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. (Book)(HL-book-prevention-20)
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)
2) 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)
3) 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)(HL-book-prevention-20)
FAQ
Will sunscreen make me vitamin D deficient?
For most people, no — typical sunscreen use has minimal impact on vitamin D levels. (3)
If you’re very consistent with daily high-SPF use and have other risk factors, deficiency can still occur — manage it with testing and supplements. (1,2)
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. (1,2)
What vitamin D level should I aim for?
General “sufficient” targets are often ≥50 nmol/L, especially at end of winter. (4,5)
For some high-risk patients, Dr Chris may recommend aiming >100 nmol/L via diet/supplements, typically keeping a supervised range around 100–150 nmol/L while avoiding excessive levels. (4,10,11)
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. (11)
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. (1,2,4)
Related pages
- (Sunscreen hub)
- (UVA vs UVB, SPF, broad-spectrum & water resistance)
- ()How to apply sunscreen properly
- (Actinic keratoses prevention & field treatment)
- (Full skin checks)
References
1.Cancer Council Australia — Sunscreen (vitamin D guidance; UV ≥3; supplementation advice). https://www.cancer.org.au/about-us/policy-and-advocacy/prevention/uv-radiation/related-resources/sunscreen
2.Cancer Council Australia — Vitamin D (sun safety position; “overexposure is never recommended”). https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/vitamin-d
3.Australian Prescriber — Sun protection: a practical guide for health professionals (real-world sunscreen use and vitamin D evidence). https://australianprescriber.tg.org.au/articles/sun-protection-a-practical-guide-for-health-professionals.html
4.RCPA — Use and Interpretation of Vitamin D Testing (25-OH-D; decision limits; seasonal context; cautions on higher limits). https://www.rcpa.edu.au/Library/College-Policies/Position-Statements/Use-and-Interpretation-of-Vitamin-D-Testing
5.Royal Children’s Hospital Clinical Guideline — Vitamin D deficiency (definitions incl. ≥50 nmol/L; toxicity definition framework). https://www.rch.org.au/clinicalguide/guideline_index/Vitamin_D_deficiency/
6.Bikle DD. Vitamin D and the skin: Physiology and pathophysiology (review: keratinocyte differentiation; skin immune roles). https://pmc.ncbi.nlm.nih.gov/articles/PMC3687803/
7.Grieco T, et al. Non-skeletal roles of vitamin D in skin (review: barrier proteins; keratinocyte homeostasis). https://www.mdpi.com/1422-0067/26/17/8520
8.Samanta S, et al. Vitamin D and immunomodulation in the skin (review: immune modulation pathways). https://www.explorationpub.com/Journals/ei/Article/10039
9.Lim A, Shayan R, Varigos G. High serum vitamin D level correlates with better prognostic indicators in primary melanoma (pilot study). https://pubmed.ncbi.nlm.nih.gov/28332194/
10.RACGP AFP — What is the optimal level of vitamin D? (debate about higher targets; evidence limitations). https://www.racgp.org.au/afp/2014/march/vitamin-d
11.RCPA Manual — Vitamin D (toxicity discussion; hypercalcaemia thresholds). https://www.rcpa.edu.au/Manuals/RCPA-Manual/Pathology-Tests/V/Vitamin-D
12.Healthdirect Australia — Vitamin D and your health (dietary sources; fortified foods). https://www.healthdirect.gov.au/vitamin-d-and-your-health
13.Eat for Health (Australian NRVs) — Vitamin D (diet sources in Australia; fortified margarine etc.). https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/vitamin-d
14.Jablonski NG. The evolution of human skin pigmentation… (diet/UV/lifestyle and vitamin D sufficiency discussion). https://pmc.ncbi.nlm.nih.gov/articles/PMC8359960/