What Does a Sunscreen's SPF and PPD Really Mean?

Last edited by Birdman on Wed Mar 16, 2011 11:55 am; edited 3 times in total

Just thought I'd like to share this extract to help us golfers understand sunscreens, how to apply, and if a higher SPF factor offers proportionately more protection. Also, not many of us know that PPD is just as important as SPF. What is interesting is that there is not much difference in protection from an SPF of 30 to an SPF of 100. Just an increment of %3.5, yet we pay so much more for sunscreens with SPF 50, 70, and 100.

Applying and using Sunscreen

Apply sunscreens to dry skin half an hour before going outside. Shake the bottle well and apply thickly and thoroughly.

"Teaspoon Rule"
Be sure to use enough sunscreen. Most people only use half as much as they are supposed to. As a rule of thumb, use one teaspoon to cover the face, neck, and ears; one teaspoon to cover the front; one teaspoon to cover the back of the body; and one teaspoon for each arm or leg not covered with clothing. A typical twist off cap from a soda bottle is about one teaspoon. If you only use half as much sunscreen as you should, you are only getting half the protection. Don't forget to put sunscreen on your ears, the base of the neck, the tops of feet, and the backs of knees. One study on photosensitive patients showed that they only applied 1/4 of the recommended amount of sunscreen.

Reapply every 2 hours. Reapply after swimming or sweating. Most sunscreens are very fragile and easily rubbed off. Some sunscreens suggest that you reapply after 2, 3 or 4 hours. Some chemical sunscreen ingredients breakdown and no longer work after a while.

Don't store sunscreen in the car and other places, where temperatures may get high. Heat may change the chemical composition of sunscreens. Throw out your old sun block. The chemical composition of sunscreens can change with age, and it may no longer perform as stated on the bottle. Check the expiration date.

Understanding SPF and PPD values of sunscreen ratings

SPF measures how well a sunscreen protects you against sunburn and UVB light. Theoretically, an SPF rating of 10 should allow you to stay in the sun ten times longer than normal. Persistent Pigment Darkening (PPD) measures how well a sunscreen protects you against UVA light. Theoretically, a PPD rating of 10 should allow you to stay out in the sun ten times longer.

People with extreme photosensitivities may have reactions in just a matter of minutes, so we need the highest SPF and PPD ratings possible. In real life, people rarely get the SPF or PPD rating on the sunscreen bottle because: not enough sunscreen is put on in the first place, or sunscreen is wiped or sweated off, or sunscreen is left on too long and is no longer effective etc. Most people only apply enough sunscreen to achieve an SPF of about a third or even a quarter of the level stated on the product.

As an example, take someone who reacts to the sun in 5 minutes that uses an SPF sunscreen of 30. But they only put on a third as much as they should have. Now assume that the SPF rating of 30 is reduced by one third to a value of 10 because he or she didn't apply enough sunscreen. An SPF of 10 is supposed increase a person's tolerance time in the sun by a multiple of 10, so they would be able to spend 50 minutes in the sun.

5 minutes x 10 =50 minutes,

where 10 is the SPF rating, 5 minutes is the the person's sun tolerance without sunscreen, and 50 minutes is the person's theoretical sun tolerance with sunscreen.

Theoretically for SPF or PPD values above 30, light protection does not increase significantly as shown in Table 2. For example, doubling the SPF from 50 to 100 only blocks an additional 1% more light. Different organizations argue that there is no need for an SPF greater than 30, and some European regulations only allows sunscreens to have a maximum SPF rating of 50+, and no higher. But if we added the real life factors, then all of those theoretical ratings get reduced by more than half to one fifth of the original SPF rating. As was shown in the previous example, those of us with extreme sun sensitivity and short sun tolerance time need those extremely high SPF ratings. On the other hand, critics argue that it is difficult to test high SPF ratings.

Table 2: Protection of sunscreens by SPF rating and PPD rating
(Most people do not apply enough sunscreen and can reduce SPF values to one third or one fourth the value on the bottle.)

SPF rating - % of UVB light blocked
(measures UVB)
2 - 50.00%
4 - 75.00%
10 - 90.00%
30 - 96.67%
50 - 98.00%
70 - 98.57%
100 - 99.00%

PPD rating - % of UVA light blocked
(measures UVA) (percentages may be incorrect, but idea is right)
2 - 50.00%
4 - 75.00%
10 - 90.00%
30 - 96.67%
50 - 98.00%
70 - 98.57%
100 - 99.00%

Select sunscreens with a high PPD rating for good UVA protection

Look for a sunscreen with a high PPD (measure of how well it protects against UVA light). The following is a suggestion of what sunscreens to try based on sunscreen research and reviews.

