Functional Labs

Get ready for your labs with confidence

Simple, step-by-step prep to help you get accurate results.

Schedule for accurate results

If you menstruate, schedule for about 7 days before your next period will start. If using birth control, go on day 3-5 of bleeding. If taking continuous birth control with no bleeding and no placebo pills, scheduling anytime is fine.


Pick a time that comfortably allows 8 hours of fasting.

3 Days Before

Stop taking all supplements. Some components may skew results.


This does not include prescription medication.

2 Days Before

Avoid seafood. Seafood intake can affect heavy metal test results.

Night Before

Finish dinner, then fast for 8+ hours. You can only drink water until your appointment.

Morning of your appointment

  • Drink a lot of water! At least 1 liter. This lab draw will require 12–14 vials of blood, and hydrating makes your blood flow faster. Don’t worry, this is standard for comprehensive testing.
  • Save your workout for after your labs.

When you get to the lab

  • Bring a copy of your lab request (printed or digital) and photo ID.
  • Do not give your insurance information or pay. We've taken care of that.
  • If asked, your clinician's name is Leo Damasco and our fax number is (415) 480-8347.


If you live in NY or NJ, you'll pay the discounted rate Parsley Health negotiated for you. Details here:

  • Initial draw: ~$275
  • Follow-up draw: ~$135
  • Clinician: Dr. Dawn Johnson
  • Fax number: 212-596-7138

What to expect after your appointment

  • If there’s a result that requires immediate medical attention, you will be contacted directly by a clinician.
  • You’ll get most of your results in 3–4 days, and your initial functional health scores.
  • Temporary update: Leptin and Omega test results are taking up to 20 days. These will automatically update as more results come in—we’ll keep you posted when they do!