Disclaimer

General information only, not medical advice. Talk to your doctor about your situation.

How Far explains research and regulation in general terms. It isn't medical advice, it isn't a substitute for a doctor who knows your history, and it doesn't recommend any test, treatment or product. Don't start, stop or change any treatment because of something you read here.

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Need help now?

If you think you're having a heart attack, stroke or other emergency, call your emergency number now; don't wait to read more. To find a free, confidential helpline in your country, visit findahelpline.com.

Some examples (check locally, as numbers can change):

• United States: emergency 911; 988 Suicide & Crisis Lifeline: call or text 988
• United Kingdom: emergency 999; NHS 111 for urgent health advice; Samaritans 116 123; or text SHOUT to 85258
• European Union: emergency 112
• Canada: emergency 911; 9-8-8 Suicide Crisis Helpline: call or text 988
• Australia: emergency 000; healthdirect 1800 022 222; Lifeline 13 11 14
• New Zealand: emergency 111; Healthline 0800 611 116; Need to talk? call or text 1737
• India: emergency 112; Tele-MANAS mental health helpline 14416

Numbers checked on 16 October 2026.

Links to other sites are provided for reference; we don't control them.