2013Annals of Internal Medicine
Hughes et al.
903 adults under 55, 4.5 years
People told to use sunscreen daily showed no detectable increase in skin ageing; those using it as they liked aged 24% more.
Find on PubMed ↗Research library · Everyday body care
Skin: protecting your largest organ
Around 80% of visible ageing on the face comes from the sun. Daily sunscreen is one of the very few anti-ageing habits proven in a randomised trial, and it also halved melanoma, the deadliest skin cancer.
Strong evidence−24%skin ageing over 4.5 years with daily sunscreen vs using it when people felt like itHughes 2013, Ann Intern Med, 903 adults
−50%new melanomas over 10 years with daily sunscreenGreen 2011, J Clin Oncol, 1,621 adults
−23%new non-melanoma skin cancers in high-risk people taking nicotinamide (vitamin B3)Chen 2015, NEJM, 386 adults
01
The basics
How skin ages
Skin has an outer layer (epidermis) that forms a waterproof barrier, and a deeper layer (dermis) full of collagen and elastin that keeps it firm and springy. After about 25, collagen falls by roughly 1% a year.
Ultraviolet light speeds this up. UVB burns the surface and damages DNA. UVA goes deeper, passes through clouds and windows, and breaks down collagen, causing wrinkles, spots and sagging, known as photoageing.
Smoking, poor sleep, high blood sugar and pollution add to the damage. The good news: skin repairs itself, especially overnight, and prescription-strength or over-the-counter retinoids help rebuild collagen.
How UV reaches your skin
UVB burns the outer layer. UVA goes deeper and breaks down collagen. Broad-spectrum sunscreen absorbs or reflects most of both.
02
How it works
From sunlight to skin damage, and back
1
UV hits skin
UVA reaches deep into the dermis; UVB hits the surface.
2
Damage builds
DNA breaks and collagen is broken down with every unprotected day.
3
Sunscreen blocks it
SPF 30 filters about 97% of UVB; 'broad spectrum' means UVA too.
4
Skin repairs
With less new damage, overnight repair and retinoids can catch up.
03
Measure it
Keeping an eye on your skin
- Check the UV index: at 3 or above, protect your skin. Many weather apps show it.
- ABCDE mole check monthly: Asymmetry, irregular Border, uneven Colour, Diameter over 6 mm, Evolving (changing). Show anything new or changing to a doctor.
- Know your skin type: fair skin that burns easily needs the most protection, but all skin types can get skin cancer.
- Full skin check: yearly with a dermatologist if you've had skin cancer, have many moles or a family history.
Try your number
LowProtectHighVery high
011
World Health Organization UV index. Protection is advised from 3 upward.
04
What the research says
The key studies
2011Journal of Clinical Oncology
Green et al.
1,621 adults, Australia
Daily sunscreen for 4 years halved new melanomas over the next 10 years.
Find on PubMed ↗2015NEJM
Chen et al. (ONTRAC)
386 high-risk adults
Nicotinamide 500 mg twice daily cut new non-melanoma skin cancers by 23% over a year.
Find on PubMed ↗2007Archives of Dermatology
Kafi et al.
36 older adults, 24 weeks
A 0.4% retinol lotion improved fine wrinkles and boosted collagen production.
Find on PubMed ↗2019British Journal of Dermatology
Passeron et al.
Review of 75 studies
Normal sunscreen use doesn't cause vitamin D deficiency in healthy people.
Find on PubMed ↗2012BMJ
Boniol et al.
Meta-analysis
Ever using a sunbed raised melanoma risk by 20%; starting before age 35 raised it by 59%.
Find on PubMed ↗05
Take action
A simple, proven skin routine
Two products do most of the work: sunscreen in the morning, a retinoid at night.
- 1
SPF 30+ every morning
Broad-spectrum, on face, neck, ears and hands. About two finger-lengths for face and neck.
- 2
Reapply outdoors
Every 2 hours, and after swimming or sweating.
- 3
Retinoid at night
Start with retinol 2–3 nights a week. Avoid during pregnancy.
- 4
Moisturise
A simple fragrance-free cream supports the skin barrier.
- 5
Shade, hats, clothing
Seek shade in the middle of the day; clothing beats sunscreen.
- 6
Check your moles
Monthly ABCDE check, and see a doctor about anything changing.
06
Myth or fact
Common myths, checked
✕ MythYou don't need sunscreen on cloudy days.
✓ FactUp to 80% of UV passes through light cloud.
✕ MythDark skin doesn't need protection.
✓ FactIt burns less, but UV still ages it and skin cancer still happens, often diagnosed later.
✕ MythSunscreen causes vitamin D deficiency.
✓ FactStudies show normal use doesn't. Diet or supplements can cover vitamin D if needed.
✕ MythExpensive creams work better.
✓ FactCheap, well-tested sunscreen and retinol beat most luxury products.
07
Questions
Frequently asked
Mineral or chemical sunscreen?
Both work. Mineral (zinc, titanium) suits sensitive skin; the best one is the one you'll use daily.
SPF 30 or 50?
SPF 30 blocks about 97% of UVB, SPF 50 about 98%. Applying enough matters more.
Do diet and sleep affect skin?
Yes. Smoking, high sugar and short sleep are linked to faster skin ageing.
08
Sources
References and related topics
- Hughes et al. (2013). Annals of Internal Medicine. 903 adults under 55, 4.5 years. PubMed ↗
- Green et al. (2011). Journal of Clinical Oncology. 1,621 adults, Australia. PubMed ↗
- Chen et al. (ONTRAC) (2015). NEJM. 386 high-risk adults. PubMed ↗
- Kafi et al. (2007). Archives of Dermatology. 36 older adults, 24 weeks. PubMed ↗
- Passeron et al. (2019). British Journal of Dermatology. Review of 75 studies. PubMed ↗
- Boniol et al. (2012). BMJ. Meta-analysis. PubMed ↗