• Vitamin C. “Vitamin C supplements work better in ascorbate form than in ascorbic acid form, which is the most common type sold,” says Manjari Chandra.
  • Zinc, another popular supplement, in excess induces a deficiency in copper levels in the body and may also cause lethargy, according to a 2010 study, The Essential Toxin: Impact of Zinc on Human Health , published in Internation Journal of Environmental Research and Public Health.
  • Ayurvedic and herbal medicines such as ashwagandha, ‘kapasura kudineer’ and ‘nilavembu kashayam’ too see heavy demand OTC.