For how we live.
Early studies made elderberry look promising for colds, and sales topped $100 million. But the trials are small, and the most rigorous one — a randomised flu trial in emergency patients — found no benefit at all.
Echinacea is a pharmacy staple every winter. But a Cochrane review of 24 trials found no reliable treatment benefit, and the largest trial shaved barely half a day off a cold — a difference too small to be sure was real.
No trial shows chicken soup cures or shortens a cold. But two small, decades-old studies found it clears nasal mucus faster than plain hot water and calms one inflammatory cell in the lab — a case for comfort, not cure.
You cannot turn a healthy immune system up like a dial, and nothing on the supplement shelf has been shown to. What the trials do show is narrower: fix a sleep deficit and you catch fewer colds.
A Cochrane review of six trials finds honey modestly eases cough in children over one, and does as well as common syrup ingredients — while regulators say those syrups do not shorten a cold. Never give honey under one.
Daily vitamin C does not stop you catching colds and does nothing once one starts. It trims a cold's length by about 8% in adults; for the heart, trials show no benefit.
A cough that outlasts the cold is normal: studies put the average at more than two weeks. Little in the pharmacy reliably shortens it, and antibiotics do not — but some symptoms are a reason to see a doctor.
With influenza, virus shedding starts within a day of infection, peaks on day two and lasts about five days on average — often before you feel your worst. Nearly a quarter of infections cause one symptom or none at all.
Colds come from viruses, not cold air. But chilling the body and breathing cold air can blunt the nose's antiviral defences enough to tip a lurking infection into symptoms.
The dripping-mucus feeling is one of the commonest causes of a lingering cough. What clears it depends on the cause — and for allergy, steroid sprays beat antihistamine pills for the drip itself.
Saline nasal irrigation has better evidence than most self-care remedies: trials support it for chronic sinus and hay-fever symptoms, and a pilot found it shortened colds. The catch is that the quality is low.
Warm steam feels good on a blocked nose, but the randomised evidence for heated, humidified air treating a cold shows no clear benefit. A humidifier is comfort, not cure — and a dirty one carries its own risk.
Most acute sinus infections clear without antibiotics — about 46% of people are better within a week regardless. Drugs speed cure in only 5 to 11 per 100, and cause side effects in more.
Started early and at high enough doses, zinc lozenges may cut a cold short by a day or two. But the evidence leans on a handful of small trials, formulation matters, and prevention claims are weaker.
The oral decongestant in most cold and sinus tablets — phenylephrine — works no better than placebo, US regulators now say. Saline and short-term sprays do more.
Most sore throats clear on their own within a week. Painkillers and honey ease the pain; antibiotics shorten symptoms by only about 16 hours and are rarely worth it.
The uncomfortable answer from the studies is that symptoms overlap too much to be sure without a test — and that most of what genuinely helps is prevention, not a cure.
Cochrane reviews covering more than 19,000 participants found no reduction in cold incidence from regular vitamin C, a possible reduction in duration from zinc, and a clear increase in adverse events.
Cochrane reviews find honey modestly eases a child's cough and does about as well as dextromethorphan, while OTC cough medicines have not beaten placebo in children. The honey trials excluded infants under one.
A Cochrane review of six trials found no benefit for the common cold and significantly more adverse effects in adults. Resistant bacterial infections were linked to 4.71 million deaths in 2021.