As we've previously mentioned, adult guinea pigs need 10-30 mg of Vitamin C per kilogram of body weight per day, and we generally like taking our vitamin C. Although some claim that guinea pigs can get enough vitamin c through diet alone, giving us a vitamin c supplement can help ensure that we're getting enough.
Keep in mind the dosage of 10-30 mg of vitamin C per kilogram of body weight (we generally weigh around 1 kg, unless you have happen to have a cuy). You can go a little over this (our vet recommend 40 ml once daily for adult guinea pigs on one of out vitamin C supplements), but don't go too far over or we could develop a condition called pseudo-scurvy. It's easier to be precise with liquid vitamin C, but if your guinea pig prefers a tablet, you can cut a 100 mg tablet into quarters for 25 mg portions.
Assuming you've been able to find a type of supplement your guinea pig will take (liquid or tablet), and you know the correct dosage (might want to check with your vet to be sure on this one), how do you know you're providing a quality supplement? It's important to know that dietary supplements are not regulated like drugs are, and there have been a lot of quality issues found with them. Some of the worst cases involve adulterated supplements containing actual drugs like amphetamines. We haven't found cases of vitamin C being adulterated with drugs like this, but one study found that 27% of vitamin C didn't meet their label claims, containing either more or less than is listed.
Fortunately, there are organizations that can help you identify quality supplements:
- The United States Pharmacopeia (USP) has a dietary supplement verification program. You can find the USP seal on many supplements from Nature Made and Kirkland, for example (see their website for a complete list). The Children's Hospital of Philadelphia considers USP to be the "gold standard" when it comes to supplement quality, so you should look for this one first. If you can't find it, there are others you can consider.
- NSF International also does dietary supplement product testing, and lets companies put their quality seal on the bottle if they pass.
- ConsumerLab.com tests dietary supplements purchased off the shelf and allows you to see the results for a fee. This includes many vitamin c brands.
- LabDoor.com provides a similar service, where they test supplements off the shelf and put the results up on their website. They let you see more information for free, though. This includes vitamin C brands.