The recommended daily collagen intake generally ranges from about 2.5 grams to 15 grams per day, depending on the desired health benefits such as skin, joint, bone, or muscle support. Research suggests:

• For skin health and joint pain, doses can be as low as 2.5 grams daily, with benefits observed up to 10 grams.
• For bone density, around 5 grams daily is common.
• For muscle mass and body composition, doses up to 15 grams daily have been studied.
• Some manufacturers and clinical trials suggest an optimal dose around 8 grams per day for skin and connective tissue benefits.
• Collagen supplements are typically hydrolyzed for better absorption, and taking doses beyond 15-20 grams per day is generally unnecessary and may reduce absorption efficiency.
• No official recommended daily allowance exists, but these studied ranges are considered safe and effective.
• Vitamin C intake is important to support collagen synthesis in the body.

In summary, a daily intake of approximately 2.5 to 15 grams of collagen peptides is often recommended to support various health benefits without adverse effects, with 8 grams being a commonly suggested optimal dose for many users.