How Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) and painkillers affect recovery and performance for running, OCR, and endurance sports
Thomas Solomon, PhD.
Updated onReading time approx 10 minutes (2500 words).
What you’ll learn:
NSAIDs and other common painkillers are used a lot by runners and endurance athletes, mostly to keep soreness down and pain quiet.
After tough exercise, these drugs are likely to reduce how sore you feel (at least a bit).
But they’re unlikely to boost performance, and using them regularly to “recover faster” might blunt training adaptations in some situations.
There are also real safety downsides (stomach, kidneys, bleeding risk, interactions).
Curious about the how and why? Scroll down for the details, the nuances, and the nerdy bits.
The information I provide is not medical advice. NSAIDs and painkillers are drugs. They can have side effects and interact with other drugs, nutrients, and medical conditions (see info on aspirin, ibuprofen, naproxen, and paracetamol/acetaminophen). Always consult your doctor to ensure that a specific NSAID or painkiller is safe for you to use.
What is inflammation?
Inflammation is your body’s “something happened, send help” response. You usually notice it as pain or soreness, swelling, redness, heat, and reduced function in the affected area. Under the hood it’s a whole immune-system drama — lots of chemical messengers going back and forth, some ramping things up (pro-inflammatory), others calming things down (anti-inflammatory).
Short-term (“acute”) inflammation is triggered by things like infections and injuries. It tends to settle within hours or days. Longer-term (“chronic”) inflammation hangs around and is common in conditions like arthritis and obesity, and it may contribute to diseases like diabetes and heart disease.
Inflammation sounds awful (and sometimes it is), so it’s easy to assume that “less inflammation = always better.” But here’s the plot twist: Exercise triggers a short-lived inflammatory response. That’s why you can feel sore after a hard workout, and why researchers can measure increases in inflammatory markers in muscle and blood. In other words, a bit of inflammation after training is basically normal physiology, not a bug in the system.
What are NSAIDs and painkillers?
Nonsteroidal anti-inflammatory drugs (NSAIDs) are a popular class of drugs that people mostly take for pain relief. Think: “I’ve got a headache, where’s the ibuprofen?” Common NSAIDs include aspirin, ibuprofen (e.g. Advil/Motrin/Nurofen), and naproxen (e.g. Aleve). Painkillers like paracetamol (also called acetaminophen; e.g. Panadol/Tylenol) often get lumped into the same conversation because they reduce pain too, even though they don’t behave exactly like classic NSAIDs.
Yes, NSAIDs reduce pain, but they might also prevent severe muscle damage.
There are a couple of small studies suggesting possible benefit. One study reported reduced muscle damage when young untrained adults took daily diclofenac sodium (e.g. Voltaren) for 2 weeks before and during 2 weeks of daily eccentric stair-stepping (see O’Grady et al. 2000). Another study found that daily ibuprofen for 14 days before electrically-induced quadriceps muscle damage improved some markers of muscle repair, despite no clear benefit for soreness or restoring strength or power (see Mackey et al. 2016). Promising, but it’s just 2 small studies — so we should keep our excitement on a short leash.
But, how do NSAIDs and painkillers work?
NSAIDs work mainly by inhibiting cyclooxygenase (COX) enzymes. COX enzymes help your body make prostaglandins, which are hormone-like molecules that contribute to fever, swelling, and pain. Drugs like aspirin, ibuprofen, and naproxen are “nonselective,” meaning they block both COX1 and COX2. Blocking COX1 reduces prostaglandins more broadly, while blocking COX2 (which is prominent in gastrointestinal and kidney tissues) helps explain why NSAIDs can increase the risk of stomach and kidney problems.
Paracetamol (acetaminophen) works differently, and the details are still a bit murky — it may influence COX activity, but it does not seem to reduce inflammation in tissues in the same way as NSAIDs. Its pain-relieving effects likely involve changes in serotonin and endocannabinoid signalling. It also tends to avoid some NSAID-type stomach side effects, but it can be toxic to the liver at high doses, especially when mixed with alcohol (see paracetamol side effects).
