Brief, non-burning sun is good for most people, and the sensible amount depends on your skin, your latitude, and the season. Sunlight makes vitamin D in the skin, releases nitric oxide that lowers blood pressure a little, sets your body clock, and lifts mood, and in one large cohort of women those who avoided the sun died sooner, by an estimated 0.6 to 2.1 years and mostly from heart disease, though that link is tangled with smoking and wealth and cannot prove cause.
Against those benefits, intermittent burning and tanning beds clearly raise melanoma, and tanning beds are a proven carcinogen. The workable path is regular short non-burning exposure: protect against burning, take more care with fair skin and midday summer sun, and never use a tanning bed.
Findings & Outcomes
What It Is
Sunlight reaching your skin is a mix of two ultraviolet bands. Ultraviolet B is the shorter, higher-energy band; it does not travel deep, it converts a cholesterol precursor at the surface of the skin into vitamin D3, and it causes most sunburn. Ultraviolet A is the longer band; it reaches deeper, drives most of the tanning and the long-term aging, and releases a store of nitric oxide from the skin into the blood. Both bands damage the DNA in skin cells, and enough of that damage, especially from burning doses, is what becomes skin cancer.
How much of this happens depends on you and on where you are:
- Skin type sets how fast you make vitamin D and how fast you burn. Fair skin that burns easily makes vitamin D quickly and reddens quickly; darker skin is more protected and needs longer sun for the same vitamin D.
- Latitude and season set how much ultraviolet B reaches the ground at all. A winter morning far from the equator carries little of it; midday summer sun near the equator carries a great deal.
- Time of day matters because ultraviolet B is strongest around the middle of the day.
This is why the sensible dose differs from person to person, with no single number that fits everyone.
What It Does
Sunlight acts through several pathways that point in opposite directions, and the two sides rest on very different evidence.
The benefits rest on the softer kind. Three are mechanisms measured directly in the skin and blood: vitamin D synthesis, a nitric oxide release that briefly lowers blood pressure, and the body-clock and mood signal of daylight. The fourth, longer life among people who get more sun, comes from watching one large group of women over about 20 years, so it shows a pattern and cannot prove cause, and it correlates with smoking, wealth and baseline health. Together they support getting regular sun; none supports seeking out more than that.
The harm rests on the stronger kind. Ultraviolet is a proven cause of melanoma and the common skin cancers, and the melanoma pattern is intermittent burning and a history of sunburn, not steady outdoor time. Tanning beds are the clearest avoidable version, worst for people who start young. The one randomized trial pointing the other way found that regular sunscreen use lowered melanoma over the following decade.
Each finding below is graded at the strength of its own evidence, and strength is not endorsement: a benefit on soft evidence and a harm on strong evidence sit side by side.
The Research & Studies
Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.
Cancer Risk And Outcome
Burning and intermittent sun raised melanoma across 57 studies, steady outdoor sun did not
Across dozens of studies, sunburn history and occasional intense sun raised melanoma risk, while steady everyday outdoor sun did not. Burning is the part that matters.
Pooling 57 observational studies, intermittent sun exposure and a history of sunburn were associated with higher melanoma risk, while high steady occupational sun exposure was inversely associated. The pattern that raises melanoma is intermittent burning, not regular outdoor time. Measured in: 57 observational studies (case-control and cohort) of cutaneous melanoma and sun-exposure patterns, published before September 2002. The component studies rely on recalled sun exposure and sunburn, which is imperfect, and the estimates vary with latitude and skin type. It establishes association with a pattern of exposure rather than a dose threshold.
The study · 1
Gandini et al., meta-analysis of risk factors for cutaneous melanoma: II. Sun exposure · Eur J Cancer 2005;41(1):45-60
Tanning beds raised melanoma about 20 percent, and 87 percent when started before age 35
People who had ever used a tanning bed had a higher chance of melanoma, and starting before age 35 nearly doubled it. More sessions meant more risk.
