Derived from the Caribbean-native guaiac tree, guaifenesin is a compound that’s been the active ingredient in various cough remedies since its FDA approval in 1952. Guaifenesin works as an expectorant — a compound that thins and loosens mucus — to support easier breathing, healthier airways, and getting a good night’s rest.
How Guaifenesin Supports Health
Guaifenesin is known to clear mucus by drawing water into the bronchi — the branch-like passages that carry air into the lungs — which thins mucus and lubricates the bronchi (1). This allows for improved mucus clearance, making it easier to breathe comfortably.
Under healthy conditions, mucus is vital for protecting our airways and lungs. However, being able to clear mucus out effectively is also needed for maintaining healthy breathing. Stressful conditions, like inflammation, smoking, or a buildup of damaging molecules called free radicals, can all reduce our ability to clear mucus effectively. Guaifenesin helps the respiratory tract to expel excess mucus through coughing, which supports healthier breathing (1).
However, guaifenesin is not just for breathing easier — this compound may also help support feelings of comfort and restfulness. Guaifenesin promotes a healthier inflammatory response, which may help support restful sleep (2).


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Supplement Safety and Side Effects
Although side effects are rare, there are some potential adverse outcomes to consider before taking guaifenesin. These adverse effects are generally mild, including gastrointestinal troubles, head pain, or feeling dizzy.
One recent safety study found that taking up to 2,400 mg of guaifenesin per day (split into two doses every 12 hours) was generally well-tolerated and considered safe, with most of both patients and researchers reporting being satisfied or very satisfied with the supplement.
Doses are generally lower when using guaifenesin for healthy breathing support — most research starts with dosages of 300 to 600 mg, twice per day. However, as always, speak with your healthcare provider before starting any new supplements or medications (3).
Key Takeaway:
- Guaifenesin is a compound found in many over-the-counter cough remedies, as it works as an expectorant to clear mucus from the airways and support easier breathing.
- The evidence for using guaifenesin for health outcomes is limited. Still, it has been linked to supporting healthy mucus levels, healthy breathing, and feelings of comfort or restfulness.
- Although guaifenesin’s side effects are generally rare and mild, more research is needed to definitively state if the purported benefits outweigh any potential long-term risks.