The short answer

Sensible sun protection does not put most Australians at risk of deficiency: typical sunscreen use has little effect on vitamin D levels, because real-world application is imperfect and incidental exposure still occurs. Very consistent daily SPF 50+ use can be linked to a higher likelihood of deficiency in some people, but the fix is testing plus diet and supplements, not extra UV — deliberate unprotected exposure at UV index 3 or above is not recommended. The standard test is 25-OH-D in nmol/L, and ≥50 nmol/L is the usual target, with supervised higher targets for very high-risk patients.

Key points
  • Vitamin D regulates bone and muscle health and has roles in skin cell maturation and immune regulation.
  • Most studies show typical sunscreen use has little effect on vitamin D levels.
  • Very consistent daily SPF 50+ use can be associated with higher deficiency risk in some people.
  • Do not "treat" low vitamin D with deliberate sun exposure at UV index 3 or above.
  • General target is ≥50 nmol/L; for high-risk skin cancer patients, supervised targets above 100 nmol/L may apply.
All 10 key points
  • Higher-risk groups include skin cancer history, darker skin, indoor lifestyle, obesity and certain conditions.
  • The standard blood test is 25-hydroxyvitamin D (25-OH-D), reported in nmol/L in Australia, not mmol/L.
  • Higher vitamin D around melanoma diagnosis is associated with better prognostic indicators, but this is association, not proof.
  • Most Australians get only a minority of their vitamin D from diet, so food works best alongside supplementation.
  • Higher supervised targets warrant monitoring, especially with kidney disease, sarcoidosis or calcium supplements.

Vitamin D matters — and so does preventing skin cancer. The reassuring reality is that sensible sun protection (including sunscreen) does not put most Australians at risk of vitamin D deficiency, and deliberate UV exposure is not recommended as a “treatment” for low vitamin D. (1–3)

Worried about vitamin D or skin cancer risk?

Book a 20-minute prevention plan with Dr Chris

What vitamin D does (and why this topic gets confusing)

Vitamin D is best known for its role in bone and muscle health via calcium and phosphate regulation. (4,5) But it’s also biologically active in skin:

  • Skin cell maturation: vitamin D signalling (via the vitamin D receptor) influences keratinocyte proliferation and differentiation (how skin cells mature). (6,7)
  • Immune regulation in skin: vitamin D has immunomodulatory roles, influencing inflammatory signalling and immune cell behaviour within the skin environment. (6,8)

Vitamin D and melanoma risk (what we can reasonably say)

Some studies have found that higher vitamin D levels around the time of melanoma diagnosis are associated with “better prognostic indicators” (for example, thinner primaries or other favourable features). This is association, not proof that vitamin D prevents melanoma or improves outcomes by itself — but it’s clinically interesting and one reason many melanoma/high-risk patients choose to keep vitamin D in a healthy range without using sun exposure. (9)

Does sunscreen “block” vitamin D?

In theory: it can reduce UVB reaching the skin

UVB contributes to vitamin D synthesis; sunscreen reduces UV reaching the skin.

In real life: the effect is usually small

Evidence summaries for clinicians note that most studies (including randomised trials) show little to no significant impact on vitamin D levels with typical sunscreen use, largely because real-world application is imperfect and incidental exposure still occurs. (3)

A practical nuance: very consistent daily SPF use may increase deficiency risk in some people

Cancer Council Australia has highlighted Australian research suggesting that very consistent daily SPF50+ use can be associated with a higher likelihood of vitamin D deficiency in some participants — while still emphasising continued sun protection and that overexposure to UV is never recommended. (1,2) Bottom line: If you’re extremely sun-protective (often the right choice for skin cancer risk), the solution is testing + diet/supplements, not chasing extra UV. (1,2)

The safest approach: protect your skin and manage vitamin D medically

  1. Don’t “treat” low vitamin D with deliberate sun exposure

When the UV Index is 3 or above, extended deliberate sun exposure without protection is not recommended — even if vitamin D is low. (1,2)

  1. If you’re concerned, measure it properly (and target the right range for you)

The standard blood test is 25-hydroxyvitamin D (25-OH-D). (4) Important note on units: vitamin D is typically reported in nmol/L in Australia (not mmol/L). Many Australian guidance sources use ≥50 nmol/L (especially end of winter) as a practical “sufficient” threshold for the general population. (4,5) Dr Chris’s practice approach for melanoma and other very high-risk skin cancer patients (supervised): we often aim for a 25-OH-D level >100 nmol/L, achieved via diet and vitamin D supplementation — not sun. For most people, 100–150 nmol/L is a reasonable and safe supervised range, while still being mindful that very high levels can be harmful. (4,10,11) If you’re aiming for higher targets, it’s sensible to do this with monitoring, especially if you have kidney disease, granulomatous disease (e.g., sarcoidosis), or are taking calcium supplements. (11)