Across 27 studies, ever using a tanning bed was associated with about 20% higher melanoma risk, rising with the number of sessions, and first use before age 35 was associated with about 87% higher risk. Measured in: 27 observational studies of sunbed use and skin cancer, pooled in a systematic review and meta-analysis. The underlying studies are observational, so residual confounding by skin type and sun-seeking behavior is possible. The dose-response and the young-age signal are consistent across studies and point one direction.
The study · 1
Boniol et al., cutaneous melanoma attributable to sunbed use: systematic review and meta-analysis · BMJ 2012;345:e4757
Regular sunscreen halved melanoma over a decade in the one randomized trial
In the one randomized trial of the question, adults who used sunscreen daily had about half the melanoma over the next decade of those who used it as they pleased, and invasive melanomas fell more clearly still. The same trial had shown sunscreen prevents the common scaly skin cancer.
In the only randomized trial of sunscreen and melanoma, adults assigned to daily sunscreen for about 4.5 years had about half the melanoma rate of those using it at their discretion over the following decade (11 versus 22 cases; hazard ratio 0.50, 95% CI 0.24 to 1.02, P = 0.051), and invasive melanomas fell more clearly (3 versus 11 cases; hazard ratio 0.27, 95% CI 0.08 to 0.97). The same trial had earlier shown regular sunscreen use prevents squamous cell carcinoma. Measured in: 1,621 adults aged 25 to 75 in Nambour, Queensland, Australia, randomized to daily versus discretionary sunscreen from 1992 to 1996 and then followed to 2006 (the Nambour Skin Cancer Prevention Trial). The overall melanoma reduction did not quite reach statistical significance (P = 0.051); the clearer signal was for invasive melanoma, on modest case numbers. This is a single trial in a high-ultraviolet, fair-skinned setting, so the size of the melanoma benefit rests on few events.
Who this may not transfer to:Conducted with fair-skinned adults in a high-ultraviolet Australian setting where melanoma stakes are unusually high. The protective direction should carry to other fair-skinned populations, though the absolute benefit depends on local ultraviolet and skin type.
The study · 1
Green et al., reduced melanoma after regular sunscreen use: randomized trial follow-up (Nambour Skin Cancer Prevention Trial) · J Clin Oncol 2011;29(3):257-263
How it works
Ultraviolet B makes vitamin D3 in the skin, the main natural source for most people
Your skin makes vitamin D when ultraviolet B light hits it, and this is where most people get most of theirs. Darker skin, winter, high latitude, sunscreen and age all lower how much you make.
Ultraviolet B light converts a cholesterol precursor in the skin into vitamin D3, the main natural source for most people. How much is made falls with darker skin, higher latitude, winter, sunscreen and age. That the skin makes vitamin D from sun is settled, but the vitamin D page shows that adding more to a person who already has enough did not deliver the wider disease prevention once hoped for; the value is in correcting a shortfall that exists.
The study · 1
Holick, vitamin D deficiency (review of cutaneous synthesis and determinants) · N Engl J Med 2007;357(3):266-281
Heart And Vascular
Ultraviolet A released skin nitric oxide and briefly lowered blood pressure in 24 volunteers
When researchers shone ultraviolet light on people's skin, it released a chemical that widened blood vessels and briefly lowered blood pressure, separate from vitamin D. It is an early clue, not a treatment.
In a small human experiment, exposing skin to ultraviolet A released nitric oxide stored in the skin into the circulation and briefly lowered blood pressure, independent of vitamin D. It offers a mechanism for why blood pressure tracks with season and latitude. Measured in: 24 healthy volunteers exposed acutely to two standard erythemal doses of ultraviolet A. This was 24 volunteers measured acutely, not a trial of health outcomes. It shows the pathway exists; it does not establish that everyday sun meaningfully lowers blood pressure over time, and the same ultraviolet carries a skin cost.
The study · 1
Liu et al. (Weller, Feelisch), UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase · J Invest Dermatol 2014;134(7):1839-1846
Longevity And Mortality
Sun avoidance tracked with 0.6 to 2.1 fewer years of life, a confounded association
In a large group of Swedish women, those who avoided the sun tended to die earlier than those who got the most, by an estimated half a year to two years. The extra deaths were mostly heart-related, not skin cancer.