So yes: if your goal is to reduce soreness, taking something that reduces pain signals has an obvious appeal.
Which is why a lot of people use NSAIDs and painkillers.
And plenty of athletes do exactly that. A 2018 survey of recreational endurance athletes reported that 68% (about 2 in 3) had used NSAIDs in the prior 12 months, and 45% (about 1 in 2) used them immediately before or after a session. More than half expected possible liver or kidney harm — yet only 26% (about 1 in 4) used NSAIDs with advice from a doctor or pharmacist.
High prevalenceThe proportion of individuals in a population who have a specific condition or characteristic at a given point in time or over a specified period. of NSAID use has also been reported in Ironman triathletes, ultrarunners, and world-class footballers.
In 2020, a survey of 806 recreational “Parkrunners” (a weekly 5 km event in the UK) found that 88% (about 9 in 10) had used an NSAID in the prior 12 months. More worrying: 1 in 4 reported an adverse reaction (usually gastrointestinal), and 1 in 5 had a pre-existing contraindication but still used NSAIDs anyway. The study also found that the longer the race, the more likely people were to take an NSAID during the event — similar patterns were reported in Ironman triathletes and ultrarunners.
So the pattern is pretty consistent: lots of use, mostly ibuprofen, patchy understanding of risks, and not much professional guidance.
Do NSAIDs and painkillers affect training adaptations?
Here comes the crunch: The short-lived inflammatory response to each workout is part of what drives muscle adaptations to training (if you want the full geek-out, it’s here: veohtu.com/muscleadaptations). So it’s reasonable to wonder whether regularly blunting that signal with NSAIDs could nudge your body toward “less adaptation, thanks.”
There’s some experimental evidence that supports that concern. For example:
— In cell culture experiments, prostaglandins — the molecules linked to fever, swelling, and pain — can stimulate muscle cell growth (see Markworth et al. 2011).
— In humans, COX enzymes are involved in muscle protein metabolism (see Trappe et al. 2011), and prostaglandin production increases in muscle after exercise (see Trappe et al. 2001).
— A single over-the-counter dose of ibuprofen or paracetamol may prevent resistance-exercise increases in muscle protein synthesis in young recreationally-active men, without reducing soreness or creatine kinase (a marker of muscle damage; see Trappe et al. 2002) and without blunting exercise-induced increases in muscle inflammation (see Peterson et al. 2003).
— Longer-term animal studies suggest chronic COX-inhibitor use can reduce muscle growth (see Soltow et al. 2006 & Novak et al. 2009) and regrowth after inactivity-related atrophy (see Bondesen et al. 2006). In humans, high doses of ibuprofen (but not aspirin) have been shown to blunt training-induced increases in muscle mass (hypertrophy) and strength in younger previously-inactive adults (see Lilja et al. 2017). But lower doses of ibuprofen or paracetamol have not been shown to reduce training-induced hypertrophy or strength gains in older previously-inactive men (see Trappe et al. 2011).
Putting that together: NSAIDs or paracetamol might not meaningfully reduce exercise-related inflammation or soreness in some contexts, but they might interfere with training signals linked to muscle protein synthesis, hypertrophy, and strength — especially in younger adults. It’s not a universal rule, but it’s enough to make “daily ibuprofen as a recovery plan” look… kinda questionable.
By the power of greyskull; that was a long intro! (Sorry… not sorry.)
But it matters, because these are drugs that some athletes pop like they’re gummy bears. To avoid a heroic cherry-picking quest, let’s lean on evidence summaries — specifically, a systematic reviewA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. and, where available, a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment.. On we go…
What is the scientific evidence on the effect of NSAIDs and painkillers on recovery and athletic performance?
First: NSAIDs and painkillers are drugs. They can cause side effects and interact with other drugs, foods, alcohol, and medical conditions. Easy access can lead to misuse, even if your intentions are pure (“I just want my legs to stop screaming”). Don’t self-prescribe if you’re unsure — ask a doctor who actually knows your medical background.
