The Guildford-based firm has been developing the product, currently branded Eroxon, for 15 years.
In its study of 232 randomised males it showed a "statistically significant improvement" for all erectile dysfunction sufferers when compared with a placebo.
Futura’s stock spiked more than 100 per cent to a day-high of 64.25p.
Importantly, the effects of the gel were both safe and "rapid" - 54 per cent of patients noticed a difference within five minutes, while 82 per cent registered a difference within 10 minutes.
This would be the first gel product in the erectile dysfunction market and will offer (ahem) stiff competition to tablet-based offerings such as Viagra if it moves forward.
Futura's chief executive James Barder told City A.M.:
We certainly think it's a breakthrough product, the key issues with the other products are speed of onset, all the other products require pre-planning and offer no spontaneity.
Eroxon, however, can form part of sexual foreplay, which is very important for men. We also have a very safe product, with no serious adverse events or effects occurring during the study. There were no withdrawals from the study either (no pun intended).
We believe this could become a first-line therapy for physicians, as topical treatments will often be the preferred first choice product for doctors.
The company said a more detailed analysis of the study's results will be carried out over the next few days and further details are expected to be provided with the group's half-year results on 13 September.