You weren't looking for a lecture on SPF when you searched this. You want to know why you go red in twenty minutes when your grandparents worked outside all day. Part of the answer is the fat your skin is built from, and that fat has changed more in the last fifty years than in the thousand before. Seed oils put a fragile fat into every cell membrane you have, and under UV that fat breaks down into the stuff that makes a burn red, hot and sore.
What burning fast costs you
The sun is one of the strongest signals your body gets. Sun on bare skin raises T, opens your arteries and makes vitamin D; the full case is in sunlight for testosterone. Aajonus went further: the sun turns the fat in your skin into vitamin D and other lipids that feed the body, grow bone and regenerate tissue (Q&A, 2005). If you burn in twenty minutes, you never get enough of it.
A burn is inflammation. UVB hits your skin cells, they release prostaglandin E2, your small blood vessels open, and the skin goes red and hot. Rhodes and colleagues (1995)¹ measured it in blister fluid: after a dose of UVB, prostaglandin E2 in the skin shot up.
Sunscreen stops the burn by blocking UVB, the band that makes vitamin D and starts the hormone signal, so it takes away the reason you went out. Aajonus called it very, very toxic, and his line on the sun itself was blunt: no damages from the sun.
What makes skin burn
In his 2005 Q&A Aajonus said it directly: the fat in the skin determines whether you use the sun's rays properly. So the question isn't how strong the sun is. It's what the sun is hitting.
Three things decide that. The first is the fat you eat, because that's what your skin is built from. The second is the oil sitting on your skin when you go out. The third is how much toxicity you carry: Aajonus said the more chemicals in your body, the more it pulls fat out of the skin to bind them, which leaves the skin short of the fat it needs to use sunlight (2012 workshop).
Treat them as suspects. You might have one or all three. The first is the one that has changed most in the last fifty years.
It's usually not the sun alone
Your skin is partly made of fat, and linoleic acid is one of its main unsaturated fats (Niki 2015²). Linoleic acid is the main fat in seed oils. It has two double bonds, which makes it easy for UV to break apart. Saturated fat, the kind in butter and beef fat, has none.
When UVB hits skin cells, their linoleic acid oxidizes into 9-HODE. 9-HODE binds a receptor on those cells and makes them release inflammatory signals, IL-6 and IL-8 among them (Hattori and colleagues (2008)³). In rodents with UVB burns, 9-HODE and 13-HODE in the skin went up, and both switch on TRPV1, the same channel that fires when you touch something hot (Sisignano and colleagues (2013)⁴). That's the sting of a sunburn.
And there's a lot more of it in us than there used to be. Linoleic acid in the body fat of US adults rose 136% over fifty years, tracking the switch to seed oils like soybean oil (Guyenet and Carlson (2015)⁵). Your grandparents' skin was built from a different fat.
Butter beats seed oil under UV. Cope and colleagues (1996)⁶ fed hairless mice butter, clarified butter, sunflower oil or margarine and then hit them with UVB or full simulated sunlight. Butter and clarified butter protected their skin immunity from the UV; sunflower oil and margarine didn't. The more of the fat was clarified butter, the more protection, in a straight line.
Seed oil makes UV damage worse, dose by dose. Black and colleagues (1985)⁷ found corn and soybean oil drove UV skin damage harder than the same amount of hydrogenated fat, and the more oil in the feed, the sooner and the more the damage showed. Hydrogenated vegetable fat is no escape: Barcelos and colleagues (2013)⁸ found trans fat raised UV oxidative damage in mouse skin, which fits what Aajonus said about heated, hydrogenated oils hardening in the body (Hot Tub Therapy).
Change the fat and the burn changes in people too. In Rhodes and colleagues (1995)¹, 13 adults with sun-sensitive skin ate more fish fat for three months. The UVB it took to turn them pink went from 19.8 to 33.8 mJ/cm², and the prostaglandin E2 that UVB raised dropped.
Figure 1
Seed oils are mostly linoleic acid. Butter and tallow barely have any.
Linoleic acid as a share of each fat's fatty acids, typical values
- Safflower oil75%
- Sunflower oil66%
- Corn oil54%
- Cottonseed oil52%
- Soybean oil51%
- Peanut oil32%
- Chicken fat20%
- Canola oil19%
- Lard10%
- Olive oil10%
- Butter3%
- Beef tallow3%
- Coconut oil2%
Linoleic acid in the fat
Figure 2
Same people, same light: 71% more UVB before going pink
Sun needed to turn the skin pink, before and after 3 months of eating more fish fat. 13 adults, Rhodes 1995
- Before19.8
- After 3 monthsmore fish fat33.8
- Change+71%
UVB to turn pink, mJ/cm²
Check which kind you have
You can get most of the way with a kitchen and a watch. Run four checks.
- Your oils. Read the label on everything you cook with and every packaged food you eat often. Soybean, sunflower, safflower, corn, cottonseed, canola, margarine and anything called vegetable oil all count.
