Sunscreen in Nepal: what the numbers on the bottle actually mean

Sunscreen is the product Nepali shoppers ask about most and understand least, and that is not anyone's fault. The labels are genuinely confusing, the marketing is loud, and most of the advice circulating online was written for people living at sea level in countries with weak winter sun.

Nepal is a different situation, and the difference is not small.

Altitude changes the maths

Ultraviolet radiation increases by roughly ten to twelve percent for every thousand metres you climb. The atmosphere above you is thinner, so less UV gets filtered out before it reaches skin. Reflective surfaces make it worse: snow throws back a large share of the UV that hits it, which means at altitude you are getting radiation from above and from below at the same time.

Kathmandu Valley sits at around 1,400 metres. The midday UV index here commonly reaches 8 to 11, which is the range meteorological services label very high to extreme. In the summer months it goes higher still, and burn times drop into the range of minutes rather than hours. Crucially, it does not collapse in winter the way it does in temperate countries, because Nepali winter skies are clear and thin.

Now put that next to where people actually go. Pokhara, Sarangkot, a weekend at Nagarkot, a trek that starts at 2,000 metres and climbs. Every one of those is a meaningfully higher UV dose than the same activity in the Terai, and most people pack for cold rather than for sun.

SPF and PA are measuring two different things

This is the part worth reading slowly, because getting it wrong is the most common reason people use sunscreen diligently and still pigment.

UVB is the burning wavelength. UVA is the one that penetrates deeper, reaches you through window glass, and stays relatively constant through the day and across seasons. UVA is the main driver of the dark patches and uneven tone that most Nepali customers are actually trying to prevent.

A sunscreen with a high SPF and no meaningful UVA protection will stop you burning while doing very little for pigmentation. If your main concern is tone and marks rather than sunburn, the PA rating is the number to check first. Look for broad-spectrum on the label alongside it.

The gap between SPF 30 and SPF 50 is smaller than the gap in how you apply it

SPF 30 blocks around 97 percent of UVB. SPF 50 blocks around 98 percent. That difference is real but modest. The difference between applying the tested amount and applying what most people actually apply is enormous.

Sunscreens are tested at two milligrams per square centimetre of skin. Studies consistently find real people apply somewhere between a quarter and a half of that. Apply half the tested amount and you do not get half the protection, you get considerably less than half, because the relationship is not linear. A generously applied SPF 30 outperforms a thin smear of SPF 50 every time.

1. For face and neck, roughly two finger lengths of product, squeezed from the base of the finger to the tip.
2. Apply it as the last step of your morning routine, before makeup, and give it a few minutes to settle.
3. Do not forget ears, the back of the neck, and the strip of scalp along a parting. These are the places people burn on treks and at weddings.
4. Reapply every two hours if you are outdoors, and after heavy sweating or swimming.

Mineral or chemical, and the white cast problem

Mineral sunscreens use zinc oxide and titanium dioxide. Chemical sunscreens use organic filters that absorb UV and convert it to heat. Both work. The practical difference for Nepali skin is cosmetic.

Mineral filters, particularly older non-micronised zinc formulations, leave a white or grey cast on medium and deep skin tones. This is the single biggest reason people abandon sunscreen. It is not vanity. Looking ashy in every photo is a genuine reason to stop using a product, and a sunscreen you stop using protects nothing.

• If you want a mineral filter without the cast, look for tinted mineral formulas. The tint cancels the whiteness and often doubles as light coverage.
• Modern chemical and hybrid filters, particularly the newer generation common in Korean and Japanese formulations, generally go on clear on Nepali skin tones.
• For oily skin through monsoon, gel and fluid textures sit better than cream. For dry winter skin the reverse is true.
• If you have reactive or rosacea-prone skin, mineral filters are usually the gentler option and the tinted versions solve the cast.

Our team at GLAMO Nepal will swatch sunscreens on your own skin before you buy, in daylight, which is the only test that tells you anything about cast.

What to carry on a trek

Trekking is where Nepali sun exposure stops being a skincare question and becomes a safety one. Higher altitude, longer exposure, reflective snow, and usually no shade at all.

• SPF 50+ with PA++++, in a formula you are willing to reapply with cold hands.
• A stick or balm format for the nose, cheekbones and ears, which take the most direct exposure.
• Lip balm with SPF. Lips burn badly at altitude and they have no melanin protection to speak of.
• A wide-brimmed hat and proper UV-blocking sunglasses. Sunscreen is one layer of defence, not the whole strategy.
• Reapply at every rest stop rather than by the clock. You will not check a watch, but you will stop for tea.

Common questions that come up at the counter

My foundation has SPF 20, is that enough?

No. The SPF in a foundation is measured at the same thick test application as standalone sunscreen, and nobody applies foundation that heavily. Treat any SPF in makeup as a small bonus on top of real sunscreen, never as a replacement for it.

I work indoors all day, do I still need it?

If you sit near a window, yes. UVA passes through ordinary glass while UVB largely does not, and UVA is the pigmentation and ageing wavelength. If you genuinely have no daylight exposure at all, the case is weaker, but the commute in and out counts and in Kathmandu that commute is often the sunniest part of the day.

Does darker skin need sunscreen?

Yes. Higher melanin gives some baseline protection against burning, which is why the myth persists. It gives very little protection against pigmentation, and pigmentation is precisely what deeper skin tones are most prone to. Melasma and post-inflammatory marks are more common and more stubborn on Fitzpatrick types III to V, and UV is the strongest driver of both.

The short version

Buy something broad-spectrum with SPF 30 or higher and a PA rating. Apply enough of it. Reapply when you are outdoors. Wear it in winter, wear it when it is hazy, and wear more of it when you go up.

Every other refinement is a rounding error next to those four habits.