What are the long term side effects of arnica compared to nsaids

The honest answer is that neither arnica nor NSAIDs has adequate long-term safety data for arthritis, and the comparison you are asking for has never been studied head-to-head beyond three weeks.

The only direct comparison is that 2007 trial: 21 days of topical arnica gel versus ibuprofen gel in 204 people with hand osteoarthritis [1]. Pain improved about the same in both groups, and hand function improved about the same [1]. That is the entire evidence base for the comparison. No trial has followed either treatment for months or years in arthritis patients [1].

For long-term NSAID use, the picture is better documented but worse for the body. Oral NSAIDs taken daily for months raise the risk of stomach bleeding, kidney damage, and cardiovascular events. Topical ibuprofen lowers but does not eliminate those risks, because some drug absorbs systemically. The 2007 trial reported only skin reactions, which were similar in both groups, and it did not measure blood levels, kidney function, or any systemic effect [1].

For arnica, there is no long-term safety data at all. The mechanism is plausible: arnica contains sesquiterpene lactones that reduce local inflammation, which is why the gel can help some people [1]. But no study has tested daily arnica use for six months or a year, so nobody knows whether chronic topical use carries hidden risks like skin sensitization or systemic absorption [1].

My call: for a few weeks of symptom relief, arnica gel is a reasonable low-risk first try, and the single trial suggests it works about as well as topical ibuprofen [1]. For long-term use, the evidence is too thin to recommend either one confidently. If you need months of daily relief, the safer path is to address the underlying inflammation through diet, movement, and weight management, and to use either gel only intermittently. Confidence: low — the comparison rests on one short trial, and long-term safety for both is unstudied.