Walk down a UK pharmacy aisle for back pain and you'll find menthol rubs, capsaicin creams, and diclofenac gel all sitting within arm's reach of each other, each implying it's the one that works. They're genuinely different products with different amounts of evidence behind them - here's what the actual research says, not just the packaging.
The Three Main Types, and How They Actually Work
Menthol and other "warming/cooling" rubs work mainly through a counterirritant effect - they stimulate cold or warm receptors in the skin, which changes what your nervous system notices and can make pain feel less prominent. It's a long-established, low-cost approach, though the formal trial evidence behind it is thinner than for the other two options here.
Capsaicin, derived from chilli peppers, works differently - with repeated use it reduces the activity of the nerve fibres that carry pain signals. It typically causes an initial burning sensation and needs consistent use over several weeks to build an effect, rather than working immediately.
Diclofenac is a topical non-steroidal anti-inflammatory drug (NSAID) - a licensed medicine, available over the counter in the UK as gels like Voltarol and generic equivalents. It works by reducing inflammation directly at the site it's applied.
What the Evidence Actually Shows
The strongest evidence of the three belongs to diclofenac. A Cochrane review of 39 studies covering over 10,000 people found topical diclofenac and ketoprofen gels clearly outperformed placebo for acute musculoskeletal pain such as strains, sprains and muscle pulls - around 7 to 8 people in 10 had much reduced pain within a week, compared with only 2 to 3 in 10 using a placebo gel, with few systemic side effects reported.
Capsaicin has moderate supporting evidence. Trials of low-dose capsaicin cream have shown a meaningful benefit over placebo for some types of pain, though it generally takes weeks of consistent use to see an effect, and the initial burning sensation causes some people to stop before then.
Menthol and similar counterirritant rubs have the least formal trial evidence of the three specifically for reducing pain, even though they're widely used and many people find them genuinely comforting. That doesn't mean they don't help - the sensory distraction effect is real for a lot of people - but it's a different kind of evidence base to diclofenac's.
How to Choose Between Them
- For a straightforward muscle strain, diclofenac gel has the strongest evidence base - read the patient leaflet, check it's suitable for you, and don't exceed the recommended amount or duration
- If you'd rather avoid an NSAID, capsaicin is a reasonable alternative, but expect an initial burning sensation and give it several weeks before judging whether it's helping
- Menthol/warming rubs are a low-cost, low-risk option for general comfort, even though the formal evidence is thinner
- Always check with a pharmacist before combining products, and don't apply any of them to broken or irritated skin
None of the above is about steering you away from evidence-based options - quite the opposite. If you're building a broader routine around movement, stretching and general topical care once anything serious has been ruled out, a simple product is worth having on hand for massage and general comfort. It isn't a replacement for diclofenac, capsaicin, or your GP's advice.
Frequently Asked Questions
Which is more effective for back pain: diclofenac or capsaicin?
Based on current evidence, topical diclofenac has the stronger and more consistent trial evidence for acute musculoskeletal pain like strains and sprains. Capsaicin has moderate evidence but requires weeks of consistent use to build an effect.
Does menthol actually reduce pain, or does it just feel like it does?
Menthol works through a genuine sensory mechanism - it stimulates cold receptors in the skin, which can change how pain is perceived. The formal trial evidence for pain reduction specifically is thinner than for diclofenac or capsaicin, but the effect isn't purely imaginary.
Can I use diclofenac gel and a menthol rub together?
Check with a pharmacist first. Generally they work through different mechanisms, but you should avoid applying multiple products to broken or irritated skin, and always follow the maximum use guidance on the patient leaflet for any medicine.
When should I see a GP about back pain?
See a GP if pain follows a fall or injury, hasn't improved after a couple of weeks, is severe or worsening, or comes with unexplained weight loss or fever. Seek emergency care immediately for numbness around the groin or inner thighs, new bladder or bowel control problems, or worsening weakness in both legs.
The Bottom Line
Menthol, capsaicin and diclofenac aren't interchangeable - they work differently and have different amounts of evidence behind them, with diclofenac currently having the strongest trial support for straightforward strains and sprains. Choosing between them is worth doing with a pharmacist's input rather than by packaging alone, and persistent or serious symptoms are always worth a proper medical assessment rather than another tube of cream.
Sources
- Cochrane, "Topical non-steroidal anti-inflammatory drugs for acute musculoskeletal pain in adults"
- Buckinghamshire Healthcare NHS Trust, "Cauda Equina Syndrome"
Ashleigh is not a medical professional and this article is not medical advice. It summarises published clinical evidence and does not recommend any specific medicine for your individual situation. Ashleigh's Organics Body Butter is a cosmetic product, not a medicine, and is not a substitute for diclofenac, capsaicin, or any other evidence-based pain treatment. If you have back pain that is severe, persistent, or accompanied by any of the warning signs above, please seek medical advice.