Looking for an energy boost, a quick way to speed up your metabolism, or balance out a vitamin deficiency? If so, you’ve probably heard of vitamin injections by now.

But do they really work, or is it just a fad? On one hand, wellness guru Gwyneth Paltrow swears it’s her ticket to better health and glowing skin; on the other hand, celebs like Hailey Baldwin and Kendall Jenner say they experienced negative reactions.

Well, we’re taking it from medical experts to give us some insight on vitamin injections. Here’s everything you need to know before you get pricked.

Vitamin injections should only be used to combat deficiencies
Studies show that 90% of people are deficient in at least one vitamin or nutrient; vitamins D, C, E, A, B12, iron, calcium, and magnesium are the most common deficiencies. While many medical and wellness centers offer vitamin cocktails, Dr. Jonathan Kuo of Hudson Wellness urges you to only use vitamin shots to combat actual deficiencies.

Supplements aren’t absorbed as quickly as vitamin shots
Vitamin shots can make a big impact on your health if you’re actually suffering from a deficiency. According to registered nurse Jamie Sherrill, supplements require a higher dosage and take longer to see results than injecting vitamins directly into the bloodstream.

Shots should only be administered by a medical professional
Look for a medical or wellness center with a certified nurse practitioner on staff. Steer clear of receiving shots from an assistant or from skin care experts. Additionally, a complete medical history should always be taken and reviewed by a medical professional before injections of any kind are given to you.

You should only get a vitamin injection once every two to four weeks
Getting a vitamin shot more often than that is not only ineffective but actually dangerous, according to Dr. Kuo. If you’re going in for regular vitamin therapy, make sure your blood results are being drawn and updated consistently. The number of vitamins you need will change as your deficiency and health improve.

Vitamins shots can’t supplement for an unhealthy diet or lifestyle
Getting vitamin therapy to cure a massive hangover or try to trick your body into thinking it can handle yet another insane work week isn’t really effective in the long run. While you might feel a temporary boost of energy from the sudden flush of vitamins you were lacking, nothing is better than a healthy diet and getting enough beauty sleep.

xx, The FabFitFun Team