One of the ‘old wives’ tales is that polidocanol is less painful, causes less necrosis and less pigmentation than STS.

This stems from the early days when Fibro-Vein and other STS based products were only available as 3% solutions. 3% STS is quite powerful and in small veins could cause pain, necrosis and pigmentation.

When people first tried polidocanol they compared 3% POL with 3% STS and concluded POL was a milder sclerosant and caused less side effects.

However since then people have realised that STS is more surface active and you should compare like for like for example 3% POL should be compared to 1-1.5% STS.

Modern studies show that where the two sclerosants are compared on a like for like basis i.e. the POL concentration is 2-3 times that of STS then the there is no difference between them in terms of pain, efficacy and side effects.

(ref. Rao J, Wildmore J & Goldman M. Double-Blind Prospective Comparative Trial between Foamed and Liquid Polidocanol and Sodium Tetradecyl Sulfate in the Treatment of Varicose and Telangiectatic Leg Veins. 2005. Dermatol Surg 31:6: pp 631-35.)

Thus provided the appropriate concentration of STS is used then injection is no more painful than with POL.