Compression socks support calf circulation, which is their real, NHS-described job, and many runners find that helps comfort and post-run swelling.
What they do not have is performance evidence: no speed or endurance gain for healthy runners. If you try them, fit matters more than brand, long runs and recovery hours are the best use, and they sit on top of, not instead of, training progression and strength work. Reaching for them because a calf repeatedly tightens or hurts mid-run is a physio or GP question, not a gear question.
What to do
Common questions
Do compression socks help with running?
Honest answer: they will not make you faster, and some runners genuinely feel better in them. The claim with real medical grounding is circulation: the NHS describes compression stockings as knee-high elastic socks that help your blood circulation, and that is also the mechanism runners are buying, steadier blood flow in the calf and less pooling and swelling. Where runners report benefits: less calf tightness and heaviness on long runs, reduced post-run swelling, and comfort for existing varicose veins or a history of calf strains. What the evidence does not support is performance enhancement: no credible case that socks add speed or endurance for a healthy runner, so buy them for comfort and recovery feel, not times. Practical guidance: graduated compression fits matter more than brand, so measure your calf and follow the size chart; wear them on long runs and in the hours after, when the swelling argument is strongest; and keep them as an extra on top of the things that actually prevent running injuries: sensible training progression, strength work, and decent shoes. If you are reaching for compression because a calf keeps tightening, hurting, or cramping run after run, treat that as a symptom worth a physio or GP look rather than a shopping problem.