skin8080 studies touch Death and serious disease with Skin.
Metabolism and hormones with Skin8080 studies touch Metabolism and hormones with Skin.

What the studies wanted

Mechanism leads by distance: 246 studies pick a pathway apart, 140 test prevention or protection, 55 chase risk, and 35 try therapy. Another 351 never declare an intent, which is itself a finding about how this literature reports itself.

UnclearNo intent the reviewers could resolve351351 studies: No intent the reviewers could resolve.
MechanismHow light does what it does246246 studies: How light does what it does.
Prevention or protectionStopping harm before it starts140140 studies: Stopping harm before it starts.
RiskWhether light raises the odds5555 studies: Whether light raises the odds.
TherapyLight as treatment3535 studies: Light as treatment.
PhototestingProvoking skin to see what happens2020 studies: Provoking skin to see what happens.
Exposure assessmentMeasuring the light itself1313 studies: Measuring the light itself.

Where the field published

The work concentrated in dermatology and photobiology journals. The top venue alone holds 84 of 803 studies.

The Journal of investigative dermatology8484 studies in The Journal of investigative dermatology.
Photochemistry and photobiology4848 studies in Photochemistry and photobiology.
The British journal of dermatology2828 studies in The British journal of dermatology.
Photodermatology, photoimmunology & photomedicine2727 studies in Photodermatology, photoimmunology & photomedicine.
Journal of photochemistry and photobiology. B, Biology2020 studies in Journal of photochemistry and photobiology. B, Biology.
Experimental dermatology1919 studies in Experimental dermatology.
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology1919 studies in Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology.
Journal of the American Academy of Dermatology1414 studies in Journal of the American Academy of Dermatology.

The shelf beside this corpus

The sunscreen registry, 1335 studies on what blocks the sun, is kept separate and is not mixed into these counts. Its venues sit elsewhere: toxicology and environmental science, not dermatology.

Contact dermatitis · 76
Environment international · 59
Environmental research · 39
The Science of the total environment · 36
The Journal of investigative dermatology · 27

What the blockers get studied

Attention in the sunscreen registry is lopsided. Oxybenzone alone draws more studies than the bottom ten chemicals combined.

oxybenzone517517 sunscreen studies mention oxybenzone.
octinoxate238238 sunscreen studies mention octinoxate.
paba200200 sunscreen studies mention paba.
titanium dioxide155155 sunscreen studies mention titanium dioxide.
zinc oxide124124 sunscreen studies mention zinc oxide.
benzophenone-1123123 sunscreen studies mention benzophenone-1.
avobenzone105105 sunscreen studies mention avobenzone.
4-mbc8686 sunscreen studies mention 4-mbc.
octocrylene8484 sunscreen studies mention octocrylene.
octisalate6969 sunscreen studies mention octisalate.

First in each topic

The earliest study sets the start of each thread in this corpus. Skin and vitamin D begin in 1922. Mind and safety follow decades later.

Skin · 1922
Vitamin D and bone · 1922
Other topics · 1951
Pain, injury and safety · 1969
Mind and mood · 1969
Cancers beyond skin · 1975
Immune and infection · 1977
Death and serious disease · 1978
Metabolism and hormones · 1981

What the design labels say

Under the reviewed taxonomy the design field is honest about its own limits: 412 of 784 studies resist a design label and sit in hatching below, not hidden. Of the rest, 103 are mechanistic dish work, 59 are randomized parallel trials, 49 are animal experiments, 43 are nonrandomized interventions, and 36 are case reports.

other or unclear412412 studies designed as other or unclear.
mechanistic in vitro103103 studies designed as mechanistic in vitro.
randomized parallel trial5959 studies designed as randomized parallel trial.
animal experiment4949 studies designed as animal experiment.
nonrandomized intervention4343 studies designed as nonrandomized intervention.
case report3636 studies designed as case report.
mechanistic ex vivo2525 studies designed as mechanistic ex vivo.
case control1818 studies designed as case control.

What nobody measured

Skin dominates the direct-sunlight work with 70 studies. The thinnest direct-sun topics are Death and serious disease (4), Cancers beyond skin (12), and Mind and mood (12). The sunscreen registry, 1335 studies on what blocks the sun, is kept separate and is not mixed into these counts.

The grid has 4 crossings with no studies at all (Filtered or ambient sunlight with Vitamin D and bone; Unclear or unverified with Cancers beyond skin; Unclear or unverified with Metabolism and hormones; Unclear or unverified with Death and serious disease) and 9 more with one or two (Filtered or ambient sunlight with Immune and infection; Filtered or ambient sunlight with Cancers beyond skin; Filtered or ambient sunlight with Metabolism and hormones; Filtered or ambient sunlight with Death and serious disease; Proxy measures with Mind and mood; Unclear or unverified with Immune and infection; Unclear or unverified with Mind and mood; Unclear or unverified with Vitamin D and bone; Unclear or unverified with Other topics). Six studies never pinned down a light source and sit in the bottom row rather than being quietly dropped. Design labels in the source data mix funding notes with study designs, so this page colors nothing by strength.

How much rests on full text

694 studies were read from full text, 90 from metadata alone, and 25 of the full texts came through OCR. The reader sees how much of the map rests on abstracts before trusting any single cell.

Full textReviewers read the whole paper694694 studies: Reviewers read the whole paper.
Metadata aloneAbstract and index record only9090 studies: Abstract and index record only.
Through OCRScanned pages read by machine, part of the full-text set2525 studies: Scanned pages read by machine, part of the full-text set.

What we could not tell

One page for the studies the facets could not resolve. Six origins unclear, 112 spectra never named, 174 measurements missing, 561 routes unreported, 48 models unclear, 412 designs unresolved, 351 intents undeclared, 10 outcomes unclassified. Hatched bars above mark the same gaps where they live; here they stand together so the reader sees how much of the map rests on papers that never said.

Route unreported561561 studies: Route unreported.
Design unclear412412 studies: Design unclear.
Intent unclear351351 studies: Intent unclear.
Measurement missing174174 studies: Measurement missing.
Spectrum never named112112 studies: Spectrum never named.
Model unclear4848 studies: Model unclear.
Outcome unclassified1010 studies: Outcome unclassified.
Origin unclear66 studies: Origin unclear.

How the studies read

Titles run a median 108 characters. The shortest is 1985’s “Sunburn and malignant melanoma.” The longest runs 243 characters (“The effect of occupational exposure to solar ultraviolet radiation on malignant skin melan…”).

Every study on this page carries our translation where one exists: 720 of 803. The record pages name the original venue so the reader can check us against it.

Light source	Skin · 660	Immune and infection · 174	Pain, injury and safety · 148	Cancers beyond skin · 132	Metabolism and hormones · 114	Mind and mood · 112	Death and serious disease · 103	Vitamin D and bone · 95	Other topics · 139
Direct sunlightSun on skin outdoors, unfiltered · 98
Filtered or ambient sunlightSun through glass, shade, or daylight in a place · 18
Solar simulatorLamps tuned to mimic the sun spectrum · 405
Lamps and devicesSingle wavelengths, tanning beds, therapy lamps · 183
Proxy measuresA job, a place, or a molecule standing in for light · 74
Unclear or unverifiedThe source never said where the light came from · 25