When researchers gave lab animals an oral supplement of spermidine, the animals lived longer and were less likely to have cancerous liver tumours than untreated animals.

There are other options, including injections, but oral supplements are the most convenient way of replenishing stores.

On offer are topical and oral supplements with high levels of antioxidants that are easy to use and bathroom-shelf friendly.

During the 2000s internet marketing and infomercials of oral supplements supposedly for colon cleansing increased.

They are added as oral supplements into the horse's diet, most commonly as ground flaxseed, or commercially-prepared products based on flaxseed and containing other ingredients, particularly rice bran.