Over about 20 years, women who avoided the sun had higher all-cause mortality than women with the most sun exposure, an estimated 0.6 to 2.1 years of shorter life expectancy. The excess deaths were cardiovascular and other non-cancer causes rather than skin cancer. Measured in: 29,518 Swedish women aged 25 to 64 at enrollment, followed roughly 20 years (the Melanoma in Southern Sweden cohort). What could explain it instead: Sun avoidance is associated with things that shorten life: it correlates with smoking, poorer baseline health and less physical and outdoor activity, and people already unwell stay indoors more, so reverse causation is plausible. The analysis adjusted for several of these but cannot remove them all.. Sun habits were self-reported at a single baseline and this is one regional cohort. The authors describe the effect size as comparable to smoking, and the same caution applies: exposure was observed, not assigned, so the number cannot be read as a treatment effect.
Who this may not transfer to:Measured only in women. The vitamin D, nitric oxide and circadian pathways proposed behind the signal are not sex-specific, but no men were in this cohort, so the size of the association is not established for them.
The study · 1
Lindqvist et al., avoidance of sun exposure as a risk factor for major causes of death (Melanoma in Southern Sweden cohort) · J Intern Med 2016;280(4):375-387
Getting the Balance Right
Ways to Do It
Almost nothing here costs money. The core of it is getting a little regular sun without burning and learning your own skin, both free. The one thing worth buying is sunscreen for the days exposure runs long, and the one thing worth refusing is a tanning bed. Start at the top.
Short, regular time outdoors with some skin uncovered lets your body make vitamin D and sets your body clock, and taken in the morning it does the most for sleep and mood. The target is light on the skin, not a burn. On a strong-sun day a few minutes on the arms and legs is plenty for lighter skin; darker skin and higher latitudes need longer. Stop well before any pinkness.
How much sun is sensible for you depends on skin type, latitude and season. Fair skin that burns easily needs very little and burns fast; darker skin makes vitamin D more slowly and tolerates more sun; midday summer sun near the equator is a different thing from a winter morning up north. Learn how quickly your own skin starts to redden and treat that as your ceiling.
The vitamin D is made early and the risk builds later, so the free move for a long day outside is a hat, a shirt and shade, not more bare-skin hours. Seeking shade around the peak of the day, roughly late morning to mid-afternoon in summer, cuts the strongest ultraviolet while leaving the gentler morning and evening sun. Clothing is the most reliable sun protection there is.
For time outdoors beyond a short sensible dose, a broad-spectrum sunscreen of SPF 30 or higher, reapplied every couple of hours and after swimming, lowers burning and cumulative damage, and in the one trial that tested it lowered melanoma too. It is for prolonged exposure, not for blocking the brief daily sun that carries the benefits. Most people apply too little; a generous layer is what reaches the labeled protection.
A tanning bed gives you the carcinogen with none of the daylight context, and it is not a safe source of vitamin D. Starting young raises melanoma risk most, and the risk climbs with each session. If you want color, a self-tanning lotion carries no ultraviolet and no skin cancer risk.
Through a dark winter, or for someone who cannot get outdoors, sun alone will not cover vitamin D. Oily fish and fortified foods carry some, and a modest daily vitamin D3 supplement covers the gap with no ultraviolet cost. The dose, and who should test, is on the [vitamin D](/go/integrative/practice/vitamin-d) page.
Brief, regular, non-burning sun, ideally toward the morning, is a reasonable habit with vitamin D, circadian and mood value. Burning and tanning beds are the parts to avoid.
Protect against burning; you do not need to avoid daylight to be safe from skin cancer.
The sensible amount shifts with the person. These push toward less sun and more protection:
- very fair skin, or many or unusual moles
- a personal or family history of skin cancer
- a suppressed immune system
- a sunny, high-ultraviolet latitude
Darker skin at a high latitude in winter pushes the other way, toward making sure you get enough.
