The pair have reached Dumfries and Galloway
Two men cycling from Land's End to John O'Groats in only their underwear are bracing themselves for encounters with the Scottish midge.
Adam Dunn and Gavin Topley, from Branksome, near Bournemouth, have taken no money, food or other clothes.
They are relying on offers of free accommodation and meals.
Mr Topley said: "We didn't take any sun cream, but we've got some now because we got burnt. We've no midge protection but we may have to if they get bad."
He added: "It might be a case of us cycling on and having to deal with it later."
The only items they have taken with them are water, ID, phones, a camera and a map.
Raising money for ActionAid, the pair have reached Dumfries and Galloway and hope to cycle into the Highlands - prime midge territory - later this week.
They have been relying on the kindness of local residents for shelter and provisions.
Mr Topley said: "The response has been really good so far and we have been meeting some interesting people.
"We've only really had one 'no' so far when we asked to fill our water bottles and the man closed his door on us."
The weather has also been favourable, with only one day where the cyclists got drenched in a thunderstorm.
The pair are hoping to raise £3,000 for ActionAid.
Mr Topley said: "Whilst we are dreading the idea of turning up in a new town, wet and tired with no offers of shelter or food, we are both really looking forward to meeting many new people and seeing more of Britain.
"When we finish, we'll have the immense satisfaction that not only have we biked over a thousand miles, but by doing so we have helped to raise money and awareness of global poverty - with the support from lots of amazing people along the way."
The biting midge is notorious for blighting holidays in Scotland and thrives in warm, damp conditions.
The Scottish tourist industry is estimated to lose about £286m a year because of the insect.
A study carried out by expert Dr Alison Blackwell found that 49% of tourists said they would not return to Scotland at the same time of year because of the insect.