Kratom Side Effects
Kratom is sold as a dietary supplement. It sits on shelves next to vitamins and protein powder. But its side effect profile reads more like a pharmaceutical drug — because pharmacologically, that's what it is.
Kratom's active compounds, mitragynine and 7-hydroxymitragynine, bind to opioid receptors in your brain. The same receptors targeted by codeine, morphine, and fentanyl. That doesn't make kratom identical to those drugs, but it does mean the side effects follow predictable patterns — and they escalate with dose and duration.
Here's what the research actually shows. No exaggeration, no minimisation. If you're already questioning your kratom use, the side effects below might help clarify where things stand. If you're ready to stop, read our full guide to quit kratom.
Short-Term Side Effects
These are the side effects that show up early — sometimes from the very first dose. Most are dose-dependent, meaning they get worse as you take more.
Nausea and vomiting. This is one of the most commonly reported kratom side effects, especially at higher doses. Your opioid receptors exist throughout your gut, and activating them disrupts normal digestive signalling. Some people vomit after their first dose. Others develop nausea gradually as tolerance builds and doses creep up.
Constipation. Opioid-induced constipation is well-documented across every substance that hits mu-opioid receptors — and kratom is no exception. Regular users frequently report going days without a bowel movement. This isn't just uncomfortable. Chronic constipation can lead to haemorrhoids, anal fissures, and in severe cases, bowel obstruction.
Dry mouth. Kratom reduces saliva production. This sounds minor, but chronic dry mouth increases your risk of tooth decay, gum disease, and oral infections. Long-term users often report significant dental problems.
Loss of appetite and weight loss. Kratom suppresses appetite in most people. Short-term, you might not notice. Over months of daily use, the weight loss becomes visible — and it's not the healthy kind. It's muscle wasting combined with nutritional deficiency.
Sweating. Excessive sweating, particularly at night, is common. Your body's thermoregulation gets disrupted by the interaction with opioid receptors in the hypothalamus.
Itching. Opioid-induced pruritus — itching without a rash — happens because opioid receptor activation triggers histamine release. Some people find this mild. Others find it maddening.
Dizziness and lightheadedness. Particularly when standing up quickly. Kratom can lower blood pressure and cause orthostatic hypotension, especially at higher doses.
Increased urination. Kratom acts as a mild diuretic for many users, which — combined with the sweating and reduced fluid intake from appetite suppression — can contribute to dehydration.
Dose-Dependent Effects
Kratom's side effects shift dramatically based on how much you take. This is because mitragynine and 7-hydroxymitragynine interact with different receptor systems at different concentrations.
Low Doses (1-5 grams)
At lower doses, kratom acts more like a stimulant. The side effects mirror that profile:
- Increased heart rate and blood pressure
- Jitteriness and anxiety
- Irritability and agitation
- Insomnia (particularly if taken in the evening)
- Pupil constriction
These effects overlap with caffeine or amphetamine-type stimulants — because at low doses, kratom's adrenergic activity dominates.
High Doses (5-15+ grams)
At higher doses, the opioid effects take over. The side effect profile shifts accordingly:
- Heavy sedation and drowsiness
- Respiratory depression (slowed breathing)
- Severe nausea and vomiting
- Cognitive impairment — brain fog, poor concentration
- Motor impairment and lack of coordination
- Constricted pupils ("pinpoint pupils")
- Euphoria followed by a crash
Respiratory depression is the most dangerous acute risk. While kratom is less potent than traditional opioids at suppressing breathing, it's not zero-risk — particularly when combined with other substances that depress the central nervous system.
Long-Term Side Effects
This is where the kratom health risks compound. Short-term side effects are annoying. Long-term side effects alter your health trajectory.
Tolerance and Dependence
The most predictable long-term effect. Your brain adapts to the constant opioid receptor stimulation by downregulating those receptors. You need more kratom to get the same effect. Eventually, you need kratom just to feel normal. This is physical dependence — and it develops in most daily users within weeks to months.
Once dependent, stopping produces kratom withdrawal symptoms — a flu-like syndrome with significant psychological distress. Understanding whether kratom is addictive is important because this progression from casual use to dependence catches many people off guard.
Liver Toxicity (Hepatotoxicity)
There are documented clinical cases of kratom-induced liver injury. Symptoms include jaundice (yellowing of skin and eyes), dark urine, fatigue, abdominal pain, and dramatically elevated liver enzymes on blood tests. A 2019 review in Pharmacotherapy identified multiple case reports of hepatotoxicity linked to kratom use.
Most cases resolved after cessation — but some required hospitalisation, and the pattern of injury suggests direct toxicity rather than an allergic reaction. The risk appears higher with concentrated extracts and prolonged use.
If you notice yellowing skin or eyes while using kratom, seek medical attention immediately.
Hormonal Disruption
Regular kratom use suppresses the hypothalamic-pituitary-gonadal axis — the hormone signalling pathway that controls testosterone and oestrogen production. Studies on chronic kratom users in Southeast Asia have found significantly lower testosterone levels compared to non-users.
The downstream effects: reduced libido, erectile dysfunction, fatigue, mood changes, reduced muscle mass, and in some cases, disrupted menstrual cycles. These effects often resolve after stopping kratom, but recovery takes time.
Hair Thinning and Skin Changes
Long-term users frequently report hair loss or thinning. The mechanism isn't fully understood — it may be related to hormonal disruption, nutritional deficiency from appetite suppression, or direct effects on hair follicle cycling. Some chronic users also report darkened or hyperpigmented skin, particularly on the face — a phenomenon documented in traditional kratom-chewing populations in Southeast Asia.
