"Best time to take collagen" and "when to take collagen" draw about 3,400 searches a month, with smaller numbers asking about morning, night and workouts. The confident answers in the search results — "morning on an empty stomach", "before bed for repair" — are not backed by trials, because no trial has compared one time of day with another. What does exist is a small set of studies that gave collagen at one chosen time for a reason, and those reasons are worth knowing. This page sets out each timing used in the research, the blood data behind the "one hour" figure, and what 147 collagen labels say. It reports evidence; it does not advise anyone when or whether to take collagen (how we work).
The short answer: there is no measured best time. The most-studied timing is about one hour before exercise, chosen because collagen's amino acids peak in the blood about an hour after a dose, and tested only on a blood marker of collagen-making, not on injuries or pain. One small trial gave collagen before bed for sleep. The joint and muscle trials gave it once a day at no fixed time, or after training. 131 of 147 labels with directions name no time at all.
The census
MuscleLedger searched PubMed on 2026-10-17 for trials of collagen or gelatin whose title or abstract mentions timing, pre-exercise, "before exercise", bedtime, "before sleep" or "time of day". It returned 11 records: four laboratory, cell or animal studies, one review, one editorial and five human studies, three of which are below. None compared two ingestion times with each other. Each gave collagen at one time and compared it with placebo, a different dose, or a different protein.
Why "one hour before exercise"
The timing comes from a 2017 study by Gregory Shaw and Keith Baar. Eight men drank 5 g or 15 g of vitamin C-enriched gelatin, or placebo, and had blood drawn every 30 minutes. Glycine, proline, hydroxyproline and hydroxylysine — the amino acids collagen is rich in — peaked one hour after the drink. An hour after each dose the men skipped rope for six minutes, three times a day for three days. With 15 g, a blood marker of new type I collagen (amino-terminal propeptide, PINP) doubled; 5 g did not raise it significantly (Shaw et al., Am J Clin Nutr 2017, PMID 27852613). Serum taken an hour after gelatin also increased collagen in engineered ligaments grown in a dish.
The reasoning is that exercise increases blood flow through tendons and ligaments, which have poor blood supply at rest, so the amino acids should be in the blood when the tissue is loaded. That is a rationale, not a tested comparison: the study did not give the same gelatin after exercise, or with no exercise at the same time, to see whether the hour mattered.
A 2019 study of collagen protein absorption in active men found the same shape: 20 g of collagen protein raised plasma glycine far more than dairy protein (peak about 683 vs 260 µmol/L), with samples every 20 minutes for three hours (Alcock et al., Front Nutr 2019, PMID 31681789).
The pre-exercise trials since
| Trial | Who | Collagen, taken 1 h before exercise | Result on the collagen-synthesis marker |
|---|---|---|---|
| Shaw et al. 2017 | 8 men, crossover | 5 or 15 g gelatin + vitamin C; rope-skipping | 15 g doubled PINP; 5 g not significant |
| Lis & Baar 2019 (PMID 30859848) | 10 recreationally active men, crossover | 15 g gelatin, hydrolysed collagen or a gummy (both), + vitamin C; rope-skipping | Gelatin and hydrolysed collagen "tended" to raise PINP ~20%; not significant because of large variability |
| Lee et al. 2024 (PMID 38007183) | 10 resistance-trained young men, crossover | 0, 15 or 30 g hydrolysed collagen + 50 mg vitamin C; heavy squats | Only 30 g raised PINP above 0 g; 15 g no different from 0 g |
| Nulty et al. 2024 (PMID 39259166) | 8 resistance-trained men aged ~49, crossover | 0, 15 or 30 g hydrolysed collagen + vitamin C; leg exercise | Both 15 g and 30 g above 0 g; 30 g above 15 g; exercise alone did not raise PINP |
All four used the one-hour-before timing; all measured a blood marker over hours, not tendon strength, injury rates or pain. The two 2024 trials, from the same Liverpool group, disagree about whether 15 g is enough. A blood rise in PINP reflects collagen made anywhere in the body, including bone, not specifically in the tendon that was exercised. Whether collagen helps joint pain over months is on collagen for joints; the tendon and ligament work is on peptides for joints and tendons.
