Diet & Nutrition
What Guinea Pigs Actually Need to Eat
A proper diet is one of the most important things you can give a guinea pig. Get it right and they thrive. Get it wrong and health problems follow quickly.
The basics
The Guinea Pig Diet Pyramid
Think of your guinea pig's diet in three tiers. Hay is the foundation — everything else builds on top of it.
Hay — the foundation
Timothy hay or meadow hay should make up roughly 80% of your guinea pig's diet and must be available at all times. Hay keeps their digestive system moving, wears down their continuously growing teeth, and prevents GI stasis. Never let the hay run out.
Fresh vegetables
Fresh leafy greens and vegetables make up the next tier. Aim for a varied mix daily — romaine lettuce, green leaf lettuce, bell peppers (an excellent Vitamin C source), cilantro, parsley, and cucumber are all great choices. Rotate variety to cover different nutrients.
Pellets — a small supplement
Guinea pigs should have only about 1/8 to 1/4 cup of pellets per day. Choose high-quality plain pellets such as Niblee, Sherwood, Science Selective, or Oxbow. Avoid colorful mueslix-style mixes with seeds, dried fruit, or unnecessary fillers — these are harmful, not helpful.
Critical nutrient
Vitamin C: Non-Negotiable
Guinea pigs cannot produce their own Vitamin C — they must get it from their diet every single day. Deficiency causes scurvy, which leads to joint pain, lethargy, rough coat, and eventually death. Fresh bell peppers are one of the best natural sources. As guinea pigs age, their need for Vitamin C increases while their ability to absorb it decreases, so supplementation becomes especially important for older pigs. A liquid Vitamin C supplement added to water or given directly is a reliable way to ensure they get enough.
Red bell pepper
Highest natural source — excellent daily staple
Green bell pepper
Good source, slightly lower than red
Parsley
High in Vitamin C, feed in moderation
Kale
Good source, rotate with other greens
Cilantro
Loved by most guinea pigs, good C content
Liquid supplement
Reliable backup, especially for older pigs
Don't Forget Sunlight
Guinea pigs benefit from exposure to UV light from the sun just as we do. Sunlight helps their bodies convert Vitamin D into a usable form, forms antioxidants that aid in disease prevention, and supports their circadian rhythm. As crepuscular animals — naturally active in the morning and evening — they are designed to catch some sun early and late in the day. They don't need hours of exposure, but do need access to shade and protection from overheating. A few rays here and there makes a real difference.
Safe to feed
Safe Vegetables & Greens
Rotate through a variety of these to keep meals interesting and nutritionally balanced.
Never feed these
Foods to Avoid
Some foods are toxic or harmful to guinea pigs. Never feed these.
Pellet quality matters
Choose Plain, Not Colorful
The colorful mueslix-style pellet mixes sold in most pet stores look appealing but are genuinely harmful. Guinea pigs pick out the seeds and sugary bits, leaving the nutritious parts behind — and the fillers cause obesity, dental problems, and digestive issues.
Stick to plain, uniform pellets from quality brands: Niblee, Sherwood, Science Selective, or Oxbow. A small amount — 1/8 to 1/4 cup per pig per day — is all they need.
Diet is just one piece of the puzzle
A proper enclosure and enrichment are just as important as what goes in the food bowl.