People with fish/shellfish/egg allergies, kidney disease, autoimmune conditions, or who are pregnant/breastfeeding should avoid or be cautious with collagen supplements, as it's an animal-derived protein, potentially triggering allergies, adding protein load to kidneys, interacting with medications, or exacerbating autoimmune responses, always requiring a doctor's approval. Vegans/vegetarians also need to avoid most types, while those with gout or digestive issues should consult a doctor due to potential protein/digestion impacts.
Collagen supplements are generally made from connective tissue, bones and other parts of cows, pigs, chicken and fish. They can contain toxins and heavy metals that could be harmful. As with all supplements, collagen is not regulated by the Food and Drug Administration (FDA).
If you're using Collagen supplements, avoid these things for best results.
Side effects from bovine collagen are rare and most studies show no adverse effects. That said, some people who take collagen have reported minor gastrointestinal side effects like nausea flatulence indigestion symptoms (like heartburn and bloating).
Some users have reported skin changes such as a mild rash, hives, or even acne after starting collagen peptide supplements. One of the causes for this could be an allergic reaction to collagen or other ingredients used in the supplement. Allergy to the collagen itself is a rare event, but it may occur.
The first signs collagen is working are often subtle skin improvements like better hydration, increased suppleness, and softer fine lines, along with stronger, faster-growing nails, usually noticed within 4-8 weeks of consistent daily use, with joint flexibility and hair changes appearing later. These early signs include skin feeling plumper, eyes/mouth area fine lines softening, and nails becoming more resilient, setting the stage for longer-term benefits.
Thickening and Hardening: Skin may feel unusually thick or tough, making it less flexible. Shiny and Tight Skin: Overproduction can lead to taut, shiny skin that restricts movement in severe cases. Color Changes: Affected areas might change in appearance, becoming lighter, darker, or even yellowish in some conditions.
Examples of High Collagen Foods
Research Link is external, Link opens in new window shows that taking 2.5 to 15 grams daily of hydrolyzed collagen is safe. A smaller dose benefits your joints and skin, while a larger amount may help with body composition and muscle mass.
Avoid collagen saboteurs: Sugar and ultra-processed foods (they trigger glycation, damaging existing collagen) Smoking + pollution (oxidative stress = collagen breakdown) Unprotected sun exposure (UVA rays are collagen's worst enemy)
Collagen peptides are usually considered the best form of collagen for ingestion. Hydrolyzed collagen should be taken if a person wants to take a collagen supplement. Hydrolyzed collagen means the collagen has been broken down into small peptides, which are easy for the body to digest.
"At this time, we do not have any strong evidence that any over-the-counter oral or a topical collagen supplement is good for anti-aging," she says. Topical collagen can be challenging for the skin to absorb because of its chemical structure. Dr. Davis suggests making simple lifestyle changes to increase collagen.
Your body doesn't suddenly collapse when you stop taking collagen—but over time, the benefits you've built up may fade. To maintain skin elasticity, joint mobility, gut integrity, and overall wellness, daily consistency matters.
While there's very little evidence to suggest collagen supplements interact with medications, there may be occasional cases where certain medicines affect how your body absorbs nutrients or supplements in general.
What Foods To Eat To Boost Collagen
These signs and symptoms include:
Top Collagen-Boosting Fruits
Five signs collagen is working include firmer, more hydrated skin with fewer fine lines, stronger and faster-growing nails, healthier and thicker-looking hair, less joint stiffness, and better gut health/recovery, with initial improvements often seen in skin and nails within weeks, while deeper benefits like joint support take longer.
Many collagen vascular diseases are autoimmune diseases, such as:
Scleroderma happens when the body produces too much collagen and it builds up in body tissues. Collagen is a fibrous type of protein that makes up the body's connective tissues, including the skin. Experts don't know exactly what causes this process to begin, but the body's immune system appears to play a role.
Bone broth
Dr. Bradley says her favorite collagen-boosting brew is bone broth. Bone broth draws collagen out of beef, chicken or fish bones, leaving a flavorful liquid that you can drink straight up or use in other dishes.
Collagen peptides, when paired with exercise, may support weight loss by reducing abdominal fat, promoting fat-free mass, and improving body composition. Collagen helps maintain lean muscle mass, alleviates joint pain for better mobility, and supports overall health, including skin, hair, and cardiovascular health.
Collagen has been extensively studied as a potential OA treatment. Research quality varies, but most findings are positive. One small observational study found that a hydrolyzed collagen called Promerim significantly reduced pain and stiffness in people with knee OA.