A Shelf Full of Similar Products
The topical pain aisle contains creams, gels, sprays, patches and roll-ons in a range of prices, and most of them contain a small number of the same active ingredients. Some cost four dollars and some cost sixty.
Two things separate them, and neither is usually what the packaging emphasizes. The first is which class of active they use, because there are two classes with quite different evidence behind them. The second is the concentration, which is printed on the box and determines both how well a product works and how safe it is.
Understanding those two distinctions takes a few minutes and makes the aisle far easier to navigate. It also explains why the strongest sensation is not the best product.
The Two Categories That Matter
Topical pain products divide into groups that work by fundamentally different routes.
Counter-irritants include menthol, camphor and methyl salicylate. They act on sensory nerve endings in the skin, producing cooling or warming sensations that compete with pain signals and, with repeated exposure, desensitize the receptors involved. They are working on your perception of the pain.
Topical NSAIDs such as diclofenac work pharmacologically. The drug penetrates to underlying tissue and inhibits the enzymes that produce inflammatory mediators, the same mechanism as an oral anti-inflammatory but concentrated at the site with less systemic exposure.
| Counter-irritants | Topical NSAIDs | |
|---|---|---|
| Examples | Menthol, camphor, methyl salicylate, capsaicin | Diclofenac gel |
| How it acts | On sensory perception in the skin | On inflammatory chemistry in tissue |
| Onset | Minutes | Days to weeks for full effect |
| Duration | Hours, fading with the sensation | Sustained with regular use |
| Evidence for osteoarthritis | Limited and mixed | Better supported, recommended in guidelines |
| Feels like it is working | Immediately and strongly | Barely noticeable |
That last row is worth sitting with, because it inverts the intuition most people use to choose. The product that produces the dramatic sensation has the weaker evidence, and the one that feels like almost nothing is the one guidelines recommend. Sensation and analgesia are not the same variable.
How Counter-Irritants Work
Menthol activates TRPM8, a receptor that normally responds to cold. The brain interprets that signal as cooling even though skin temperature has barely changed. Camphor acts on related channels producing warmth. Capsaicin, from chilli peppers, works differently again, initially producing burning and then depleting the neurotransmitter that carries pain signals from those nerve endings.
The reason this reduces pain is partly explained by gate control theory: sensory input travelling along large nerve fibres can inhibit pain signals travelling along smaller ones at the level of the spinal cord. Rubbing a knock is the everyday version. Counter-irritants provide a stronger and longer version of the same input.
This is genuine and it is modest. Cochrane reviews of topical rubefacients containing salicylates have generally found limited evidence for musculoskeletal pain, with quality varying considerably between studies. The relief is real for many people, temporary, and symptomatic. Nothing about it modifies an underlying condition.
Why the Concentration Is the Number to Read
Products containing these actives in the United States are regulated as over-the-counter drugs rather than as supplements, which has a useful consequence: they must carry a Drug Facts panel listing each active ingredient and its concentration.
The FDA's external analgesic monograph sets ranges for each.
| Active | Monograph range | What the range means |
|---|---|---|
| Menthol | 1.25 to 16 percent | Lower end gives mild cooling; upper end is intense |
| Camphor | 3 to 11 percent | Toxic if ingested, particularly by children |
| Methyl salicylate | 10 to 60 percent | Systemically absorbed. The safety-critical figure |
| Capsaicin | 0.025 to 0.25 percent | Burning on first use, easing with repetition |
Ranges exist because both ends matter. Below them the effect becomes unreliable; at the upper end, particularly for methyl salicylate, the safety margin narrows.
A product that does not state its concentrations cannot be assessed on either count. This is the single most useful check in the aisle, and it is one line on the box. Arctic Blast is one commercial example sold without published concentrations for any of its actives, at several times the price of pharmacy products using the same class of ingredient. Our full Arctic Blast review covers what is and is not disclosed. The check applies to any product: find the percentages, and if they are not there, that is the finding.
Creams, Gels, Patches and Sprays
The same active ingredient behaves differently depending on how it is delivered, and format is worth a moment's thought rather than treating it as packaging.
Creams and ointments are the most common. Ointments are greasier and stay on the skin longer, which increases contact time and absorption. Creams rub in more readily and are easier to use during the day.
Gels tend to spread thinly and dry quickly, and they are the usual format for topical NSAIDs, partly because the alcohol base assists penetration. This is one reason diclofenac gel and a menthol cream are not interchangeable in how they are applied.
Patches deliver a fixed quantity over a set period and hold the active against one area, which suits a localized problem such as a specific joint. Because they are occlusive, they increase absorption relative to an equivalent cream, which matters for the safety considerations below.
Sprays and roll-ons are convenient for reaching a back or shoulder without assistance, and they make the applied quantity harder to judge, which is a drawback where the daily maximum matters.
A practical point across all of them: apply to clean dry skin, use roughly the amount the label specifies rather than more, and wash hands afterwards unless the hands are the treated area.
The Ingredient That Deserves Respect
Methyl salicylate, also sold as oil of wintergreen, is the topical analgesic active most worth understanding, because it is genuinely capable of harm and its reputation as a folk remedy understates that.
