Commercial products purported to improve the growth rate, horn quality, strength, and resilience of the equine hoof. Most rely on Biotin for their effect, with other nutrients added for supposed or potential benefits, just in case. Biotin is in any case made by microbes in the hind gut and production is normally sufficient to meet demand.
The hoof wall takes 9-12 months to grow down from the coronary band to the bearing surface, so any supplement needs to be administered for at least that long. A handful of studies in horses have indicated that in some, but not all cases, additional biotin will exert a positive effect on hoof horn quality. Most studies showed no effect on hoof wall growth rate except for one study in ponies which indicated a rate increase of 15%. It seems that some causes of poor quality hoof horn are responsive to biotin supplementation and doses of between 5mg and 30mg per day have been used, with around 15mg – 20mg/Day probably being appropriate for most horses. Improved horn quality may also be linked to other nutrients, particularly calcium, and the calcium: phosphorous balance, with sulphur, zinc and selenium also postulated as being involved. More research is needed to establish which if any of these may be helpful and also their combinations. Meanwhile supplements have to rely primarily on biotin for which there is some genuine scientific validation.