Percent Concentration Matters
Just because an active ingredient is in a sunscreen doesn’t mean it can protect you sufficiently. What’s important is the amount of it, known as the percent concentration. If you were to randomly sample 100 sunscreens on the market today, you might be surprised by the wide range of concentrations found in formulas – from very little to the legal maximum.
More often than not, there isn’t enough of an active ingredient. This should not surprise you, as lower concentrations require lower raw material costs. Also, a formula with a higher concentration of actives is much more difficult to formulate into a cosmetically acceptable product.
What Sunscreen Percentage of Active Ingredients Is Adequate?
There are no standard guidelines. My view is that, the higher the better, so long as you don’t clog your pores. Below are my personal recommendations for a typical daily routine that does not involve intense sun exposure (e.g. trekking in the Sahari Desert) or intense physical activity.
You might hear differing opinions from other professionals. There is no right answer because what you need depends on your situation and habits, such as where you are, how often you re-apply, whether you’re sweating from physical activity, etc.
For Regular Daily Protection
| Zinc Oxide | 5% minimum; 10-20% is ideal. It is more common to see 2-7% concentrations. 25% is the legal maximum. Anything at this level in a cream form will be very thick and uncomfortable for daily wear on the face. Unless you are extremely photosensitive, this level would be more appropriate for intense sunshine, e.g. trekking in the desert, skiing, or hiking at high altitude. In mineral powder form, over 15% is ideal |
| Titanium Dioxide | 5% minimum;25% is the legal maximum. Same notes for Zinc Oxide apply. |
| Avobenzone | 3% (maximum allowed and the standard concentration used now) Don’t accept anything less than 3%. |
| Ecamsule (Mexoryl SX) | 3% (maximum allowed) |
Tricky Scenarios
Let’s look at some ambiguous scenarios you may come across.
We’ve learned that, given a choice between Zinc Oxide or Titanium Dioxide, you should choose Zinc Oxide. Quite often, a formula will combine both. Let’s say you’re comparing that with a formula that only has Zinc Oxide. What do you do?
Example 1:
Brand A: 15% Zinc Oxide
Brand B: 7% Zinc Oxide + 8% Titanium Dioxide
This is a clear case. Choose Brand A. While the total percent concentration of active ingredients is the same for both (15%), Brand A will give you more UVA protection, all other things being equal between both brands.
Example 2:
Brand A: 5% Zinc Oxide
Brand B: 2% Zinc Oxide + 6% Titanium Dioxide
Tricky, eh? The answer is not clear or definitive. On the one hand, you want the one that provides the MOST coverage of the UVA spectrum (UVA-1 and UVA-2). On the other hand, you want a higher concentration of active ingredients.
While you might be tempted to Choose Brand B because it offers a higher total percentage of actives (8%) than Brand A (5%), you’re getting more Zinc Oxide in Brand A. I would choose Brand A, all other things being equal. I might choose Brand B over Brand A if it contained good antioxidants and Brand A didn’t.
There are no hard rules because there are other factors that determine whether a sunscreen will be effective (i.e. how it has been manufactured, performance ingredients in the formula). My personal rule of thumb is: choose the formula that offers a higher percentage of Zinc Oxide.