Ü Relax is generally safe for most healthy adults when used occasionally, but it carries real risks worth understanding before you drink it. The product’s main active ingredient, kava, has a well-documented history of causing liver injury in rare cases, serious enough that several countries have banned or restricted kava products entirely. The other ingredients, including ashwagandha, carry their own cautions. Here’s what you need to know to make an informed decision.
What’s Actually in Ü Relax
Ü Relax is a flavored drink made by Calming Co. that contains noble kava, ashwagandha, L-theanine, lemon balm, and sweeteners (allulose and stevia extract). The company describes these as “clinically-tested ingredients” at “ideal dosages,” but does not publicly disclose the specific milligram amounts of each active ingredient on its product page. That lack of transparency makes it harder to evaluate exactly how much of each substance you’re consuming per serving.
The product is not NSF-certified or USP-verified, which are the gold standards for supplement quality. Those certifications involve independent lab testing to confirm that what’s on the label matches what’s in the bottle, plus screening for contaminants and undeclared ingredients. Without that kind of third-party verification, you’re relying on the company’s own quality claims.
The Kava Liver Risk
Kava is the ingredient that raises the most serious safety questions. The FDA issued a consumer advisory in 2002 after more than 25 cases of severe liver injury were reported internationally in people using kava products. Germany, Switzerland, France, Canada, and the United Kingdom all banned or restricted kava sales in response. Some of those cases involved hepatitis-like reactions with rash, fever, and jaundice. In the worst cases, patients developed massive liver cell death.
The NIH’s LiverTox database assigns kava a likelihood score of “A,” meaning it is a “well known cause of clinically apparent liver injury.” That’s the highest certainty rating.
The picture is more nuanced than a blanket warning, though. Researchers reviewing the reported cases have pointed out that many were poorly documented, involved higher-than-recommended doses taken for longer than recommended, or occurred alongside other medications and herbal supplements. Some experts believe the liver damage may stem from poor extraction methods, contaminated products, or the use of non-noble kava plant parts (stems and leaves rather than the root). Ü Relax specifies it uses “noble kava,” which is traditionally considered the safer variety. Still, the exact mechanism behind kava liver toxicity remains unclear, and there is no reliable way to predict who might be vulnerable.
How Kava Works in Your Body
Kava’s relaxing effects come from compounds called kavalactones, which enhance the activity of your brain’s main calming system. Specifically, the primary kavalactone (kavain) amplifies the effect of GABA, a chemical messenger that slows nerve activity and promotes relaxation. It works at a different site on nerve cell receptors than benzodiazepines like Valium or Xanax do, but the end result is similar: reduced anxiety, muscle relaxation, and a sense of calm.
According to the company, you may notice a tingling sensation in your mouth and lips within about 5 minutes. A wave of relaxation typically sets in around 10 minutes, building to a calm, mildly euphoric feeling by 20 minutes that can last 2 to 3 hours.
Ashwagandha Side Effects
Ashwagandha, the second key ingredient, is generally well tolerated for short-term use (up to about three months), but its long-term safety profile is unknown. Common side effects are mild: stomach upset, loose stools, nausea, and drowsiness.
More concerning are case reports of liver injury linked to ashwagandha. The NIH documents multiple cases of people taking 450 to 1,350 mg daily for as little as one week to four months who developed signs of liver damage, including jaundice, nausea, lethargy, and abdominal discomfort. Some of these individuals had pre-existing liver conditions. The fact that both kava and ashwagandha have independent associations with liver injury is worth noting, since Ü Relax combines them in one product.
Ashwagandha can also affect thyroid function. Clinical research shows it can raise thyroid hormone levels, which is a problem if you take thyroid medication or have a thyroid condition. It may also interact with diabetes medications, blood pressure drugs, immunosuppressants, and sedatives.
Who Should Avoid Ü Relax
Certain groups face higher risks:
- People with liver disease or a history of liver problems. Both kava and ashwagandha have been linked to liver injury, and combining them creates an additive concern.
- Anyone taking sedatives, anti-anxiety medication, or antidepressants. Kava enhances GABA activity in the brain, which can amplify the effects of benzodiazepines, sleep aids, and other sedating drugs. This combination can lead to excessive drowsiness or dangerous over-sedation.
- People who drink alcohol. Animal studies show that combining kava with alcohol worsens liver damage, including visible changes to liver tissue and increased cell death. One small human trial found no performance impairment from the combination, but the liver toxicity data from animal research is concerning enough to take seriously.
- Pregnant or breastfeeding women. There is limited safety data for kava during pregnancy, and studies have shown kava compounds pass into breast milk. Health authorities recommend avoiding it.
- People with thyroid conditions. Ashwagandha can shift thyroid hormone levels, potentially interfering with thyroid medication or worsening thyroid disorders.
- Men with hormone-sensitive prostate cancer. Some experts advise against ashwagandha use in this population due to its hormonal effects.
What “Safe” Realistically Means Here
For a healthy adult with no liver issues, no thyroid condition, and no medications that interact with sedatives, an occasional Ü Relax is unlikely to cause harm. Kava has been consumed traditionally in Pacific Island cultures for centuries, and the serious liver cases appear to be rare. L-theanine and lemon balm, the remaining active ingredients, have strong safety profiles with minimal reported side effects.
The risks increase with regular or heavy use, combining it with alcohol, or stacking it with other supplements or medications that affect the liver or the nervous system. Because the company does not disclose exact ingredient amounts, it’s difficult to compare what you’re getting per serving against the doses studied in clinical research. If you decide to use it, paying attention to how your body responds, particularly any signs of digestive upset, unusual fatigue, or yellowing of the skin, gives you the best early warning that something isn’t agreeing with you.