BROKEN ARROW, OK, January 12, 2026 (EZ Newswire) -- feel free CLASSIC contains 1.75 g of natural kratom leaf per 1 fl oz serving, delivering 20 mg of mitragynine — at the lower end of doses examined across 19 clinical trials that have established a substantial body of scientific evidence supporting the safety of natural kratom leaf.

A comprehensive peer-reviewed study published in Therapeutic Drug Monitoring marks the latest addition to this research, examining natural botanical material identical to what is used in feel free CLASSIC.

All clinical studies to date have focused exclusively on natural kratom leaf and powder. No comparable clinical research exists for kratom extracts, concentrates, or synthetic mitragynine compounds.

The randomized, double-blind, placebo-controlled trial evaluated 116 healthy volunteers over 47 days, making it the largest controlled kratom administration study conducted to date. Researchers administered both single doses and 15 consecutive daily doses of natural kratom leaf powder at levels ranging from 6.65 mg to 53.2 mg of mitragynine.

Study Findings

The study reported no serious adverse events or deaths across any dose levels tested. Treatment-emergent adverse events were generally mild and increased with dose. Researchers found no evidence of meaningful abuse potential or withdrawal, and no clinically significant abnormal findings in blood pressure, heart rate, respiratory rate, or blood oxygen levels.

These results align with findings across clinical studies of natural kratom leaf. A Johns Hopkins survey of 2,798 kratom users found that only 0.6% sought medical treatment for adverse effects, noting that “serious adverse effects were uncommon.”

Previous controlled clinical trials have reported similar safety profiles. A study by Tanna et al. involving 12 participants who consumed kratom tea containing 39mg of mitragynine reported no serious adverse events. Earlier research involving chronic kratom users who received doses ranging from 6.25 mg to 23 mg of mitragynine in kratom tea reported no adverse events.

Distinguishing Natural from Synthetic

The pharmacology of natural kratom leaf differs substantially from synthetic opioids. The study notes that mitragynine and 7-hydroxymitragynine are partial agonists of the μ-opioid receptor. Unlike full agonists such as morphine and fentanyl, mitragynine poorly activates the β-arrestin-2 pathway, which is implicated in adverse effects including respiratory depression and constipation.

The research confirmed that 7-hydroxymitragynine is not present in detectable levels in fresh kratom leaves, but forms as a metabolite when the body processes mitragynine through the CYP3A4 enzyme pathway. Mitragynine also demonstrates activity at multiple receptor systems including adrenergic, serotonergic, dopaminergic, and adenosinergic receptors, distinguishing its pharmacology from traditional opioids.