  1. Supplement if needed (often the simplest, safest fix)

Supplementation is usually safer than increasing UV exposure. Your GP will tailor dose based on:

  • your baseline level
  • your risk factors and season
  • your medical history and other meds (5)

Foods that help (yes — diet can matter)

Most Australians only get a minority of vitamin D from diet, but food can still contribute meaningfully — especially alongside supplementation. (12,13) Foods that contain vitamin D include: (12,13)

  • oily fish (salmon, sardines, mackerel, herring)
  • egg yolks
  • UV-exposed mushrooms
  • fortified foods (e.g., some milks/alternatives, margarine, some cereals)

A quick evolutionary aside (because it’s fascinating)

There’s an ongoing scientific discussion about how diet, UV environment, and lifestyle shaped human skin pigmentation. Some researchers suggest that in certain high-latitude populations, traditional diets rich in marine foods may have supported vitamin D sufficiency, potentially influencing selective pressures on pigmentation — but it’s complex and not a single-factor story. (14)

Who is more likely to be vitamin D deficient?

You’re more likely to need a proactive plan if you: (1,4)

  • have had skin cancers / lots of actinic keratoses (and avoid sun appropriately)
  • have naturally darker skin
  • cover most skin for cultural/religious reasons
  • spend most time indoors (frail/elderly, institutionalised, housebound)
  • have obesity
  • have conditions/medications affecting absorption/metabolism
  • are pregnant/breastfeeding with risk factors, or have an infant at risk

If this sounds like you, book a prevention plan — we’ll protect your skin and keep vitamin D in a healthy range safely.

Book a 20-minute prevention plan with Dr Chris

Frequently asked questions

  • Will sunscreen make me vitamin D deficient?
    For most people, no — typical sunscreen use has minimal impact on vitamin D levels.
  • Should I stop sunscreen to improve vitamin D?
    Usually, no. In Australia, deliberate unprotected UV exposure is not recommended as a vitamin D strategy because UV increases skin cancer risk.
  • What vitamin D level should I aim for?
    General “sufficient” targets are often ≥50 nmol/L, especially at end of winter.
  • What level is “too high”?
    Toxicity is uncommon but real — the risk rises at very high 25-OH-D levels and is typically related to excess supplementation. Pathology guidance notes hypercalcaemia isn’t usually seen until substantially higher levels, and toxicity definitions often focus on markedly elevated levels with hypercalcaemia.
  • I’ve had melanoma or lots of skin cancers — how do I get vitamin D safely?
    Continue strong sun protection and manage vitamin D with blood testing and supplements, not sun exposure.

References

  1. Cancer Council Australia — Sunscreen (vitamin D guidance; UV ≥3; supplementation advice).
  2. Cancer Council Australia — Vitamin D (sun safety position; overexposure is never recommended).
  3. Australian Prescriber — Sun protection: a practical guide for health professionals (real-world sunscreen use and vitamin D evidence).
  4. RCPA — Use and Interpretation of Vitamin D Testing (25-OH-D; decision limits; seasonal context; cautions on higher limits).
  5. Royal Children's Hospital Clinical Guideline — Vitamin D deficiency (definitions incl. ≥50 nmol/L; toxicity definition framework).
  6. Bikle DD. Vitamin D and the skin: physiology and pathophysiology. Rev Endocr Metab Disord. 2012;13(1):3-19.
  7. Grieco T, et al. Non-skeletal roles of vitamin D in skin (review: barrier proteins; keratinocyte homeostasis). Int J Mol Sci. 2025;26(17):8520.
  8. Samanta S, et al. Vitamin D and immunomodulation in the skin (review: immune modulation pathways). Explor Immunol.
  9. Lim A, Shayan R, Varigos G. High serum vitamin D level correlates with better prognostic indicators in primary melanoma: a pilot study. Australas J Dermatol. 2018;59(3):e221-e225.
  10. RACGP AFP — What is the optimal level of vitamin D? (debate about higher targets; evidence limitations).
  11. RCPA Manual — Vitamin D (toxicity discussion; hypercalcaemia thresholds).
  12. Healthdirect Australia — Vitamin D and your health (dietary sources; fortified foods).
  13. Eat for Health (Australian NRVs) — Vitamin D (diet sources in Australia; fortified margarine etc.).
  14. Jablonski NG. The evolution of human skin pigmentation involved the interactions of genetic, environmental, and cultural variables. Pigment Cell Melanoma Res. 2021;34(4):707-729.

Related

Portrait of Dr Christopher Irwin

By Dr Christopher Irwin, MBChB, FRACGP, MMed (Skin Cancer), FACAM, MSCCA

Last reviewed 2026-06-06 · Editorial policy