- Eating out. Count how many meals a week you don't make yourself. Restaurant fryers, chips, mayo, dressings and sauces are nearly always seed oil.
- Your animal fat. Chicken and pork fat carry the oil the animal was fed, so grain-fed chicken skin is about 20% linoleic acid. Beef, lamb and butter stay around 3%.
- Your burn clock. On a clear day, go out at noon on skin you haven't washed that morning and time how long it takes to go pink. Write it down and repeat it once a month.
Reading your result
If you cook with seed oil or eat out most days, the fat is the main driver. That's most people.
If you already cut the oils but shower with soap every morning and never let yourself tan, the oil on your skin is the weak point.
If you eat clean and keep your skin's oil on and still burn fast, Aajonus would point at toxicity: the body is spending the skin's fat to bind what it's carrying. That takes time and fat, not a lotion.
If yours is seed oil: how long it takes to clear
The goal is zero seed oil, not less of it. A spoon of sunflower oil a day still adds more linoleic acid than a stick of butter.
Some of it moves fast. When people switched diets, the linoleic acid in their blood, red cells and the cells lining their cheeks changed within the first two weeks (Hodson and colleagues (2014)¹⁰). Cheek cells are a lot like skin cells, so the surface starts changing quickly.
Stored body fat is slow. It turns over with a half-life of 200 to 270 days (Strawford and colleagues (2004)¹¹), so half the stored seed oil is gone in seven to nine months and most of it in about two years. Your burn clock should improve in steps across that whole time.
Don't reach for fish oil capsules or antioxidant pills to speed it up. Get your fish fat from raw fish and oysters. Antioxidant pills can backfire; Black (2015)⁹ warned that they can do harm once they meet the cell's own antioxidant defenses.
Figure 3
Half your stored seed oil is gone in 7 to 9 months
Share of stored linoleic acid left after you stop eating it, from the measured turnover of body fat (Strawford 2004)
- Start100%
- 6 months53–63%
- 1 year28–39%
- 18 months15–25%
- 2 years8–15%
- 3 years2–6%
Stored linoleic acid left
If yours is your skin's oil: keep it on
Aajonus was clear on this: don't shower or bathe the morning of a day you sunbathe. Washing removes the body's natural oils, and those oils are a natural sunblock (Beneficial Home Baths).
Tan slowly. The Primal Diet says to start with 30 minutes on the first day of the season and go a bit longer each day.
For skin that has been damaged a long time, he found that raw meat slices on the face at night started to revitalize it, so it could handle the sun better (Q&A, 2005).
How to sunbathe without burning, without sunscreen
The main lever is the fat you eat. Raw unsalted butter and raw cream are the base. Add raw eggs, raw beef and lamb fat, raw fish and oysters, and warm raw milk; the full case for that last one is in raw milk for looksmaxxing. Cut every seed oil, and don't cook anything in oil. Aajonus matched the meat to the skin: if you hold a tan well, eat more fish, fowl and seafood; if you're pale, eat more red meat, but always eat both (2008 workshop).
On the skin, his formula was one part each of coconut cream, raw butter and raw cream, with half a teaspoon of raw honey and an eighth of a teaspoon of royal jelly per eight ounces, blended. It has to be all three: coconut cream alone, cream alone or butter alone, you'll burn (2002 workshop).
When someone at a workshop said they'd stopped burning after raising their fat, he said butter helps that the most and prevents burn (2013 workshop).
- Eat raw fat every day: butter, cream, eggs, meat fat, raw fish.
- No seed oils, no margarine, nothing fried, and as few restaurant meals as you can manage while the stored fat turns over.
- Don't shower the morning you sunbathe.
- For a block, put raw coconut cream on the night before; it's 78% oil and needs the night to soak in. Coconut oil on its own is a tanning lotion, not a block (2010 workshop).
- Out in the sun, fresh raw milk on the skin blocks it. Even if you go very red, Aajonus said it's gone by the next morning (2010 workshop).
- Day one of the season: 30 minutes. Then a little longer each day.
- If you do burn, put on raw milk, raw butter or his skin formula, or raw egg white.
| Seed-oil diet | Raw animal fat | |
|---|---|---|
| Main fat in your skin | Linoleic acid, two double bonds | Saturated and monounsaturated fat |
| Under UV | Oxidizes into 9-HODE and 13-HODE | Holds up; butter protected mouse skin |
| How long it lasts | Keeps building up while you eat it | Membranes in weeks, stored fat in one to two years |
What the sun-care aisle sells for burning
Nobody buys sun care to burn less next year. They buy it to get through today.
Sunscreen is the main one. Aajonus said it's very toxic, and that people eating properly don't need it (2012 workshop). His best sunscreen was coconut cream (2008 workshop). Tanning beds he called very toxic too (Q&A, 2002).
After-sun gels, fish oil capsules and antioxidant pills all work around the fat in your skin instead of changing it. We aren't recommending any of them.
