12. CoQ10
Even though it’s not a true vitamin, Coenzyme Q10 (CoQ10) is found in every cell in the body. Your body produces CoQ10 in small amounts to help convert food into energy.
However, supplementing with it shows protective effects on the heart, especially after a heart attack (42, 43).
The normal reference range for total CoQ10 blood test is 433-1,532 mcg/L. Supplementation with CoQ10, between 100-200 mg per day is recommended (44). Dietary sources of CoQ10 include organ meats, sardines, and peanuts (45).
13. L-Carnitine
This naturally occurring amino acid is a common supplement for athletes. L-carnitine transports fatty acids into your cells for energy usage (46). The effectiveness of L-carnitine as a training supplement is limited to those with a deficiency (47).
However, it has therapeutic effects in the treatment of congestive heart failure and the overall improvement of cardiac function (48, 49). According to the Mayo Clinic, L-carnitine is found to be especially effective when used after a heart attack (50).
Your body makes L-carnitine, so there’s no recommended daily intake. A normal serum free carnitine blood test result would be between 19.3-53.9 µmol/L for females and 38.8-69.5 µmol/L for males.
For those deficient or looking to supplement, between 500-2000 mg/day is considered standard (51). However, your doctor may recommend a different dosage for certain medical conditions.