Hemby, S
For L-glutamine, which is used by the gut cells themselves, a powder can be quite effective because the target destination is the digestive tract

The current evidence base primarily from animal studies and limited human trials suggests the following potential applications: Improved sleep quality increased proportion of slow-wave sleep, reduced sleep latency, fewer nocturnal cortisol spikes Cortisol normalisation reduced HPA hyperactivation, particularly relevant in high-stress or metabolically burdened patients Nociceptive effects several studies indicate DSIP modulates pain processing, with implications for patients whose poor sleep is pain-driven (3) Antioxidant activity may reduce oxidative stress markers, which are elevated in both sleep-deprived and insulin-resistant individuals Neuroendocrine support preliminary evidence of effects on LH, FSH, and somatostatin hormones that regulate testosterone, oestrogen, and growth hormone release Potential stress adaptation some data suggest DSIP may reduce the physiological stress response magnitude without blunting alertness It is important to be precise here

Further research is needed to elucidate potential mechanisms related to L-citrulline supplementation in other aspects of performance. Source : Journal of the International Society of Sports Nutrition Published online 2023 Apr
The key to GHK-Cu is consistency
For instance, PJ34 (PubChem CID: 4858) has been shown to attenuate NAD + depletion and triglyceride accumulation in HFD-fed mice (Huang et al