What if we told you there was a one-stop solution to nearly all your hair-colour quandaries? Seriously, try us: Want to go darker, but aren’t 100% sure you should make the move? Looking to make that grown-out, summer balayage look pulled-together and fresh for fall? Wish your highlights popped, hair was silkier, or shined like Demi Moore’s? Pining for a change, but don’t have hours to sit in the chair — or the stack of hundos to pay for it? Looking to take down brassiness, hydrate curls, add dimension, or stamp out tired ombré? Want to steer clear of follicle-thrashing ammonia and bleach? Then, all roads lead to trying a gloss treatment.“Typically, glossing is less pricey than an allover colour, highlights, or balayage, but the benefits are endless,” confirms Andy James , a colourist at L.A.’s Benjamin Salon. The versatile treatment typically costs well under $100 (£80) and can last for weeks.We know, it seems too good to be true: How on earth does glossing address so many hair woes, all without damaging tresses? Maddison Cave , a colourist at Rita Hazan Salon in New York City, explains: “Technically, it’s a demi-permanent (in-between semi- and permanent), which means that it deposits tone into the hair strand, but does not lift or lighten hair colour.” What’s more, the formulas are free of bleach and ammonia, so treatments can actually leave hair more conditioned than before and shiny as all get-out.As if that weren't enough happy hair news, it gets even better: Fall and winter may be the best time of year to take advantage of the treatment’s transformational assets. Because according to Dana Ionato , a colourist with Sally Hershberger Salon in Manhattan, glosses are essential during the changing seasons — particularly in colder months. “The natural lighting outside actually changes during the seasons,” she says. “In winter, especially in New York City, natural light tends to be grey outside.” Hair colour that looked radiant in summer can suddenly seem to wash out complexions when temperatures drop.“Doing a gloss on your hair is the perfect solution,” Ionato says. “Using warmer tones will help balance how your hair appears in the dull, cooler lighting, while golden, richer tones help your hair look shiny and less opaque.” With a quick tone treatment done in the sink, a shift in hair colour can make skin pigment look less dull and grey and make eyes pop, she notes.So we’re calling it: Gloss treatments are the unsung heroes of the hair-colour world — but not for long. Because after you check out these transformational hair looks from some of L.A.’s top colourists, ahead, you, me, and everyone we know will be bombarding salons to get in on the action — and emerging with shinier hair, just in time for the holidays.