How It Works
Anatomy of the Practice
1Ultraviolet B makes vitamin D
The shorter ultraviolet B band converts a cholesterol precursor in the surface of the skin into vitamin D3, the main natural source for most people. Production climbs quickly and then levels off well before the skin reddens, so once you are on the way to a burn you are adding skin damage without adding vitamin D. How much you make falls with darker skin, higher latitude, winter, sunscreen and age.
2Ultraviolet A releases nitric oxide
The longer ultraviolet A band reaches deeper and releases a store of nitric oxide from the skin into the blood, which relaxed blood vessels and briefly lowered blood pressure in a small experiment, separate from vitamin D. It is a plausible reason blood pressure tends to run higher in winter and at higher latitudes, and it remains an early mechanism, not a treatment.
3Light sets the body clock
Light reaching a specialized set of retinal cells sets the master clock in the brain, and morning light pulls that clock earlier while late light pushes it later. This is the pathway behind daylight improving morning alertness, bringing sleep on earlier, and lifting mood, and it is why sun taken toward the morning does the most.
4Ultraviolet damages skin DNA
The same ultraviolet that does all this also damages the DNA in skin cells. The body repairs most of it, but not all, so damage accumulates over a lifetime and occasionally becomes a mutation that grows. Burning doses cause the most damage, which is why the melanoma pattern is intermittent burning, not steady outdoor work.
Two of these pathways continue on their own pages. What vitamin D does in the body, and where the large trials found its limits, is on the vitamin D page: correcting a shortfall that exists is worthwhile, while topping up a person who already has enough did little in those trials. The clock-setting pathway, and why morning light and a dark evening pull the same way, is on the circadian entrainment page.
Go Deeper
- Vitamin D: what the sun-made vitamin actually does, a sensible dose, and why topping up an already-sufficient person did little in the big trials.
- Morning light: the circadian half of the benefit, and how to get the body-clock return without seeking a tan.
- Nitric oxide and the endothelium: the blood-vessel lining and the nitric oxide pathway the skin feeds into.
- Evening light and screens: the other end of the daily light signal, protecting the dark so the daytime sun holds.
- Circadian entrainment: how light sets the master clock, the mechanism underneath the timing advice.
The Chinese Medicine View
Chinese medicine reads sun and warmth as Yang: active, warming, outward, the quality that rises with the day. The tradition has long valued sensible sun and outdoor movement as ways to support the body's Yang and its vitality, and rising with the light and living in phase with the day sits close to the opening instruction of the tradition's founding text, which tells a person in spring and summer to rise early with the sun. That framing lines up loosely with sunlight being where the skin makes vitamin D and where the body clock takes its cue, offered here as a way to place the practice, not as validation of it.
The tradition also cautions clearly. Too much sun and heat is its own recognized harm. Summerheat, a category of external heat, is described as consuming the body fluids and the Qi, and heatstroke sits squarely in it, so working or lying in strong midday sun is something the classics warn against. A person of a hot or dry constitution, or one already showing signs of Yin deficiency such as night sweats, a dry mouth and a red tongue with little coating, would be counseled toward the gentler morning sun and shade at midday, not toward more heat. In that frame sensible sun is a moderate, timed thing that supports Yang without scorching the fluids, a reasonable way for a reader who thinks in these terms to hold the same balance the modern evidence describes. It is a lens, and the risk and benefit numbers stand on the studies.
Cautions For This Practice
Extra restraintEverything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
Never burn, and protect children especially
A sunburn is skin damage, and sunburn history is one of the clearest melanoma risk factors, with childhood and adolescent burns carrying particular weight. The single most protective habit on this page is to stop well before the skin reddens, and to keep children out of burning sun with shade, clothing and sunscreen. Cumulative ultraviolet over a lifetime also ages the skin and adds to skin cancer risk, so the aim is regular non-burning exposure.
Tanning beds are a proven carcinogen
A tanning bed delivers ultraviolet with none of the daylight context, ever using one is tied to higher melanoma risk, and starting before age 35 is tied to nearly double the risk, rising with each session. It is not a safe way to get vitamin D or a base tan. If you want color, a self-tanning lotion carries no ultraviolet.
