Hovenia dulcis — the Japanese raisin tree — has been used in East Asian traditional medicine for centuries, particularly in Korea, China, and Japan, where it's been documented as a remedy for alcohol-related discomfort since at least the Tang Dynasty.
In recent years, it's attracted serious scientific attention. Here's what the research actually says.
The Active Compound: Dihydromyricetin
The primary bioactive compound in Hovenia dulcis extract is dihydromyricetin (DHM), a flavonoid that has been the subject of a growing number of peer-reviewed studies. DHM is extracted primarily from the fruit peduncles of the tree — the small stalks the fruit hangs from — which contain the highest concentration of the compound.
How DHM Works
DHM's primary mechanism of action relates to alcohol metabolism. Research suggests it works on two fronts:
Acetaldehyde clearance. DHM appears to upregulate the activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) — the enzymes responsible for breaking down ethanol and acetaldehyde respectively. By supporting the efficiency of these enzymes, DHM may help reduce the accumulation of acetaldehyde, the toxic byproduct most responsible for how you feel the morning after.
GABA receptor modulation. Some research indicates DHM may act as a GABA-A receptor antagonist, helping to counteract some of the neurological effects of alcohol — including the rebound anxiety and sleep disruption that often follows a night of drinking.
What the Studies Show
A landmark study published in the *Journal of Neuroscience* (2012) demonstrated that DHM significantly reduced intoxication and hangover symptoms in rodent models. Subsequent human-focused research has been more limited but consistently promising — showing improvements in next-day alertness, mood stability, and subjective wellbeing in participants who took DHM before drinking.
It's worth noting that most clinical research uses doses in the range of 300–600mg of DHM. The quality and standardisation of the extract matters significantly — not all Hovenia dulcis products are equivalent.
Why We Use It
Hovenia dulcis Complex is the centrepiece of the Reeva formula. We use a standardised extract with a defined DHM concentration, taken before drinking so the compound is present in your system at the point when acetaldehyde begins to accumulate.
It's the ingredient with the most robust evidence base for alcohol-specific support — which is exactly why it anchors everything else we've built around it.