It is absorbed systemically. Salicylate toxicity from topical application is documented, including fatal cases. The circumstances that raise risk are specific and avoidable: application over large body areas, repeated application beyond label directions, use under bandages or occlusive wraps, use with a heating pad, application to broken skin, and use immediately before or after strenuous exercise, when skin blood flow is elevated.
It interacts with warfarin. Topical methyl salicylate has been associated with raised INR and bleeding events in anticoagulated patients. Anyone on warfarin or another anticoagulant should ask a pharmacist before using any salicylate-containing topical product.
It is acutely toxic if swallowed. Concentrated oil of wintergreen is among the more dangerous substances found in an ordinary bathroom, and a small quantity can be lethal to a young child. It smells pleasant, which is precisely the problem. Products containing it belong out of reach and out of sight.
Camphor deserves the same caution regarding ingestion, since it causes seizures in children.
General cautions across the class: do not apply to broken, irritated or sunburned skin, do not bandage tightly or apply heat, wash hands after use and avoid contact with eyes and mucous membranes, and stop if a rash or increasing irritation develops. Some products also contain botanical oils such as St. John's wort that cause photosensitivity, making treated skin more likely to burn in sunlight.
Choosing Between Them
The reasonable approach depends on what the pain is.
For osteoarthritis, particularly of the knee or hand, topical NSAIDs have the better evidence and appear in treatment guidelines. They act slowly and undramatically, which makes them easy to abandon before they have had a fair trial.
For acute muscle soreness, minor strains and stiffness, counter-irritants are reasonable, inexpensive and act quickly. Expectations should be set at temporary symptomatic relief.
For nerve-related pain, capsaicin has a specific evidence base, requires consistent use over weeks, and causes burning initially that typically diminishes.
For anything persistent, the more useful question is what is causing it. Topical products manage symptoms; they do not diagnose. The NIH's overview of osteoarthritis covers the range of approaches, and the strongest evidence in that area remains with exercise, particularly strengthening the muscles supporting an affected joint.
On price, the useful discipline is comparing cost per gram at a stated concentration. A large tube of 10 percent menthol at a few dollars and a small bottle at sixty dollars with no stated concentration are not competing on the same terms.
When to See a Doctor
Any joint that is swollen, warm or red, or morning stiffness lasting more than 30 minutes, or symmetrical involvement of the same joints on both sides, points toward inflammatory arthritis rather than ordinary wear. That responds considerably better to early treatment, and delay has a cost measured in permanent joint damage.
Pain following an injury, a joint that locks or gives way, pain that wakes you at night, or pain accompanied by fever or unexplained weight loss all warrant assessment. A single joint that becomes acutely hot, swollen and severely painful over hours needs urgent attention.
And pain being managed with a topical product for months is worth reviewing with a clinician, since ongoing symptomatic treatment is not the same as knowing what is being treated. This article describes what the evidence indicates in general terms and is not a substitute for individual medical advice.
Frequently Asked Questions
Do menthol creams actually reduce pain?
They produce genuine, temporary symptomatic relief through counter-irritation: menthol activates cold-sensing receptors, and that sensory input competes with pain signals and desensitizes the receptors involved. Cochrane reviews of topical salicylate rubefacients have found limited evidence with variable study quality. The relief is real and does not modify any underlying condition.
Are topical NSAIDs better than menthol products?
For osteoarthritis, topical NSAIDs such as diclofenac have better evidence and appear in treatment guidelines, while counter-irritant rubefacients have limited and mixed support. The difference is counterintuitive in use, because NSAIDs produce almost no sensation and take days to weeks to reach full effect, whereas counter-irritants feel dramatic within minutes.
Why does concentration matter on the label?
The FDA external analgesic monograph sets ranges for each active, for example 1.25 to 16 percent for menthol and 10 to 60 percent for methyl salicylate. Below the range the effect becomes unreliable, and at the upper end, particularly for methyl salicylate, the safety margin narrows. Products regulated as over-the-counter drugs must print these figures on a Drug Facts panel, so a product that does not state them cannot be assessed on either effectiveness or safety.
Can topical pain products interact with medication?
Yes. Methyl salicylate is absorbed systemically and has been associated with raised INR and bleeding in people taking warfarin or other anticoagulants. Anyone on a blood thinner should ask a pharmacist before using a salicylate-containing topical. People with aspirin or salicylate allergy should avoid them entirely.
What should I avoid doing when using them?
Do not apply to broken, irritated or sunburned skin, do not cover with tight bandages or occlusive wraps, and do not combine with heating pads, since all of these increase absorption. Avoid application immediately before or after strenuous exercise. Wash hands after use and keep away from eyes. Store out of reach of children, since concentrated methyl salicylate is acutely toxic if swallowed and camphor can cause seizures in children.
The Bottom Line
Topical pain products fall into two groups. Counter-irritants such as menthol and camphor act on sensation, work within minutes, and have limited evidence. Topical NSAIDs act on inflammatory chemistry, take longer, produce almost no sensation, and are better supported for osteoarthritis. The intensity of what you feel is not a measure of how much analgesia you are getting.
The most useful habit in this aisle is reading the Drug Facts panel for the concentration of each active, since it governs both effect and safety margin, and treating methyl salicylate with the respect a systemically absorbed salicylate deserves. Where those figures are not printed, the product cannot be judged on either count, whatever else the packaging says.