Methodology

How we score insect repellents

Every score on this site comes from the same published rules, applied by code to every product the same way, including any brand we feature. There is no pay-for-placement and no grading on a curve: a 70 means the same thing everywhere on the site.

The short version

Every product gets a single 0–100 score, built from four things: how well it works (45%), the evidence behind it (25%), how gentle it is on skin (15%), and how honest the brand is about what is inside (15%). We add those up, subtract a penalty for a couple of specific problems (explained below), and that is the number.

A few problems are serious enough that we will not recommend a product no matter how it scores. Those are the red flags below. Everything we do is shown on each product page, so you can check our work.

What we reward, and what we penalize

We reward

Protection that actually lasts
Evidence at the dose that is really in the bottle
Honest claims and reapplication advice
Gentle, well-tested ingredients
Full ingredient disclosure

We penalize

Over-promising on how long it lasts
Claims that go beyond the evidence
Strong skin irritants and allergens
Secret “proprietary” blends and hidden amounts
Skipping EPA registration when it is required
Sunscreen + repellent combos (the CDC advises against them)

What goes into the score

The overall score is a fixed, weighted average of the four parts below, using the same weights for every product. Each part is scored from 0 to 100 and comes with a written explanation on the product page, so you can always see why a number is what it is.

How well it works

45% of the score

Does it actually keep bugs off, and for how long?

The main question: how many hours until the first bite gets through? We count mosquito protection more than tick protection (65% to 35%), because that is what most people are buying these products for.
Each extra hour counts a little less than the one before it. Going from 0 to 2 hours of protection matters far more than going from 10 to 12. An honest product you reapply every hour or two still scores as genuinely useful. A steady 1–2 hours of complete protection lands around 65 out of 100, while all-day protection of 8 hours or more earns full marks.
If a product has an EPA-approved protection time printed on its label, we use it (treated as a best-case maximum). Otherwise we estimate the time from the active ingredient, how concentrated it is, and the format (spray, lotion, balm), using published studies.
When our estimate is less certain, we say so with a confidence label on the product page instead of quietly lowering the score.

Evidence & honest claims

25% of the score

Is there real science behind it, and does the label tell the truth?

We start from the best published research on the product's active ingredients, but only give full credit when the amount in the bottle is close to the dose that was actually tested. A tiny trace of a well-studied ingredient does not inherit its reputation.
Then we fact-check the marketing. Claims backed by evidence add points; vague or unsupported claims subtract them. An unsupported claim costs the product even if it is the only claim on the label, and saying nothing earns nothing.
Over-promising is penalized on purpose: an 'all-day' or 'long-lasting' claim that the real protection time cannot back up costs extra. Telling you honestly how often to reapply earns a small credit.
Research on the specific product (not just its ingredients) adds a few points.

Skin safety

15% of the score

How gentle is it on skin?

Built from published skin-safety research (the EPA's safety reviews, the Cosmetic Ingredient Review, the fragrance industry's safety data, and CDC guidance), not from marketing or how 'natural' a product sounds.
Every product starts at 100 and loses points for its riskiest ingredient: allergy and irritation risk, harm to aquatic life, ingredients not advised for children under 3, and ingredients where caution is advised during pregnancy.
So gentle, well-tested actives like picaridin and IR3535 score high, while strong essential-oil irritants like cinnamon, clove, and lemongrass score lower, even though they are 'natural.'

Ingredient transparency

15% of the score

How much does the brand actually tell you is in the bottle?

Points are earned for disclosure: publishing a full ingredient list, stating how concentrated the active ingredients are, disclosing the concentrations of all ingredients, and listing the inactive ingredients too.
A 'proprietary blend' or secret formula simply cannot earn those points. There is nothing extra to game, and no penalty for naming ingredients honestly.