Before bed
One trial gave collagen at night. Thirteen athletic men with self-reported sleep complaints took 15 g of collagen peptides or placebo one hour before bed for seven nights, in a crossover. On the seventh night, polysomnography recorded fewer awakenings with collagen (21.3 vs 29.3), and diary awakenings were fewer across the week. Sleep duration, time to fall asleep, sleep efficiency, subjective sleep quality and most cognitive tests did not differ (Thomas et al., Eur J Nutr 2024, PMID 37874350). The paper states that the funders supplied the supplements and that two authors were employees of Rousselot, a collagen manufacturer.
The authors chose collagen for its glycine content. The trial did not compare bedtime with any other time, so it does not show that night is better than morning — only that this dose at this time reduced awakenings in this group. How collagen interacts with sleep and other recovery claims is on peptides for sleep and recovery.
After training, and once a day
The muscle trials of collagen peptides took the opposite approach: the supplement was given after training sessions, on the logic that protein after exercise supports muscle repair. Those trials, and why collagen does less for muscle protein synthesis than whey, are on collagen peptides for muscle growth and collagen vs whey protein.
The longer trials — on joint pain, bone and skin — compare a daily dose with placebo over months. They were not designed to test timing, so they cannot show whether it matters. The daily amounts used across the literature are on how much collagen per day.
What 147 labels say
MuscleLedger read a random sample of 150 on-market collagen-peptide powder labels from 87 brands in the NIH Dietary Supplement Label Database on 2026-10-17. Three had no directions recorded.
| Timing in the label's directions | Labels (of 147) |
|---|---|
| No time of day mentioned | 131 |
| "Empty stomach" | 6 |
| Morning or with breakfast | 4 |
| "Any time" | 4 |
| Before bed or in the evening | 2 |
| After exercise | 1 |
| Before exercise | 0 |
Some labels use more than one phrase. The makers themselves, in other words, mostly do not specify a time, and none of the sampled labels repeats the one timing that has been studied most. "Empty stomach" — the most common specific instruction — has no trial behind it that MuscleLedger found.
Vitamin C at the same time
Every pre-exercise trial in the table above added vitamin C to the collagen drink, because the enzymes that stabilise new collagen need it. None tested collagen with versus without vitamin C taken together, so the trials cannot say whether co-timing it matters. MuscleLedger did not find a trial that tested it.
What is not established
- Whether any time of day produces a different result from any other. No comparison trial.
- Whether taking collagen an hour before exercise changes tendon or ligament strength, injury rates or pain. The trials measured a blood marker over hours.
- Whether an empty stomach changes absorption. Not tested in the studies found.
- Whether the bedtime sleep result holds in people without sleep complaints, in women, or without industry supply. One trial of 13 men.
Sources
All opened 2026-10-17.
- Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K. "Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis." Am J Clin Nutr 2017;105(1):136–43. PMID 27852613
- Lis DM, Baar K. "Effects of Different Vitamin C-Enriched Collagen Derivatives on Collagen Synthesis." Int J Sport Nutr Exerc Metab 2019;29(5):526–31. PMID 30859848
- Lee J et al. "The Collagen Synthesis Response to an Acute Bout of Resistance Exercise Is Greater when Ingesting 30 g Hydrolyzed Collagen Compared with 15 g and 0 g in Resistance-Trained Young Men." J Nutr 2024;154(7):2076–86. PMID 38007183
- Nulty CD et al. "Hydrolyzed collagen supplementation prior to resistance exercise augments collagen synthesis in a dose-response manner in resistance-trained, middle-aged men." Am J Physiol Endocrinol Metab 2024;327(5):E668–77. PMID 39259166
- Thomas C et al. "Collagen peptide supplementation before bedtime reduces sleep fragmentation and improves cognitive function in physically active males with sleep complaints." Eur J Nutr 2024;63(1):323–35. PMID 37874350
- Alcock RD, Shaw GC, Tee N, Burke LM. "Plasma Amino Acid Concentrations After the Ingestion of Dairy and Collagen Proteins, in Healthy Active Males." Front Nutr 2019;6:163. PMID 31681789
- NIH Office of Dietary Supplements, Dietary Supplement Label Database — dsld.od.nih.gov (API v9): random sample of 150 on-market collagen-peptide powder labels, read 2026-10-17.
- PubMed census: (collagen OR gelatin) AND timing terms AND (supplement OR ingestion), 11 records, run 2026-10-17.