Of course, sustainability and sanitary care have long been friends. The Mooncup (the UK's foremost reusable menstrual cup) has environmentalism at its heart, but now its appeal is broadening beyond its original niche market.Like the tampon, the menstrual cup has been around in one form or another since the 1930s. But it was only in 2002 that Su Hardy replaced latex with medical-grade silicone rubber to create the Mooncup. Now, it's sold in 55 countries."The growth has been substantial," says Kath Clements, Mooncup's campaigns and marketing manager. "The perception of the Mooncup seems to be changing as the conversation around periods is changing – that's helped us in becoming more and more normalised."Although the Mooncup may be beginning to hit the mainstream, the only way it's going to truly integrate into the wider industry in the future is if it is introduced as a viable option to girls at an earlier age."Sanitary products are introduced in schools, then you sleepwalk through the habit of reaching for the same things every month until something wakes you up and makes you reflect," says Clements."We need a less biased introduction of the options. We wouldn't necessarily say that a menstrual cup is the first solution for a young girl – for some it is, for some it's not. But if from the outset we sit in a position of holding the power of making a choice, then you can choose what's appropriate for you through many different phases of your life."Because, of course, there are other options, and one that has garnered a fair bit of attention of late is Thinx . Launched last year and marketed as "period panties" (that phrase might be the ickiest bit about them), Thinx are essentially knickers that you bleed into, wash and wear again. Designed to hold up to two tampons-worth of blood, and resolutely leak-resistant and anti-microbial, you can choose to wear the pants with other protection, or simply by themselves.But are they too much of a mental leap for women that have been taught to use tampons or pads for most of their menstruating life? "It's a no brainer once you get over the idea of bleeding into your underwear," founder Mili Agrawal told Refinery29. "The majority of women around the world wear pads which are uncomfortable, bulky and unhygienic. Thinx offers comfort, support, peace of mind and freedom. They let you forget about your period."