Keto gummies are increasingly popular dietary supplements marketed as having the ability to support weight loss, and improve energy, digestion and mental focus. According to Forbes, however, health experts are not entirely convinced.

“Keto gummies claim that they can promote energy, focus and weight loss, but there isn’t any scientific evidence to support these claims,” Dolores Woods, a registered dietitian with UTHealth Houston School of Public Health, told Forbes. “The safety and efficacy of the use of exogenous ketones in the form of beta-hydroxybutyrate (D-BHB) has not been documented in scientific literature.”

Health supplements advertised as “keto gummies” do not always even contain exogenous ketones, but rather consist of apple cider vinegar supplements, Forbes reported.

Those that do feature exogenous ketones usually consist of the ketone known as D-beta-hydroxybutyrate, which is produced naturally by the liver as an alternative energy source for the body. Forbes contined. The liver produces the ketone when blood sugar and insulin levels decrease. Keto gummies also often consist of sugar, coconut oil, ginger extract, organic beet juice powder, organic pomegranate juice powder, natural flavorings and other substances.

Wan Na Chun, a registered dietitian nutritionist and nutrition consultant for Health Insiders, informed Forbes that keto gummies are not regulated by the Food and Drug Administration in the same way as medications. She also said research concerning the long-term effects of keto gummies is limited.

According to Woods, keto supplement consumption can also come with unwanted side effects.

“Some people may experience nausea and vomiting due to the sugar alcohol in the ingredients,” Woods told Forbes. “Sorbitol is a common sugar alcohol used to sweeten keto gummies, and it can cause gastrointestinal distress.”

Some keto gummies also consist of herbal extracts capable of affecting certain medications, Forbes wrote. One ingredient sometimes found in these supplements, garcinia cambogia, can cause liver toxicity, headaches, nausea and diarrhea.