Son, Hyunjun Lee Journal: Food & function Journal ranking: Q1 Key takeaways: Oral intake of collagen peptide NS, containing Gly-Pro and Pro-Hyp, significantly improves skin hydration, elasticity, desquamation, and wrinkling in women aged 30 to 60 years without causing side effects
2018;26:931 Li Y, Tian H, Zeng H, Zhang Y, Yin T, He H, et al
If the goal is skin-specific benefit with an evidence base you can actually check, topical is not the compromise option it's often framed as
GHK-Cu is the same tripeptide complexed with a copper(II) ion
elegans through increased resistance to environmental stressors
Abdomen (best for most people) Location: 2+ inches away from belly button in any direction Why it's best: Plenty of subcutaneous fat on most people Easy to reach yourself Consistent absorption Large area for rotation Least painful for most people How to inject: Pinch skin to create fold Insert needle at 45-90 degrees into fold Inject slowly Release pinch, remove needle Tips: Avoid area within 2 inches of navel (more nerves) Rotate quadrants (upper right, upper left, lower right, lower left) Stay away from old injection sites for 1-2 weeks Thighs (outer) Location: Outer middle third of thigh Why it works: Good subcutaneous fat layer Easy to see what you're doing Convenient if sitting How to inject: Sit down Locate outer third of thigh (between hip and knee) Pinch skin to create fold Insert at 45-90 degrees Tips: Avoid inner thigh (more pain, blood vessels) Stay on outer portion Can alternate legs Love handles / lower back Location: Sides of lower back, where you'd pinch "love handles" Why it works: Usually good fat layer Alternative if abdomen is overused Some people find it less painful How to inject: Can be awkward to reach May need to twist Works but not first choice for most Upper arms (back of) Location: Back of upper arm (tricep area) Why it works: Good subcutaneous layer Works if you're lean elsewhere Challenge: Hard to reach yourself Difficult to pinch with one hand while injecting with other Better for partner-assisted injections Best sites ranked: Abdomen (easy, consistent, lots of real estate) Thighs (good alternative) Love handles (if needed) Arms (difficult solo) Rotation strategy: Have at least 8-10 injection sites you rotate through Don't inject same spot more than once per week Track sites if doing daily injections Step-by-step: Your first peptide injection Here's exactly how to do it, start to finish