Watch changing moles and spots
Get any mole or spot checked by a doctor if it changes over time, using the ABCDE signs: an uneven or Asymmetric shape, an irregular Border, more than one Color, a Diameter larger than a pencil eraser, or Evolving in size, shape or color, and anything that bleeds, itches or will not heal. Caught early, melanoma and the common skin cancers are usually very treatable, so a changing spot is worth a prompt appointment.
Personal or family history of skin cancer means much less sun
If you have had a melanoma or other skin cancer, a family history of melanoma, many or unusual moles, or very fair skin that burns easily, the balance shifts hard toward protection. This is a conversation with a dermatologist about how much sun is safe for you and how often to have your skin checked, not a general rule.
Some medications and conditions make skin far more sun-sensitive
Certain drugs, including some antibiotics such as doxycycline, some diuretics, retinoids and St John's wort, make the skin burn much faster, as do conditions like lupus. If you take a medication that lists photosensitivity, treat your usual sun tolerance as much lower and cover up or use sunscreen sooner.
A suppressed immune system raises skin cancer risk sharply
Organ transplant recipients and others on long-term immune-suppressing treatment have a much higher rate of skin cancer and need strict, consistent sun protection and regular skin checks. For this group the balance sits firmly on the protection side.
Darker skin needs more sun for vitamin D, fair skin burns fast
Skin type moves the whole calculation. Darker skin is more protected from burning and skin cancer but makes vitamin D more slowly, so it needs longer sun for the same amount and is more likely to fall short at high latitudes. Very fair skin makes vitamin D quickly but burns fast, so it needs less sun and more protection. Set your own dose to your skin, not to a single rule.
Protect the eyes
Ultraviolet harms the eyes over time, contributing to cataracts and other damage, and staring at the sun can injure the retina. Sunglasses that block ultraviolet are worth wearing in bright conditions, and the instruction to get morning light means facing the open sky, not looking toward the sun.
Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.
Common Questions
How much sun do I actually need for vitamin D?
Less than most people think, and it depends on your skin and where you live. For lighter skin under strong summer sun, a few minutes on the arms and legs several times a week supports vitamin D, taken well short of any pinkness. Darker skin and higher latitudes need longer, and a dark winter will not deliver it at all. The aim is brief, regular, non-burning exposure, well short of a mark on the skin.
Is any amount of sun safe?
Regular non-burning exposure is the sensible target, not either extreme. Avoiding the sun entirely was tied to higher overall mortality in a large cohort of women, mostly from heart disease rather than skin cancer, and it costs the vitamin D, body-clock and mood benefits of daylight. Burning and tanning beds are the parts that clearly raise melanoma. So the workable position is to get brief regular sun while protecting against burning, and to protect harder if your skin type or history puts you at higher risk.
Are tanning beds ever a good idea?
No. Tanning beds deliver a proven carcinogen, ever using one is tied to higher melanoma risk, and starting before age 35 is tied to nearly double the risk, rising with each session. They are not a safe source of vitamin D, and a base tan gives very little protection while adding damage. For winter vitamin D, food and a modest supplement do it with no ultraviolet; for color, a self-tanning lotion carries no risk.
Does sunscreen block vitamin D?
In theory it reduces the ultraviolet B that makes vitamin D, but in real use most people apply too little and reapply too rarely for it to matter much, and studies of regular sunscreen users have generally not found them short of vitamin D. The sensible order is to get your brief daily sun without burning, then use sunscreen for the longer exposures where the risk outweighs any extra vitamin D, which is made early in a session anyway.
Is the sun or a supplement the better way to get vitamin D?
For most people with regular access to daylight, brief non-burning sun is the natural source and comes with the body-clock and mood benefits a pill does not. Where sun is scarce, through a dark winter, for shift workers, or for anyone who cannot get outdoors, a modest daily vitamin D3 supplement covers the gap without any ultraviolet cost. The supplement replaces the vitamin D, not the other things daylight does, so it stands in for the months and situations that need it; it is not a full swap.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 6 sources on this page independently checked and cross-referenced.
Thomas Dehli, Founder & Editor, Sacred Lotus
Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.
Evidence strength
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