Women should be told now when the tampon tax will be abolished, an MP has said, as the UK's largest supermarket announced a price cut for the products.
Tesco said its 5% reduction on the cost of women's sanitary products would cover the VAT levied on these items.
Labour MP Paula Sherriff, who has led the campaign for VAT to be cut to zero, said she hoped other retailers would follow suit.
Most have promised to apply a price cut when VAT is reduced.
The minimum VAT rate is set at EU level. The European Commission is aiming to bring in a zero rate for sanitary products in 2018.
Tesco is the first retailer to announce that it will cut its own prices before the headline tax rate has changed.
Michelle McEttrick, Tesco's brand director, said: "For many of our customers, tampons, panty liners and sanitary towels are essential products.
"However, the cost of buying them every month can add up, and for many women and girls it can be a real struggle on top of other essential items."
Other major supermarkets and pharmacies have agreed in writing to reduce the cost of sanitary products when the VAT charge is reduced, following fears of a repeat of the situation in France where prices failed to fall following a VAT cut. Ms Sherriff said they could now follow Tesco's lead.
"It would have been completely unacceptable if abolishing the tampon tax had just led to big businesses boosting their bottom line at the expense of women buying what are essential goods, which is why we pushed the supermarkets to sign up to a deal to pass the cut on," she said.
"But this goes a step even further, by reducing prices right now - and I hope the other big retailers now consider doing the same.
"With retailers coming on board, the UK government and European leaders should set a clear timetable for the tampon tax to be abolished."
At present, the government spends the proceeds from the tax on sanitary products on women's charities after hundreds of thousands of people signed a petition calling for the products to be exempted from tax altogether.
The government said the latest £12m of funding announced in March benefitted 70 UK charities.
However, MPs and campaign groups criticised the £250,000 grant awarded to anti-abortion group Life - one of the largest amounts from the government fund. Life said the money supported a project for homeless pregnant women in London.
An HMT spokesperson said: "We strongly support cutting VAT to zero on tampons and that's why the Finance Act 2016 included legislation to make this happen - however we cannot do this under current EU law.
"In the meantime, we're awarding £15m a year to women's charities - equivalent to the amount of VAT raised from the sale of women's sanitary products".