The tampon tax has been abolished from New Year's Day - a move which should save the average woman £40 over her lifetime.
VAT on women's sanitary products has been slashed to zero after Chancellor Rishi Sunak committed to ending the widely unpopular tax on tampons and pads.
It means there will be a cut of 7p on a pack of 20 tampons and 5p on 12 pads.
EU law had prevented member states from reducing the rate below 5%, which meant period products were treated as luxury items and not essentials.
But the zero rate VAT on the period products started on January 1, the first day the laws no longer apply to the UK.
Mr Sunak, who pledged to scrap the tampon tax in his March budget, said: "I'm proud that we are today delivering on our promise to scrap the tampon tax. Sanitary products are essential so it's right that we do not charge VAT.
"We have already rolled out free sanitary products in schools, colleges and hospitals and this commitment takes us another step closer to making them available and affordable for all women."
Speaking during Wednesday's Brexit debate, Sir Bernard Jenkin, Conservative chairman of the Commons Liaison Select Committee, raised the issue and said: "I feel we're having a debate about a glass being half-full or a glass being half-empty.
"But I think it's worth reminding ourselves that we will be able to do things like abolish the tampon tax, which so many honourable ladies opposite railed against the Government about, only because we're leaving the EU."
Felicia Willow, chief executive of women's rights charity the Fawcett Society, said: "We warmly welcome the scrapping of VAT on all sanitary products from January 1 2021 and congratulate the Government on taking this positive step.
"It's been a long road to reach this point, but at last the sexist tax that saw sanitary products classed as non-essential, luxury items can be consigned to the history books."