Seizures
Rare, but documented. Case reports describe seizures in kratom users, particularly at high doses or when combined with other substances. The mechanism may involve kratom's interaction with ion channels or its effects on seizure threshold. The unregulated nature of kratom products makes it difficult to determine whether seizures are caused by mitragynine itself or by adulterants.
The Unregulated Product Problem
Here's a kratom danger that has nothing to do with the plant's pharmacology — and everything to do with the market it's sold in.
Kratom is not regulated as a pharmaceutical. There is no standardised dosing. No required testing. No quality control oversight. What this means in practice:
Variable potency. Mitragynine content varies dramatically between batches, strains, and vendors. One bag might contain 1% mitragynine. Another from the same vendor might contain 2.5%. You're guessing your dose every time. Extracts amplify this problem — concentrated products can be 10-50x more potent than raw powder.
Contamination. In 2018, the FDA linked a multistate Salmonella outbreak to contaminated kratom products — 199 people were infected across 41 states. Heavy metals (lead, nickel, cadmium) have been detected in tested kratom products. You're ingesting whatever was in the soil, the processing facility, and the packaging.
Adulteration. Some kratom products have been found to contain synthetic opioids, prescription medications, or other undisclosed active ingredients. A product labelled as "enhanced kratom" may contain compounds far more dangerous than mitragynine. You don't know what you're actually taking.
This isn't fear-mongering. It's the reality of consuming an unregulated botanical product that activates opioid receptors. Every dose is a gamble on quality.
Drug Interactions
Kratom doesn't exist in isolation. Many users take other substances — prescribed or otherwise — and the interactions can be dangerous.
CNS depressants (alcohol, benzodiazepines, opioids). Combining kratom with other central nervous system depressants increases the risk of respiratory depression, excessive sedation, and overdose. Most kratom-associated deaths involve polysubstance use — particularly combinations with benzodiazepines or other opioids.
Antidepressants (SSRIs, SNRIs, MAOIs). Kratom has serotonergic activity. Combining it with antidepressants that also increase serotonin levels raises the risk of serotonin syndrome — a potentially life-threatening condition characterised by agitation, rapid heart rate, high blood pressure, muscle rigidity, and hyperthermia.
CYP enzyme interactions. Kratom is metabolised by cytochrome P450 enzymes, particularly CYP3A4 and CYP2D6. It also inhibits these enzymes, meaning it can alter the metabolism of other medications you're taking — making them either more potent or less effective. This is particularly concerning with medications that have narrow therapeutic windows.
If you're taking any medication and using kratom, your doctor needs to know. The interaction profile is complex and poorly studied.
Withdrawal Side Effects
When you stop taking kratom after regular use, your body goes through withdrawal. The side effects of kratom withdrawal include muscle aches, nausea, diarrhoea, anxiety, insomnia, irritability, sweating, and depression. Symptoms typically begin within 12-24 hours of your last dose and peak around days 2-3.
We've written a complete breakdown of kratom withdrawal symptoms — every symptom, when it hits, and how long it lasts. If you're considering stopping, that page is your roadmap. For medical support and tapering strategies, see our guide to kratom detox.
FDA Warnings and Safety Data
The FDA has not approved kratom for any medical use. Their position has been consistently cautionary:
- In 2018, the FDA identified 44 deaths associated with kratom use, though the majority involved polysubstance use — other opioids, benzodiazepines, or alcohol were present in most cases.
- The DEA considered scheduling kratom as a Schedule I substance in 2016 but withdrew the proposal after public backlash. It remains legal at the federal level but banned or restricted in several states and municipalities.
- The FDA has issued multiple import alerts and seized kratom shipments, citing undisclosed drug claims and contamination.
- The National Institute on Drug Abuse (NIDA) classifies kratom as an "emerging drug of abuse" and has funded research into its effects and addiction potential.
The lack of approved medical use means there are no established safe doses, no drug interaction databases, and no long-term safety data from controlled trials. What we know comes from case reports, observational studies, and animal research — all of which paint a picture of a substance with real risks that escalate with dose and duration.
What to Do If You're Experiencing Side Effects
If you're reading this because kratom side effects are piling up — that's worth paying attention to. Side effects don't decrease with continued use. They compound.
If you're ready to stop, start with our full guide to quit kratom. If you want to understand the withdrawal process before committing, read about kratom withdrawal symptoms and kratom detox options.
If you want to track your recovery once you've made the decision — counting days works. The psychology of streaks is real, and watching the number climb reinforces every difficult day.
If you're in crisis right now — experiencing severe side effects, thoughts of self-harm, or medical symptoms like jaundice or seizures — go to crisis support or call emergency services. This isn't something to manage alone.
Frequently Asked Questions
What are the most common kratom side effects?
The most commonly reported kratom side effects are nausea, constipation, dry mouth, increased urination, and loss of appetite. At higher doses, sedation, dizziness, and sweating become more common. With regular use, tolerance, dependence, and withdrawal symptoms develop. Most short-term side effects are dose-dependent — higher doses cause more problems.
Can kratom damage your liver?
Yes, though it's relatively rare. There are documented cases of kratom-induced hepatotoxicity — liver inflammation that can cause jaundice, fatigue, dark urine, and elevated liver enzymes. Most cases resolved after stopping kratom use, but some required hospitalisation. The risk appears to increase with higher doses and longer duration of use. If you notice yellowing skin or eyes, seek medical attention immediately.
Is kratom safe to take every day?
No substance that activates opioid receptors is safe to take daily long-term without medical supervision. Daily kratom use leads to tolerance (needing more for the same effect), physical dependence (withdrawal when you stop), and an increasing side effect profile. The unregulated nature of kratom products — with no standardised dosing and variable potency — adds additional risk.