Ayurvedic treatment is the second major draw of Kovalam after the beach itself. The word "Ayurveda" covers a wide spectrum here, from the 30-minute oil massage sold to passing tourists on the beachfront strip, to multi-week residential programmes involving diet, herbal treatments, and panchakarma (detoxification) under medical supervision. Both ends of the market exist in Kovalam, and the difference in quality, cost, and intent is substantial.
For a serious treatment, look for a clinic that has an Ayurvedic doctor (vaidya) on staff who conducts a consultation before any treatment begins. The Kerala government's tourism certification system classifies Ayurvedic centres by their standards; look for a "Green Leaf" or "Olive Leaf" rated centre if quality matters to you. A basic shirodhara (warm oil poured in a continuous stream on the forehead) or abhyanga (full-body oil massage) from a reputable clinic costs more than the beachfront equivalent but is a genuinely different experience.
For short stays, a single-session treatment at one of the better guesthouses or mid-range hotels is more sensible than signing up for a multi-week programme you have no way to evaluate in advance. Word of mouth from other travellers at the guesthouses is the most reliable guide to quality.