Second: some drugs violate sport rules. NSAIDs like aspirin, ibuprofen, and paracetamol are not currently prohibited in-competition or out-of-competition by WADA, but rules can change. Always check WADA’s prohibited list and cross-check medications on Global DRO.
Third: every workout triggers a short-lived inflammatory response — and that’s normal. Acute inflammation only becomes a problem when it doesn’t resolve, or when it stacks up alongside weak anti-inflammatory defences. In training, that short-term inflammatory signal helps drive adaptation. So, in the exercise context, a bit of acute inflammation is your friend — the sensible friend who tells you to grow stronger, not the friend who drinks all your beer and sets your kitchen on fire.
So… are you “supposed” to take NSAIDs after every session?
Several narrative reviews argue that the potential adverse effects of NSAIDs are not trivial (see Pedersen et al. 2022, Ziltener et al. 2010, Lundberg et al. 2018, & Warden et al. 2010). An analysis of 18,820 patients reported that NSAIDs accounted for 30% of hospitalisations due to adverse drug reactions (see Pirmohamed et al. 2004). There’s also evidence that chronic NSAID use may affect bone growth and potentially delay stress fracture healing, which makes sense because prostaglandins are involved in bone metabolism (see Ziltener et al. 2010, Vuolteenahoet al. 2008). During exercise, NSAID use has been associated with hyponatremia, reduced renal blood flow, and gastrointestinal bleeding (see Pedersen et al. 2022, Lundberg et al. 2018, & Warden et al. 2010), and taking NSAIDs before exercise can increase core temperature in some cases (see Emerson et al. 2020). This is among the reasons UTMB banned NSAIDs from in-competition use, which is sensible given the lack of clear knowledge about the health effects of repeated NSAID use during prolonged endurance events.
None of this means NSAIDs and painkillers are useless. They have a real role in managing acute pain. Sports medicine clinicians do use NSAIDs in athletes (Ziltener et al. 2010), but usually for short periods (a few days), and the decision depends on the injury type, the level of dysfunction, and the severity of pain. If you’ve got persistent injury pain or persistent training-related soreness, using NSAIDs or painkillers daily long-term is unwise, because it may impair healing (after injury) and/or adaptation (during training). If pain sticks around, get proper assessment — doctor, qualified sports physio, the whole sensible-adult package.
But what about “recovery” after hard sessions?
A meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. by Morelli et al. 2017 reported a small beneficial effect of NSAIDs on reducing muscle soreness, creatine kinase (a marker of muscle damage), and the loss of muscle strength after muscle-damaging exercise. But the analysis mixed human and animal studies, multiple types of NSAIDs, and both pre-exercise and post-exercise dosing — and it found large variability between studies. Also, the findings were limited to ibuprofen, naproxen, and diclofenac sodium; there was no included data on aspirin or paracetamol. So, more high-quality human studies are needed — ideally a randomised controlled trialThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment/control..
And what about performance?
In healthy people, taking an NSAID before or during exercise appears to have neither a beneficial nor detrimental effect on performance outcomes such as strength, power, time trials, and time to exhaustion (see Cornu et al. 2020). That analysis pooled a broad range of outcomes into “performance,” so we still need more targeted studies for specific drugs and specific exercise types.
One meta-analysis found a trivial performance benefit of paracetamol for time-to-exhaustion endurance tests when taken 45 to 60 minutes before exercise (see Grgic et al. 2021). But the evidence base is small (often fewer than 20 participants per study), and there’s currently very little data in actual athletes. Also, that same meta-analysis found no benefit for time trial performance, and that lack of benefit for running time trial (and race) performance was supported by 2 randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment/control. (see de Souza et al. 2022 & Huffman et al. 2022).
In young healthy adults, regular use of non-selective COX inhibitors (e.g. NSAIDs like aspirin, ibuprofen, & naproxen) does not appear to enhance performance (see Cornu et al. 2020 & Alturki et al. 2018). However, the quality of evidence is low, so more high-quality trials are needed to make firmer conclusions.
