The safety profile of vitamin E supplementation in guinea pigs is generally favorable, though as a fat-soluble vitamin, it can accumulate in body tissues with excessive intake. The margin between therapeutic and toxic doses is wider for vitamin E than for vitamin D, making serious toxicity relatively uncommon. However, very high doses over extended periods could potentially cause adverse ...
Supplements are not "free" calories just because they are healthy. Keep in mind your pig's overall food and nutritional intake when adding supplements. Some vitamins, minerals, supplements are toxic if overdosed, others will be excreted in urine if not needed. Two supplements that are recommended for all pet pigs are selenium and vitamin e.

One of the most common nutritional issues in guinea pigs is vitamin C deficiency (scurvy). Guinea pigs, like humans and some other mammals, can't make vitamin C and must get it from their diet. Vitamin C is essential for healthy skin, joints, blood vessels, and other tissues. Without enough vitamin C, guinea pigs can lose their appetite, develop dental problems, have swollen joints, bleed ...

Vitamin C can be included in creep diets in addition to Vitamin E but only where diets are prepared as meal or are pelleted using cold water - hot pelleting will destroy Vitamin C. The increasing use of organic acid supplements - especially in young pig diets - can provide additional bio-flavenoids to support the Vitamin E antioxidant system.