Why Do Some People Tan While Others Don't?

Two people, the same beach, the same sun. One turns golden, the other turns red. Why? That is the question Jen, Chris and Jamie set out to answer this week, and the answer surprises almost everyone. Tanning isn't a skill you build over a summer. Whether you can tan at all is settled by your genes, and it was decided before you were born. The team unpack what a tan really is (a repair job, not a sign of health), why everyone has roughly the same number of pigment cells but wildly different results, and the two pigments that decide whether you go bronze or go pink. Along the way they bust the base tan myth, put sunbeds firmly in their place, and explain why the person who moves abroad and looks "permanently tanned" is actually showing years of damage. Chris, a formulation scientist who has spent decades working in sun protection, also lays out what genuinely protects your skin. Key Point timestamps: 00:34 What a tan actually is 06:59 Why some people tan and others only burn 10:50 The Fitzpatrick scale and what it means 13:18 What actually protects you (and the truth about sunbeds) (Timestamps are based on the transcript section markers and should be verified against the final edit.) A Tan Is a Repair Job, Not a Sign of Health (02:34) Whatever your skin tone, you carry roughly the same density of pigment-making cells, about 1,200 per square millimetre. The pigment they make is melanin, the skin's own sunscreen. The catch is that skin doesn't make more melanin because the sun is good for it. It makes more because ultraviolet light has already caused damage. UVB harms a skin cell, a protein called p53 (nicknamed the guardian of the genome) raises the alarm, and that signal tells your pigment cells to start producing melanin. The damage always comes first. "A tan is a repair job. It's not a glow of good health." (Chris) Why Some People Tan and Others Only Burn (06:59) There isn't one melanin; there are two. Eumelanin is the dark, more protective pigment that absorbs and safely disperses UV. Pheomelanin is the reddish one that offers little protection and can even trigger oxidative stress. Chris compares your pigment cells to little printing shops. The question was never how many you have, since everyone has about the same number. It's which melanin cartridges are loaded inside them, and that is largely genetic. Around 1 in 20 people, the classic redheads, make almost entirely pheomelanin and barely any eumelanin, so they burn and freckle however careful they are. The Fitzpatrick Scale and What It Means (10:50) Dermatologists grade skin from 1 to 6 on how readily it burns and tans, using the Fitzpatrick scale, developed in the 1970s. Even the darkest, type 6 skin offers natural protection roughly equivalent to an SPF of only 10 to 13, and that is a rough comparison. Every skin type can still burn and be damaged. An older version of the scale wrongly suggested darker skin was safe, and that myth causes real harm because skin cancers can get spotted later. "So it's protection that turns up late and leaves early." (Jamie) What Actually Protects You (and the Truth About Sunbeds) (13:18) If the tan isn't doing the protecting, something else has to. Chris recommends a broad-spectrum sunscreen (covering UVA and UVB) at SPF 25 or higher, reapplied through the day, plus clothing, shade and avoiding the midday sun. Sunbeds are not a gentler option. They deliver very concentrated UV, most of the damage is invisible, and starting young sharply raises the risk of serious skin cancer. And the pale person who moves somewhere sunny and looks bronzed years later? That is accumulated UV injury, not a built-up tan. "There's no such thing as a safe tan, and you sadly can't train your skin into making one either." (Jen) About So That's Why So That's Why is a weekly podcast where Jen, Chris and Matt unpack the science behind everyday health questions. No jargon, no judgment, just genuine curiosity and proper research. Website: https://www.vegetology.com/so-thats-why-podcast