The story may differ in older hospitalised people with acute inflammatory conditions, where regular prescription anti-inflammatory drug use (both non-selective COX inhibitors and selective COX2 inhibitors) can improve performance and muscle weakness (see Alturki et al. 2018). In older adults, regular use of non-selective COX inhibitors may also enhance training-induced increases in strength (see Alturki et al. 2018). This may relate to reducing age-related chronic inflammation, but mechanisms are not fully known. The quality of evidence is good, but there are few studies, so additional high-quality randomised controlled trials would strengthen confidence.
Can NSAIDs and painkillers enhance recovery and athletic performance?
Taking an NSAID after muscle-damaging exercise is likely to lower feelings of muscle soreness. The effect sizeA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. is small.
NSAIDs and painkillers are unlikely to improve performance in healthy people. People with chronic pain or chronic inflammatory conditions should consult their doctor for guidance on exercise and medication use.
Due to limited direct comparisons, it is unclear how effects differ between trained athletes and untrained people, and between males and females. More research is needed in females because they are underrepresented in this field.
Keep in mind: there is high heterogeneity (variability)Heterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. in study designs and effects between studies, and a moderate to high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the published results accurately reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, precision, and publication bias. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. Whereas, low certainty means more doubt and less confidence, and that future studies could easily change current conclusions. is low. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after the exposure to treatment/control. are needed to increase confidence in the overall effects reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
A regular habit of using NSAIDs or painkillers to mask pain and blunt soreness may be detrimental for training adaptations, recovery from injury, and muscle growth. So, taking them every day so you “feel” recovered after every session is unwise — the inflammatory response after exercise is an athlete’s friend. In plain terms: the widespread habitual use of NSAIDs and painkillers in athletes is not justified by current evidence. That said, taking the occasional dose is unlikely to be a problem.
Always remember: time and money spent “doing recovery” with something that has no obvious benefit might be better spent sitting down, resting, eating something nutritious, and doing something calm.
How to use this: If you truly need a painkiller for short-term pain, use the lowest effective dose for the shortest time — and don’t use it to “push through” an injury or to make hard training feel easy. If pain or soreness is persistent, get assessed by a medical doctor and a qualified sports physiotherapist rather than self-medicating your way through it (your kidneys will thank you, probably). And, keep it legal: always check your event’s rules and the current WADA prohibited list for updates on NSAIDs use in sport.
Strengthen the fight for clean sport
Remember: You are the only person responsible for what goes in your body! Ignorance is not an excuse! Stay educated. Be informed.
Consult WADA’s prohibited list, cross-check your meds against the Global DRO drug reference list, and only choose supplements that have been tested by an independent body (e.g., Informed Sport or LabDoor).
Information you can trust. All content on Veohtu is meticulously researched and written by Thomas Solomon, PhD. He does not sell supplements, recovery products, or ad space, and he has no sponsorships, brand affiliations, or ambassador roles. Everything you read reflects his independent views, shaped solely by peer-reviewed scientific evidence — and that will never change.
Full list of meta-analyses examining NSAIDs and painkillers for recovery
Here are the meta-analyses I've summarised above:
Prevalence, frequency, adverse events, and reasons for analgesic use in youth athletes: A systematic review and meta-analysis of 44,381 athletes. Julie Rønne Pedersen, Alessandro Andreucci, Jonas Bloch Thorlund, Merete Møller, Louise Kamuk Storm, Alessio Bricca. J Sci Med Sport. 2022
Effects of Paracetamol (Acetaminophen) Ingestion on Endurance Performance: A Systematic Review and Meta-Analysis. Jozo Grgic, Pavle Mikulic. Sports. 2021
Non-steroidal anti-inflammatory drugs on core body temperature during exercise: A systematic review. Emerson DM, Chen SC, Kelly MR, Parnell B, Torres-McGehee TM. J Exerc Sci Fit. 2021
Effect of Non-Steroidal Anti-Inflammatory Drugs on Sport Performance Indices in Healthy People: a Meta-Analysis of Randomized Controlled Trials. Cornu C, Grange C, Regalin A, Munier J, Ounissi S, Reynaud N, Kassai-Koupai B, Sallet P, Nony P. Sports Med Open. 2020
Impact of drugs with anti-inflammatory effects on skeletal muscle and inflammation: A systematic literature review. Alturki M, Beyer I, Mets T, Bautmans I. Exp Gerontol. 2018
Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury. A Systematic Review and Meta-analysis. Kimberly M. Morelli, Laura B. Brown, Gordon L. Warren. Am J Sports Med. 2017
And, here is the list of narrative reviews I summarised above:
List ordered newest to oldest.
