How Many Veins Are Treated in a Session? We would love to continue the session until we have managed to treat all your veins, but if your veins are extensive, this is simply not possible, as the safe dose would likely be exceeded. Further sessions of foam sclerotherapy (or microsclerotherapy) may be needed to treat any veins remaining after the first session. All of our microsclerotherapy sessions conform to the strict guidelines of maximum doses allowable of the sclerosant. We advise you to point out which veins are bothering you the most. If possible, our specialists will start treating those first, in case the safety limit is reached before managing to treat all of the veins. The number of sessions that you will require is dependent on two main factors: How many veins you have to start with How well your veins respond to treatment (some veins may need treating again). On initial assessment, we will try to advise how many sessions you are likely to require, based on our past patients’ experiences. Prior to booking an appointment, we are happy to send photos of your veins on to a consultant to review, to see if they can advise how many sessions you may need.