The toll of island living becomes obvious when Jack's appearance from day 1 is compared to Jack's appearance at the end of Season 1.
Basic hygiene was one of the many difficulties that the survivors faced since their modern luxuries were stripped from them upon arriving on The Island. The survivors found difficulty in everything from bathing to shaving. This became increasingly evident when many of the survivors' appearances changed drastically within the first few weeks. Some aspects of hygiene are noted as unbelievable in the Season 4 DVD extra The Oceanic Six: A Conspiracy of Lies.
Until the discovery of The Hatch, the survivors bathed in the sea water. As the weeks continued, the attempts to keep up to modern hygiene standards appeared vain and the outward appearances of the survivors worsened. The discovery of The Swan became an answer to many of the survivors' problems, including hygiene. Within the Hatch was a single shower-head with fresh water, though sulfuric in smell. Razor-blades were also discovered, making shaving a possibility again. Sun was also seen teaching Walt to clean his teeth with an aloe plant; it can be assumed that this was passed on to the other losties. These modern conveniences were briefly appreciated, as they were destroyed when the Hatch imploded at the turning of the fail-safe key. However, the supply drop may have given the castaways enough razors, soap and other supplies for hygiene to last them for another six months, when the next supply drop was scheduled.
Damon Lindelof and Carlton Cuse stated on Sky One television special 'Lost: The answers are here' that one of the redshirts was a hairdresser who had been at a hairdressing competition in Sydney prior to the crash; she found her suitcase full of utensils and haircare products and had been giving the survivors haircuts.
by the Others
While the survivors struggled to keep clean on the beach, the Others had working showers and sinks located in the Barracks. In addition, they had a working shower room located in The Hydra. In order to fool the survivors into thinking they were dirty and unkempt, the Others covered their bodies in dirt and wore ragged clothing.
by the DHARMA Initiative
The Swan and the Hydra both contained showers, as did the Barracks. In addition, The Pearl contained a working toilet and sink, and The Flame appeared to have all the conveniences required for modern living, likely including (although not shown) a bathroom and a shower.
Low hygienic standards on the Island could also cause serious problems (as when Ben's surgical scar became infected, placing his life in danger), and even lead to ethical dilemmas; one of Jack's most controversial decisions in Season 1 was the burning of the fuselage, in order to eliminate the health hazard of the decaying bodies. Sayid, among others, demanded that the individual religious beliefs of the dead be respected. ("Tabula Rasa")
- An easter egg on the season 2 DVDs has Jorge Garcia briefly explaining the specifics of sweat on the show, which according to him is the topic of many fan questions. (He points out his soaked shirt as "fake", the beads on his face as "real", and his arm sweat as "a mixture".)
- MADtv's parody offers an explanation for the seemingly never-changing length of Jack's stubble: He is using an inefficient razor he made from a twig and a seashell.