Vitamin D helps guinea pigs absorb calcium and phosphorus for strong bones and teeth. Indoor guinea pigs are at particular risk of deficiency because they get limited sunlight exposure. Vitamin D works together with calcium — without enough D, calcium absorption drops even if dietary calcium is adequate.
Best provided through brief daily access to indirect sunlight or UVB lighting. A small window of natural light for 15-30 minutes helps significantly.
0.01% of daily nutrient intake
Vitamin D makes up 0.01% of your guinea pig's total daily nutritional requirements by weight. That's a tiny amount — but it matters.
Weak bones, poor teeth, lethargy, and in young guinea pigs, rickets-like symptoms (bowed legs, stunted growth).
Excessive Vitamin D causes calcium to deposit in soft tissues (kidneys, blood vessels). This is primarily a risk from over-supplementation, not from food.
Vitamin D is required for calcium absorption in the gut. Without adequate Vitamin D, dietary calcium passes through without being absorbed — regardless of how much calcium is in the food. This is particularly relevant for indoor guinea pigs with limited sunlight.
What this means: Ensure indoor guinea pigs get some indirect natural light or UVB exposure to support calcium absorption from their vegetable diet.
