How much sunscreen should I apply to my face?

The recommended amount for the face and neck is approximately 1/4 teaspoon (1.25ml) of sunscreen, which equals about a nickel-sized dollop. Most people apply 20–50% of the recommended amount, which significantly reduces the actual SPF protection. For a sunscreen labeled SPF 50, applying half the recommended amount gives roughly SPF 17 real-world protection. Apply to completely dry skin, and wait 15–30 minutes before sun exposure for chemical sunscreens (mineral sunscreens work immediately).

Does sunscreen need to be reapplied indoors?

If you are near windows, yes — UVA rays (which cause aging and skin cancer) penetrate glass. UVB rays (which cause burning) are blocked by standard glass. For desk work near a window, reapply SPF once in the morning. For outdoor activities, reapply every 2 hours or immediately after swimming or sweating. A setting spray SPF or powder SPF makes reapplication over makeup practical.

What is the difference between PA rating and SPF?

SPF measures UVB protection only — the rays that cause sunburn. PA rating (used in Asian sunscreens) measures UVA protection: PA+ = some UVA protection, PA+++ = high, PA++++ = maximum. Western sunscreens use the term "broad spectrum" to indicate UVA protection, but this is a binary pass/fail — it does not quantify the degree of UVA protection. PA++++ Japanese/Korean sunscreens often provide superior UVA protection compared to most Western broad-spectrum formulas. For anti-aging, UVA protection matters more than the SPF number.

sunscreen · Review

Beauty of Joseon Relief Sun Review: The Best $18 Sunscreen on Amazon

Beauty of Joseon Relief Sun: Rice + Probiotics SPF 50+ is the sub-$20 Korean SPF everyone actually uses. Here's why it earns the reputation.

Our verdict

Beauty of Joseon Relief Sun: Rice + Probiotics SPF 50+

$18

9.3

out of 10

Check price →

Last updated April 12, 2026 · 5 min read · First published Apr 2026

Heads up — this post has affiliate links. We may earn a small commission if you buy something, at no extra cost to you. We only link to stuff we'd actually tell a friend about.

What we like

✓ Korean chemical SPF 50+ PA++++ at $18
✓ Dewy, skin-like finish with no white cast
✓ Fragrance-free, alcohol-free
✓ Contains rice extract + fermented ingredients for barrier support
✓ Works on every skin tone tested
✓ Light enough for humid weather

What bugs us

✗ Small 50ml size lasts about 5-6 weeks at full dose
✗ Not water-resistant
✗ Some find the dewy finish too shiny for oily skin
✗ Occasionally sold as gray-market import on Amazon

The short answer

Beauty of Joseon Relief Sun SPF 50+ is the best sub-$20 face sunscreen available. Korean chemical formula with PA++++ UVA protection, dewy finish, zero white cast, barrier-supporting rice extract. Basically the “no excuses” SPF.

If you’ve ever said “I can’t afford good sunscreen,” this is the post that removes that excuse.

What $18 buys you

The short answer

Relief Sun contains chemical UV filters (octisalate, octocrylene, ethylhexyl triazone) in a light essence base with rice extract, niacinamide, and grain water. SPF 50+ PA++++ in a 50ml tube.

The formula:

UV filters: octisalate, octocrylene, ethylhexyl triazone, iscotrizinol
Niacinamide: barrier support, brightening
Rice extract: antioxidants, skin softening
Grain water: humectant
Rating: SPF 50+ PA++++

The star filter here is ethylhexyl triazone — one of the newer European-approved filters that American sunscreens don’t have access to.

Real performance

I’ve used Relief Sun for 8 months as a daily driver.

Texture: watery essence. Goes on light, absorbs within 60 seconds.

Finish: dewy, slightly glowy. Looks like healthy skin.

Under makeup: fine, but wait 60-90 seconds. Can pill with very silicone-heavy foundations.

Humidity: holds up better than thick American SPFs.

Sensitive skin: never stung, never broke me out.

Why it beats American budget options

The short answer

Compared to American drugstore SPF (CeraVe, Neutrogena), Relief Sun uses newer UV filters unavailable in the US, provides PA++++ UVA coverage, and has a more cosmetically elegant finish — all at a similar or lower price.

CeraVe Hydrating Mineral SPF 30: $16. Good, but mineral, can leave slight cast.

Neutrogena Ultra Sheer: $9. Uses pre-1999 US filters. Dries down drier.

Relief Sun: $18. Better filters, better finish, PA++++ rating.

The import question

The short answer

Beauty of Joseon products are legally imported into the US via Amazon. The FDA hasn’t approved some of the UV filters in the formula, but personal import for individual use is permitted. Check the seller’s rating above 4.5 stars for authenticity.

Amazon Beauty of Joseon:

Sold by BOJ’s own official store in some regions
Also sold by verified Korean beauty importers
Avoid sellers under 4.5 stars
Subscribe-and-save often available

Who should buy Relief Sun

Relief Sun is for:

Anyone on a tight budget
People who want cosmetically elegant SPF
All skin tones
Dry-to-normal skin types
Daily-wear, non-sport use

Skip if you:

Need water-resistance (beach, pool)
Have very oily skin (may feel too dewy)
Are allergic to chemical filters

Comparison to pricier options

vs EltaMD UV Clear ($41): EltaMD is better for sensitive/acne skin. Relief Sun wins on price and finish.

vs Supergoop! Unseen ($38): Unseen is a makeup primer; Relief Sun is a daily SPF. Different use cases.

vs Anessa ($32): Anessa wins for sweat/humidity. Relief Sun wins for daily comfort and price.

Check current price on Amazon →

The verdict

Score: 9.3/10. The best value face sunscreen on Amazon. If you can’t justify $40 SPF, this is the one that makes the math work.

Ready to buy?

Grab the Relief Sun: Rice + Probiotics SPF 50+ on Amazon

Check current price →

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