Collagen is the most abundant protein in the human body, providing the structural framework for skin, bones, muscles, and tendons. As a supplement, it is typically consumed as hydrolyzed collagen or collagen peptides, which are broken down into smaller amino acid chains for easier absorption. Many people take collagen to support skin elasticity and joint health. However, some users report experiencing sleep disturbances, prompting an investigation into this unexpected reaction and the supplement’s effect on the body’s biochemistry.
Analyzing the Claim: Is There a Direct Link to Insomnia?
The current scientific consensus does not support a direct causal link between standard collagen peptide supplementation and acute insomnia. Collagen is essentially a protein source, and it is generally recognized as safe for consumption. Clinical trials and studies investigating the effects of collagen on overall health rarely report insomnia as a common adverse side effect.
While anecdotal reports of sleep disruption exist, they are not backed by widespread clinical data suggesting collagen is a stimulant. The lack of a consistent, scientifically-verified mechanism for collagen to cause sleeplessness is a significant finding. In fact, many research efforts focus on collagen’s potential to improve sleep, complicating the claim that it causes insomnia. The physiological response to a protein-rich supplement can vary significantly among individuals.
Some individuals may experience a mild stimulating effect due to the metabolic demands of digesting a large protein load close to bedtime. The body must expend energy to process the amino acids, which can interfere with the relaxation needed for sleep onset. This mild disruption is transient and often resolved by adjusting the timing or dosage of the supplement. When isolated from other factors, pure collagen peptide is not recognized as a stimulant like caffeine.
The Amino Acid Connection: How Collagen May Support Sleep
Contrary to causing insomnia, the unique amino acid profile of collagen is often associated with promoting better sleep quality. Collagen is notably rich in glycine, an amino acid that makes up about one-third of its total content. Glycine acts as an inhibitory neurotransmitter in the central nervous system, meaning it can calm down excessive neural activity in the brain. This calming effect is one of the primary mechanisms by which collagen supplementation is thought to aid relaxation and sleep.
Research has shown that consuming glycine before bed can help to reduce the time it takes to fall asleep, known as sleep latency. This effect is believed to be partially due to glycine’s ability to lower the core body temperature. A slight drop in core body temperature is a natural physiological signal that initiates sleep, and glycine appears to enhance this process by promoting increased blood flow to the extremities.
Studies using 3 grams of glycine have demonstrated improvements in subjective sleep quality and a reduction in daytime sleepiness and fatigue. The amino acid may stabilize sleep patterns and shorten the time spent in non-rapid eye movement (NREM) sleep latency. By acting on N-methyl-D-aspartate (NMDA) receptors in the brain’s master clock, glycine helps modulate both thermoregulation and circadian rhythms to support the natural onset of sleep.
Non-Collagen Factors That Could Disrupt Sleep
If a person experiences insomnia after starting collagen, the cause is often related to non-collagen factors or the user’s specific habits. Many commercial collagen powders contain additional ingredients intended to boost efficacy or flavor. Common additives like B vitamins, particularly B12, are known for their role in energy metabolism and can be mildly stimulating if taken late in the evening.
Certain products may also contain high doses of other stimulating compounds such as green tea extract or coenzyme Q10, which can interfere with sleep onset. Even high levels of Vitamin C, sometimes included to aid collagen synthesis, can be stimulating. It is recommended to examine the full ingredient list for any hidden stimulants that may be impacting sleep quality.
The timing and size of the dose can also play a role in sleep disruption. Taking a large amount of any protein supplement immediately before lying down can trigger digestive discomfort, such as bloating or gas, as the body struggles to process the load. This physical discomfort can prevent a person from falling asleep or cause them to wake up. Adjusting the supplement time to earlier in the day or reducing the dosage can often mitigate these issues.