What is the Effect of Paracetamol (Acetaminophen) Ingestion on Exercise Performance? Current Findings and Future Research Directions. Jozo Grgic. Sports Med. 2022 → see a letter to the editor from Holgado et al. 2022 and the reply from Grgic et al. 2022.
Analgesic and anti-inflammatory drugs in sports: Implications for exercise performance and training adaptations. Lundberg TR, Howatson G. Scand J Med Sci Sports. 2018
Effects of prostaglandins and COX-inhibiting drugs on skeletal muscle adaptations to exercise. Trappe TA, Liu SZ. J Appl Physiol. 2013
The use of nonsteroidal anti-inflammatory drugs for exercise-induced muscle damage: implications for skeletal muscle development. Schoenfeld BJ. Sports Medicine. 2012
Non-steroidal anti-inflammatory drugs for athletes: An update. Ziltenera JL, Leala S, Fournier PE. Ann Phys Rehabil Med. 2010
Prophylactic Use of NSAIDs by Athletes: A Risk/Benefit Assessment. Warden SJ. Phys Sportsmed. 2010 → “Scientific evidence for such benefits is sparse, and athlete rationale for using prophylactic NSAIDs for their preemptive analgesic and anti-inflammatory effects appears at odds with current understanding of the underlying pathology of many sports related injuries”.
Non-steroidal anti-inflammatory drugs, cyclooxygenase-2 and the bone healing process. Vuolteenaho K, Moilanen T, Moilanen E. Basic Clin Pharmacol Toxicol. 2008
Nonsteroidal Antiinflammatory Drugs in Tendinopathy: Friend or Foe. Magra M, Maffulli N. Clin J Sports Med. 2006
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Who is Thomas Solomon?
My knowledge has been honed following 20+ years of running, cycling, hiking, cross-country skiing, lifting, and climbing, 15+ years of academic research at world-leading universities and hospitals, and 10+ years advising and coaching in athletic performance and lifestyle change.
I have a BSc in Biochemistry, a PhD in Exercise Science, and over 90 peer-reviewed publications in medical journals.
I'm also an ACSM-certified Exercise Physiologist (ACSM-EP), an ACSM-certified Personal Trainer (ACSM-CPT), a VDOT-certified Distance Running Coach, and a UKVRN Registered Nutritionist (RNutr).
Since 2002, I’ve conducted biomedical research in exercise and nutrition and have taught and led university courses in exercise physiology, active recovery, biochemistry, and molecular medicine.
And, with my personal experience of competing on the track (800m to 10,000m), the road (5 k to marathon), on the trails, and in the mountains, by foot, bicycle, cross-country ski, and during obstacle course races (OCR), I deeply understand what it's like to train and compete — I've been there, done it, and gotten sweat, mud, and tears on my t-shirt.
Disclaimer: I occasionally mention brands and products, but it is important to know that I don't sell recovery products, supplements, or ad space, and I'm not affiliated with / sponsored by / an ambassador for / receiving advertisement royalties from any brands. I have conducted biomedical research for which I’ve received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, the A.P. Møller Foundation, and the Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on R&D grant applications, and I provide research and scientific writing services for Examine.com. Some of my articles contain links to information provided by Examine.com but I do not receive any royalties or bonuses from those links. Importantly, none of the companies described above have had any control over the research design, data analysis, or publication outcomes of my work. I research and write my content using state-of-the-art, consensus, peer reviewed, and published scientific evidence combined with my empirical evidence observed in practice and feedback from athletes. My advice is, and always will be, based on my own views and opinions shaped by the scientific evidence available. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.