Broad Spectrum Sunscreen: What the Label Actually Promises
"Broad spectrum" means a sunscreen passed a test showing it absorbs across both UVB and UVA, not just the burning UVB band. It is a pass or fail label: it tells you UVA protection clears a minimum, not how much there is. For a measure of how much, look at the PA rating or a UVA-PF number.
Most people read "broad spectrum" as a promise of complete protection. It is narrower than that, and more useful once you know what it measures. This guide explains what the test checks, where the threshold sits, and how the label fits next to the SPF and PA numbers on an Indian sunscreen.
Two kinds of UV, two different jobs
Sunlight that reaches skin carries two bands of ultraviolet light. UVB is the shorter band. It causes sunburn, and it is what the SPF number describes. UVA is the longer band. It does not burn as readily, which is why it is easy to forget, but it reaches deeper into skin and is linked to tanning, pigmentation and the signs of photoageing. UVA also passes through cloud and window glass more easily than UVB.
A sunscreen can score a high SPF while doing comparatively little against UVA, because SPF is measured by the delay to redness, and redness is driven mainly by UVB. That gap is the reason the broad spectrum test exists.
How "broad spectrum" is tested
The best-known definition is the US one. Under the FDA's sunscreen rule (21 CFR 201.327), a thin film of the product is applied to a roughened plate and exposed to a set dose of UV. Its absorbance is then measured at every nanometre from 290 to 400 nm, which covers UVB and UVA.
From that curve the lab calculates the critical wavelength: the point by which the sunscreen has done 90 per cent of all its absorbing across the range. If the mean critical wavelength is 370 nm or higher, the product qualifies as broad spectrum. In plain terms, the test asks whether the sunscreen's protection reaches far enough into the long UVA wavelengths, rather than stopping early.
Europe adds a second condition. The European Commission's 2006 recommendation on sunscreen claims (2006/647/EC) asks for the same 370 nm critical wavelength, and also a UVA protection factor of at least one third of the labelled SPF. That second rule ties UVA protection to the SPF: the higher the SPF, the more UVA protection the product must also show. Products that meet it often carry "UVA" printed in a circle, an industry convention set by Cosmetics Europe.
The in vitro method for measuring UVA protection is standardised as ISO 24443:2021.
What the label does not tell you
Because it is a threshold, "broad spectrum" is the same word on a product that just clears the bar and on one that clears it comfortably. It does not rank sunscreens against each other, and the US version does not scale with SPF. Two broad spectrum sunscreens can differ a great deal in how much UVA they block.
It also says nothing about dose. Every number on a sunscreen label, SPF, PA and the broad spectrum result, is measured at a test amount of 2 mg per square centimetre of skin. Most people apply far less, and protection falls with it. Our guide to how much sunscreen to apply on your face turns that figure into a practical amount.
Broad spectrum, SPF and PA side by side
| Label | What it describes | How it is expressed | What it does not tell you |
|---|---|---|---|
| SPF | Protection against UVB, the band that burns | A number (for example 30, 50) | How much UVA protection the product has |
| Broad spectrum | Whether protection extends across UVA as well as UVB | Pass or fail | How much UVA protection; one pass looks like any other |
| PA | How much UVA protection, graded from in vivo testing | PA+ to PA++++ | Differences within the top grade, which is open-ended |
| UVA in a circle (EU) | UVA protection at least one third of the SPF, plus the 370 nm test | Logo | The exact UVA protection factor |
The most informative pairing on a label sold in India is usually SPF with a PA grade. The PA system, used across Asia, is based on persistent pigment darkening measured on people (ISO 24442), and it grades how much UVA protection a product gives. Our explainer on what PA means in sunscreen covers the four grades. For the UVB side, see SPF 30 vs 50.
How to read a label in practice
- Look for both halves of the picture: an SPF number for UVB, and either a PA grade or a broad spectrum or UVA claim for UVA.
- If the label shows a PA grade, use it to compare UVA protection. PA+++ and PA++++ are the higher grades.
- Treat "broad spectrum" on its own as a minimum standard met, not a ranking.
- Choose a texture you will wear generously every day. The best label does little at half the dose.
- Reapply outdoors every two to three hours, and after towelling off.
Where Origin and Aura sit
Both Artisun sunscreens are labelled broad spectrum and carry the top PA grade. Origin is SPF 50+, PA++++, with a dewy finish. Aura is SPF 40, PA++++, with an invisible finish, dosed at a minimum of two pearls. They are alternatives, chosen by finish and the day's weather, rather than layers.
Frequently asked questions
Is broad spectrum the same as PA++++?
No. Broad spectrum is a pass or fail test of how far protection reaches into UVA. PA++++ is the highest grade of how much UVA protection a product gives. A sunscreen can carry both, and the PA grade is the more detailed of the two.
Does a higher SPF mean better UVA protection?
Not by itself. SPF measures UVB protection. Under the EU recommendation, a product making UVA claims must show UVA protection of at least one third of its SPF, but the SPF number alone does not tell you that.
Do I need broad spectrum sunscreen indoors?
UVA passes through window glass more readily than UVB, so if you sit near a window for long periods, UVA protection is the part that matters indoors.
Is a sunscreen without the words "broad spectrum" unprotected against UVA?
Not necessarily. Labelling rules differ by country. Many sunscreens sold in India show UVA protection as a PA grade rather than the words "broad spectrum". Check for one or the other.
Does broad spectrum mean water resistant?
No. Water resistance is a separate test and a separate claim. Broad spectrum describes the range of UV a product absorbs, nothing more.
Sources
- US Food and Drug Administration. 21 CFR 201.327, Over-the-counter sunscreen drug products; required labeling based on effectiveness testing, paragraph (j), Broad spectrum test. Federal Register 76 FR 35620, 17 June 2011.
- European Commission. Commission Recommendation 2006/647/EC of 22 September 2006 on the efficacy of sunscreen products and the claims made relating thereto.
- ISO 24443:2021. Cosmetics: Determination of sunscreen UVA photoprotection in vitro.
- ISO 24442:2022. Cosmetics: Sun protection test methods, in vivo determination of sunscreen UVA protection.
Last updated 16 October 2026
