When Should You Take Collagen?

You may hear that collagen is best in the morning, before bed, on an empty stomach or with vitamin C. Here are common suggestions side by side with what research shows.

When you take collagen, amino acids and small peptides (chains of 2–3 amino acids) produced by digestion enter the blood. Studies have used markers such as hydroxyproline (Hyp), which is abundant in collagen, to see how many hours after ingestion they rise.

Doses, sources and what was measured (peptides or amino acids) differ between studies, but all showed the same pattern: a peak about 1–2 hours after ingestion, then a decline over several hours.

All studies were small and involved healthy people (mostly young men). Rising in the blood and changes occurring in the body are separate questions. The 2025 study was conducted by researchers at a collagen ingredient company.

You often hear that morning or bedtime is best, but we found no human study comparing times of day for taking collagen, either for blood levels or for changes in the body.

On the other hand, most absorption studies were done on an empty stomach: the 2005 and 2007 Japanese studies after a 12-hour fast, the 2019 Australian study after an overnight fast, and the 2025 study in a fasting state. These show what happened when it was taken fasting; they did not compare it with taking it with a meal. How absorption changes with food is not known from the studies we found.

Vitamin C

Vitamin C is described as essential for producing collagen, one of the proteins that make up the body. In other words, vitamin C is used when the body makes collagen.

Whether taking vitamin C together changes collagen absorption or blood levels was not examined in the studies introduced here. The exercise studies in the next section used vitamin C-enriched gelatin.

In coffee

Polyphenols, abundant in coffee, tend to bind to proline-rich proteins, so a 2025 study examined absorption of collagen mixed into coffee. Bovine collagen hydrolysate was dissolved in water or coffee and taken on an empty stomach, and blood was followed for 360 minutes (6 hours).

This study was conducted by researchers at a collagen ingredient company. We found no study testing other drinks such as tea.

Studies in the USA and Australia gave collagen (gelatin) 1 hour before exercise and measured PINP in the blood, a substance released when type I collagen is made.

Both were small studies of young active men, measuring a blood marker within a few days. They do not show whether the same applies to older or inactive people, or whether any part of the body changes.

Is morning or night better for taking collagen?
We found no human study comparing times of day, so research cannot say which is better.

Is it better on an empty stomach?
Most absorption studies were done fasting, but we found no study comparing this with taking it with a meal.

How soon does it rise in the blood?
Studies report a peak about 1–2 hours after ingestion, falling to about half the peak at 4 hours.

Do I need to take it with vitamin C?
Vitamin C is described as essential for the body to make collagen. However, whether taking them together changes absorption was not examined in the studies introduced here.

Can I mix it into coffee?
In a study dissolving it in coffee, peptide uptake was similar to water; some amino acids differed.