Europeans sunscreens (best):
Some ingredients are only available in Europe.

Anthelios 60 XL cream UVA: IPD 80, PPD 28
by Laroche-Posay with Mexoryl XL, Mexoryl SX
Especially designed for those who need the strongest possible sun protection Protection
Reviews: For 16 Against 11

La Roche Posay Anthelios Dermo-Kids Crème 60 PPD 28
with Mexoryl XL & SX, Tinosorb S, BMDM, TO2
Reviews: For 15 Against 4

Vichy Capital Soleil Ultra Fluide SPF 60 PPD 20
with Mexoryl XL & SX, Tinosorb S, TO2, Ethylhexyl triazone, BMDM
Reviews: For 8 Against 2

Canadian sunscreens: (next best)
Some ingredients are only allowed in Canada.

Anthelios L, SPF 60, PPD 15.
Solar intolerance sunscreen by LaRoche-Posay
with Mexoryl SX, Parsol 1789 and titanium dioxide.

Vichy Capital Soleil SPF 60, estimated PPD 15
with mexoryl SX, 3.5% BMDM, 4% TiO2, 5% 4-MBC.
Vichy SPF 60 appears to be the most cosmetically elegant, highly protective Canadian sunscreen. It is fragrance-free, unlike LRP Anthelios L SPF 60.

Ombrelle SPF 60
with Mexoryl (some complain of it being sticky)

United States sunscreens: (not as good)
Some of the best UVA ingredients are not allowed in the U.S.

Total Block SPF 65
with Benzophenone-3, Octyl Methoxycinnamate,Octocrylene, Titanium Dioxide, Zinc Oxide

Very Active Golfer Posts : 554 Join date : 2011-02-10

i have heard that sunscreen contains a chemical compound causing cancer.

is that true??

(this concern is coming from a smoker)

Master wrote:: i have heard that sunscreen contains a chemical compound causing cancer.

is that true??

(this concern is coming from a smoker)

Dunno man, either way, whether it happens from the inside or outside, result is the same, still KO right? Stretcher

Birdman ex sunscreen promoter?

Check out the knowledge! Laughing

Last edited by Birdman on Wed Mar 16, 2011 1:26 pm; edited 2 times in total

No la CP, extract and edit only.

You the Chemical Pro!

Point is, SPF 50 enough oredi, anything higher is just throwing money down the drain lor... 0.57% extra protection pay an extra $3 to $4 which is a quarter more of the sunscreen's price, don't make sense to me at least.

But I guess peace of mind is pricless. Very Happy

True, I think I'll just get the SPF 50 next time.

But you know la, 70 > 50.

Damn marketing ploy! Mad

Yup, I know... last time also thought higher the better, "what's a few dollars more for a 20 times increase in protection from 50 to 70 SPF?" I used to think.

Bodoh! ROFL

A few things to note here. Do not think of how many percent more as it is misleading.

SPF 2 means you can stay outside for twice as long. Hence 50%. Cos in 1 min, you have half the sun damage(50%) compared to someone not using sunblock and 100% in two minutes.

So although SPF 30 appears only marginally better than SPF 50, we are talking amount substantial amount here. It is almost double the damage from someone using SPF 50.

But is SPF 70 better than SPF 50? That becomes debatable. The amount of sun one can endure differs from ppl(dark ppl can endure more than fairer). Based on tolerance without any sunblock, we can calculate SPF to use by dividing the total time by the actual tolerance. Eg, 10 mins of sun(recommended by Doc to have vitamin D) and I game of golf 5 hours to include some waiting and misc(300mins). Then SPF 30 is sufficient. But if you play 2x18, you will want SPF 60. If not you end up with double the damage.

For fairer ppl, the tolerance might be less than 10mibs. In that case SPF 30 is not enough for a game.

Super Active Golfer Posts : 1121 Join date : 2009-06-21

almost all golfers apply sunscreen 5 mins before tee off or even at the 1st hole, some like mysef even apply only when there is sun....all these the wrong method

the korean ladies (long sleeve, long pants, oversized sunglasses, neck cover, large hat, two gloves and no gap between the glove and shirt sleeve) method is still the best....

tronos wrote:: the korean ladies (long sleeve, long pants, oversized sunglasses, neck cover, large hat, two gloves and no gap between the glove and shirt sleeve) method is still the best....

See anyone like that on the course now, sure run away one. Macham radiation suit. ROFL