Quick answerMost people tolerate collagen well; trials report few side effects beyond mild digestive discomfort. The real cautions are allergies (beef, fish and egg), the 100 mg of vitamin E for people on blood thinners, and the extra vitamin C for people prone to kidney stones.
Possible side effects
| Ingredient | What to know |
|---|---|
| Bovine, marine and eggshell collagen | Fullness, bloating, mild nausea or an aftertaste. Allergic reactions in people sensitive to fish or eggs. |
| Vitamin E, 100 mg | Well below the 1,000 mg upper limit, but vitamin E can add to the effect of blood thinners. |
| Vitamin C, 426 mg | Can cause loose stools at higher intakes. High-dose vitamin C may raise kidney stone risk in people prone to them. |
| Polypodium leucotomos | Generally well tolerated; occasional stomach upset or itching. |
| Copper, 2 mg | Within safe limits (upper limit 10 mg); add any copper from a multivitamin. |
| Vitamin D2, niacinamide, hyaluronic acid | Safe at these doses for most adults. |
Medications to watch
- Blood thinners such as warfarin: vitamin E may add to the bleeding risk.
- Chemotherapy and radiation: ask your oncologist before taking high-dose antioxidants such as vitamins C and E.
Who should check with a doctor first
- People with fish, shellfish, egg or beef allergies.
- People with kidney disease or a history of kidney stones.
- Pregnant or breastfeeding women.
- Anyone on blood thinners.
- Vegetarians and vegans, for whom the product is not suitable.
Back to the Collagen Refresh review.
Frequently asked questions
Does Collagen Refresh have side effects?
Collagen is generally well tolerated. The most common complaints are a feeling of fullness, bloating or a lingering taste. The bigger issues are allergies, because it contains beef, fish and egg ingredients.
Can I take Collagen Refresh if I am allergic to fish or eggs?
No. It contains marine collagen peptides and eggshell membrane collagen.
Is Collagen Refresh vegetarian?
No. All three collagen sources are animal-derived: beef, eggshell membrane and fish.