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

SkinCeuticals Phloretin CF Review: C E Ferulic for Oily Skin

Phloretin CF is SkinCeuticals' vitamin C serum for oily and combination skin. Same Duke patent, oilier-skin formulation.

Our verdict

SkinCeuticals Phloretin CF Antioxidant Serum

$182

9.3

out of 10

Check price →

Last updated April 13, 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

✓ Same Duke patent ratio as C E Ferulic
✓ Premium Beauty listing
✓ Better for oily/combo skin than CEF
✓ Includes phloretin (additional antioxidant)
✓ Visible brightening + photoprotection

What bugs us

✗ $182 is luxury pricing
✗ Strong fermented smell
✗ Can be drying for very dry skin

The short answer

SkinCeuticals Phloretin CF is C E Ferulic reformulated for oily and combination skin. Same Duke patent, lighter texture, added phloretin antioxidant. At $182 it’s the same investment as CEF — pick based on your skin type.

If C E Ferulic feels too rich on your skin, this is the version for you.

CEF vs Phloretin CF

Feature	C E Ferulic	Phloretin CF
Skin type	Normal/dry	Oily/combo
Key actives	15% L-ascorbic + 1% vit E + 0.5% ferulic	2% phloretin + 10% L-ascorbic + 0.5% ferulic
Texture	Slightly heavier	Lighter
Price	$182	$182
Premium Beauty	Yes	Yes

What phloretin adds

Phloretin is a natural antioxidant from apple peel and white birch root. It enhances vitamin C’s photoprotective effect and adds anti-inflammatory action particularly useful for acne-prone skin.

12-week results

Week 4: brightening visible
Week 8: significant photoprotection synergy with SPF
Week 12: even tone, fewer pimples
Best paired with EltaMD UV Clear or Supergoop Unseen for combo skin

Check current price on Amazon →

The verdict

Score: 9.3/10. C E Ferulic for oily skin. Same gold standard at the same price.

Ready to buy?

Grab the Phloretin CF Antioxidant Serum on Amazon

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SkinCeuticals · sunscreen

C E Ferulic Vitamin C Serum

An honest look at CE Ferulic vs Maelove ($30), Timeless ($25), and Naturium ($22). Here's what the $182 actually buys you — and which dupe gets 80% of the way.

9.6/10Read review →

Anessa · sunscreen