ingestible · for muscle cramps
Tonic Water (Low-Dose Quinine)
Reviewed by the Nimbera editorial team · Last updated May 2026
How to use
Drink 6-8 oz (180-240 ml) of standard tonic water in the evening. This provides a very low quinine dose (approximately 83 mg per liter) that some people find helpful for nocturnal cramps without the risks of pharmaceutical quinine.
How it works
Quinine decreases the excitability of motor end plates by increasing the refractory period of muscle fibers, reducing the frequency of spontaneous cramp-generating discharges. The mechanism involves sodium channel stabilization in excitable membranes.
Where to buy
Any grocery store or supermarket - standard tonic water brands such as Schweppes or Fever-Tree. Avoid diet versions as quinine content may vary.
Typical cost: $3-$6 per liter
Safety notes
Pharmaceutical-dose quinine can cause serious adverse events including thrombocytopenia, hemolytic uremic syndrome, and cardiac arrhythmias - this is why prescription quinine was withdrawn from the US market for cramps. Tonic water doses are far lower but still not recommended during pregnancy, in those with G6PD deficiency, or in anyone with cardiac arrhythmias.
Drug & supplement interactions
- Always tell your doctor or pharmacist about any supplements you take.
- Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
- Herbal remedies can affect how the body absorbs or metabolises drugs.
- Check drugs.com interactions checker before starting.
Clinical source
Cochrane - El-Tawil et al. 2015This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.