Studies have found that 2.5 to 15 g of collagen per day appears to be safe and effective . Collagen is available in powder, liquid, and supplement form, so it’s recommended to take the amount specified on the packaging.
Paul, C., Leser, S., & Oesser, S. (2019). Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance. Nutrients, 11(5), 1079. https://doi.org/10.3390/nu11051079