Red flags: kept separate from the score

Some problems should not be quietly averaged into a number, because that would hide them. So we keep them separate. A flagged product still gets its honest score, shown right next to the reason we would steer you elsewhere. You might see “scored 44, not recommended: potentially not EPA compliant.” The number stays comparable with everything else on the site; the flag tells you why we would still pass. Two of these flags also lower the score directly (a 20-point penalty each), because selling a repellent that skips required EPA registration, or mixing it with sunscreen, is a genuine problem rather than a footnote.

Potentially not EPA compliant: Sold without EPA registration, even though its active ingredients do not all qualify for the 'minimum-risk' exemption that would let a repellent skip registration legally, so no regulator has reviewed it. We treat this as a real defect: on top of the flag, it costs a flat 20-point penalty. Products that follow the rules (either EPA-registered, or using only exempt minimum-risk ingredients) are never penalized.
Formula not fully disclosed: There is no ingredient list, or the active-ingredient concentrations are hidden, so there is no way to independently check whether the product works.
No proven mosquito protection: Mosquito protection is essentially none: minimal, unproven, impossible to estimate from the listed ingredients, or about 6 minutes (0.1 hours) or less even in the best case.
Combination sunscreen/repellent: Products that mix sunscreen and repellent into one. The CDC and EPA advise against them: sunscreen needs frequent reapplication while repellent should be used sparingly, so combining them leads to overexposure and increases how much of the repellent your skin absorbs. Like skipping EPA registration, this costs a flat 20-point penalty. Apply the two separately instead.

What the verdict labels mean

Recommended: Passes every red-flag check and scores 75 or higher.
Recommended with caveats: Scores 55–74. A solid product with real trade-offs, which we spell out in the scorecard.
Situational pick: Scores 40–54. Genuinely useful in specific situations (a short evening on the porch), but not your main line of defense.
Not recommended: Either it tripped one of the red flags above, or it scored below 40. We always show the actual number next to the reason, so nothing is hidden behind a single label.

How to read the number

It is one scale, everywhere. A 70 means the same thing on every product, in every category, because we do not grade on a curve. Since no plant-based repellent lasts as long as DEET or picaridin, the best natural pick will always score below the best heavy-duty spray, and we do not paper over that. Instead, within a category we highlight the leaders, so the best natural option clearly reads as the best of its kind even when its number is lower than a strong DEET spray.

In short: the number tells you how well something protects, how safe it is, and whether the label can be trusted. The category tells you what it is best for.

Where the protection times come from

You will see two numbers on a product page. Complete protection is the standard health agencies use: how long after you apply until the first bite gets through. That is the headline number across the site. Partial protectionis the fading tail afterward, the stretch where it still cuts bites meaningfully (down to roughly half) before wearing off. We show both so a result like “6–7 hours, fading to about 12” is clear instead of misleading.

When a product has an EPA-approved time on its label, we use it and mark it verified. For everything else we estimate the time from the active ingredient, how concentrated it is, and the format, anchored to published studies in our research library (including the well-known Fradin & Day protection-time study, a double-blind field trial in Senegal, repellency time-courses, and botanical dose-response data). Plant-based ingredients drop off sharply below roughly 4–5% concentration, because that is what the data shows. Every estimate carries a confidence label and a short note explaining how we got there.

Price & value

We do not fold price into the score, because a cheap product that does not work is not a good deal. Instead, where we have prices, we show cost per hour of protection on the product page, so you can compare what you pay against what you actually get, not just the size of the bottle.

Money and independence

We earn money two ways, and you should know about both. Some retailer links earn us a commission when you buy through them. And we make Notch: buy a competitor through our links and we earn a small affiliate cut, but buy Notch and we keep the full margin. We name that incentive rather than hide it.

What it cannot do is move a score. The rules above are applied by code, the same way for every product, Notch included, before any link is attached, and the full breakdown is shown on every product page so you can check our work.

When a product is good, we say so. When a brand hides what is in the bottle, we say that too, directly. Read more about who we are and how we keep this honest on the about page.